Which one of the following muscles is NOT found in the anterior compartment of the forearm?

Question

BlackTom AI · Accepted Answer

Let’s break down the question by first identifying the anatomical compartments of the forearm. The forearm splits into an anterior (flexor) compartment and a posterior (extensor) compartment, separated largely by the interosseous membrane and the septa. Now assess each option in that context.

Option a: Pronator teres. This muscle originates from the medial epicondyle of the humerus and the ulna, and it crosses the elbow to pronate the forearm. It is classically categorized as an anterior compartment muscle, primarily involved in forearm flexion and pronation. Thus, this option is consistent with the anterior compartment.

Option b: Pronator quadratus. This is a square-shaped muscle located in the distal forearm, lying deep to the flexor muscles and attaching between the distal ulna and radius. It functions chiefly to pronate the forearm and stabilizes the distal radioulnar joint. It belongs to the anterior (flexor-pronator) compartment, so it is not the correct choice for "NOT in the anterior compartment."

Option c: Flexor carpi ulnaris. This muscle runs along the medial side of the forearm and flexes and adducts the hand at the wrist. It is supplied by the anterior compartment of the forearm (ulnar nerve) and is a classic example of an anterior compartment muscle. Therefore, it fits inside the anterior compartment.

Option d: Flexor pollicis longus. Located deep in the anterior forearm, this muscle flexes the thumb (pollex) and is a standard member of the anterior compartment. Its innervation is the anterior interosseous branch of the median nerve. So, this option is also consistent with the anterior compartment.

Option e: Extensor digitorum. This muscle extends the fingers (digits) and is situated in the posterior forearm compartment, together with other extensor muscles that cross the wrist. It is supplied mainly by the posterior interosseous nerve (a branch of the deep radial nerve) and does not belong to the anterior compartment. Therefore, this option is the one that does not belong to the anterior forearm compartment.

In summary, options a, b, c, and d describe muscles located in the anterior compartment of the forearm, each contributing to flexion or pronation. Option e describes a muscle in the posterior (extensor) compartment, making it the correct choice for "NOT found in the anterior compartment."

Which one of the following muscles is NOT found in the anterior compartment of the forearm?

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类似问题

Identify the muscle labelled #6 [ Select ] pronator teres brachialis supinator brachioradialis anconeus and the muscle labelled #7 [ Select ] pronator teres supinator pronator quadratus brachioradialis

The arrow is pointing to the _brachioradialis _, this muscle _can move the forearm (radioulna joints) depending on the forearm position. _.

Question at position 18 The flexor digitorum superficialis originates from the medial epicondyle of the humerus.TrueFalse

Which one of the following muscles is found in the anterior compartment of the forearm?

Identify the indicated muscle.

Posterior forearm muscles generally produce what action?

Which of the following muscles is part of the posterior compartment of the forearm?

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