Abductor Pollicis Brevis Muscle, Anterior View

Description

Arising from the flexor retinaculum and the tubercles of the scaphoid and trapezium, the abductor pollicis brevis forms the superficial, lateral border of the thenar eminence on the palmar (anterior) aspect of the hand. Its muscle belly sits radial to the long flexor tendons entering the carpal tunnel and runs distally toward the base of the proximal phalanx of the thumb, where it blends with the extensor expansion. Proximally, the distal forearm flexor mass continues into slender tendons crossing the wrist, held close to the carpus by fibrous bands consistent with retinacular and digital pulley structures. Relationships are clear. Palmar anatomy at the thenar eminence matters because small shifts in tendon, retinacular, or muscular contour often mirror common pathology. Median nerve compression in carpal tunnel syndrome can denervate the thenar muscles, and early abductor pollicis brevis weakness is a practical bedside finding, classically tested by resisted palmar abduction of the thumb at the carpometacarpal joint. This anterior perspective also supports surgical orientation: the recurrent motor branch of the median nerve courses toward the thenar compartment and is at risk during open carpal tunnel release, where thenar muscle position guides safe dissection. Use this artwork in upper limb anatomy teaching to anchor thenar surface landmarks to deep carpal tunnel contents, or in hand therapy materials that differentiate palmar abduction (abductor pollicis brevis) from extension and radial abduction driven by extensor pollicis longus and abductor pollicis longus. It also suits surgical texts and patient education sheets on carpal tunnel syndrome, thenar atrophy, and post release rehabilitation. Anatomical accuracy verified by SciePro's Medical Advisory Board.