A muscle that flexes and adducts the wrist is the a. palmaris longus b. flexor carpi ulnaris c. flexor digitorum d. flexor carpi radialis
The correct answer and explanation is:
Correct Answer: b. flexor carpi ulnaris
Explanation (300 words):
The flexor carpi ulnaris is the correct answer because it performs both flexion and adduction of the wrist. To understand this, let’s break down the function and anatomy of the relevant muscles:
1. Flexor Carpi Ulnaris:
- Location: Runs along the ulnar (medial) side of the forearm.
- Primary Functions:
- Flexes the wrist (bends the hand toward the forearm).
- Adducts the wrist (moves the hand toward the midline, or ulnar side, of the body).
- Insertion: Pisiform, hook of hamate, and base of the 5th metacarpal.
Since it pulls the wrist both downward (flexion) and medially (adduction), it’s the only option that does both.
2. Palmaris Longus:
- Function: Primarily assists in flexing the wrist, but does not adduct or abduct.
- Not everyone has this muscle (it is absent in about 10-15% of the population).
3. Flexor Digitorum (Superficialis/Profundus):
- These muscles flex the fingers, especially the interphalangeal joints, and assist in wrist flexion.
- They do not adduct the wrist.
4. Flexor Carpi Radialis:
- Function: Flexes and abducts the wrist (moves it toward the thumb side, or radial side).
- This is the opposite of adduction, so it is not correct.
Conclusion:
Among the listed options, only the flexor carpi ulnaris performs both flexion and adduction of the wrist. This makes option (b) the most accurate and anatomically correct choice.