Download Grip and Pinch

Power grip and pinch are generated through a combination of the intrinsic and
extrinsic hand muscles.
The intrinsic muscles of the hand consist of the interossei (4 dorsal and 3 palmar), the
adductor pollicis muscle, the hypothenar muscles (opponens digiti quinti, flexor digiti
quinti, abductor digiti quinti), the thenar muscles (abductor pollicis brevis, flexor
pollicis brevis, opponens pollicis), and the lumbricals.
The median and ulnar nerves control the performance of the intrinsic muscles.
The ulnar nerve supplies the interossei, adductor pollicis, hypothenar muscles, medial
2 lumbricals, and deep portion of the flexor pollicis brevis.
median nerve innervates the majority of the thenar muscles and the lateral 2
lumbricals.
A low median nerve paralysis affects the thenar muscles of the thumb and the lateral 2
lumbricals. The thumb loses motion and coordination, which will hinder the
formation of opposition pinch and have a deleterous affect on grasp.
Types of pinch
1. Tip pinch
2. Pulp pinch
3. Key pinch
4. Chuck or tripod pinch
Key pinch is the most powerful
Types of grip
1. Hook grip
a. fingers are not completely flexed.
b. A powerful movement used in many activities of daily living, such as
pulling oneself out of a chair.
c. requires functioning MCPJs and at least some amputation stumps of
the proximal phalanges of the fingers.
2. Full grip
a. requires flexion at all the interphalangeal joints, in some instances in
permanently flexed positions.
b. permits one to grasp objects firmly, such as a baseball bat, golf club, or
rung of a ladder.
3. twist grip,
a. probably the most complex type of grip because it requires the breadth
of the palm for torque and pull-through of the flexor tendons for
strength.
b. weakened by narrowing the breadth of the palm with metacarpal
ablations.