Lec.7,intercostal spaces

Anatomy for physical Therapy and Respiratory Care under graduate students

1. Prepared by:
Dr. Kamal Motawei
THORAX
Thoracic Wall
College of Medicine
Anatomy Dept.
2013-2014

2. 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

3. 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.

6. 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.

7. 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.

8. deepest layer; it is
incomplete layer.
It is represented by
three patches; anterior,
lateral and posterior.
It crosses more than
one intercostal space.

9. Action
1) narrow the intercostal spaces.
So, they either raise or lower
ribs according to which rib is
more stable, the 1
st
or the 12
th

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

11. 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.

12. Posterior Intercostal
veins:
Rt. side: into azygos vein
Lt. side: hemiazygos veins
Anterior intercostal
veins:
Drain into the internal
thoracic vein & the
musculophrenic v.

14. Internal thoracic artery:
Origin: 1
st
part of the subclavian
artery
Course: deep to the costal
cartilages a finger breadth
lateral to the edge of the
sternum
Ends in the 6
th
intercostal space
by dividing into 2 branches.
Branches:
Anterior intercostal arteries
Perforating arteries
Mediastinal a.
Pericardiacophrenic artery
Superior epigastric a
Musculophrenic a

16. 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 (7
th
-11
th)

17. The 1
st
intercostal nerve has no cutaneous
branches. Also, most of the primary ramus
share in the brachial plexus
The lateral cutaneous br. of the 2
nd
intercostal
nerve is called intercostobrachial nerve as it
communicates with medial cutaneous nerve of
the arm
The 7
th
to the 11
th
nerves supply the anterior
abdominal wall.

18. Needle thoracostomy
Tube thoracostomy
Thoracotomy
Intercostal nerve block

19. Intercostal muscles
Diaphragm
Levator costarum
Serratous posterior
superior
Serratous posterior
inferior