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The muscles of the hand are the skeletal muscles responsible for the movement of the hand and fingers. The muscles of the hand can be subdivided into two groups: the extrinsic and intrinsic muscle groups. The extrinsic muscle groups are the long flexors and extensors. They are called extrinsic because the muscle belly is located on the forearm ...
It tends to separate the fingers as it extends them. In the fingers, the extensor digitorum acts principally on the proximal phalanges, acting to extend the metacarpophalangeal joint . Extension of the proximal and distal interphalangeal joints , however, is mediated predominantly by the dorsal and palmar interossei and lumbricals of the hand .
Some fibers insert into the finger's dorsal aponeurosis, which is why the muscle acts similar to a dorsal interosseus muscle. [ 2 ] Additionally, the ulnar-most portion of the tendon inserts into the little finger's digital cord, and the muscle thus forms part of a structure that flexes the metacarpophalangeal joint and extends the ...
Flexor digitorum profundus originates in the upper 3/4 of the anterior and medial surfaces of the ulna, interosseous membrane and deep fascia of the forearm. The muscle fans out into four tendons (one to each of the second to fifth fingers) to the palmar base of the distal phalanx.
The movements which occur in these joints are flexion, extension, adduction, abduction, and circumduction; the movements of abduction and adduction are very limited, and cannot be performed while the fingers form a fist. [2] The muscles of flexion and extension are as follows:
Pronation at the forearm is a rotational movement at the radioulnar joint, or of the foot at the subtalar and talocalcaneonavicular joints. [ 11 ] [ 12 ] For the forearm, when standing in the anatomical position , pronation will move the palm of the hand from an anterior-facing position to a posterior-facing position without an associated ...
The ED inserts into the middle and distal phalanges to extend the fingers and wrist. Opposite the head of the second metacarpal bone, the EI joins the ulnar side of the ED tendon to extend the index finger. The EDM has a similar role for the little finger. The ECU inserts at the base of the 5th metacarpal to extend and adduct the wrist.
These three muscles form the fleshy mass at the base of the little finger, and are solely concerned with the movement of digit V. The other two muscles that make up the hypothenar muscle group are the abductor digiti minimi and the opponens digiti minimi. In anatomical position from medial to lateral is the abductor digiti minimi, flexor digiti ...