1. Anatomy and Physiology
West Chester University
Spring 2014

2. CN V: Trigeminal
• CN V primarily responsible for mastication and sensation to the
face. Innervating the tensor velar palatine, partially responsible for
flattening and tensing of the soft palate and opening of the
eustachian tube. Innervating an extrinsic laryngeal muscle (the
anterior belly of the digastric) it also assists in the upward and
anterior movement of the larynx.
• Testing: unilateral paralysis of CN V=deviation of the jaw to the side
of the lesion and an inability to force the jaw to the opposite side of
the lesion. Problems result from lower motor neuron lesions. UMN
lesions that are unilateral do not affect cranial nerves since nuclei
receive so many axons from the hemisphere.
• Sensory component to be tested: eyes closed and a cotton swab is
used to stoke the face in 3 different areas of the nerve.

3. CN VII: Facial
• Facial nerve responsible for all movements of facial expression.
• CN VII enables you to wrinkle your forehead, close your eyes tightly,
close your mouth tightly, pull back the corners or your mouth and
tense your cheeks, pull down the corners of your mouth and tense
your anterior neck muscles.
• Facial nerve also assists in pulling the larynx yp and back. Provides
motor innervation to the sublingual and submaxillary salivary
glands, guards the middle ear by innervating the stapedius muscle
which dampens excessive movement of the ossicles in the presence
of a loud noise. Also is partially responsible for taste.
• See pg. 147-148 Neurology of Speech Pathology for motor testing

4. CN VIII: Vestibulocochlear
CN IX: Glossopharyngeal
• CN VIII-takes afferent information from the internal ear
to the nervous system. Responsible for sound
sensitivity and changes in equilibrium. Testing
vestibular function is not for the speech pathologist.
• CN IX-efferent to one muscle only-the stylopharyngeus.
This muscle dilates the pharynx laterally and
contributes to the elevation of the pharynx and larynx.
Helps to clear the pharynx and larynx for swallowing.
Testing: most of the functions of CN IX cannot be
tested separately from those of CN X as the vagus has
the predominant control over laryngeal and pharyngeal
sensory and motor function-testing the gag-see pg. 151
of Neurology for Speech/Language Pathology.

5. CN X: Vagus
• Vagus means “wanderer”
• Testing: Palatal fx: palate at rest, palatal archesobserve symmetry, phonate “ah”; gag reflex;
Laryngeal function eval by direct or indirect
laryngoscopy to assess vocal cords, finer analysis
of vocal cord movement using laryngeal
stroboscopy-damage to the vagus nerve may
cause paralysis or paresis of the vocal cord.
Preliminary assessment of laryngeal function
done through clinical voice eval-pg. 153/154
Neurology for SLP

6. CN XI: Spinal Accessory
CN XII: Hypoglossal
• CN XI: primary function is motor to help turn, tilt and thrust forward
the hear or raise the strenum and clavicle if the head is in a fixed
position and to the trapezius muscle responsible for shrugging the
shoulders.
• CN XII: innervates the muscles for tongue movement: four intrinsic
muscles of the tongue control tongue shortening, concaving
(turning the tip and lateral margins upward), narrowing, elongating
and flattening. Extrinsic muscles for tongue protrusion
(genioglossus), drawing the tongue upward and backward
(styloglossus), retraction and depression of the tongue
(hyoglossus), the hyloglossus acts with the chondroglossus to
elevate the hyoid bone, thus participating in phonation. Testing: pg
156/157/158
• Cranial nerve assessment critical for swallowing and speech
production. Motor exam for swallowing should consist of the same
maneuvers as for speech exam.

7. Development
• Week 1-Fertilization-zygote is formed (union of sperm and ova),
slowly divides via mitotic division; blastocyst attaches to uterine
lining (endometrium)
• Week 2- blastocyst becomes completely implanted; 3 preliminary
structures begin to form
• Week 2.5 (day 18) neural groove-forms with folds on either side,
neural plate-thickening of embryonic ectoderm, neural crest cellsform the sensory ganglia; in the head region neural crest cells
migrate into the pharyngeal arches
• Week 3-follows the frist missed menstrual period, embryo
develops:endoderm,mesoderm,ectoderm; neural vesicles visible at
3 weeks-prosencephalon (forebrain), mesencephalon (midbrain),
rhombencephalon (hindbrain)
• Week 4- cranial 2/3 of neural tube develop into a future brain,
caudal 1/3 will become the spinal cord

