Intrinsic Minus Hand (Claw Hand)

DISCUSSION: The clinical presenatation is consistent with a claw hand deformity characterized by MCP hyperextension and IP joint flexion.

Imbalance between strong extrinsics and deficient intrinsics is the pathoanatomic process of a claw hand, also called intrinsic minus hand deformity. Intrinsic minus hand posture can result from a variety of causes including ulnar or median nerve palsy, Volkmann’s ischemic contracture, leprosy, hereditary motor-sensory neuropathy, failure to splint a crush-injured hand using intrinsic plus posture, or compartment syndrome of the hand, as was the case in this clinical vignette.

Ouellette et al performed a retrospective review of nineteen patients managed with fasciotomy for compartment syndrome of the hand. They found that the most consistent clinical finding in making the diagnosis of compartment syndrome was a tense, swollen hand in an intrinsic minus position.

Dellaero et al, in their review of compartment syndrome of the hand, discuss the etiology, diagnosis, and treatment of acute hand compartment syndrome. They emphasize that the main goal in the management of ischemic contracture is restoration of function; however the return of normal limb functionality is an unlikely result.

Figure A is a clinical photograph showing a classic claw hand deformity. Notice the MCP hyperextension and IP joint flexion.

Incorrect Answers:
1. Answer choice 1 describes the pathoanatomy of swan neck deformity leading to hyperextension of the PIP joint and DIP flexion.
2. Answer choice 2 describes the mechanism for lumbrical plus deformity characterized by paradoxical extension of the IP joints while attempting to flex the digits.
3. Answer choice 3 describes the mechanism for a quadrigia effect characterized by an active flexion lag in multiple digits adjacent to an FDP injury.
4. Answer choice 4 describes the pathoanatomy of an intrinsic plus hand characterized by MCP flexion and IP joint extension.

DISCUSSION: Failure to splint the hand in an intrinsic positive position leads to increased extrinsic finger flexor tension, leading the DIP and PIP joints to have an increasing flexion position. Illustration A and B show a clinical image and illustration of intrinsic minus hand.