Muscles of the hand Flashcards
What does INTRINSIC muscles of the hand refer to?
Muscles that originate within the hand and insert within the hand
What does EXTRINSIC muscles of the hand refer to?
Muscles that originate within the forearm and insert within the hand
What are the muscles of the THENAR compartment of the hand?
Thenar = thumb
- Abductor pollicis brevis
- Flexor pollicis brevis
- Opponens pollicis
What is the thenar eminence?
The muscular prominence on the radial aspect of the palm
Opponens Pollicis
O: Trapezium and flexor retinaculum
I: Lateral border of 1st metacarpal
I: Median nerve
A: Opposes thumb (medially rotating and flexing 1st metacarpal)
Abductor Pollicis Brevis
O: Scaphoid, trapezium and flexor retinaculum
I: Lateral border of proximal phalanx of thumb
I: Median nerve
A: Abducts the thumb
Flexor Pollicis Brevis
O: Trapezium and flexor retinaculum (superficial head) Trapezoid and capitate (deep head)
I: Ulnar aspect of base of proximal phalanx of thumb
I: Ulnar nerve
A: Flexes metacarpophalangeal joint of thumb
What is the muscles of the adductor compartment of the hand?
Adductor pollicis
Adductor Pollicis
O: Shaft of 3rd metacarpal (transverse head) Capitate and base of 2nd and 3rd metacarpals (oblique head)
I: Ulnar aspect of base of proximal phalanx of thumb
I: Ulnar nerve
A: Adduct thumb
What are the muscles of the hypothenar compartment of the hand?
- Opponenes digiti minimi
- Abductor digiti minimi
- Flexor digiti minimi brevis
What is the hypothenar eminence?
A muscular prominence on the ulnar aspect of the palm
Opponens Digiti Minimi
O: Hook of the hamate and flexor retinaculum
I: Ulnar margin of 5th metacarpal
I: Ulnar nerve
A: Rotates the 5th metacarpal towards the palm = opposition against the thumb
Abductor Digiti Minimi
O: Pisiform and tendon of flexor carpi ulnaris
I: Base of proximal phalanx of little finger
I: Ulnar nerve
A: Abducts little finger
Flexor Digiti Minimi Brevis
O: Hook of the hamate and flexor retinaculum
I: Base of proximal phalanx of little finger
I: Ulnar nerve
A: Flexion of metacarpophalangeal joint of little finger
What are the muscles of the central compartment of the hand?
- Palmaris brevis
- Palmar interossei
- Dorsal interossei
- Four lumbricals (2x radial, 2x ulnar)
Palmaris Brevis
O: Palmar aponeurosis and flexor retinaculum
I: Dermis of skin on medial margin of hand
I: Ulnar nerve
A: Wrinkles the skin of hypothenar eminence, deepens the curvature of the palm and improving grip
Lumbrical I (unipennate)
O: FDP to index finger
I: Extensor digitorum to index finger
I: Median nerve
A: Flexion at metcarpophalanheal joint, extension at interphalangeal joints
Lumbrical II (unipennate)
O: FDP to middle finger
I: Extensor digitorum to middle finger
I: Median nerve
A: Flexion at metcarpophalanheal joint, extension at interphalangeal joints
Lubrical III (bipennate)
O: FDP to middle and ring finger
I: Extensor digitorum to ring finger
I: Ulnar nerve
A: Flexion at metcarpophalanheal joint, extension at interphalangeal joints
Lubrical IV (bipennate)
O: FDP to ring and little finger
I: Extensor digitorum to little finger
I: Ulnar nerve
A: Flexion at metcarpophalanheal joint, extension at interphalangeal joints
Dorsal Interossei I (bipennate)
O: Shaft of the first and second metacarpals
I: Radial aspect of base of proximal phalanx of index finger
I: Ulnar nerve
A: Abducts the index finger DAB, assists lumbricals in flexing MCPJ and extending IPJ
Dorsal Interossei II (bipennate)
O: Shaft of the second and third metacarpals
I: Radial aspect of base of proximal phalanx of middle finger
I: Ulnar nerve
A: Radially abducts middle finger DAB, assists lumbricals in flexing MCPJ and extending IPJ
Dorsal Interossei III (bipennate)
O: Shaft of the third and fourth metacarpals
I: Ulnar aspect of base of proximal phalanx of middle finger
I: Ulnar nerve
A: Ulnar abducts middle finger DAB, assists lumbricals in flexing MCPJ and extending IPJ
Dorsal Interossei IV (bipennate)
O: Shaft of the fourth and fifth metacarpals
I: Ulnar aspect of base of proximal phalanx of ring finger
I: Ulnar nerve
A: Abducts ring finger DAB, assists lumbricals in flexing MCPJ and extending IPJ
Palmar Interossei I (unipennate)
O: Shaft of second metacarpal
I: Ulnar side of base of proximal phalanx of the index finger
I: Ulnar nerve
A: Adducts index finger PAD
Palmar Interossei II (unipennate)
O: Shaft of fourth metacarpal
I: Radial side of base of proximal phalanx of ring finger
I: Ulnar nerve
A: Adducts ring finger PAD
Palmar Interossei III (unipennate)
O: Shaft of fifth metacarpal
I: Radial side of base of proximal phalanx to little finger
I: Ulnar nerve
A: Adducts little finger PAD
