Thoracic Wall Muscles

Question 1

Serratus Posterior Superior

Answer 1

O: Nuchal Ligament; SP of C7-T3
I: Superior Borders of Ribs 2-4
N: Intercostal Nerve 2-5
A: Elevates upper 4 ribs to increase AP diameter of thorax; proprioception

Question 2

Serratus Posterior Inferior

Answer 2

O: SPs of T11-L2
I: Inferior Borders of Ribs 8-12 (at angles)
N: APRs to T9-T12 Thoracic Spinal Nerves
A: Depresses inferior ribs to counteract diaphragm; proprioception

Question 3

Levator Costarum

Answer 3

O: TPs of T7-T11
I: Subjacent ribs between tubercle and angle
N: PPRs C8-T11
A: Elevate ribs

Question 4

External Intercostals

Answer 4

O: Inferior Border of Ribs
I: Superior Border of Ribs below
N: Intercostal Nerve
A: Elevate ribs during forced inspiration

Question 5

Internal Intercostals

Answer 5

O: Inferior Border of Ribs
I: Superior Border of Ribs below
N: Intercostal Nerve
A: Interosseous part: depresses ribs; Interchondral part: elevates ribs; during active (forced) respiration

Question 6

Innermost Intercostal

Answer 6

O: Inferior Border of Ribs
I: Superior Border of Ribs below
N: Intercostal Nerve
A: Interosseous part: depresses ribs; Interchondral part: elevates ribs; during active (forced) respiration

Question 7

Subcostal

Answer 7

O: Internal surface of lower ribs near their angles
I: Superior Borders of 2nd or 3rd ribs below
N: Intercostal Nerve
A: Probably act in same manner as internal intercostal muscles

Question 8

Transversus Thoracis

Answer 8

O: Posterior Surface of Lower Sternum
I: Internal surface of costal cartilages 2-6
N: Intercostal Nerve
A: Weakly depress ribs; proprioception