Canine radiographs

Canine Radiographs Click skeleton to enter Credits Canine Radiographs is licensed by The Royal Veterinary College under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 UK: England & Wales License What do I need to know?

Canine Radiographs Credits What do I need to know? Canine Radiographs is licensed by The Royal Veterinary College under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 UK: England & Wales License Click skeleton to enter Click on the anatomy you wish to view Click here to go back to Title Page © Royal Veterinary College 2009

Click on the anatomy you wish to view Click on the anatomy you wish to view Click here to go back to Title Page © Royal Veterinary College 2009

The Head Tympanic Bullae Mandible Nasal chambers Larynx Skull Frontal sinuses

The Skull Skull: Ventrodorsal (V-D) view Young Skull: Lateral view Skull: V-D view, Calvaria Skull: Lateral view, Calvaria

Skull : V-D view Full screen Labels Pot For this ventrodorsal view the endotracheal tube has been removed to prevent superimposition with anatomical structures. Try to identify the rami of the mandible, the zygomatic arches, the external auditory canals and the atlas.

Condyloid process Angular process Rostral alar foramen Mandible Mandibular symphysis Occipital condyle Paracondylar process Tympanic bulla Foramen lacerum Foramen ovale Zygomatic arch Coronoid process Mental foramen Pot Comparison © Royal Veterinary College 2009

Labels Pot Comparison © Royal Veterinary College 2009

No Labels Nasal conchae Ethmoidal conchae Pterygoid bone Air within external acoustic meatus Parcondylar process of occipital bone Wing of atlas Alantoaxial joint Upper premolar 4 Vomer bone Zygomatic arch Coronoid process of mandible Angular process of mandible Temporomandibular joint Tympanic bulla 2 nd cervical vertebrae (axis) Zygomatic process of temporal bone Frontal bone Jugular foramen Occipital condyle Pinna Medial border of orbit Atlantoccipital joint Medial border of mandible Condyloid process of mandible © Royal Veterinary College 2009

Young Skull : Lateral view Full screen Labels Pot 1 Pot 2 This radiograph shows a typical appearance of the canine skull in a lateral radiograph. The dog was anaesthetised for radiography, hence the endotracheal tube. Dorsal to the endotracheal tube is a band of soft tissue separating the oropharynx from the nasopharynx; this is the soft palate.

Frontal sinus Olfactory bulb Hard palate Nasal septum (cartilage) Genioglossal m. Geniohyoid m. Body of tongue Soft palate Basihyoid bone Epiglottis Oesophagus Longus colli m. Ventral straight muscle of the head Opening of phargyngeal tube Medulla oblongata Pons Fourth ventricle Cerebellum Interthalamic adhesion Corpus callosum Sternohyoid m. Pituitary gland (hypophysis)

1 2 3 4 5 6 7 8 9 10 1 = Nasal bone 2= Incisive bone 3=Maxilla 4=Lacrimal bone 5= Frontal bone 6=Parietal bone 7=Occipital bone 8= Temporal bone 9=Basisphenoid bone 10= Mandible A B A=Atlas B=Axis Infraorbital foramen Orbit Supraorbital process Zygomatic arch Paracondylar process External acoustic meatus Retroarticular process Condyloid process Coronoid process Angular process Pterygopalantine fossa Mental foramen Tympanic bulla © Royal Veterinary College 2009

No Labels Incisive bone Root of canine tooth Hard palate Nasal bone Ethmoidal conchae Cranial border of orbit Frontal bone Frontal sinus Oral cavity Zygomatic arch Coronoid process of mandible Tympanic bulla Wings of atlas Endotracheal tube Mandible Soft Palate Condyloid process Hyoid apparatus Calveria Sagittal crest

Skull : V-D view, Calvaria Full screen Labels Pot This ventrodorsal radiograph of the same dog, as in the following lateral radiograph, shows a distinct opaque, slightly wiggly line on the mid-line superimposed on the calvaria, which represents the thick mid-line crest that was noted on the lateral view. This ventrodorsal also provides a clear view of the mandibular condyles, the zygomatic arches and the external ear canals.

No Labels Mandible Nasal conchae Pterygoid bone Condyloid process of mandible Air within external acoustic meatus Wing of atlas Alantoaxial joint Lower premolar 4 Zygomatic arch Coronoid process of mandible Angular process of mandible Temporomandibular joint Tympanic bulla 2 nd cervical vertebrae (axis) Frontal bone Medial border of orbit Rostral & caudal alar foramen Suture line Endotracheal tube Upper molar 1 Alar notch © Royal Veterinary College 2009

Skull : Lateral view, calvaria Full screen Labels Pot In this dog the frontal sinuses are relatively large and the crest on the dorsal aspect of the skull is relatively tall giving the impression that the calvaria (bones around the brain) are extremely thick in this dog. In reality it is only the crest that is thick, the bones to either side will be relatively much thinner. Compared to humans in which the bones around the brain are very thin and there is very minimal soft tissue coverage, the skull and brain of the dog are well protected by large chewing muscles and is therefore relatively infrequently injured compared to humans. This well-positioned lateral view shows the temporomandibular joints and the tympanic bullae which are almost perfectly superimposed. It also gives a good view of the endotracheal tube in the oral cavity and extending down through the larynx towards the trachea, the soft palate and the nasopharynx.

1 2 3 4 5 6 7 8 9 10 1 = Nasal bone 2= Incisive bone 3=Mandible 4=Lacrimal bone 5= Frontal bone 6= Frontal bone 7=Occipital bone 8=Temporal bone 9=Basisphenoid bone 10= Mandible A B A=Atlas B=Axis Infraorbital foramen Orbit Supraorbital process Zygomatic arch Paracondylar process Jugular foramen Retroarticular process Condyloid process Coronoid process Angular process Pterygopalantine fossa Mental foramen Tympanic bulla © Royal Veterinary College 2009

Labels © Royal Veterinary College 2009

No Labels Frontal sinus Dorsal tubercle of atlas Lateral vertebral formen Wing of atlas Tympanic bulla Hyoid apparatus Angular process Condyloid process Retroarticular process Soft palate Tooth root Endotracheal tube Hard palate Frontal bone Coronoid process Zygomatic arch Temporozygomatic suture Axis External acoustic meatus Atlas

The Frontal Sinuses Frontal sinuses: R-Cd view

Frontal sinuses : R-Cd view Full screen Labels This radiograph is made by placing the dog in dorsal recumbency and angling the head so that the hard palate is perpendicular. The x-ray beam is centred on the dog’s external nares so that the diverging beam passes through the frontal sinuses and projects them dorsal to the remainder of the skull. This radiograph is sometimes difficult to get straight, but is a very useful way of examining the frontal sinuses which are frequently affected in dogs with nasal disease or trauma. Notice that the internal septation of the frontal sinuses is not perfectly symmetrical; this is a typical normal variant.

No Labels Right frontal sinus Left frontal sinus Supraorbital process (zygomatic process of frontal bone)

The Tympanic Bullae Tympanic Bullae: R-Cd, open-mouth view

Tympanic Bullae : R-Cd, open-mouth view Full screen Labels This is another radiograph made with the dog in dorsal recumbency. This time the mouth is held widely open and the x-ray beam directed in such a way that it bisects the angle formed by the maxilla and mandible. The rounded thin-walled lucent structures each side of mid-line are the tympanic bullae. In this dog the thin bulla wall gives the appearance of a soap bubble; it has a similar appearance in cats. In many small breeds of dog the tympanic bullae are relatively smaller and flatter in shape. The commonest abnormality affecting the tympanic bullae is otitis media; this is visible radiographically as an increased opacity in the tympanic cavity as a result of exudate and/or granulation tissue. Frequently the bulla wall is thickened as a result of chronic inflammation.

No Labels Nasal Cavity Upper cheek tooth Petrous part of temporal bone Atlanto-occipital joint Mandible 2 nd cervical vertebrae (axis) Atlantoaxial joint Tympanic bullae Nasopharynx Jugular foramen

The Larynx Larynx: Lateral view Larynx: Lateral view, brachycephalic

Larynx : Lateral view Full screen Labels Pot This radiograph of the larynx made in an anaesthetised dog after the endotracheal tube has been removed shows the oropharynx, nasopharynx, larynx and cranial part of the trachea, all outlined by gas within the predominantly soft tissue surroundings. The delicate hyoid bones and the laryngeal cartilages and the tracheal rings (which are partially calcified) are also visible. A radiograph such as this requires a much lower exposure than a radiograph of the cervical spine.

Masseter m. Stylohyoid bone Ceratohyoideus m. Thyrohoid bone Thyroid cartilage Thyrohyoideus m. Trachea Sternothyroideus m. Cricothyroideus m. Hyoglossus m. Mylohyoideus m. Styloglossus m. Sternohyoideus m. Geniohyoideus m. Body of tongue

No Labels Tympanic bulla Atlas Wing of atlas Cervical vertebrae 2 Cervical vertebrae 3 Cervical vertebrae 4 Soft palate Stylohoid bone Epihyoid bone Ceratohyoid bone Epiglottis Basihyoid bone Arytenoid cartilage Thyroid cartilage Cricoid cartilage Air in the oesophagus Trachea Tracheal rings Thyrohyoid bone

Larynx : Lateral view, brachycephalic Full screen Labels Pot 2 Radiographs of brachycephalic dogs such as the Bulldog, Pug or cavalier King Charles spaniel show why so many of these dogs are affected by excessive respiratory noise or snoring or dysnoea. In this instance, the trachea is narrow for the size of the dog and the airway through the larynx and nasopharynx is virtually obliterated by collapse of the thick surrounding soft tissues. Brachycephalic obstructive airway syndrome (BOAS) is the name given to the problems associated with this extreme conformation. Pot 1

Cerebellum Pons Frontal sinus Nasopharynx Hard palate Nasal septum; cartilage Body of tongue Mandible Genioglossus m Geniohyoid m Soft palate Hyoid apparatus Epiglottis Thyroid cartilage Trachea

1 2 3 4 5 6 7 8 9 1 = Nasal bone 2= Incisive bone 3=Maxilla 4=Lacrimal bone 5= Frontal bone 6= Frontal bone 7=Occipital bone 8=Temporal bone 9= Mandible Infraorbital foramen Orbit Supraorbital process Zygomatic arch Paracondylar process External acoustic meatus Retroarticular process Condyloid process Coronoid process Angular process Pterygopalantine fossa Mental foramen Tympanic bulla Temporozygomatic suture External sagittal crest

No Labels Atlas Axis Soft Tissue Hyoid apparatus Trachea Spine of the scapula Shoulder joint Humerus

The Mandible Mandible: IO view

Mandible : IO view Full screen Labels By placing the dog in dorsal recumbency and putting the radiographic film in the oral cavity for a ventrodorsal projection, a view of the rostral part of the mandible may be obtained. Just as for the intraoral dorsoventral, which is very useful for examining the nasal cavity, this radiograph provides a nice view of the mandible without superimposition by other structures. Note the variation in the size and shape of the incisors which is typical and unimportant. Similarly notice the rough appearance of the bone on each side of the mandibular symphesis; this is also normal.

