Lec.7,intercostal spaces

Prepared by: Dr. Kamal Motawei

THORAX

Thoracic Wall College of Medicine

Anatomy Dept.

2013-2014

The thoracic wall is formed by: Posteriorly: thoracic

vertebrae Laterally: ribs and

intercostal spaces Anteriorly: sternum

& costal cartilages. Superiorly: thoracic

outlet and suprapleural membranes

Inferiorly: diaphragm

Def.: spaces between the ribs (also, between the costal cartilages anteriorly).

So, they are 11 in number.

Each space contains: Intercostal muscles:

external, internal and innermost.

Intercostal vein, artery and nerve (VAN) in the neurovascular plane; between the internal intercostal and the innermost intercostal muscles.

Superficial layer; its

fibers are directed downward and forward from the inferior border of the rib above to the upper border of the rib below.

It extends from the rib tubercle behind to the costochondral junction in front, where it is replaced by the anterior intercostal membrane.

Intermediate layer; its

fibers are directed downward and backward from the subcostal groove of the rib above to the upper border of the rib below.

It extends from the sternum in front to the angles of the ribs behind, where it is replaced by the posterior intercostal membrane.

deepest layer; it is incomplete layer.

It is represented by three patches; anterior, lateral and posterior.

It crosses more than one intercostal space.

Action 1) narrow the intercostal spaces. So, they either raise or lower

ribs according to which rib is more stable, the 1st or the 12th

This means they are responsible for inspiration and forced expiration.

2) Their tone prevents sucking and bulging of the intercostal spaces during inspiration and expiration.

Nerve supply: Intercostal nerves and their

collateral branches

Posterior Intercostal Arteries: Upper 2: br. from the

superior intercostal a. of the costocervical trunk of the subclavian a.

Lower 9: from the descending aorta

Anterior intercostal arteries: (2 in each space)

Upper 6: from the internal thoracic a.

Lower 5: from the musculophrenic a.

Posterior Intercostal veins: Rt. side: into azygos vein

Lt. side: hemiazygos veins

Anterior intercostal veins: Drain into the internal

thoracic vein & the musculophrenic v.

Internal thoracic artery: Origin: 1st part of the subclavian

artery Course: deep to the costal

cartilages a finger breadth lateral to the edge of the sternum

Ends in the 6th intercostal space by dividing into 2 branches.

Branches: Anterior intercostal arteries Perforating arteries Mediastinal a. Pericardiacophrenic artery Superior epigastric a Musculophrenic a

Anterior primary rami of the upper 11 thoracic nerves.

Branches: White and gray rami

communicants

Collateral br.

Lateral cutaneous br.

Anterior cutaneous br.

Muscular br.

Pleural sensory branches

Peritoneal sensory branches (7th -11th)

The 1st intercostal nerve has no cutaneous branches. Also, most of the primary ramus share in the brachial plexus

The lateral cutaneous br. of the 2nd intercostal nerve is called intercostobrachial nerve as it communicates with medial cutaneous nerve of the arm

The 7th to the 11th nerves supply the anterior abdominal wall.

Needle thoracostomy

Tube thoracostomy

Thoracotomy

Intercostal nerve block

Intercostal muscles

Diaphragm

Levator costarum

Serratous posterior superior

Serratous posterior inferior