Thumb and index finger pinching dysfunction

Introduction The clinical manifestations of the median nerve in the hand nerve injury, the thumb abduction dysfunction caused by the abductor pollicis of the thumb and the dysfunction of the thumb and forefinger. The innervation of the hand is mainly from the median nerve, the ulnar nerve and the phrenic nerve. Because of the nerve damage, not only will it cause sensory disturbances, but also often involve the movement of the hand and sympathetic nerve function. Therefore, the influence of the opponent's function is great. If it is not treated in time, once the small muscles of the hand shrink, it will Affect the effect of treatment. Therefore, the injury to the hand nerve should be discovered in time and treated in time.

Cause

Causes

Cuts, stab wounds, hand wounds and forearm injuries can cause nerve damage in the hands.

an examination

Related inspection

Flexural extensor muscle strength test thumb-to-the-occipital muscle strength test bone and joint soft tissue CT examination

A more specific auxiliary examination after nerve injury is an electromyogram, but electromyography is often less accurate for acute nerve injury. Therefore, electromyography is generally used for cases of nerve damage that last more than one month. For compressional nerve injury and closed traumatic nerve injury, B-ultrasound or magnetic resonance imaging can also be performed to determine the location, severity and cause of the compression.

If you want to check for sympathetic damage, you can use the ninhydrin test to check for sweat secretion in the nerve distribution area. Because of the non-clinical routine examination of this experiment, it is necessary to prepare the ninhydrin test paper by itself, so it is not commonly used.

Differential diagnosis

The sensory nerve of the finger is the nerve root from the cervical spinal cord, which forms the brachial plexus in the neck, and then divides the phrenic nerve and the ulnar nerve to the upper arm and the peripheral nerve to the hand and fingers. If the nerves in these areas are damaged, there is inflammation or tumor, it can cause paresthesia and finger numbness.

The muscles of the wrist and fingers flexing and stretching and the branches of their innervation are located at the proximal end of the forearm. The median nerve, the ruler and the sacral nerve in the proximal and elbow of the forearm can cause dysfunction of the flexion and extension fingers. When the hand is traumatized, the forearm is often involved. In the distal end and the wrist, in addition to the sacral nerve only causes the sensation of the tiger's mouth to be reduced, the median and ulnar nerve injury can lead to internal muscle dysfunction and important sensory disturbance of the hand. Its main performance is:

1. Median nerve: Thumb abductor dysfunction caused by thumb abduction dysfunction and thumb and forefinger dysfunction, palmar sacral half, thumb, food, middle and ring finger squat side half palm face, thumb joints and food , middle and ring refers to the sensory disturbance of the distal semi-final interphalangeal joint, which is mainly characterized by the disappearance of the index finger.

2. Ulnar nerve: ring and small finger claw deformity caused by interosseous muscle and sacral muscle paralysis, that is, metacarpophalangeal joint overextension, interphalangeal joint flexion deformity; Froment sign caused by interosseous muscle and thumb muscle paralysis Figure 2), when the index finger is pressed against the thumb, the proximal interphalangeal joint of the index finger is obviously flexed, the distal interphalangeal joint is overextended, the metacarpophalangeal joint is overextended, the interphalangeal joint is flexed; and the palm ruler and ring finger The ulnar side of the ulnar side and the little finger, the ulnar side of the hand and the ulnar side of the one side of the ulnar side of the sensory dysfunction, mainly manifested as the disappearance of the little finger.

3. phrenic nerve: the phrenic nerve has no movement branch below the wrist, only the sensory dysfunction of the proximal part of the proximal interphalangeal joint of the three sides of the hand and the temporal side of the sacral side, mainly manifested as a partial sensation of the dorsal aspect of the tiger's mouth or disappear.

4. Nerve damage in the palms and fingers: often injured and refers to the total nerve and the intrinsic nerve, which can cause sensory dysfunction on the adjacent side of the two fingers and sensory dysfunction on the side of the finger.

The history of trauma can be clearly diagnosed based on the location of the injury, the area in which the hand feels lost, and the paralysis of each finger movement.

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