Anatomy Exam Brachial Plexus Structures 3

Question 1

The long thoracic nerve innervates which muscle and arises from which roots?

Accepted Answer

Serratus anterior; C5, C6, C7

Answer

The long thoracic nerve (of Bell) arises from C5, C6, C7 roots and innervates the serratus anterior.

Question 2

The thoracodorsal nerve innervates the latissimus dorsi and arises from which cord?

Accepted Answer

Posterior cord

Answer

The thoracodorsal nerve is a branch of the posterior cord (C6–C8) and innervates the latissimus dorsi.

Question 3

Which nerve arises from the posterior cord and supplies the teres major and subscapularis?

Accepted Answer

Lower subscapular nerve

Answer

The lower subscapular nerve (C5–C6) innervates both teres major and the lower portion of subscapularis.

Question 4

A patient has loss of sensation over the medial arm. Which nerve is most likely injured?

Accepted Answer

Medial cutaneous nerve of the arm

Answer

The medial cutaneous nerve of the arm (medial brachial cutaneous nerve) provides sensation to the medial surface of the arm.

Question 5

Which division-level structure of the brachial plexus is located posterior to the clavicle?

Accepted Answer

Divisions

Answer

The divisions of the brachial plexus lie posterior to the clavicle, between the trunks and cords.

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