8. Development
• Weeks 6-12-cerebral hemisphere
• Programmed cell death: more neurons than are needed are made
during development-neurons unsuccessful at making their
connections are then lost by a pre-programmed neuronal cell
death.
• Schizencephaly-split brain-showed asymmetry for speech and
language functions indicating that the corpus callosum plays a role
in transmitting language and experiments led to speculations that
the two hemispheres function differently but integrated in brain
function
• Spina bifida-divided spinal column, failure of caudal part of the
neural tube closure
• Synaptic plasticity-modifications to neuronal connections after
development is complete; can be made as an alternative pathway if
damage occurs (therapy)

10. White Matter
• Subcortical-myelinated axons, relay system of
motor impulses to the spinal cord, muscles
and brain; makes up 60% of the brain;
consumes 6% of the cerebral oxygen
• Motor and sensory pathways

11. Grey Matter
• Cortex
• Master commander-where motor function
originates
• Brain surface-6 layers
• Makes up 40% of the brain
• Consumes 94% of the cerebral oxygen

12. Definitions
• Neurophysiology-study of the chemical process of
the neurosystem and why it works
• Neuropsycholgy-psychologist who specializes in
the study of mood/affect disorders due to
damage of the nervous system
• Neuroscience: study of anatomical structures,
cellular functions and physiological processes of
the nervous system; focuses on the foundation of
normal brain function (thus making the
identification of abnormal sites/functions easier

13. Terms of orientation
• Planes of reference:
*defined relative to imaginary axes of the
body-you can rotate a structure in space and still
discuss
the orientation of its parts.
*Frontal section or frontal view-divides the
body into the front and back sections
*Frontal or coronal view-divides the body into
front and back

14. Terms of orientation
*Sagittal section-divides the body into right
and left halves
*Transverse section-divides the body into
upper and lower halves.
*Anterior (ventral)-front surface of the body
*Posterior (dorsal)-toward the back
*Peripheral-away from the center
*Superficial-confined to the surface

15. *Reference for an organ-deep to another-closer to the axis of the
body
-distal-away from the midline
-medial-toward the midline
-Prone-on the belly/in a horizontal position
with the face down
-Supine-on the back/body in a horizontal
position with the face up

16. • Horizontal or transverse
• Vertical or coronal
• Diagonal

17. DIRECTIONALITY SELF TEST
• Using your hands in relation to yourself:
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Show SUPERIOR TO YOUR HEAD
INFERIOR TO YOUR BODY
ANTERIOR TO YOUR FACE
POSTERIOR TO YOUR HEAD
ABDUCT YOUR ARM
ADDUCT YOUR ARM
DIVIDE YOUR FACE SAGITTALY
DIVIDE YOUR FACE TRANSVERSLY
POINT TO THE MEDIAL ALSPECT OF YOUR FACE
POINT TO THE LATERAL ASPECT OF YOUR FACE

18. Body Planes

19. Why Is This Important?
• Good question!
• All clinicians working with anatomical
structures should know position to self and in
relation to others
• Why? For assessment, documentation and
treatment purposes

20. Nervous Tissue
• Nervous tissue is a highly specialized
communicative tissue
• Nervous tissue consists of neurons or nerve cellsbuilding block cells of the nervous system, comes
in many sizes and shapes, brain has 100 billion
neurons
• Function of nervous tissue is to transmit
information from one neuron to another, from
neurons to muscles or from sensory receptors to
other neural structures

21. Nervous System
• The basic unit of the nervous system are
neurons. All structures are made up of
neurons
• Nervous tissue-neurons which transfer
information; a communicating tissue; glial
cells-support tissue-without glial cells the
neurons would be incapable of storing
information in long term memory,; critical in
development of synapses which initiates
communication between neurons

22. Central Nervous System
• CNS includes the brain-(cerebrum, cerebellum, sub
cortical structures, brainstem) and the spinal cord; all
of the CNS components are housed within bone-skull
or vertebral column
• Cerebrum/cerebral cortex-most complex structure of
the nervous system- all conscious sensory awareness
and motor function, including perception, awareness,
motor planning, preparation, cognitive function,
attention, decision-making, voluntary motor inhibition,
language and speech function.
• The brain is categorized into the autonomic nervous
system and the somatic nervous system

23. Autonomic Nervous System
• The autonomic nervous system (ANS) governs involuntary
activities of the visceral muscles or “viscera” including
glandular secretions, heart functions, digestive functions
• ANS may be further divided into two subsystems:
• sympathetic system-responds to stimulation through
energy expenditure; sympathetic responses include
vasoconstriction (constriction of blood vessels-increase in
blood pressure, dilation of pupils, cardiac acceleration
(fight or flight responses)
• Parasympathetic system-”conserves energy”- which
counters the responses of the sympathetic systemparasympathetic responses include slowing the heart rate,
decreasing blood pressure and constriction of pupils.

