Unit III - Sternum & Clavicle

Question 1

What muscle attaches to the superior surface of the sternum?

Answer 1

Sternocleidomastoid muscle

attachment: lateral aspect of mastoid process & superior nuchal line –> manubrium & medial 1/3 clavicle
function: flexion of head & neck, contralateral rotation of head
innervation: accessory n.
blood supply: occipital, posterior auricular, superior thyroid, suprascapular a.

Question 2

What muscle attaches to the anterior surface of the manubrium?

Answer 2

Sternocleidomastoid muscle

attachment: lateral aspect of mastoid process & superior nuchal line –> manubrium & medial 1/3 clavicle
function: flexion of head & neck, contralateral rotation of head
innervation: accessory n.
blood supply: occipital, posterior auricular, superior thyroid, suprascapular a.

Question 3

What muscles attach to the posterior surface of the manubrium?

Answer 3

(1) sternohyoid muscle
attachment: posterior side of proximal clavicle & manubrium –> inferior border of body of hyoid
function: depresses the hyoid
innervation: ansa cervicalis
blood supply: superior thyroid a.

(2) sternothyroid muscle
attachment: posterior aspect of manubrium –> thyroid lamina
function: depression of elevated larynx
innervation: ansa cervicalis
blood supply: superior thyroid a.