No Labels Lower incisor 1 Lower incisor 2 Lower incisor 3 Lower premolar 1 Lower canine Lower premolar 2 Lower premolar 3 Lower premolar 4 Lower molar 1 Mandibular symphysis © Royal Veterinary College 2009

The Nasal chambers Nasal chambers: IO view, young adult Nasal chambers: IO view Nasal chambers: IO view, dolicocephalic Nasal chambers: IO view, brachycephalic Nasal chambers: Lateral view Dacryorhinocystogram: Lateral view

Nasal chambers : IO view, young adult Full screen Labels Pot An excellent examination of the nasal cavity in a dog or cat can be done by placing the film in the oral cavity and making a dorsoventral radiograph so that only the nasal cavity appears in the image. This view enables detailed comparison of left and right sided structures. Notice that the nasal cavity is filled with numerous tiny linear structures oriented roughly parallel to the mid-line in the rostral part of the nasal cavity, and forming a more complicated pattern in the middle of the nasal cavity. These small lines represent the shadows cast by the nasal turbinates and their mucosae. This is a young adult dog; it has its permanent dentition (no deciduous teeth are visible) but the adult teeth appear very hollow because the pulp cavity is wide and the dentine is thin. As a dog ages the pulp cavity steadily reduces in size so the teeth become progressively more solid in appearance.

Canine Upper premolar 1-4 Upper incisors 1-3 Interincisive suture Palatine fissure Upper Molar 1 & 2 Zygomatic arch Pterygoid bone Rostral alar foramen Foramen ovale Tympanic bulla Paracondylar process Choanal region Presphenoid bone Basisphenoid bone Foramen lacerum Jugular foramen Hypoglossal canal Occipital condyle Pot Comparison © Royal Veterinary College 2009

No Labels Nostril Interincisive suture Palatine fissure Superimposed dorsal & ventral nasal conchae Ethmoidal conchae Maxillary recess Canine tooth Dental cavity Upper premolar 1-4 Upper Molar 1 Upper incisors 1-3 © Royal Veterinary College 2009

Nasal chambers : IO view Full screen Labels Pot A similar radiograph to that described previously comes from a dog of similar skull conformation, that is mesaticephalic. This dog is slightly older than the previous one as evidenced by the relatively smaller pulp cavities best seen in the canine teeth.

No Labels Nostril Interincisive suture Palatine fissure Superimposed dorsal & ventral nasal conchae Ethmoidal conchae Maxillary recess Canine tooth Dental cavity Upper premolar 4 © Royal Veterinary College 2009

Nasal chambers : IO view, dolicocephalic Full screen Labels Pot In a long nosed dog the nasal cavity is relatively elongated and a wide diastema is frequently present between the first and third premolars.

No Labels Nostril Interincisive suture Palatine fissure Superimposed dorsal & ventral nasal conchae Ethmoidal conchae Canine tooth Upper premolar 1 Upper Molar 1 Upper incisors 1-3 Upper premolar 4 Upper Molar 2 Large gap between 1 st & 3 rd premolar © Royal Veterinary College 2009

Nasal chambers : IO view, brachycephalic Full screen Labels Pot This radiograph of the nasal cavity of a Bulldog clearly shows foreshortening of the nasal cavity compared to that seen in mesaticephalic or dolicocephalic dogs. With this foreshortening comes a relative increase in opacity of the nasal structures because the skull is relatively thicker at this point and because of the abundant, often folded, skin over the face. Orientation of the teeth in the maxillary arcade is often abnormal in such dogs, with the third premolar aligned roughly transverse to the arcade in this example.

No Labels Nostril Interincisive suture Palatine fissure Superimposed dorsal & ventral nasal conchae Ethmoidal conchae Canine tooth Upper premolar 1-4 Upper Molar 1 Upper incisors 1-3 Upper Molar 2 © Royal Veterinary College 2009

Nasal chambers : Lateral view Full screen Labels The nasal cavity of the dog requires a lower radiographic exposure than the thicker parts of the skull because it contains air and relatively delicate bones, hence a separate lateral radiograph is sometimes made specifically of the nasal region. One problem with this radiograph is that it superimposes the left and right sides. Many dogs with nasal disease have a symmetrical or even unilateral lesions which are difficult to recognise on the lateral view in which they are superimposed by the normal (unaffected) side. The same comment applies to the frontal sinuses.

No Labels Incisive bone Root of canine teeth Hard palate Nasal bone Ethmoidal conchae Cranial border of orbit Frontal bone Frontal sinus Oral cavity Zygomatic arch Coronoid process of mandible Upper Molar 1 Upper Molar 2 U. Premolar 4 U. Premolar 3 U. Premolar 2 U. Premolar 1 U. Canine U. Incisor 1 U. Incisor 2 U. Incisor 3

Dacryorhinocystogram : Lateral view Full screen Labels This lateral radiograph of the nasolacrimal duct is made by infusion of a small volume of contrast medium through a fine catheter inserted into a lacrimal punctum. In a normal dog the contrast flows down the nasolacrimal duct and drains into the nasal cavity as seen here.

No Labels Catheter in ventral lacrimal punctum Nasolacrimal duct Duct discharging into floor of vestibule

The Thoracic Limb The Shoulder The Elbow The Radius and Ulna The Carpus The Manus

The Shoulder Shoulder: lateral view Shoulder: Cr-Cd view Large Shoulder: lateral view Immature Shoulder: lateral view Immature shoulder arthrogram: lateral view

Shoulder: lateral view This radiograph is usually made with the animal in lateral recumbency with the shoulder of interest on the down side. The limb is protracted to move the humerus away from the sternum for clearer visualisation. The tip of an endotracheal tube is superimposed on the scapula in this dog. If the tube is inadvertently superimposed over the shoulder joint, it can interfere with visualisation of the bones. Labels Pot Full screen

Dorsal border of scapula Infraspinatus m Supraspinatus m Stump of trapezius m Teres major m Latissimus dorsi m Triceps brachii m – long head Olecranon Triceps brachii m – lateral head Cleidobrachialis m Extensor carpi radialis m Common digital extensor m. Rhomboid m Deltoid m Brachioradialis m Lateral digital extensor m Ulnaris lateralis m Flexor carpi ulnaris Canine Forelimb ; Left, lateral view Pot Comparison © Royal Veterinary College 2009

Full screen Pot © Royal Veterinary College 2009

Supraspinous fossa Humerus Head of humerus Shoulder joint Infraglenoid tubercle Acromion process Infraspinous fossa Scapular spine ET tube within the trachea Supraglenoid tubercle Greater tubercle Deltoid tuberosity No labels Intertubercular groove © Royal Veterinary College 2009

Shoulder: Cr-Cd view This radiograph is usually made with the animal in dorsal recumbency with the limb extended. Notice that the medial aspect of the scapulohumeral joint is wider on the medial aspect giving it a wedged-shape; this is completely normal in the dog and cat. Labels Pot Full screen

Dorsal border of the scapula Rhomboid m Supraspinatous m Cut edge of trapezius pars cervicalis Deltoid m Triceps brachii m – lateral head Cleidobrachialis m Brachialis m Extensor carpi radialis m Common digital extensor m Lateral epicondyle of humerus Medial epicondyle of humerus Canine Forelimb; Left, cranial view. Pot Comparison

No labels Acromion process Scapula spine Glenoid cavity of scapula Greater Tubercle Tricipital line Deltoid Crest Supraglenoid tubercle Teres major tuberosity Lesser tubercle of humerus © Royal Veterinary College 2009

Large Shoulder: lateral view Labels Pot Full screen An example of the shoulder in a larger dog, which has a somewhat flatter humeral head and wider glenoid fossa than the other dog.

No labels Supraspinous fossa Supraglenoid tubercle Greater tubercle Deltoid tuberosity Scapula spine Infraspinous fssa Infraglenoid tubercle Head of humerus Intertubercular groove © Royal Veterinary College 2009

Immature Shoulder : lateral view Labels Pot Full screen The proximal humeral physis is open. This dog is 6-9m old.

No labels Supraspinous fossa Supragleoid tubercle Greater tubercle Deltoid tuberosity Scapula spine Infraspinous fossa Infraglenoid tubercle Head of humerus Prox. Physis of humerus Intertubecular groove © Royal Veterinary College 2009

Compared to the previous radiograph, 5ml of radiographic contrast medium (iohexol @100mgI/ml) was injected into the scapulohumeral joint using a lateral approach. The joint is quite well filled, showing the caudal compartment and the cranial compartment. The cranial compartment surrounds the biceps tendon, which appears as a curvilinear filling defect within the contrast medium. This appearance is normal. Immature Shoulder Arthrogram : Lateral view Labels Full screen

No labels Contrast media within the shoulder joint. Contrast media in the intertubecular groove, beneath the biceps tendon. © Royal Veterinary College 2009

The Elbow Immature Elbow: lateral view Immature Elbow: Cr-Cd view Flexed Elbow: lateral view Immature Elbow: Cr-Med, Cd-Lat Oblique view Immature Elbow: Cr-Lat, Cd-Med Oblique view

Immature Elbow : Lateral view Labels Pot Full screen This joint belongs to a 6m old Labrador. Notice the open growth plates at the distal humerus, proximal radius and olecranon process of the ulna.

