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. 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)
11. 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
13. Muscles of the
Thoracic Wall
•Transversus thoracis
•Subcostal
•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.
14. 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)
15. 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.
16. 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.
17. 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)
18. 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
19. 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.
20. 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
21. 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.
