Anatomy Exam Muscles of the Rotator Cuff 2

Question 1

Which rotator cuff muscle is primarily responsible for initiating abduction of the arm (first 15 degrees)?

Accepted Answer

Supraspinatus

Answer

The supraspinatus initiates abduction for the first 15 degrees before the deltoid becomes the primary mover.

Question 2

The infraspinatus muscle inserts onto which part of the greater tubercle of the humerus?

Accepted Answer

Middle facet

Answer

The infraspinatus inserts onto the middle facet of the greater tubercle of the humerus.

Question 3

Which nerve innervates the teres minor muscle?

Accepted Answer

Axillary nerve

Answer

The teres minor is innervated by the axillary nerve (C5, C6), specifically its posterior branch.

Question 4

A patient cannot internally rotate their arm against resistance. Which rotator cuff muscle is most likely injured?

Accepted Answer

Subscapularis

Answer

The subscapularis is the primary internal rotator among the rotator cuff muscles.

Question 5

What is the primary blood supply to the supraspinatus tendon's critical zone?

Accepted Answer

Suprascapular artery

Answer

The suprascapular artery provides the main blood supply to the supraspinatus, though its 'critical zone' near the insertion is relatively avascular.

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