Weakness due to compression of C6, C7, and C8 nerves will affect what motion?

Weakness due to compression of C6, C7, and C8 nerves will affect what motion?

• A. Abduction of the wrist
• B. Flexion of the wrist
• C. Extension of the wrist
• D. Sensation in the fingers

Answer: (B)

The correct answer is associated with the role of the C6, C7, and C8 nerves in motor function. These nerve roots contribute to the innervation of various muscles in the upper extremity. Specifically, C6 primarily contributes to shoulder and elbow flexion, C7 plays a key role in extension of the elbow and also affects wrist function, and C8 is important for hand function and grip strength. When considering wrist movements, the muscles responsible for flexion (such as the flexor carpi radialis and flexor carpi ulnaris) are predominantly innervated by the median and ulnar nerves, which receive their fibers from the C6, C7, and C8 spinal levels. Thus, compression of these nerve roots would significantly weaken the muscles that allow for flexion of the wrist. This understanding clarifies why weakness due to compression of the C6, C7, and C8 nerves would most directly impact the ability to flex the wrist. This motion involves the contraction of flexor muscles that, if compromised, would lead to decreased strength in wrist flexion.

The correct answer is associated with the role of the C6, C7, and C8 nerves in motor function. These nerve roots contribute to the innervation of various muscles in the upper extremity. Specifically, C6 primarily contributes to shoulder and elbow flexion, C7 plays a key role in extension of the elbow and also affects wrist function, and C8 is important for hand function and grip strength.

When considering wrist movements, the muscles responsible for flexion (such as the flexor carpi radialis and flexor carpi ulnaris) are predominantly innervated by the median and ulnar nerves, which receive their fibers from the C6, C7, and C8 spinal levels. Thus, compression of these nerve roots would significantly weaken the muscles that allow for flexion of the wrist.

This understanding clarifies why weakness due to compression of the C6, C7, and C8 nerves would most directly impact the ability to flex the wrist. This motion involves the contraction of flexor muscles that, if compromised, would lead to decreased strength in wrist flexion.