Anatomy Exam Brachial Plexus Structures 2

Question 1

Which roots of the brachial plexus form the upper trunk?

Accepted Answer

C5 and C6

Answer

The upper trunk is formed by the union of the C5 and C6 ventral rami.

Question 2

The suprascapular nerve arises from which part of the brachial plexus?

Accepted Answer

Upper trunk

Answer

The suprascapular nerve branches directly from the upper trunk before cord formation.

Question 3

Which nerve of the brachial plexus is most commonly injured in a posterior shoulder dislocation?

Accepted Answer

Axillary nerve

Answer

The axillary nerve is most vulnerable in shoulder dislocations due to its proximity to the surgical neck of the humerus.

Question 4

The medial cutaneous nerve of the forearm is a direct branch of which cord?

Accepted Answer

Medial cord

Answer

The medial cutaneous nerve of the forearm arises directly from the medial cord of the brachial plexus.

Question 5

Which terminal branch of the brachial plexus carries fibers exclusively from C5 and C6?

Accepted Answer

Musculocutaneous nerve

Answer

The musculocutaneous nerve is derived from C5–C7 but its motor contribution to the flexors is predominantly C5–C6.

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