Human Anatomy and Physiology : Identifying Muscles of the Upper Extremities

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

Example Question #21 : Identifying Muscles Of The Upper Extremities

Which muscle is responsible for the extension of the 5th digit in the hand?

Possible Answers:

Extensor carpi ulnaris

Extensor digiti minimi

Extensor digitorum

Extensor carpi radialis brevis

Correct answer:

Extensor digiti minimi

Explanation:

A muscle that would only be responsible for the pinky finger would be a small one. In addition, extensor muscles of the hand are located in the posterior compartment, whereas flexors are located anteriorly. Of the following choices, the smallest muscle is the extensor digits minimi, which is also located posteriorly. It aids in abduction of the 5th digit as well.

Example Question #22 : Identifying Muscles Of The Upper Extremities

The triceps brachii is innervated by which nerve?

Possible Answers:

Ulnar nerve

Radial nerve

Median nerve

Musculocutaneous nerve

Correct answer:

Radial nerve

Explanation:

The correct answer is the radial nerve. This is because the muscle is located in the posterior compartment of the arm, which means we are looking for a nerve that runs deep in the arm. For this reason, the only viable answer choice is the radial nerve.

Example Question #131 : Muscles

What is the innervation of the abductor digiti minimi?

Possible Answers:

Superficial branch of the ulnar branch

Deep branch of the ulnar nerve

Median nerve

Deep branch of the radial nerve

Correct answer:

Deep branch of the ulnar nerve

Explanation:

The abductor digiti minimi is a muscle found in the pinky finger. It is innervated by the deep branch of the ulnar nerve. Its origin is the pisiform and the insertion is the base of the proximal phalanx of the 5th digit on the ulnar side. 

Example Question #22 : Identifying Muscles Of The Upper Extremities

Which muscle does not attach to the coracoid process?

Possible Answers:

Short head of biceps brachii

Pectoralis major

Pectoralis minor

Coracobrachialis

Correct answer:

Pectoralis major

Explanation:

Three muscles attach to the coracoid process in the upper extremity. The pectoralis minor, coracobrachialis, and the short head of biceps brachii all attach to the coracoid process. The pectoralis major does not attach to the coracoid process, but it attaches to the humerus (deltoid also attaches to the humerus).

The musculocutaneous nerve (C5, C6, C7) runs the length of corachobrachialis and brachialis. 

Example Question #23 : Identifying Muscles Of The Upper Extremities

Which of the following wrist extensors is also an elbow flexor?

Possible Answers:

Extensor carpi radialis longus

Extensor carpi ulnaris

Extensor carpi radialis brevis

Extensor digitorum

Correct answer:

Extensor carpi radialis longus

Explanation:

Although all of the muscles listed above extend the wrist, as well as ulnarly or radially deviate the (depending on the muscle and the source being cited), on the extensor carpi radialis longus is able to flex the elbow. The extensor carpi radialis longus attaches more proximally on the humerus than the other wrist extensors, placing it further from the elbow's axis of rotation, which may explain why it can flex the elbow, but the other wrist extensors cannot.

Example Question #24 : Identifying Muscles Of The Upper Extremities

Which of the following muscles receives its primary blood supply from the brachial artery?

Possible Answers:

Subscapularis

Deltoid

Teres minor

Biceps

Teres major

Correct answer:

Biceps

Explanation:

The only muscle listed that receives its primary blood supply from the brachial artery is the biceps (more specifically known as the biceps brachii). 

The other muscles listed receive their blood supply as follows:

Deltoid: Thoracoacromial artery, and anterior and posterior circumflex humeral arteries

Subscapularis: Subscapular artery

Teres major: Subscapular and circumflex scapular arteries

Teres minor: Posterior circumflex humeral artery and circumflex scapular artery

Example Question #141 : Muscles

A patient presents with pain in the anterior portion of their upper arm, a noticeable lump, and cannot perform elbow flexion. What muscle is likely ruptured? 

Possible Answers:

Biceps brachii

Latissimus dorsi

None of these

Triceps brachii

Infraspinatus

Correct answer:

Biceps brachii

Explanation:

The biceps brachii's main action is flexion of the elbow, and therefore would be the most likely ruptured muscle. Triceps brachii, infraspinatus, and latissimus dorsi are all located posterior on the shoulder complex, and therefore would not perform elbow flexion, or result in a lump on the anterior portion of the upper arm. 

Example Question #142 : Muscles

Which upper extremity muscle does not make up the rotator cuff group?

Possible Answers:

Infraspinatus

Teres minor

Teres major

Supraspinatus

Subscapularis

Correct answer:

Teres major

Explanation:

Teres major is not included in the rotator cuff. The rotator cuff muscles insert along the along the head of the humerus, allowing it to move through abduction, internal and external rotation.

Example Question #143 : Muscles

Which muscle originates on the coracoid process?

Possible Answers:

Anterior head of deltoid

Triceps brachii

Biceps brachii

Teres minor

Coracobrachiallis

Correct answer:

Coracobrachiallis

Explanation:

The coracobrachialis originates on the coracoid process, and inserts to the medial shaft of the humerus. The cheat in this question is to look at the base word - coracobrachialis.

Example Question #144 : Muscles

Which muscle(s) is/are the primary mover(s) of scapular retraction?

Possible Answers:

Teres major and teres minor

Latissimus dorsi

Middle trapezius and rhomboids

Pectoralis major

Levator scapulae

Correct answer:

Middle trapezius and rhomboids

Explanation:

The rhomboids, which are located medially to the scapula assist with scapular retraction- or the movement of bringing the scapula medially. In addition, the middle trapezius also allows for this movement due to its insertion on the spine, and covering the scapula. 

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