Muscles of the Thoracic Region - Listed
Alphabetically
|
| Muscle |
Origin |
Insertion |
Action |
Innervation |
Artery |
Notes |
| diaphragm |
xiphoid process, costal margin, fascia over the
quadratus lumborum and psoas major mm.(lateral & medial arcuate
ligaments), vertebral bodies L1-L3 |
central tendon of the diaphragm |
pushes the abdominal viscera inferiorly, increasing the
volume of the thoracic cavity (inspiration) |
phrenic nerve (C3-C5) |
musculophrenic a., superior phrenic a., inferior
phrenic a. |
left crus attaches to the L1-L2 vertebral bodies, the
right crus attaches to the L1-L3 vertebral bodies |
| external intercostal |
lower border of a rib within an intercostal space |
upper border of the rib below, coursing, downward and
medially |
keeps the intercostal space from blowing out or sucking
in during respiration |
intercostal nerves (T1-T11) |
intercostal a. |
11 in number; they extend from the tubercle of the rib
to the costochondral junction; continuous with the external intercostal
membrane anteriorly |
| innermost intercostal |
upper borders of a rib |
fibers course up and medially to insert on the inferior
margin of the rib above |
keeps the intercostal space from blowing out or sucking
in during respiration |
intercostal nerves (T1-T11) |
intercostal a. |
innermost intercostal mm. have the same fiber direction
as the internal intercostal mm., the only difference being that they lie
deep to the intercostal neurovascular bundle |
| internal intercostal |
upper border of a rib |
lower border of rib above, coursing up and medially |
keeps the intercostal space from blowing out or sucking
in during respiration |
intercostal nerves (T1-T11) |
intercostal a. |
11 in number; they extend from the margin of the
sternum to the angle of the rib; continuous posteriorly with the
internal intercostal membrane |
| levatores costarum |
transverse processes C7-T11 |
rib below its origin, medial to the angle |
elevates the rib |
dorsal primary rami of spinal nerves C7-T11 |
deep cervical a., intercostal aa. |
these are fairly small and insignificant muscles |
| subcostalis |
angle of ribs |
angle of a rib 2-3 ribs above origin |
compresses the intercostal spaces |
intercostal nerves |
intercostal a. |
subcostalis, transversus thoracis & innermost
intercostal mm. make up the deepest intercostal muscle layer |
| transversus thoracis |
posterior surface of the sternum |
inner surfaces of costal cartilages 2-6 |
compresses the thorax for forced expiration |
intercostal nerves 2-6 |
internal thoracic a. |
transversus thoracis, subcostalis & innermost
intercostal mm. make up the innermost intercostal muscle layer |
Potete
inviare a