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ByDr./ Ihab Samy
Lecturer of Surgical OncologyNational Cancer Institute
Cairo University2013
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
Sternum
Applied NotesSince 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.
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.
Typical Rib
Head Neck Tubercle Shaft
Angle
Atypical Rib
•The first rib
•Small and flattened from above downward
Applied NotesCervical 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
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.
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)
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
Muscles of the Thoracic Wall
•External layer external intercostal•Internal layer internal intercostal•Innermost layer Transversus thoracic (anterior) Innermost (lateral) Subcostal (posterior)
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.
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)
Arterial Blood Supply to the Thoracic WallEach 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.
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.
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)
Applied NotesSkin 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
Suprapleural MembraneIt 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.
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
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.
Thank You