24. Somatic Nervous System
• Somatic nervous system-voluntary bodily
functions-under our conscious control

25. Embryology
• During the 4th week of embryonic development the brain
(encephalon) is composed of the prosencephalon
(forebrain), mesencephalon (midbrain) and
rhombencephalon (hindbrain)
• Brain or encephalon further differentiates into the:
• Telencephalon-cerebral hemispheres
• Diencephalon-thalamus/hypothalmus
• Mesencephalon-midbrain
• Metencephalon-pons, cerebellum. The term bulb/bulbar
refers to the pons and medulla but is often used to refer to
the entire brainstem, including the midbrain
• Myelencephalon-medulla oblongata

26. Cranial Nerves
• Cranial nerves are represented by roman
numerals and represent the inverse height in the
brainstem. CN’s 1-4 are at the level of the
midbrain; CN’s V-VIII are at the level of the pons;
CN’s IX-XIII are found in the medulla.
• Cranial nerves are based on 7 categories
• Cranial nerve functions are divided into general
and special with areas of service being somatic
and visceral. Nerves can be efferent, afferent or
mixed efferent/afferent

27. Cranial Nerves
• CN I-Olfactory Nerve (Special Visceral Afferent)not a true cranial nerve because it reaches the
brain without passing through the thalamus.
Mediates the sense of smell (olfaction)
• CN II-Optic Nerve (Special Somatic Afferent)associated with the visual system
• CN III-Oculomotor Nerve (General Somatic
Efferent/General Visceral Efferent)=GSE-all
extrinsic ocular muscles except superior oblique
and lateral rectus; GVE=light and accommodation
reflexes (pupil restriction and focus)

28. Cranial Nerves (cont.)
• CN IV-Trochlear nerve (General somatic efferent) arises
from the trochlear nucleus of the midbrain and
innervates the ipsilateral superior oblique muscle of
the eye which turns the eye down and slightly out.
• CN V-Trigeminal nerve (general somatic
afferent/special visceral efferent)-important mixed
nerve for speech production-provides motor supply to
the muscles of mastication and transmits sensory
information from the face. The nerve arises from the
the motor trigeminal nucleus and sensory nucleus of
the trigeminal within the upper pons and emerging
from the pons at the level of the superior margin of the
temporal bone. The nerve divides into 3 components:

29. Cranial Nerves (con’t)
• CN V-Trigeminal Nerve (con’t)
•
opthalmic branch-entirely sensory; the GSA
•
component transmits general sensory info
from the cornea, iris, upper eyelid, front of scalp
•
•
•
•
•
Maxillary branch-only sensory-the GSA
component transfers info from lower eyelid,
nose, palate, upper jaw
Mandibular branch-sensory and motor-GSA
component transfers info from lower jaw and teeth, mucosa, cheeks,
temporomandibular joint, anterior two thirds of the tongue; SVE
component transfers info
•
to the muscles of mastication (internal and external pterygoid,
temporalis, masseter) tensor tympani NOTE: taste is not mediated by the
trigeminal nerve but pain from biting the tip of your tongue is.

30. Cranial Nerves (con’t)
• CN VI-Abducens (General Somatic Efferent)-lateral
rectus muscle for ocular abduction
• CN VII-Facial Nerve (SVE,SVA,GVE) this nerve provides
efferent innervation to the facial muscles of expression
and tear glands, sense of taste for a portion of the
tongue. It communicates the X vagus, V trigeminal, VIII
vestibularcochlear and IX glossopharyngeal nerves;
SVE-to facial muscles of expression, platysma,
buccinator; SVA-taste, anterior two-thirds of the
tongue; GVE-lachrymal gland (tears) mucous
membrane of mouth and nose

