Intermediate Back Muscles

Question 1

Intermediate back muscles are (hypaxial/epaxial) meaning they are still innervated by _____ rami. What two muscles are these?

Answer 1

Hypaxial, ventral
Serratus post. Inf.
Serratus post. Sup.

Question 2

What is the origin of Serratus Post. Sup.

Answer 2

Lower ligamentum nuchae
SPs of C7-T2/3

Question 3

What is the insertion of Serratus Post. Sup.

Answer 3

Ribs 2-5 lateral angle

Question 4

What is the innervation of Serratus Post. Sup.

Answer 4

First 4 intercostal nerves (ventral rami of first 4 thoracic nerves)

Question 5

What is the blood supply of Serratus Post. Sup.

Answer 5

Highest intercostal A.
Post. Intercostal Aa.

Question 6

What is the action of Serratus Post. Sup.

Answer 6

Inspiration: elevate ^ribs

Question 7

What is the origin of Serratus Post. Inf.

Answer 7

SPs of T10-L2

Question 8

What is the insertion of Serratus Post. Inf.

Answer 8

Lower 3-4 ribs lateral to angles

Question 9

What is the innervation of Serratus Post. Inf.

Answer 9

Lowest 4 intercostal nerves (ventral rami of lower thoracic)

Question 10

What is the blood supply of Serratus Post. Inf.

Answer 10

Post. Intercostal Aa.

Question 11

What is the action of Serratus Post. Inf.

Answer 11

Inspiration: depress lower ribs down + back