Adductor Pollicis Muscle

The adductor pollicis muscle is a fan-shaped muscle supplied by the deep branch of the ulnar nerve with two heads (oblique and transverse) of origin between which the radial artery passes. The oblique head arises from the second and third metacarpals... 

Laycock JR, Smith CE, Donati F, Bevan DR. Sensitivity of the adductor pollicis and diaphragm muscles to atracurium in a hemiplegic patient. Anesthesiology 1987 67(5) 851-3. 

Assessment of neuromuscular block usually is performed by stimulation of the ulnar nerve. Responses are monitored from compound action potentials or muscle tension developed in the adductor pollicis (thumb) muscle. Responses to repetitive or tetanic stimuli are most useful for evaluation of blockade of transmission. Thus, stimulus schedules such as the train of four and the double burst or responses to tetanic stimulation are preferred procedures. Rates of onset of blockade and recovery are more rapid in the airway musculature (jaw, larynx, and diaphragm) than in the thumb. Hence, tracheal intubation can be performed before onset of complete block at the adductor pollicis, whereas partial recovery of function of this muscle allows sufficient recovery of respiration for extubation. 

The flexor pollicis longus tendon traverses the thenar eminence between the superficial and deep bellies of the flexor pollicis brevis muscle. It then enters the osteofibrous canal of the thumb to insert at the volar aspect of the base of the distal phalanx. At the metacarpal head level, this tendon courses between two sesamoid bones, one (lateral) included in the combined tendon of the flexor pollicis brevis and abductor pollicis longus, the other (medial) in the adductor pollicis tendon. 

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