Anatomy of the Thumb Flashcards
Opponens Pollicis
O: Flexor retinaculum and trapezium tubercle
I: Entire length of the 1st metacarpal (radial side)
A: Opposition
N: Median
Adductor Pollicis
(Oblique & Transverse Fibers)
OBLIQUE FIBERS:
O: Capitate and bases of the 2nd and 3rd metacarpals
I: Extensor expansion
TRANSVERSE FIBERS:
O: Palmar surface of the 3rd metacarpal
I: Base of the proximal phalange
A: Thumb palmar adduction; Assits with opposition and MP flexion
N: Ulnar
Abductor Pollicis Brevis
O: Flexor retinaculum, trapezium tubercle, and scaphoid tubercle
I: Base of the 1st proximal phalange, radial side and extensor hood
A: Thumb radial abduction, wrist radial deviation, assists with wrist flexion
N: Median
Abductor Pollicis Longus
O: Posterior/Proximal surface of the ulna, inferior of the ulna, inferior supinator origin interosseous membrane, and posterior/middle two-thirds of the radius
I: Base of the 1st metracarpal (radial side)
A: Thumb radial abduction, wrist radial deviation, assists with wrist flexion
N: Radial
Extensor Pollicis Brevis
O: Posterior surface of the radius (distal to the EPL)
I: Base of the 1st proximal phalange
A: Thumb MP extension, thumb radial abuduction, and assists with wrist radial deviation
N: Radial
Extensor Pollicis Longus
O: Posterior/middle one-third of the ulna
I: Base of the 1st distal phalange (dorsal surface)
A: Thumb MP extension; Assists with wrist radial deviation and extension
N: Radial
Flexor Pollicis Brevis
(Superficial and Deep Heads)
SUPERFICIAL HEAD:
O: Flexor retinaculum and trapezium
N: Median
DEEP HEAD:
O: Trapezoid and capitate
N: Ulnar
BOTH:
I: Base of the 1st proximal phalange (radial side)
A: Thumb MP flexion, palmar abduction, and opposition
Flexor Pollicis Longus
O: Anterior surface of the radius (below the tuberosity), interosseous membrane, and medial coronoid process
I: Base of the distal phalange (palmar surface)
A: Thumb IP flexion; Assists with thumb MP flexion and wrist flexion
N: Median
