The median nerve innervates the flexors of the wrist and the fingers and gives the thumb, the forefinger and the middle finger their sensitivity.
High median nerve palsy
This refers to a lesion of the median nerve in the arm or elbow, due to a direct wound or a fracture-dislocation of the elbow.In high median nerve palsy, there is a failure of finger flexion with loss of sensitivity for the first 3 fingers and a typical hand deformity.
Low median nerve palsy
This refers to a lesion at forearm or wrist level, due to a direct wound or a fracture-dislocation of the wrist. In low median nerve palsy, the sensory deficit (anaesthesia) is predominant but there is also a deficit in thumb opposition.
Wherever the lesion is sited, emergency surgery will be necessary for bone stabilization in case of fracture-dislocation, or perform a surgical exploration if there is a wound.
In closed injuries, if recovery doesn’t begin 5 months from injury, nerve exploration surgery will be necessary.
For paralysis diagnosed late, (over one year from injury), forearm tendon transfer procedure will restore finger flexion (synchronization) and thumb flexion (opposition tendon transfer). More exceptionally, thumb sensitivity may be addressed by sensitive neurotisation or using a pediculed flap of the fourth finger tip.