31. Cranial Nerves (con’t)
• CN VIII-Vestibulocochlear Nerve (SSA)-auditory nervevestibular branch and acoustic branch/cochlear
sensation-mediates auditory information and sense of
movement in space.
• CN IX-Glossopharyngeal Nerve (GSA,GVA,SVA,GVE,SVE)
sensory and motor functions; GVA-somatic
(tactile,thermal,pain sense) from posterior one third of
tongue, tonsils, upper pharynx, Eustachian tube,
mastoid cells; SVA-taste, posterior one third of tongue;
GSA-somatic sense of external auditory meatus and
skin of ear; SVE-innervation of stylopharyngeus,
superior pharyngeal constrictor; GVE-innervation of
parotid gland for salivation

32. Cranial Nerves (con’t)
• CN X-Vagus Nerve (GSA,GVA,SVA,GVE,SVE)motor and sensory-GSA-cutaneous sense from
external auditory meatus; GVA-sensory from
pharynx, larynx, trachea, esophagus, viscera of
thorax, abdomen; SVA-taste buds near
epiglottis and valleculae; GVE-to
parasympathetic ganglia, thorax, abdomen;
SVE-striated muscles of larynx and pharynx

33. Cranial Nerves (cont.)
• CN XI-Accessory Nerve (SVE) Cranial portion joins with
the X Vagus to form recurrent laryngeal nerve to
innervate intrinsic muscles of larynx; spinal portion
innervates sternolcleidomastoid and trapezius
• CN XII-Hypoglossal Nerve (GSE)-innervation to the
motor function of the tongue-each hypoglossal nucleus
served by the contralateral corticbulbar tract- NOTE:
lesion of LMN produces ipsilateral damage (tongue
deviates toward side of damage)because fibers of the
corticobulbar tract decussate before reaching the
hypoglossal necleus; left UMN damage=right tongue
weakness

34. Classes of Cranial Nerves
• GSA General Somatic Afferent (sensory)-related to pain,
temperature, mechanical stimulation of somatic structures
(skin,muscles,joints)
• GSA General Somatic Efferent (motor) innervates skeletal (striated)
muscles
• GVA General Visceral Afferent (sensory)from receptors in visceral
structures (e.g digestive tract)
• GVE General Visceral Efferent (motor) autonomic efferent fibers
• SSA Special Somatic Afferent –special senses-sight, hearing,
equilibrium
• SVA Special Visceral Afferent-special senses of smell, taste
• SVE Special Visceral Efferent-innervation of muscle of branchial arch
origin: larynx, pharynx, face

35. Swallowing
• Gustation-(taste)-taste derives the desire to continue
eating which fulfills nutritional requirements. Taste
receptors (taste buds) are a class of sensors known as
chemoreceptors which respond when specific
chemicals come in contact with them
• Zones of taste receptors-sweet tastes being sensed at
the tip, salty ath the sides in front and sour at the sides
in the back, bitterness on the posterior tongue; reality
is that all tastes can be sensed all over the tongue
• Papillae are prominences on the tongue, pink or gray in
color and make the tongue look rough.

36. Swallowing
• Taste is mediated by 3 cranial nerves-VII facial nerve=sense
of taste from the anterior 2/3rd’s of the tongue involving
sweet, salty, sour sensations; IX glossopharyngeal nerve
transmits primarily bitterness information from the
posterior 1/3rd of the tongue; VII facial innervates the taste
receptors of the palate; X Vagus innervates the taste
receptors of the epiglottis and esophagus
• Tastes elicit salivation as well as ingestive responses
including tongue protrusion to receive the food, release of
insulin, mastication and deglutition. Bitter and sour tastes
typify poisons and often will elicit protective responsesgagging, coughing, apnea, salivation-tastes can elicit motor
responses than may or may not be under volitional (or
conscious) control

37. Swallowing
• Olfaction (smell)plays a role in appetite and taste-olfactory sensors
last about 60 days before being replaced by new sensors
• Tactile (touch) mediated by mechanoreceptors which are sensors
that are sensitive to physical contact. 4 classes of thermal stimwarm, hot, cool, cold
• Salivation (production and release of saliva into the oral cavity)-a
motor response, essential component of taste, mastication,
deglutition-when saliva mixes with tasteless starch, the
combination produces sugars that taste sweet and make the food
more desirable. Product of 3 major glands-parotid, submandibular,
sublingual
• Glands are activated by the stimulation of taste receptors (anterior
2/3rds of the tongue), mediated by VII facial nerve (sublingual and
submandibular) and IX glossopharyngeal nerve (parotid gland)