Humerus Lateral humeral epicondyle Lateral collateral ligament Supinator m Radius Stump of triceps brachii m Olecranon Anconeus m Interosseus space Ulna Canine Elbow; Lateral view Pot Comparison

No labels Humerus Craniolateral tuberosity of olecranon Anconeal process Ulna Radius (Olecranon) Medial epicondyle of humerus Lat. Epicondylar crest Med. border of supratrochlear foramen Elbow (cubital)Joint Prox. Radial physis Prox. Ulnar epiphysis Lat. Epicondyle of humerus Prox. Ulnar physis © Royal Veterinary College 2009

Young Elbow: Cr-Med, Cd-Lat Oblique view Labels Pot Full screen The elbow has been pronated, so the articulation between the humerus and the radius is emphasised. This radiograph is rarely made in clinical practice.

Humerus Stump of triceps brachii – long head Craniolateral tuberosity of olecranon Olecranon Lat. Epicondyle of humerus Coronoid process Ulnar Pronator teres m. Flexor carpi radialis m. Radius Canine elbow; Medial view Pot Comparison

No labels Humerus Supratrochlear foramen Anconeal process Lateral condyle Prox. Radial physis Radius Coronoid process Olecranon Medial epicondyle Medial condyle Ulna © Royal Veterinary College 2009

Immature Elbow : Cr-Lat, Cd-Med Oblique view Labels Pot Full screen In this radiograph the elbow has been supinated, producing a view of the medial aspect of the humeral condyle and the joint between the humerus and medial coronoid process of the ulna. This view might be useful if there is fragmentation of the medial coronoid process.

No labels Humerus Supratrochlear foramen Articulating surfaces: humerus and ulna Olecranon Anconeal Process Articulating surfaces: Humerus and radius Prox. radial epiphysis Prox. radial physis Radius Lateral Humeral epicondyle Medial coronoid process of ulna © Royal Veterinary College 2009

Immature Elbow : Cr-Cd view Labels Pot 1 Full screen The same dog as the previous lateral. Notice the angular shape of the humeral condyle, which articulates on the lateral aspect with the radius and on the medial aspect with the medial coronoid process of the ulna. The medial aspect of the elbow is a frequent site of lesions in dogs with elbow arthritis. Pot 2

Brachialis m Radial nerve Lateral humeral epicondyle Supinator muscle Radius Humerus Canine left Elbow; Cranial view

Humerus Supratrochlear foramen Lateral humeral epicondyle Medial humeral condyle Coronoid process of ulna Pronator teres m Supinator m Radius Canine right elbow ; Cranial view Pot Comparison

No labels Body of Humerus Olecranon Medial Humeral epicondyle Medial Coronoid process of ulna Radius + ulna superimposed Supratrochlear foramen Lateral epicondyle Elbow (cubital joint) Prox. radial epiphysis Prox. radial physis © Royal Veterinary College 2009

Flexed Elbow : lateral view Labels Pot Full screen This radiograph, with the elbow maximally flexed, is done to examine the anconeal process. This is considered one of the first places that osteophytes develop in dogs with elbow arthritis and hence this view is frequently used by clinicians looking for signs of arthritis. Suspected ununited anconeal process is another indication for this radiograph.

No labels Anconeal process Olecranon Lateral epicondyle of humerus Condyle of humerus Body of humerus Head of radius Coronoid process Radius Medial border of humeral condyle Ulna © Royal Veterinary College 2009

The Radius and Ulna Immature Radius and Ulna: Lateral view Immature Radius and Ulna: Cr-Cd view

Immature Radius and Ulna: Lateral view Labels Full screen This radiograph of a young cross bred dog shows the normal curved shape of the radius and the straighter ulna. Open growth plates are visible at the proximal and distal radius and ulna. The distal ulnar physis is shaped like a cone, hence has a V-shape in the radiograph. The accessory carpal bone projects on the palmar aspect of the carpus.

No labels Distal physis of humerus Body of humerus Humeral condyle Prox. radial physis Proximal radial epiphysis Radius Nutrient foramen of radius Distal radius epiphysis Intermedioradial carpal bone Distal row of carpal bones Distal radial physis Metacarpal bones Prox. Ulnar epiphysis Anconeal process Ulna Prox. Ulnar physis Distal ulnar physis Distal ulnar epiphysis Accessory carpal bone Metacarpal bone 1 Prox phalanx of digit 1 © RVC 2009 Caudal border of lateral epicondyle of humerus © Royal Veterinary College 2009

Immature Radius and Ulna : Cr-Cd view Labels Full screen This radiograph is of the same limb as the previous. The limb is relatively straight with some lateral deviation of the paw. This degree of mild lateral deviation is normal and must be distinguished from a valgus deformity, which can occur in dogs following premature closure of the distal ulna growth plate. This view is useful when examining dogs with signs of angular limb deformity.

No labels Distal humeral physis Lateral humeral epicondyle Distal humeral epiphysis Prox. Radial physis Radius Distal ulna physis Distal ulna epiphysis Distal radial epiphysis Distal radial physis Accessory carpal bone Intermedioradial carpal bone 2 nd Carpal bone 1 st Carpal bone Metacarpal 1 Proximal phalanx of digit 1 Distal phalanx of digit 2 Metacarpal 2 Humerus Olecranon Medial humeral epicondyle Prox. Radial epiphysis Ulna Ulna carpal bone Carpal bone 4 Carpal bone 3 Metacarpal 5 Metacarpal 4 Metacarpal 3 Distal metacarpal physis

The Carpus Immature Carpus: Lateral view Immature Carpus: D-P view

Immature Carpus : Lateral view Labels Pot Full screen Radiograph of the same dog as in the dorsopalmar view. An open growth plate is visible in the accessory carpal bone.

Lateral digital extensor m Ulnaris lateralis m Carpus Metacarpus Flexor carpi ulnaris m Common digital extensor m Distal limb ; Lateral view Accessory Carpal bone Pot Comparison

No labels Radius Distal ulna epiphysis Distal radial epiphysis Distal radial physis Accessory carpal bone Intermedioradial carpal bone 1 st Carpal bone Metacarpal 1 Proximal phalanx of digit 1 Distal phalanx of digit 2 Metacarpal 2 Ulna Ulna carpal bone Carpal bone 4 Carpal bone 3 Metacarpals Distal ulna physis © Royal Veterinary College 2009

Immature Carpus : D-P view Labels Pot 1 Full screen This radiograph of the carpus of a 3m old puppy shows the growth plates at the distal radius, ulna and metacarpals. Notice that in each instance the metaphysis adjacent to the open physis appears more opaque and wider than the diaphysis of the bone. This is a normal appearance and should not be misinterpreted as a sign of metabolic bone disease. Pot 2

Flexor carpi radialis m. Adductor pollicis longus m. Extensor retinaculum Extensor carpi radialis m. Common digital extensor m. Lateral digital extensor m. Ulnaris lateralis m. Tendon of common digital extensor m. Distal limb; Dorsal view Deep digital flexor m Flexor carpi ulnaris Accessory carpal bone Flexor retinaculum Tendon of deep digital flexor tendon Digit 1 Metacarpal pad Digital pad Distal limb; Palmer view Pot Comparison © Royal Veterinary College 2009

Carpal tunnel Metacarpal 1 Metacarpal 3 Metacarpal 4 Adductor m digit 4 Superficial digital flexor m Paired sesamoids of digit 5 Flexor carpi ulnaris Superficial digital flexor m Interosseus m Adductor m digit 5 Carpus Ulnaris lateralis m Flexor carpi ulnaris m Distal forelimb; Palmer view © Royal Veterinary College 2009

No labels Radius Distal ulnar physis Distal ulnar epiphysis Distal radial epiphysis Distal radial physis Accessory carpal bone Intermedioradial carpal bone Sesamoid bone of adductor pollicis longus m. 2 nd Carpal bone 1 st Carpal bone Metacarpal 1 Proximal phalanx of digit 1 Distal phalanx of digit 2 Metacarpal 2 Ulna Ulna carpal bone Carpal bone 4 Carpal bone 3 Metacarpal 5 Metacarpal 4 Metacarpal 3 Distal metacarpal physis Distal Metacarpal 2 physis Distal Metacarpal 2 epiphysis Prox. Physis of prox. phalanx Distal Metacarpal epiphysis Prox. Phalanx © Royal Veterinary College 2009

Manus : D-P view Labels Pot 1 Full screen Pot 2 In this radiograph of the manus you should be able to identify the distal radius and ulna, the proximal and distal rows of carpal bones, the metacarpals and phalanges of each digit plus a number of sesamoid bones. For example, there is a small rounded bone on the medial aspect of the carpus, which is a sesamoid in the tendon of insertion of the abductor pollicis longus and there are paired, somewhat elongated palmar sesamoids superimposed on each of the distal metacarpals of digits 2-5. The very small rounded dorsal sesamoids that exist at the metacarpal phalangeal joints are not clearly visible in this radiograph. The carpus includes two rows of bones: adjacent to the distal radius is the wide radial carpal bone, adjacent to the distal ulna is the relatively square ulna carpal, and superimposed on the joint between these bones is a rounded, opaque structure, which represents the accessory carpal bone. The distal row of carpal bones includes numbers 1,2,3 and 4, each of which is found at the proximal end of the relevant metacarpal, although note that carpal bone 4 articulates both with the fourth and the fifth metacarpal. Also note that the first digit (the dew claw) has a very reduced metacarpal and only two phalanges. Another feature worth mentioning is the large pad on the palmar aspect of the paw, which creates a lucent line across the distal part of the proximal phalanges that could occasionally be mistaken for a phalangeal fracture.

