Grasping a cup primarily requires muscles innervated by which nerve roots?

Grasping a cup primarily requires muscles innervated by which nerve roots?

• A. C5–C6
• B. C6–C8, T1
• C. L4–L5
• D. T2–T3

Answer: (B)

Grasping a cup relies on the coordinated action of finger flexors in the forearm and intrinsic hand muscles that fine-tune grip. The muscles that flex the fingers (FDS and FDP) receive nerve input from roots around C7–C8 and C8–T1, while the intrinsic hand muscles that position the thumb and spread or stabilize the fingers are innervated by nerves carrying fibers from C8–T1 (with median and ulnar nerves supplying the thenar, lumbricals, and interossei). Because the grip requires these distal finger and hand muscles, the nerve roots involved span from C6 through T1, with the most critical activity centered on C8–T1. Including C6 accounts for proximal contributions that support grip stability, such as wrist flexors. That combination best matches the roots needed for a functional grasp.

Grasping a cup relies on the coordinated action of finger flexors in the forearm and intrinsic hand muscles that fine-tune grip. The muscles that flex the fingers (FDS and FDP) receive nerve input from roots around C7–C8 and C8–T1, while the intrinsic hand muscles that position the thumb and spread or stabilize the fingers are innervated by nerves carrying fibers from C8–T1 (with median and ulnar nerves supplying the thenar, lumbricals, and interossei). Because the grip requires these distal finger and hand muscles, the nerve roots involved span from C6 through T1, with the most critical activity centered on C8–T1. Including C6 accounts for proximal contributions that support grip stability, such as wrist flexors. That combination best matches the roots needed for a functional grasp.