Muscles Of The Rib Cage

Question 1

Rectus Capitis posterior minor

Answer 1

O: tubercle of posterior arch of the atlas C1
I: medial inferior nuchal line
K: Extends the head @ spinal joints
N: Suboccipital

Question 2

Rotatores

Answer 2

O: TVP of Cervical, thoracic and lumbar regions (C1-C7, T1-12, L1-5)
I: lamina and TVP’s 1-2 segments above
K: stabilizes, extends and rotates the spine @ spinal joints
N: Dorsal Rami of spinal nerves

Question 3

Semispinalis

Answer 3

O: TVP’s of C4-T12
I: SP’s of Cervical and thoracic regions
K: Extension and Contralateral rotation of the head, neck and thorax
N: dorsal rami of spinal nerves

Question 4

Serratus posterior inferior

Answer 4

O: SP of T11-L2
I: inferior aspect of ribs 9-12
K: depression of the ribs 9-12
N: Ventral rami of lower thoracic nerves

Question 5

Serratus posterior superior

Answer 5

O: Ligamentum nuchae, SP’s of C7-T3
I: Superior aspect of ribs 2-5
K: Elevates ribs 2-5 @ sternocostal and costospinal joints
N: Ventral Rami of upper thoracic nerves

Question 6

External intercostals

Answer 6

O: intercostal spaces of ribs 1-12
I: From the inferior border of one rib to the superior border of the rib below
A: Elevate ribs 2-12 @ Sternocostal and costospinal joints
Contralateral rotation of the trunk @ spinal joints
N: Intercostal nerves

Question 7

Internal intercostals

Answer 7

O: intercostal spaces of ribs 1-12
From the superior border of one rib
I: To the inferior border of the rib above
A: Depresses ribs 1-11 at the sternocostal and costospinal joints
N: intercostal nerves

Question 8

Diaphragm

Answer 8

O: internal surfaces of Rib cage (Ribs 7-12), sternum, xiphoid process and L1-L3
I: central tendon of the diaphragm
A: increases the volume (expands) the thoracic cavity during abdominal breathing
RMA: increases the volume (expands) the thoracic cavity during thoracic breathing
N: phrenic nerve C3-C5

Question 9

Transversus Thoracis

Answer 9

O: internal surfaces of the sternum, the xiphoid process and adjacent costal cartilages
I: internal surfaces of costal cartilage 2-6
A: Depresses ribs 2-6 @ sternocostal and costospinal joints
N: intercostal

Question 10

Levatores Costarum

Answer 10

O: TVP’s of C7-T11
I: Ribs 1-12 inferiorly
A: Elevate the ribs at the sternocostal and costospinal joints
N: Dorsal rami of Spinal nerves

Question 11

Subcostales

Answer 11

O: Ribs 10-12 internal surface near the angle
I: Ribs 8-10 internal surface near the angle
A: Depress ribs 8-10 @ sternocostal and costospinal joints
RMA: Elevates ribs 10-12 @ sternocostal and costospinal joints
N: intercostal nerves 8-11