Intermediate Back Muscles

Question 1

Serratus posterior superior

Answer 1

Origin: ligamentum nuchae and spines of C7 to T3 vertebrae
Insertion: 2nd to 4th ribs
Nerve: first 3 T-spine nerves
Action: elevates ribs

Question 2

Serratus posterior inferior

Answer 2

Origin: T11 - L2 vertebral spines
Insertion: lower 4 ribs
Nerve: last 4 T-spine nerves
Action: aids in respiration by holding ribs steady when diaphragm moves superiorly