Question

1. Which of the following muscles functions to MEDIALLY ROTATE the humerus at the glenohumeral joint?

a. pectoralis minor muscle

b. rhomboideus major/minor muscle

c. quadratus lumborum muscle

d, infraspinatus muscle

e. latissimus dorsi muscle

2. sternocleidomastoid muscle, splenius capitus muscle, posterior digastric muscle (and even the longissimus capitus muscle) What do they have in common

a. they are all innervated by the spinal accessory nerve CN XI

b. they all function to rotate the head from side to side

C. they all attached to the mastoid process of the temporal bone

D. A and C

E. all the above

3. Which of the following muscle components of the 'erector spinae' is found most medial (not intermediate) to the other two component muscles?

a. Erector spinae - spinalis muscle

b. Erector spinae - longissimus muscle

C. Erector spinae- iliocostalis muscle

Answer 1

1. Answer is option E. latissimus dorsi

Actions of this muscle are : Extends, adducts, and medially rotates humerus

2. Answer is option C.they all attached to the mastoid process of the temporal bone

The splenius capitis muscle is innervated by the posterior ramus of spinal nerves C3 and C4. Not CN XI. Hence, option A and D are wrong. Not all of these muscles help in rotation of head from side to side. They also help the head to raise and bow. Hence, option B is wrong.

3. Answer is option A.Erector spinae - spinalis muscle

The order of the erector spinae muscles from lateral to the medial are Iliocostalis, longissimus and spinalis in that order.