No labels Distal ulna – styloid process Distal radius Accessory carpal bone Intermedioradial carpal bone Sesamoid bone of adductor pollicis longus m. Carpal bone 2 1 st Carpal bone Metacarpal 1 Proximal phalanx of digit 1 Distal phalanx of digit Ulna carpal bone Carpal bone 4 Carpal bone 3 Metacarpal 5 Metacarpal 4 Metacarpal 3 Metacarpal 2 Proximal phalanx Middle Phalanx Styloid process of radius © Royal Veterinary College 2009

The Pelvic Limb The Femur The Stifle The Tarsus The Hip (covered in “ The Pelvis ”)

The Femur Femur: Lateral view Femur: Cr-Cd view Femoral Arteriogram: Lateral view

Femur : Lateral view Full screen Labels Pot This radiograph is made with the animal in lateral recumbency with the femur to be radiographed on the table and the upper limb rotated out of the primary x-ray beam. The thigh of the dog is much thicker proximally than distally, which means that making the radiograph of the femur is compromise between adequately exposing the proximal part and not over-exposing the distal part. Note that in a typical dog the femur has a gentle curve. This means that an intramedullary pin cannot normally be inserted all the way down the medullary cavity. Note that this patient is a male.

Sacrotuberous ligament Gemelli mm Medial gluteal m External obturator m Quadratus femoris m Semimembranous m Gastrocenemius m Ilium Deep gluteal m Rectus femoris m Adductor magnus m Abductor cruris caudalis m Semitendinous m Stump of Piriform m Vastus lateralis m © Royal Veterinary College 2009

No Labels Ischiatic tuber Intertrochanteric crest Lesser trochanter of femur Body of femur Medial & lateral sesamoid bones of gastrocnemius muscle Wall of intercondylar fossa of femur Superimposed medial and lateral condyles of femur Sesamoid bone of popliteus m Fibula Tibia Body of ilium Patella Head of femur Os Penis Acetabula incisura © Royal Veterinary College 2009

Femur : Cr-Cd view Full screen Labels A corresponding cranial caudal view of the same femur as in the Lateral Femur radiograph shows that in the sagittal plane the bone is almost perfectly straight. In this well positioned radiograph the patella is superimposed over the mid-line of the femur.

No Labels Head of femur Neck of femur Greater trochanter of femur Trichanteric fossa and intertrochanteric crest Lateral border of tuber ischiadicum Lateral sesamoid of gastrocnemius m Lateral condyle of femur Medial condyle of femur Patella Hip joint Obturator foramen Lesser trochanter Ischiatic tuber Body of femur Medial sesamoid of gastrocnemius m

Femoral Arteriogram : Lateral view Full screen Labels Pot Injection of radiopaque contrast medium into the abdominal aorta has opacified the arteries of the pelvis and pelvic limb. In this radiograph the femoral artery and its branches are clearly seen, mainly on the caudal aspect of the femur.

No Labels Lateral circumflex from external iliac a Femoral artery from external iliac artery Descending genicular artery Popliteal artery Proximal caudal femoral artery Saphenous artery Middle caudal artery Distal caudal femoral artery © Royal Veterinary College 2009

The Stifle Stifle: Lateral view Stifle: Cd-Cr view Immature Stifle: Lateral view Immature Stifle: Lateral view Immature Stifle: Cd-Cr view Stifle: Lateral view, tibial tuberosity fusion

Stifle : Lateral view Full screen Labels Pot The stifle is one of the most commonly radiographed joints of the dog and it is well worth being familiar with its radiographic anatomy. Note the patella and the two fabellae, sesamoid bones embedded in the gastrocnemius tendon. Note also a lucent space on the cranial aspect of the joint that is formed by a fat pad between the patellar tendon and the joint. This is a useful anatomical feature because any joint effusion will tend to impinge upon the fat pad from the caudal aspect and reduce its size in a lateral radiograph.

Patella Patella ligament Fibula Tibia Femur Trochlea Medial & lateral condyles of femur Caudal cruciate ligament Femoropatella ligament Medial & lateral collateral ligament Menisci Patella ligament Patella ligament

No Labels Femur Fibula Tibia Medial sesamoid bone of gastrocnemius m Lateral sesamoid bone of gasrocnemius m Medial and lateral condyles of femur Tibial tuberosity Patella Trochlea of femur Infrapatella fat body Cranial intercondylar area of tibia Lateral supracondylar tuberosity Sesamoid bone within tendon of popliteus m. Femoropatella joint Femorotibial joint © Royal Veterinary College 2009

Stifle : Cd-Cr view Full screen Labels Pot Although it is possible to extend the stifle with a dog in dorsal recumbency for a craniocaudal radiograph, it is often easier to place the dog in sternal recumbency and extend the limb caudally for a caudocranial radiograph, using the dog’s body weight to better extend the joint. Again note the position of the patella, which is projected some distance proximal to the joint when the stifle is properly extended. Note also the medial and lateral fabellae, which are unequal in size and shape. The fibula lies on the lateral aspect of the tibia.

No Labels Femur Patella Lateral sesamoid bone of gastrocnemius m Lateral condyle of femur Fibula Intercondylar fossa of femur Medial sesamoid bone of gastrocnemius Medial condyle of femur Medial condyle of tibia Medial & lateral intercondylar tubercle of tibia Tibial tuberosity Cranial border of tibia © Royal Veterinary College 2009

Immature Stifle : Lateral view Full screen Labels Pot This radiograph of a five month old Labrador shows open growth plates at the distal femur, proximal tibia and proximal fibula. Note the separate centre of ossification at the tibial tuberosity and the wide and irregular physis between it and the tibial crest. This is considered to be a normal appearance. In this dog the medial fabella is positioned slightly distal compared to the lateral; this is considered normal variant.

No Labels Femur Patella Fibula Medial fabella of gastrocnemius muscle. Lateral & medial condyle of femur Tibial tuberosity Distal femoral physis Head of fibula (epiphysis) Prox. fibula physis Prox. Tibial physis Prox. Tibial epiphysis Tibial tuberosity physis Interossoeus space © Royal Veterinary College 2009

Immature Stifle : Lateral view Full screen Labels Pot This radiograph of a slightly younger dog than in the other lateral immature stifle example shows a roughened appearance of the femoral condyles, which could be mistaken for some form of joint disease; however, this is a normal appearance in a skeletally immature animal in which the subchondral bone has not completely ossified and has an uneven interface with the overlying articular cartilage. Within a few weeks this rough appearance will be replaced by a perfectly regular distinct curve.

No Labels Femur Patella Fibula Sesamoid bone of gastrocnemius Lateral & medial condyle of femur Tibial tuberosity Distal femoral physis Head of fibula (epiphysis) Prox. fibula physis Prox. Tibial physis Prox. Tibial epiphysis Distal femoral epiphysis © Royal Veterinary College 2009

Immature Stifle : Cd-Cr view Full screen Labels Pot This is a caudo-cranial view of a stifle. As in the lateral immature stifle radiograph, it shows open growth plates in the distal femur, proximal tibia and proximal fibula and the position of the medial fabella.

No Labels Femur Patella Lateral sesamoid bone of gastrocnemius m Lateral condyle of femur Fibula Intercondylar fossa of femur Medial sesamoid bone of gastrocnemius Medial condyle of femur Medial condyle of tibia Medial & lateral intercondylar tubercle of tibia Tibial tuberosity Cranial border of tibia Distal femoral physis Head of fibula (epiphysis) Prox. fibula physis Prox. Tibial physis © Royal Veterinary College 2009

Stifle : Lateral view, tibial tuberosity fusion Full screen Labels Pot This radiograph is of a nine month old dog in which the growth plates are almost closed. The growth plate of the tibial tuberosity has an interesting pointed shape. This is a normal anatomical variant.

No Labels Femur Patella Fibula Tibial tuberosity Cranial border of tibia Distal femoral physis Prox. Tibial physis Tibial tuberosity growth plate Infrapatellar fat pad Patellar ligament Sesamoid bones of gastrocnemius Femoral condyles © Royal Veterinary College 2009

The Tarsus Immature Tarsus: Lateral view Immature Tarsus: D-P view

Immature Tarsus : Lateral view Full screen Labels Pot This radiograph of a four month old dog shows open growth plates at the distal tibia and at the tip of the tuber calcis. The proximal intertarsal and tarsometatarsal joint appear wide, which is a normal appearance at this age; these joints will gradually become narrower with skeletal maturity. Note the linear soft tissue structure that runs from the tuber calcis proximally, roughly parallel to the distal tibia; this is the Achilles tendon.

Reflected tendon of Deep Digital Flexor m. Cut end of Superficial Flexor tendon. Abductor digit V muscle Common calcanean tendon Proximal extensor retinaculum Peroneus longus m. Extensor digitorum lateralis m Peroneus brevis m Deep Digital Flexor tendon Tarsus Interosseus m. (Digit V) Proximal digital annular ligaments (Distal is missing). Superficial Digital Flexor tendon © Royal Veterinary College 2009

No Labels Tibia Calcanean tuber Calcanean physis Calcaneus Central tarsal bone Achilles tendon Tarsal bone 4 Metatarsal bone 1 Tibia Distal tibial physis Distal tibial epiphysis Trochlea of talus 2 nd & 3 rd Tarsal bone Superimposed metatarsals 2-5 © Royal Veterinary College 2009

Immature Tarsus : D-P view Full screen Labels Pot The dorsoplantar radiograph of the same dog as in the previous radiograph again shows the relatively wide proximal intertarsal and tarsometatarsal joints and open growth plates at the distal tibia and distal fibula. The tuber calcis is a relatively substantial piece of bone that is superimposed on the tibiotarsal joint and tends to obscure it in the DP view.

