superficial muscles of thenar eminance

• Flexor Pollicis Brevis: Most medial of thenar muscles

  O: Flexor retinaculum and tubercle of trapezium

  Capitate and trapezoid (deeper)

  R: Distally (with sesamoid bone forming within tendon)

  I: Lateral side base of proximal phalanx of thumb

  A: Flexion of thumb at MCP and CMC joints

  NS: Recurrent (lateral) branch median nerve (C5-8, T1)

  Deeper part: ulnar nerve (C(7), 8, T1)
• Abductor Pollicis Brevis: Most lateral and superficial muscle of thenar eminence

  O: Flexor retinaculum, tubercles of scaphoid and trapezium

  R: Distally

  I: Lateral side base proximal phalanx of thumb

  A: Abducts thumb at CMC and MCP joints

  NS: Recurrent (lateral) branch median nerve (C5-8, T1)