Functional positioning of the thumb is paramount to the restoration of lateral pinch to the hands in patients with tetraplegia as the result of spinal cord injury. Useful lateral pinch can be provided to patients with at least wrist extension control preserved by use of a combination of flexor pollicis longus tenodesis or transfer and carpometacarpal and inter phalangeal joint stabilization. In patients who retain function in the brachioradialis, extensor carpi radialis longus and brevis, pronator teres, and flexor carpi radialis, strong grasp as well as effective lateral pinch can be restored to the hand by surgery. Thumb control for flexion and extension is provided by tendon transfer to the flexor pollicis longus and tenodesis or transfer to the extensor pollicis longus. proper positioning for lateral pinch can be accomplished by either arthrodesis of the first metacarpal-trapezial joint or tendon transfer to restore adduction-opposition to the thumb. The surgical concepts presented in this paper have been applied to the functional reconstruction of the hands of more than 50 patients with spinal cord injury during the last 15 years. The patients have been pleased with the significant improvement in function, strength, and speed that has resulted from surgery and have been cooperative advocates as the alternate methods of thumb control have been evaluated.