Long digital extensor m. Proximal extensor retinaculum Tibialis cranialis muscle Distal extensor retinaculum

No Labels Gastrocnemius m superimposed on the tibia. Body of fibula Lateral malleolus of fibula Tarsal bone 4 Calcaneus Tarsocrural joint Sustentaculum tali of calcaneus Central tarsal bone Metatarsels 2-5 Talus Tarsal bone 2 Tarsal bone 3 © Royal Veterinary College 2009

The Pelvis The Hip joint The Pelvic bones

The Pelvic Bones Pelvis: Lateral view Pelvis: V-D view Pelvis: V-D view

Pelvis : Lateral view Full screen Labels This lateral radiograph shows the pelvis, the lumbosacral joint and the first few caudal vertebrae. The end of the tail is relatively thin and therefore is over-exposed in this radiograph and cannot be seen. Note that the two halves of the pelvis and the coxofemoral joints are almost perfectly superimposed in this well positioned radiograph, which makes them difficult to examine because a structure on one side effectively hides that on the other side. For this reason, it is usual to position one of the femurs more cranial than the other and to place a left or right marker adjacent to it so that at least the femurs can be distinguished in a lateral radiograph.

No Labels Caudal vertebrae 1 Hip joint (right) Superimposed ischiatic tuber Superimposed obturator foramina Pelvic symphysis Left femur Right femur Head of femur (right) Caudal extremity of L6 Intervertebral disc space between L7 & S1 Vertebral canal at L7 Left & right dorsal iliac crest Sacrum Hip joint (right) Body of ilium

Pelvis : VD view Full screen Labels This ventrodorsal shows clearly the bones forming the pelvis and the coxofemoral joints. For this radiograph the dog has been positioned in dorsal recumbency and the pelvic limbs have been extended fully. The femurs are parallel and the patella is superimposed over the distal femur. It is usually necessary to use sticky tape or a Velcro band to keep the femurs in this position, which is very unnatural for a dog. Note the shape of the proximal femur which has a distinct neck and rounded head that is well seated in the acetabulum. The sacroiliac joints may also be examined in a ventrodorsal view, although they are not clearly visible because they are slightly oblique to the primary x-ray beam and because the rough surface of the bones forming the joint means there is no clearly discernible joint space. The sacroiliac joint is prone to luxation following trauma such as hit by car.

No Labels Left transverse process of L7 Wing of ilium Sacrum Iliopubic eminence Head of femur Neck of femur Greater trochanter Trichanteric fossa & intertrochanteric crest Obturator foramen Ischiatic tuber Femur Patella Intervertebral disc space between L7 &S1 Right sacroiliac joint Body of ilium Right hip joint Lesser trochanter Pubis Ischiatic table Lateral fabella of gastrocnemius m © Royal Veterinary College 2009

Pelvis : V-D view Full screen Labels Compared to the other VD Pelvic radiograph this film has a higher contrast, a slightly speckly appearance and improved definition of the borders of the bones. It is an example of a computed radiograph whereas the previous was a radiographic film. Vets are increasingly using computed (digital) radiography to produce images such as this, which are viewed on a monitor rather than as a piece of film placed on a light box. As in the previous dog, the coxofemoral joints are clearly visible with a normal relationship between the femoral head and the acetabulum. The radiographic joint space forms a narrow curve of uniform width on the cranial aspect of the coxofemoral joint. The subchondral plate of the acetabulum is quite broad and very opaque radiographically whereas the convex surface of the adjacent femoral head is less opaque. The narrow lucent space between them represents the articular cartilage on each side of the joint plus a film of interposed synovial fluid.

No Labels Wing of ilium Sacrum Iliopubic eminence Head of femur Neck of femur Greater trochanter Trichanteric fossa & intertrochanteric crest Obturator foramen Ischiatic tuber Femur Intervertebral disc space between L7 &S1 Right sacroiliac joint Body of ilium Right hip joint Lesser trochanter Pubis Ischiatic table Faeces in descending colon © Royal Veterinary College 2009

The Hip joint Pelvis: V-D view, Hip dysplasia

Pelvis : V-D view, Hip dysplasia Full screen Labels This radiograph of a young dog shows subluxation of the left coxofemoral joint, which is a typical appearance for hip dysplasia. Note the scrotum on the midline; some vets will routinely cover it with a lead sheet to protect the testicles from x-rays.

No Labels Wing of ilium Sacrum Iliopubic eminence Head of femur Neck of femur Greater trochanter Obturator foramen Ischiatic tuber Femur Patella Intervertebral disc space between L7 &S1 Right sacroiliac joint Body of ilium Right hip joint Lesser trochanter Fovea capitis Pubis Ischiatic table Lateral sesamoid bone of gastrocnemius m Faeces in descending colon Scrotum © Royal Veterinary College 2009

The Thorax General Thorax views The Ribs The Heart The Lungs The Oesophagus The Thymus

General Thorax views Thorax: Overweight, DV view Thorax: Overweight, lateral view Thorax: Lateral view Thorax: Left lateral view Thorax: Right lateral view Thorax: VD view

Thorax : Overweight, DV view Labels Full screen This radiograph shows that although there is air within both the left and right lung the cardiac border is indistinct. The cranial mediastinum is wide as a result of fat deposition.

No Labels Apex of Heart Ribs Diaphragm Rib 1 Aortic arch Left ventricle Cranial vena cava Trachea © Royal Veterinary College 2009

Thorax : Overweight, Lateral view Labels Full screen Pot In this radiograph of an obese Terrier the presence of intrathoracic and intra abdominal fat means that the lung is less well inflated than in the other radiographs. For this reason intrathoracic structures are more difficult to see, for example the heart has a much less well defined border than in the other radiographs.

No Labels Thoracic aorta Tracheal bifurcation Pulmonary vessels to caudal lobes of lungs Left crus Right crus Liver Left ventricle Heart apex Right ventricle Cr. lobar Pulmonary artery. Cr. lobar Pulmonary vein Trachea Stomach Spleen

Sympathetic trunk Dorsal intercostal a.v. Oesophagus Thoracic aorta Vagus n.: dorsal & ventral branches Left principal bronchus Diaphragm Phrenic n. Mediastinum: over the right accesssory lung Right auricle Mediastiinum:over right middle lung lobe Left ventricle Paraclonal a.v. Right ventricle Left auricle Right cranial lung lobe Internal thoracic a.v. Vago-sympathetic trunk Middle cervical ganglion (sympathetic) Subclavian a. Cervicothoracic ganglion

Thorax : Lateral view Labels Full screen Pot This radiograph shows a relatively deep chested dog. The heart, aorta and pulmonary vessels are clearly visible, although (unusually) the caudal vena cava is not. Note that the trachea, the lungs and other intrathoracic structures are visible because of the air contained in the thorax. When we make thoracic radiographs, we try to expose the film at peak inspiration in order to maximise the amount of air in the lung and hence maximise the visibility of intrathoracic structures. In animals with relatively little air in the lungs (e.g. because of pneumonia) it can be difficult to see anything radiographically.

No Labels Thoracic aorta Tracheal bifurcation Pulmonary vessels to caudal lobes of lungs Left crus Right crus Caudal vena cava Liver Left ventricle Heart apex Right ventricle Cr. Lobar Pulmonary artery Cr. Lobar Pulmonary vein Trachea Cranial vena cava

Thorax : Left lateral view Labels Full screen Pot This radiograph is of the same dog as the right lateral and shows the difference in the appearance of the diaphragm with the animal laying on its left: now the diaphragmatic crura diverge. This difference between left and right is often observed in dogs.

No Labels Thoracic aorta Tracheal bifurcation Pulmonary vessels to caudal lobes of lungs Left crus Right crus Caudal vena cava Liver Left ventricle Heart apex Right ventricle Right cr. Lobar Pulmonary artery Right cr. Lobar Pulmonary vein Trachea

Thorax : Right lateral view Labels Full screen This radiograph is made with the animal in lateral recumbency with its right side down. Note that the diaphragm has a smooth continuous curved shape and that the diaphragmatic crura are parallel, almost superimposed. Contrast this appearance with that of the left lateral radiograph. Pot

No Labels Thoracic aorta Pulmonary vessels to caudal lobes of lungs Left crus Right crus Caudal vena cava Liver Left ventricle Heart apex Right ventricle Cr. Lobar Pulmonary artery Cr. Lobar Pulmonary vein Trachea

Thorax : VD view Labels Full screen Pot A ventrodorsal radiograph that shows the normal position of the heart, slightly to the left of mid-line, and the caudal vena cava to the right of mid-line.

No Labels Cr Vena Cava Rt. atrium Rt. Ventricle Ca. Vena cava Pulmonary artery Lt. atrium Aorta Lt. Ventricle Caudoventral mediastinum © Royal Veterinary College 2009

L. auricle R. auricle Aorta Brachiocephalic trunk L. Subclavian artery Apex R. ventricle L. ventricle L. atrium Pulmonary trunk Left subclavian artery Brachiocephalic trunk Cranial vena cava Caudal vena cava Azygous vein L. pulmonary artery R. pulmonary artery L. pulmonary veins R. pulmonary veins

The Heart Angiogram: LV injection, lateral view Angiogram: RV injection, lateral view

Angiogram : LV injection, lateral view Labels Full screen The heart normally has a uniform soft tissue opacity in radiographs and the internal structures (e.g. chambers, valves) are not visible. These structures can be outlined by injecting contrast medium which mixes with the blood. In this instance, a catheter has been passed up the aorta (where was it inserted into the dog?) until its tip is in the left ventricle. Injection of contrast outlines the left ventricle, aorta, coronary arteries, brachiocephalic trunk and left subclavian artery. This appearance is normal. (Ignore the catheter cranial to the heart; it is relevant for the next radiograph.)

