Intermediate Extrinsic

Question 1

Serratus Posterior Superior

Answer 1

Origin: nuchal ligament and spinous processes of C7-T3

Insertion: superior aspect of ribs 2-5

Innervation: ventral rami of upper thoracic nerves

Blood Supply: posterior intercostal arteries

Action: elevates ribs for inspiration

Question 2

Serratus Posterior Inferior

Answer 2

Origin: spinous processes of T11-L2

Insertion: inferior aspect of ribs 9-12

Innervation: ventral rami of lower thoracic nerves

Blood Supply: posterior intercostal arteries

Action: depresses ribs for expiration