2. Structure of the Thoracic Wall
• Outside skin and by muscles attaching the
shoulder girdle to the trunk.
• Inside lined with parietal pleura.
• Framework
Posteriorly :the thoracic part of the vertebral
column
Anteriorly : the sternum and costal cartilages
Laterally : the ribs and intercostal spaces
Superiorly : the suprapleural membrane
Inferiorly : the diaphragm
4. Applied Notes
• Since the sternum possesses red
hematopoietic marrow throughout life, it is a
common site for marrow biopsy.
•
• The sternum may also be split (median
sternotomy) at operation to allow the
surgeon to gain easy access to the heart, great
vessels, and thymus.
5. Ribs
There are 12 pairs of ribs, all of which are attached
posteriorly to the thoracic vertebrae .The ribs are
divided into three categories:
True ribs: The upper seven pairs are attached
anteriorly to the sternum by their costal cartilages.
False ribs: The 8th, 9th, and 10th pairs of ribs are
attached anteriorly to each other and to the 7th rib by
means of their costal cartilages and small synovial
joints.
Floating ribs: The 11th and 12th pairs have no anterior
attachment.
8. Applied Notes
Cervical Rib :
A rib arising from the anterior tubercle of the
transverse process of the seventh cervical
vertebra
occurs in about 0.5% of humans
May be connected to the first rib by a fibrous
band, or may articulate with the first rib.
Pressure the lower trunk of the brachial plexus
the subclavian artery
• Rib Excision
9. Costal Cartilages
• Costal cartilages are bars of cartilage connecting
the upper seven ribs to the lateral edge of the
sternum and the 8th, 9th, and 10th ribs to the
cartilage immediately above. The cartilages of
the 11th and 12th ribs end in the abdominal
musculature.
• The costal cartilages contribute significantly to
the elasticity and mobility of the thoracic walls.
• In old age, the costal cartilages tend to lose
some of their flexibility as the result of
superficial calcification.
10.
11. Thoracic Vertebrae
The 1st and 12th are called atypical and
the rest are typical.
•body (1)
•superior and inferior demifacets (2,3)
•pedicle (4)
•superior and inferior articular processes
(5, 6)
•transverse process (with an articular
process) (7,10)
•lamina (8)
•spinous process (9)
•superior and inferior notches (13,12)
•vertebral canal(14)
•not a bone but an integral part of the
vertebral column is the intervertebral disk
(11)
12. Joints of the Chest Wall
Manubriosternal joint (cartilaginous) Small angular movement.
The xiphisternal joint (cartilaginous) fuses at middle age.
Joints of the Heads of the Ribs
The first rib and the three lowest ribs have a single synovial joint with
their corresponding vertebral body.
the second to the ninth ribs, a synovial joint with the corresponding
vertebral body and that of the vertebra above it.
Joints of the Tubercles of the Ribs a synovial joint with the transverse
process of the corresponding vertebra .
Joints of the Ribs and Costal Cartilages These joints are cartilaginous
joints. No movement is possible.
Joints of the Costal Cartilages with the Sternum
The first costal (cartilaginous) No movement
2nd
-7th
synovial
16. The diaphragm
•The diaphragm
closes the thoracic
outlet and separates
the thoracic cavity
from the abdominal
cavity.
•The diaphragm is
the most important
muscle of the
thoracic wall. During
normal respiration,
this muscle is the
primary component.
17. Arterial Blood Supply to the Thoracic Wall
Three sources of blood supply:
•Axillary
• supreme thoracic (2)
• lateral thoracic (3)
•Subclavian
• superior intecostal
• internal thoracic (or mammary)
artery (1)
• anterior intercostal branches
•Aorta
• intercostal arteries (4)
18. Arterial Blood Supply to the Thoracic Wall
• Each intercostal space : 1 large single posterior
intercostal artery 2 small anterior intercostal
arteries.
• The posterior intercostal arteries :the first two
spaces are branches from the superior intercostal
artery. the lower nine spaces are branches of the
descending thoracic aorta.
• The anterior intercostal arteries :the first six
spaces are branches of the internal thoracic
artery. The anterior intercostal arteries of the
lower spaces are branches of the musculophrenic
artery.
19. Venous drainage of thoracic wall
• The corresponding posterior intercostal veins
drain backward into the azygos or hemiazygos
veins
• the anterior intercostal veins drain forward
into the internal thoracic and musculophrenic
veins.
20. Nerves of the Thoracic Wall
•The thoracic wall is supplied by
the intercostal nerves which are
the anterior primary rami of spinal
nerves.
•spinal cord (1)
•dorsal (sensory, afferent) root (3)
•ventral (motor, efferent) root (2)
•spinal nerve (4)
•dorsal primary ramus (mixed) (5)
•ventral primary ramus (mixed) (6)
•white communicating ramus (8)
•gray communicating ramus (7)
•sympathetic ganglion (9)
21. Applied Notes
• Skin Innervation of the Chest Wall and Referred Pain
Above the level of the sternal angle supraclavicular
nerves (C3 and 4).
Below the level of the sternal angle the anterior and
lateral cutaneous branches of the intercostal nerves
Posteriorly the posterior rami of the spinal nerves
the 7th to 11th intercostal nerves leave the thoracic
wall and enter the anterior abdominal wall : pleurisy
referred pain abdominal pain
• Intercostal Nerve Block
22. Suprapleural Membrane
• It is a dense fascial layer
• Tent-shaped fibrous sheet
• Attached laterally to the medial border of the
first rib and costal cartilage.
• At its apex to the tip of the transverse process of
the seventh cervical vertebra.
• Medially to the fascia investing the structures
passing from the thorax into the neck. It
• Protects the underlying cervical pleura and resists
the changes in intrathoracic pressure occurring
during respiratory movements.
23. Applied Notes
• During Neck surgery (e.g Neck dissection)
injury of the suprapleural membrane may
happen leading to pneumothorax
• Stab wound at the root of the neck
pneumothorax
24. Endothoracic Fascia
• Thin layer of loose connective tissue that
separates the parietal pleura from the
thoracic wall.
• The suprapleural membrane is a thickening of
this fascia.
