OVERVIEW OF THORACIC WALL BY ATIBA, Pthoracic artery (branch of the first portion of subclavian artery). • The 7th-9th intercostal space through musculophrenic artery (internal thoracic

OVERVIEW OF THORACIC WALLBY

ATIBA, P.M

ANA 202

GROSS ANATOMY OF THORAX

29/01/2020 Gross Anatomy of Thoracic Wall 1

MUSCLES

EXTERNAL INTERCOSTAL

INTERNAL INETRCOSTAL

INNERMOST INETRCOSTAL

SUBCOSTALIS

TRANSVERSUS THORACIS


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EXTERNAL INTERCOSTALSAttachments: Originate at the lower border of the rib, inserting into the superior border of the rib below.

Actions: Elevates the ribs, increasing the thoracic volume.



EXTERNAL INTERCOSTALS

Actions: Elevates the ribs, increasing the thoracic volume.

Innervation: Intercostal nerves (T1-T11)



Internal

Intercostals

Attachments: Originates from the lateral edge of the costal groove and inserts into the superior surface of the rib below.



Internal

Intercostals

Actions: The interosseous part reduces the thoracic volume by depressing the ribcage, and the interchondral part elevates the ribs.

Innervation: Intercostal nerves (T1-T11).



Innermost

Intercostals

Attachments: Originates from the medial edge of the costal groove and inserts into the superior surface of the rib below.



Innermost Intercostals

Actions: The interosseous part reduces the thoracic volume by depressing the ribcage, and the interchondral part elevates the ribs.

Innervation: Intercostal nerves (T1-T11)



Transversus

Thoracis

Attachments: From the posterior surface of the inferior sternum to the internal surface of costal cartilages 2-6.

Actions: Weakly depress the ribs.

Innervation: Intercostal nerves (T2-T6).29/01/2020 Gross Anatomy of Thoracic Wall 9

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Subcostals

•Attachments: These originate from the inferior surface of the lower ribs, near the angle of the rib. They then attach to the superior border of the rib 2 or 3 below.




Subcostals

•Actions: Depress ribs during forced expiration; Support intercostal spaces and thoracic cage.

•Innervation: Intercostal nerves




BLOOD SUPPLY

The Intercostal spaces are supply by;

• The posterior intercostal artery and

• Two branches of anterior intercostal arteries.




BLOOD SUPPLY

• The Posterior Intercostal arteries supply;

• The first two intercostal spaces through superior intercostal artery (branch of costocervical trunk of subclavian artery).

• The 3rd-11th intercostal space through descending thoracic aorta.




BLOOD SUPPLY

• The Anterior Intercostal arteries supply;

• The 1st-6th intercostal spaces through internal thoracic artery (branch of the first portion of subclavian artery).

• The 7th-9th intercostal space through musculophrenic artery (internal thoracic artery).




Venous drainage

• The corresponding posterior intercostal vein drains into azygos or hemiazygos veins, while the anterior intercostal veins drain into internal thoracic or musculophrenic veins.




Lymphatic drainage

• It is drain into parasternal and intercostal lymph nodes.

• The parasternal and intercostal lymph nodes from the upper thorax drain into bronchomediastinaltrunk




Lymphatic drainage

• The intercostal lymph nodes from the lower thorax drains into the thoracic duct.




NERVE• The thoracic wall is

primarily innervated by the intercostal nerves, which are the anterior rami of spinal nerves of T1-T11 and the anterior ramus of T12 is a subcostal nerve.




ASSIGNMENT

• List other muscles of the thoracic wall.

• Describe the proximal attachment, distal attachment, innervation and main action of the above named muscles.


Documents

OVERVIEW OF THORACIC WALL BY ATIBA, Pthoracic artery (branch of the first portion of subclavian artery). • The 7th-9th intercostal space through musculophrenic artery (internal thoracic