No Labels Left subclavian a Thoracic aorta Left crus of diaphragm Right crus of diaphragm Gas in pylorus of stomach Common carotids Brachiocephalic trunk R + L internal thoracic arteries Left ventricle

Angiogram : RV injection, lateral view Labels Full screen Pot In this instance, a catheter has been passed down a jugular vein. Injection of contrast outlines the right atrium, right ventricle and pulmonary arteries. This appearance is normal. (The thin black line crossing the caudal part of the lungs is an artefact that occurred because the film was inadvertently folded before processing.)

No Labels Left pulmonary artery Right pulmonary artery Pulmonary arterial supply to the right middle lobe Pulmonary trunk Cranial lobar pulmonary artery Right ventricle

The Lungs Bronchogram: Lateral view Pulmonary Vasculature: Bulldog, DV view Pulmonary Vasculature : Close-up, Lateral view

Bronchogram : Lateral view Labels Full screen Pot 1 Pot 2 In the days before flexible endoscopy, vets sometimes did bronchography to examine the airways. In this radiograph a small volume of barium sulphate suspension has been infused into the trachea and the lung inflated to spread it along the bronchial mucosa. It is amazing how clearly the bronchi are seen isn’t it? Notice that they have straight or gently curved walls and gently tapering lumen. This appearance is normal.

No Labels Bronchi of caudal lobes Bronchus– end on Tracheal bifurcation Trachea Right principle bronchus to cranial lobe

Cranial part of cranial lobe of left lung Caudal part of cranial lobe of left lung Caudal lobe of left lung Caudal interlobular fissure of left lung Interlobular fissure of cranial lobe of left lung Accute margin Cardiac notch Obtuse margin Trachea Right ventricle of heart Left ventricle of heart

Trachea Bifurcation of the trachea Primary bronchii Right cranial lobes Caudal lobes Bronchioles Left cranial lobe © Royal Veterinary College 2009

Pulmonary Vasculature : Bulldog, DV view Labels Full screen Pot This radiograph shows the right and left caudal lobar arteries and veins superimposed over the cranial part of the abdomen. It is useful to examine these vessels in dogs or cats with suspected cardiac failure. Pulmonary congestion is often visible as enlargement of the veins relative to the arteries. The dorsoventral view gives a better depiction of these vessels than a ventrodorsal.

No Labels Heart Left caudal lobar vessels Diaphragm Right caudal lobar vessels Air in the fundus of stomach

Pulmonary Vasculature : Close-up, Lateral view This radiograph shows the right cranial lobar artery and vein. They are roughly parallel, similar in size and gradually taper as they extend towards the periphery of the lung. Labels Full screen Pot 1 Pot 2

No Labels Tracheal bifurcation Right ventricle Cr. Lobar Pulmonary artery Cr. Lobar Pulmonary vein Trachea Cr. Lobar bronchus

The Ribs Crusty Ribs: Lateral view

Crusty Ribs : Lateral view Labels Full screen It is common to observe large irregular exostosis at the costochondral junctions of old dogs. This appearance is considered an age-related change and should not be confused with disease. Pot

No Labels Caudal vena cava Liver Left ventricle Heart apex Right ventricle Exotoses at costochondral junctions

The Oesophagus Oesophagram: lateral view

Oesophagram : lateral view View in sequence The oesophagus is not normally visible radiographically, although it might be if it is dilated or has abnormal contents. To make the oesophagus visible and to assess its function, we perform contrast radiography. This series of radiographs made at 1 second intervals shows a bolus of food/barium mixture passing through the thoracic oesophagus, leaving a slight mucosal coating behind. This is a normal appearance. Pot

No Labels Oesophageal bolus Thoracic aorta Superimposed caudal lobar branches of pulmonary arteries & veins Bronchiole Finish Sequence Caudal Vena Cava

No Labels Oesophageal bolus Thoracic aorta Caudal Vena Cava Bronchiole

No Labels Oesophageal bolus Caudal Vena Cava Thoracic aorta

No Labels Caudal Vena Cava Superimposed caudal lobar branches of pulmonary arteries & veins Oesophagus Finish Sequence Thoracic aorta

The Thymus Thymus: DV view Thymus: Lateral view

Thymus : DV view Labels Full screen A dorsoventral radiograph of a 3-month-old pup shows a broad curved soft tissue structure on the left cranial aspect of the heart. This is the thymus, which will shortly involute and cease to be visible radiographically.

No Labels Rt. atrium Rt. Ventricle Lt. atrium Lt. Ventricle Thymus © Royal Veterinary College 2009

Thymus : Lateral view Labels Full screen This radiograph of a 3-month-old pup shows a lack of ossification of the distal part of the rib which is therefore not visible radiographically. Notice how the thymus is virtually invisible on a lateral view. Pot

Lung (left) Diaphragm Oesophagus Thymus Common carotid a. Heart © Royal Veterinary College 2009

No Labels Thoracic aorta Left crus Right crus Liver Left ventricle Heart apex Right ventricle Trachea Non-ossified costochondral junction

The Abdomen General Abdomen views The Reproductive System The Kidneys and Ureters The Bladder and Urethra The Gastrointestinal System The Spleen The Liver

The Gastrointestinal System Caecum detail: VD view Gastric Antrum: Left lateral view Gastric Antrum: Right lateral view Gastric Rugae: Lateral view Pneumogastrogram: VD view Pneumogastrogram : Lateral view

Caecum detail : VD view Full Screen Labels This close up view of part of the ventrodorsal abdominal radiograph of the dog shows gas filling the caecum, which lies just right of the mid-line at the level of L3 to L5. This is a normal appearance.

No Labels Gas filled caecum L3 L4 L5 © Royal Veterinary College 2009

Gastric Antrum: Right lateral view Full Screen Labels This lateral radiograph of a large dog was made with the dog lying in right recumbency. Gas is visible in the gastric fundus, but the antrum and body of the stomach are predominantly fluid-filled and appear as a regular rounded structure in the cranioventral part of the abdomen. This appearance can be mistaken for a ball in the stomach. Pot 1 Pot 2

Enlarged spleen Descending colon Reflected abdominal muscles & skin Greater omentum Left lateral lobe of liver

Caudal division of cranial lobe of left lung Caudal lobe of left lung Longissimus thoracic m Iliocostalis m Left kidney Stomach; fundus Stomach; body Left lateral lobe Left medial lobe Diaphragm Left ventricle Left auricle Pericaridal fat

No Labels Right kidney Gas filled colon Small intestines Fluid filled gastirc body and antrum Liver Gas filled gastric fundus

Gastric Antrum: Left lateral view Full Screen Labels By repositioning the dog into left recumbency, gas can be redistributed in the stomach and now fills the gastric antrum. The fluid that was in the antrum and body has now moved into the fundus, so the appearance of the stomach is now the opposite of what it was in right lateral recumbency. The presence of gas in the antrum makes gastric foreign body unlikely. Pot 2 Pot 1

Descending duodenum Greater omentum

Right kidney Caudate lobe of liver Right lateral lobe of liver Caudal, middle & cranial lobes of the right lung Diaphragm Quadrate lobe Right medial lobe Left lateral lobe Stomach; antrum

No Labels Small intestines Gas filled gastirc body and antrum Liver Fluid filled gastric fundus

Gastric Rugae : Lateral view Full Screen Labels This close-up view of part of the lateral abdominal radiograph of a dog shows the appearance of the gastric rugae, which in this instance are well outlined by gas. They have fairly uniform thickness and an undulating course. As the stomach distends, gastric rugae are stretched out and flattened and are less visible radiographically.

Pneumogastrogram : VD view Full Screen Labels This ventrodorsal radiograph of a dog with an air filled stomach shows the relatively large rounded fundus of the stomach, which lies to the left of midline, and the more oblong gastric body extending across the mid-line to the right where the pyloric canal connects the gastric antrum with the duodenum. The duodenum is the most lateral of the gas-filled intestinal loops visible in this radiograph. Pot 1 Pot 2 Pot 3

Right medial lobe of liver Left lateral lobe Stomach; antrum Stomach; fundus Left lobe of pancreas Descending duodenum Right lobe of pancreas Cranial duodenal flexure Caudal duodenal flexure © Royal Veterinary College 2009

Sternum Left lateral lobe Left medial lobe Diaphragm Quadrate lobe Xiphoid process Right medial lobe Right kidney Caudal vena cava Stomach; fundus Left kidney © Royal Veterinary College 2009

Stomach Enlarged spleen Greater omentum Descending duodenum

No Labels Caudal lobar branches of pulmonary vessels superimposed on the liver Gas in gastric fundus Liver Gas in duodenum Gas in gastric antrum

Pneumogastrogram : Lateral view Full Screen Labels For this radiograph a large bore gastric tube has been passed and the stomach inflated to more clearly demonstrate its size, position and shape. Pot 1 Pot 2

Serratus dorsalis pars cranialis Serratus dorsalis pars caudalis Perirenal fat Cut edge of internal abdominal oblique Left lobe of pancreas Stomach; fundus External intercostal m

Right lobe of pancreas Descending duodenum Stomach; antrum Left lateral lobe Serratus dorsalis pars cranialis

The Kidneys and Ureters Intra-venous Ureterogram (IVU): VD view Nephrogram: VD view, DSA Renal non-selective angiogram: VD view

Intra-venous Ureterogram (IVU) : VD view Full Screen Labels This ventrodorsal radiograph was made several minutes after injection of contrast medium into a peripheral vein. Circulation of the contrast through the heart and lungs is followed by systemic distribution to all organs, including the kidneys. The kidneys filter contrast and excrete it into the renal pelvis and ureters which are visible clearly in this instance. This procedure is called an intravenous urogram (IVU). Opacification of the renal collecting system, pelvis and ureters is also known as a pyelogram. Note that the urinary bladder has been filled with air (pneumocystogram) to help identify it and to improve visualisation of the ureters as they pass over the urinary bladder in this view. Each ureter in this dog passes in a caudal direction and then makes an approximately 180º turn before draining into the bladder. This is a completely normal appearance. Pot 1 Pot 2 Pot 3

