Certified Hand Therapist (CHT) Practice Exam

The correct choice highlights that intrinsic muscles are unique in that they both originate and insert within the confines of the hand itself. This characteristic allows them to control more nuanced movements of the fingers. Intrinsic muscles, including the interossei, lumbricals, and thenar and hypothenar muscles, are primarily responsible for fine motor skills, enabling actions such as gripping, pinching, and intricate finger movements.

Understanding the nature of intrinsic vs. extrinsic muscles is essential. Extrinsic muscles, on the other hand, originate in the forearm and insert into the hand. They primarily enable gross movements such as wrist flexion and extension, as well as finger flexion and extension, but they do not contribute as much to the fine motor control that intrinsic muscles offer. The distinction lies in their anatomical locations and functions, influencing how they contribute to hand movements and stability.