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