Renal artery Renal vein Ureter Arcuate aa Cortex Medulla Renal sinus

Renal artery Ureter Interlobar artery Interlobular artery Pelvis recess Impression of renal crest

Aorta Vena cava Oesophagus Quadrate lobe of liver Left medial lobe of liver Left lateral lobe of liver Gall bladder Right medial lobe Right kidney Renal a&v Adrenal gland Left kidney Caudal vena cava © Royal Veterinary College 2009

Nephrogram : VD view, DSA Full Screen Labels This radiograph was made in a similar way to the renal non-selective angiogram, but the technique of digital subtraction has enabled other abdominal structures not containing contrast medium to be removed from the image, leaving a particularly clear depiction of the contrast within the aorta and its various branches. Contrast medium arriving in the kidneys is quickly distributed evenly through the cortex where it is filtered by the glomerulus. Opacification of the renal parenchyma is known as a nephrogram. Pot 1 Pot 2 Pot 3

No Labels Interlobar aa Renal aa External iliac a Internal iliac a Median sacral a Celiac a Cr. Mesenteric a © Royal Veterinary College 2009

Renal non-selective angiogram : VD view Full Screen Labels This radiograph was made during injection of contrast medium into the mid-abdominal aorta via a catheter and shows contrast predominantly filling the renal arteries and the interlobar arteries of the kidneys. In many dogs, each kidney has two renal arteries. Pot 1 Pot 2 Pot 3

No Labels Interlobar aa Renal aa Deep circumflex a External iliac a Internal iliac a Median sacral a © Royal Veterinary College 2009

The Bladder and Urethra Male Urethrogram: Lateral view Bladder: Lateral view, Pelvic

Male Urethrogram : Lateral view Full Screen Labels This radiograph was made during injection of contrast medium into a urethral catheter and shows the contrast within the penile and pelvic urethra, the bladder and a small amount of contrast refluxing up one of the ureters. Note the uniform calibre of the urethra as it bends around the caudal aspect of the ischium before becoming wider within the pelvis. An elongated gas bubble is present in the caudal part of the pelvic urethra and could be confused with a lesion.

No Labels Bladder Ureter Preprostatic urethra Slight dorsal dip marks the seminal colliclus Isthmus (narrowing of lumen) Penile urethra © Royal Veterinary College 2009

Bladder : Lateral view, Pelvic Full Screen Labels This radiograph of a small breed female dog shows contrast medium (and a large air bubble) in the vagina and uterus. The oblique filling defect in the uterus dorsal to the bladder represents the site of the cervix. In this dog the urinary bladder has a very wide neck, which is located within the pelvis. Dogs (male or female) with this conformation often have urinary incontinence. Pot Note: Male dog used for photo, female in radiograph!

Bladder Rectum Adductor m. Symphyseal surface of os coxae Rectus abdominis m. Lips of vulva Sacrum 7 th Lumbar vertebra Spinal cord Intervertebral disc Anus Urethra Vestibule

The Reproductive System Vaginogram: Lateral view, Oestrus Uterus: Lateral view, Metoestrus Prostate: Lateral view

Vaginogram : Lateral view, Oestrus Full Screen Labels This radiograph was made by injection of contrast medium into the vagina and urethra of an entire female dog. Contrast opacifies the urethra, bladder, vagina and the two horns of the uterus, which are visible as narrow coiled structures superimposed on the craniodorsal aspect of the bladder. The large diameter of the vagina and the open cervix are compatible with oestrus. Pot Note: Male dog used for photo, female in radiograph!

Dorsomedian fold continuing the cervix Vestibule Clitoris External urethral orifice Vagina Bladder Cervix Right uterine horn Broad ligament Right ovary © Royal Veterinary College 2009

Uterus : Lateral view, Metoestrus Full Screen Labels In this lateral abdominal radiograph the uterus can be faintly seen as a curved elongated, faintly lumpy-appearing structure superimposed over the bladder. This appearance is normal, although the uterus in many dogs is too small to be seen radiographically. Pot Note: Male dog used for photo, female in radiograph!

No Labels L5 Ventral abdominal wall Bladder Faeces in descending colon Uterus Left kidney Small intestines © Royal Veterinary College 2009

Prostate : Lateral view Full Screen Labels In this radiograph of a male dog a rounded soft tissue structure is visible just caudal to the bladder and ventral to the faeces-filled colon at the pelvic inlet. This is the prostate. It is often difficult to see the prostate because it is usually within the pelvis, so is obscured by the surrounding bones. In entire male dogs the prostate gradually enlarges with increasing age and moves cranially so that it becomes visible cranial to the pelvic inlet, as in this instance. Note the triangular lucency that occupies the angle formed by the ventral abdominal wall, the ventral wall of the bladder and the cranioventral aspect of the prostate; this is abdominal fat and it is the fact that it is less opaque than soft tissues that enables visualisation of the prostate. Pot 2 Pot 1

Bladder Deferent duct Pelvic urethra Prostate gland Retractor penis m. Bulbospongiosus m. Body of penis Ischiocavernosus m. over left crus Anus Rectum

Bladder Deferent duct (right) Kidney (left) Ureter (right) Urethra Bulbospongiosus m. Right crus Retractor penis m. Testis (right) Testicular vessels Dorsal a. and v. of penis Anus Bulbus glandis Pars longa glandis Spermatic cord Prepuce Descending colon

No Labels Ilium Hip joint L5 Femoral head Prostate Fat between bladder neck & abdominal wall Ventral abdominal wall Bladder © Royal Veterinary College 2009

General Abdomen views Abdominal Aortogram: Lateral view Abdomen: Lateral view Abdomen: VD view Pup Abdomen: Lateral view

Abdominal Aortogram : Lateral view Full Screen Labels This lateral radiograph was made immediately after injection of positive contrast medium into the left ventricle and shows opacification of the abdominal aorta and its major branches. Pot 1 Pot 2 Pot 3 Muscle layers

Internal abdominal oblique m External abdominal oblique m Transverse abdominal m External abdominal oblique m Internal abdominal oblique m

No Labels Right kidney Left kidney L4 Bladder Small intestines Aorta Celiac a Cr. Mesenteric a Renal aa External iliac aa Internal iliac aa Deep femoral aa

Abdomen : Lateral view Full Screen Labels This is a typical lateral abdominal radiograph of a dog, in which the abdominal viscera are visible but are difficult to discern because of superimposition and because of the similar opacity of the organs and surrounding tissues. The liver is present on the cranioventral aspect of the abdomen between the stomach, which is gas-filled, and the diaphragm. In this instance the caudal port of the liver extends several centimetres caudal to the last ribs and some would interpret this as enlarged. Just caudal to the liver is an oblong soft tissue structure that corresponds to the tail of the spleen. Dorsal to this there are numerous loops of small intestine, some containing gas which makes them easier to see, and others containing a small amount of fluid. Dorsal to the small intestinal loops and bladder is the colon. This is recognisable because of its speckled content, which represents faeces. The kidneys are relatively difficult to see in many dogs and this is no exception. The left kidney is present in the mid-dorsal abdomen from the level of L2 to L4. The right kidney overlaps with the left and occupies the region from approximately T13 to L2. Pot 2 Pot 1 Pot 3 Muscle layers

No Labels Gas in body of stomach Right kidney Left kidney L4 Faeces in descending colon Bladder Small intestines Tail end of spleen Caudal extremity of liver

Abdomen : VD view Full Screen Labels This is the corresponding ventrodorsal view to the previous lateral. Again it is difficult to discern the individual abdominal organs in this typical dog. The left kidney is visible from approximately L1 to L3 with the elongated curvilinear spleen lateral to it and overlapping its caudal pole. The right kidney is virtually invisible. In this dog most of the small intestine appears to lie to the right of midline; this is not abnormal. The stomach is gas-filled, as it was in the lateral view, and has a rounded fundus to the left of midline and a narrower, more elongated body that crosses the midline towards the antrum, which lies on the right. The gas-filled piece of small intestine seen superimposed over the right 12 th and 13 th ribs is probably the duodenum, although its connection to the stomach is not visible. An incidental finding in this dog is the unusual left rib at T13, which is shorter and thicker than the other ribs. This represents transitional anatomy, having some of the features of a normal rib and some of the features of a normal lumbar transverse process. Transitional thoracolumbar vertebrae or lumbosacral vertebrae are commonly seen in dogs but are usually of no clinical significance. Pot 2 Pot 4 Pot 3 Pot 1

No Labels Gas within fundus of stomach Transitional left rib of T13 Left kidney Faeces within descending colon Vertebrae L5 Duodenum Gas filled antrum of stomach Body of spleen © Royal Veterinary College 2009

Pup Abdomen : Lateral view Full Screen Labels This lateral abdominal radiograph of a very young puppy shows open growth plates in the vertebrae, the pelvis and distal femurs. The abdomen has a virtually featureless, uniform opacity except for a few gas shadows in the stomach and parts of the intestine. Other abdominal organs are invisible. This is a normal appearance that occurs because in neonatal puppies and kittens there is very little abdominal fat, and in the absence of fat there is no contrast (difference) between the opacity of the different abdominal structures which therefore merge into one uniform grey.

