Upper Limb Muscles of the Hand Flashcards
What are the two groups of muscles in the hand?
Extrinsic - anterior and posterior compartments of the forearm, control crude movements and produce grip.
Intrinsic - within hand itself, responsible for fine motor functions of the hand.
What are the thenar muscles?
Three short muscles at the base of the thumb. They produce a bulge, the thenar eminence. Control fine movements of the thumb.
What innervates the thenar muscles?
Median nerve.
What are the proximal attachments of the opponens pollicis?
Flexor retinaculum and tubercles of scaphoid and trapezium.
What are the distal attachments of the opponens pollicis
Lateral side of 1st metacarpal.
What is the opponens pollicis innervated by?
Recurrent branch of median nerve (C8, T1).
What is the arterial supply of the opponens pollicis?
Superficial palmar branch of the radial artery.
What is the action of the opponens pollicis?
To oppose thumb, it draws 1st metacarpal medially to centre of palm and rotates it medially.
What are the proximal attachments of the abductor pollicis brevis?
Flexor retinaculum and tubercles of scaphoid and trapezium.
What are the distal attachments of the abductor pollicis brevis
Lateral side of base of proximal phalanx of thumb.
What is the abductor pollicis brevis innervated by?
Recurrent branch of median nerve (C8, T1).
What is the arterial supply of the abductor pollicis brevis?
Deep palmar arterial arch.
What is the action of the abductor pollicis brevis?
Abducts thumb, helps oppose it.
What are the proximal attachments of the flexor pollicis brevis?
Flexor retinaculum and tubercles of scaphoid and trapezium.
What are the distal attachments of the flexor pollicis brevis?
Lateral side of base of proximal phalanx of thumb.
What is the flexor pollicis brevis innervated by?
Superficial head by recurrent branch of median nerve (C8, T1).
Deep head by deep branch of ulnar nerve (C8, T1).
What is the arterial supply of the flexor pollicis brevis?
Superficial palmar branch of radial artery.
What is the action of the flexor pollicis brevis?
Flexes thumb.
What is the hypothenar eminence?
The muscular protrusion on the medial side of the palm, at the base of the little finger. From the hypothenar muscles.
What are the proximal attachments of the abductor digiti minimi?
Pisiform.
What are the distal attachments of the abductor digiti minimi?
Medial side of base of proximal phalanx of 5th digit.
What is the abductor digiti minimi innervated by?
Deep branch of ulnar nerve (C8, T1).
What is the arterial supply of the abductor digiti minimi?
Ulnar artery.
What is the action of the abductor digiti minimi?
Abducts 5th digit, assists in flexion of its proximal phalanx.
What are the proximal attachments of the flexor digiti minimi brevis?
Hook of hamate and flexor retinaculum.
What are the distal attachments of the flexor digiti minimi brevis?
Medial side of base of proximal phalanx of 5th digit.
What is the flexor digiti minimi brevis innervated by?
Deep branch of ulnar nerve (C8, T1).
What is the arterial supply of the flexor digiti minimi brevis?
Ulnar artery.
What is the action of the flexor digiti minimi brevis?
Flexes proximal phalanx of 5th digit.
What are the proximal attachments of the opponens digiti?
Hook of hamate and flexor retinaculum.
What are the distal attachments of the opponens digiti?
Medial border of 5th metacarpal.
What is the opponens digiti innervated by?
Deep branch of ulnar nerve (C8, T1).
What is the arterial supply of the opponens digiti?
Ulnar artery.
What is the action of the opponens digiti?
Draws 5th metacarpal anterior and rotates it, bringing 5th digit into opposition with thumb.
Why are lumbricals important?
They link the extensor tendons to the flexor tendons.
What happens as a result of denervation of the lumbricals?
Ulnar claw and hand of benediction.
What are the proximal attachments of the 1st and 2nd lumbricals?
Lateral two tendons of flexor digitorum profundus (as unipennate muscles).
What are the distal attachments of the 1st and 2nd lumbricals?
Lateral sides of extensor expansions of 2nd-5th digits.
What are the 1st and 2nd lumbrical innervated by?
Median nerve (C8, T1).
What is the arterial supply to the 1st and 2nd lumbricals?
Superficial palmar arterial arch.
What is the action of the 1st and 2nd lumbricals?
Flex metacarpophalangeal joints, extend interphalangeal joints of 2nd-5th digits.
What are the proximal attachments of the 3rd and 4th lumbricals?
Medial three tendons of flexor digitorum profundus (as bipennate muscles).
What are the distal attachments of the 3rd and 4th lumbricals?
Lateral sides of extensor expansions of 2nd-5th digits.
What are the 3rd and 4th lumbrical innervated by?
Deep branch of the ulnar nerve (C8, T1).
What is the arterial supply to the 3rd and 4th lumbricals?
Superficial palmar arch.
What is the action of the 3rd and 4th lumbricals?
Flex metacarpophalangeal joints, extend interphalangeal joints of 2nd-5th digits.
What are the two groups of interossei muscles?
Dorsal and palmar interossei.
What are the proximal attachments of the dorsal interossei?
Adjacent sides of two metacarpals, as bipennate muscles.
What are the distal attachments of the dorsal interossei?
Bases of proximal phalanges, extensor expansions of 2nd-4th digits.
What are the dorsal interossei innervated by?
Deep branch of ulnar nerve (C8, T1).
What is the arterial supply to the dorsal interossei?
Palmar metacarpal arteries, dorsal metacarpal arteries.
What is the action of the dorsal interossei?
Abduct 2nd-4th digits from axial line, act with lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints.
What are the proximal attachments of the palmar interossei?
Palmar surfaces of 2nd, 4th, and 5th metacarpals, as unipennate muscles.
What are the distal attachments of the palmar interossei?
Bases of proximal phalanges, extensor expansions of 2nd, 4th, and 5th expansions.
What are the palmar interossei innervated by?
Deep branch of ulnar nerve (C8, T1).
What is the arterial supply to the palmar interossei?
Palmar metacarpal arteries.
What is the action of the palmar interossei?
Adduct 2nd, 4th, and 5th digits toward axial line, assist lumbricals in flexing metacarpophalangeal joints and extending interphalageal joints, extensor expansions of 2nd-4th digits.
What are the other muscles in the hand that are no thenar, hypothenar or lumbrical muscles?
Palmaris brevis and adductor pollicis.
What are the proximal attachments of the palmaris brevis?
Palmar aponeurosis and flexor retinaculum.
What are the distal attachments of the palmaris brevis?
The dermis of the skin on the medial margin of the hand.
What is the palmaris brevis innervated by?
Ulnar nerve (C8, T1).
What is the arterial supply of the palmaris brevis?
Ulnar artery.
What is the action of the palmaris brevis?
Wrinkles the skin of the hyperthenar eminence and deepens the curvature of the hand, improving grip.
What are the proximal attachments of the adductor pollicis?
Oblique head - bases of 2nd and 3rd metacarpals, capitate, and adjacent carpals.
Transverse head - anterior surface of shaft of 3rd metacarpal.
What are the distal attachments of the adductor pollicis?
Medial side of base of proximal phalanx of thumb.
What is the adductor pollicis innervated by?
Deep branch of ulnar nerve (C8, T1).
What is the arterial supply of the adductor pollicis?
Deep palmar arterial arch.
What is the action of the adductor pollicis?
Adducts thumb towards lateral border of palm.