No Labels Physes Ilium Pubis Liver Ischium

The Spleen Spleen: Lateral view

Spleen : Lateral view Full Screen Labels A lateral abdominal radiograph shows the spleen having a more elongated and shapely demarcated appearance than in the ‘ Abdomen: Lateral View ’ radiograph. The appearance of the spleen depends greatly on its position in the abdomen and as it is somewhat mobile it can vary from dog to dog and even from minute to minute. It is very easy to over-interpret the appearance of the spleen because of these variations. Dorsal to the spleen in the mid-abdomen there are a few small intestinal loops which are non-dilated and dorsal to that there is gas outlining the large intestine and caecum. The bladder occupies the caudoventral part of the abdomen and has the large intestine and rectum draped over its dorsal aspect. Pot

No Labels Ascending colon Lumbar vertebrae 5 Faeces within descending colon Ventral extremity of spleen Non dilated small intestine Caecum Bladder

Liver : Portogram Full Screen Labels This ventrodorsal radiograph is made immediately following injection of contrast medium into a mesenteric vein at laparotomy. Contrast within the vein flows cranially into the hepatic portal vein and into the intrahepatic branches of the portal vein. This is a normal study. In this image, the blood vessels appear as black structures, which is the opposite of what you might have been expecting based on experience of other angiograms. This is a digital subtraction angiogram in which the other parts of the body such as the bones and the other abdominal organs do not contribute to the image, and the contrast medium appears as black on a uniform grey background. This technique makes it possible to see clearly the tiny portal branches extending out into the periphery of the liver.

The Spine Cervical region Thoracic region Lumbar region Sacral region Coccygeal vertebrae Atlas Axis Cervical, thoracic & lumbar The Vertebrae;

1 2 3 4 5 1= Dorsal Tubercle 2= Cranial articular fovea 3= Transverse process 4= Body 5= Dorsal arch 6= Arch 7= Caudal articular fovea 8= Odontoid process (fovea for dens) 9= Ventral tubercle 10= Lateral vertebral foramen 11= Transverse foramen Cranial aspect 6 3 7 8 9 1 10 6 3 9 11 Lateral aspect Caudal aspect ATLAS

1= Transverse process 2= Body 3= Spinous process 4= Caudal articular process 5= Cranial articular process 6= Dens (Odontoid process) 7= Transverse canal 8= Body of axis 9= Arch 1 2 3 4 5 6 7 3 4 1 1 8 7 3 9 4 1 6 5 6 10 Cranial aspect Lateral aspect Caudal aspect AXIS

1 1= Spinous process 2= Body 3= Transverse process 4= Vertebral foramen 5= Lamina 6= Cranial articular surface 7= Caudal articular surface 8= Mamillary process 9= Caudal costal fovea 10= Cranial costal fovea 11= Cranial articular process 12= Caudal articular process 2 3 4 5 1 6 3 2 1 7 6 2 3 1 5 7 8 9 2 10 11 1 6 2 3 2 4 1 6 9 2 1 8 6 11 12 4 2 3 1 8 4 2 12 1 12 8 3 2 Cranial Lateral Caudal Cervical v. Thoracic v. Lumbar v.

Cervical region Yorkshire Terrier cervical spine : Lateral view, neutral position Yorkshire Terrier cervical spine : Lateral view, flexed position Puppy cervical spine : Lateral view Cervical spine survey : Lateral view Cervical myelogram : Lateral view

Yorkshire Terrier cervical spine : Lateral view, neutral position In small and toy breeds of dogs the vertebral canal is relatively wider than in large breeds. This lateral radiograph of a Yorkshire terrier shows the wide gap between the vertebral bodies and the corresponding dorsal laminae, which are projected dorsal to the articular facets. C1 looks tall and narrow compared with its appearance in large breed dogs. Full Screen Labels Pot

Atlas Axis 3 rd Ce 4 th Ce 5 th Ce 1 2 3 3 3 3 3 4 4 4 4 4 5 6 7 8 1= Lateral vertebral foramen 2= Wing of atlas 3= Spinous processes 4= Transverse processes 5= Extended plate of transverse process of Ce 6 6= Vertebral foramen 7= Cranial articular process 8= Caudal articular process

No Labels Dorsal tubercle of atlas (C1) Tympanic bulla Transvese process (wings) of atlas Spinous process of axis (C2) Ventral tubercle of atlas Dorsal & ventral borders of vertebral canal Cranial articular process of C4 Caudal articular process of C3 Endotracheal tube within trachea Intervertebral foramen between C4 &C5 Intervertebral disc space between C4 &C5 Extended plate of transverse process of C6

Yorkshire Terrier cervical spine : Lateral view, flexed position Another radiograph of the same Yorkshire terrier made with the head ventroflexed shows that flexion occurs at the occipitoatlantal joint (“yes” joint) but not at the atlantoaxial joint (“no” joint). This appearance is normal. In dogs suspected of having atlantoaxial subluxation, abnormal displacement of C1 may occur when the neck is manipulated, typically producing a widened gap between C1 and C2 in a ventroflexed lateral radiograph like this. Full Screen Labels Pot

No Labels Dorsal tubercle of atlas (C1) Tympanic bullae Transverse process (wings) of atlas Spinous process of axis (C2) Endotracheal tube within trachea Atlanto - occipital condyle External occiptal protruberance © Royal Veterinary College 2009

Puppy cervical spine : Lateral view Just as in the limb bones, open physes are normally visible in the vertebral bodies in dogs less than 9 months old. Each vertebral body (except C1) has two physes. Full Screen Labels Pot

No Labels Atlas (cervical vertebrae 1) Spinous process of axis (C2) Dorsal & ventral borders of vertebral canal Endotracheal tube within trachea Intervertebral disc space between C4 &C5 Dorsal spinous process of C7 Open physes of C3

Cervical spine survey : Lateral view This lateral radiograph of the cervical spine shows the normal features of the 7 cervical vertebrae. C2 (axis) is the easiest to recognise because of its large dorsal spine. Immediately cranial to it is the spineless dorsal lamina of C1 (atlas). The wings of the atlas are superimposed over the cranial aspect of the body of C2. The cervical vertebrae are well aligned and the intervertebral spaces are regular in width. C6 is recognisable because of the large bent transverse processes, which project ventral to the vertebral body in a lateral radiograph. Full Screen Labels Pot

No Labels Dorsal tubercle Lateral vertebral foramen Stylohyoid bone Tympanic bulla Occipital condyle Atlas (cervical vertebrae 1) Transvese process (wings) of atlas Spinous process of axis (C2) Ventral tubercle of atlas Dorsal & ventral borders of vertebral canal Cranial articular process of C4 Caudal articular process of C3 Transvese process axis (C2) Cr. & Cd. Transverse processes Endotracheal tube within trachea Intervertebral foramina between C4 &C5 Intervertebral disc space between C4 &C5 Extended plate of transverse process of C6 Dorsal spinous process of C7

Cervical myelogram : Lateral view Injection of contrast medium into the subarachnoid space of the same dog as in the cervical spine survey image outlines the spinal cord, which is now visible as a lucent space between the two thin contrast lines. The ventral contrast line bends slightly dorsal above the intervertebral spaces, most noticeable at C2-3 and C6-7; this appearance is normal. Full Screen Labels Pot

No Labels Atlas (cervical vertebrae 1) Transvese process (wings) of atlas Spinous process of axis (C2) Dorsal & ventral borders of vertebral canal Transvese process axis (C2) Endotracheal tube within trachea Intervertebral disc space between C4 &C5 Extended plate of transverse process of C6 Dorsal spinous process of C7 Contrast media within subarachnoid space

Thoracic region Thoraco-lumbar myelogram : Lateral view, large dog Thoraco-lumbar spondylosis : Lateral view

Thoraco-lumbar myelogram : Lateral view, large dog The thoracolumbar region (T11-L2) is a frequent site of disc prolapse in dogs. This radiograph show the normal appearance of a thoracolumbar myelogram in a large breed dog. The contrast lines are regular and gently curved, with no sign of deviation over the intervertebral spaces. It is normal for the dorsal contrast line to be thicker than the ventral. This radiograph is slightly oblique - as you can see from the lack of superimposition of the ribs (ribs on one side projected dorsal to contralateral ribs) - but this is not a major problem; in a perfect lateral both sets of ribs may be superimposed over the myelogram, making it hard to see clearly. It is sometimes easier to see the myelogram in a slightly oblique radiograph like this. Full Screen Labels Pot

Spinous process Tubercle Head Caudal articular process Angle Body Vertebral body Neck

No Labels Caudal articular process Cranial articular process Dorsal spinous process Thoracic vertebrae 13 Transverse process of L3 Dorsal & ventral borders of vertebral foramen Intervertebral foramina Contrast medium within the subarachnoid space

Thoraco-lumbar spondylosis : Lateral view In middle aged or old dogs (and cats), exostoses are frequently observed arising from the ventral and lateral aspects of the vertebral bodies adjacent to the end-plates. These exostoses can be quite large and pointed and extend ventral to the intervertebral space, sometimes bridging the space with solid bone. This condition is called spondylosis deformans. It is not a cause of clinical signs. Full Screen Labels

No Labels Caudal articular process Cranial articular process Dorsal spinous process Thoracic vertebrae 13 Exostoses Transverse process of L3 Dorsal & ventral borders of vertebral foramen Intervertebral foramina

Lumbar region Lumbar spine : Lateral view Lumbar myelogram : Lateral view Lumbar epidurogram : Lateral view

Lumbar spine : Lateral view This lateral radiograph of the lumbar spine shows the normal features of the 7 lumbar vertebrae, which are well aligned and the intervertebral spaces are regular in width. L7 is often a bit shorter than the others, although that is not very noticeable in this dog. Full Screen Labels Pot

Mamillary process Accessory process Spinous process Vertebral body Transverse process

No Labels Caudal articular process Cranial articular process Dorsal spinous process 1 st Lumbar vertebrae Vertebral body Transverse process of L4 Dorsal & ventral borders of vertebral foramen Wings of the ilium Sacrum Intervertebral foramina L7

Lumbar myelogram : Lateral view This lumbar myelogram shows the very regular, almost straight, contrast lines that we see in large breed dogs. Note that the ventral contrast line goes over each intervertebral space (i.e. over each disc) without any dorsal deviation. Also note the gradually tapered thecal sac, which contains the cauda equina. In this dog it terminates at the cranial aspect of the sacrum. Full Screen Labels Pot

No Labels Caudal articular process Cranial articular proc

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