MSK - Muscles of the hand Flashcards
Where are the extrinsic hand muscles located? What do they control?
- Anterior and posterior compartments of the forearm
- Control crude moments and produce a forceful grip
Where are the intrinsic hand muscles located? What do they control?
- Located within the actual hand
- Control fine motor movements
Name the THREE thenar muscles. What are they responsible for?
- Opponens Pollicis
- Abductor Pollicis Brevis
- Flexor Pollicis Brevis
Responsible for movements of the thumb
What is the thenar eminence?
The bulge produced by the muscle bellies of the three thenar muscles
Which nerve innervates the thenar muscles?
Median nerve
What is the origin of opponens pollicis?
- Tubercule of the trapezium and associated flexor retinaculum
Where does opponens pollicis insert?
Lateral margin of the metacarpal of the thumb
What are the actions of opponens pollicis?
- Opposition of the thumb
medially rotates and flexes the metacarpal on the trapezium
Where is opponens pollicis found?
- Deep to abductor pollicis brevis
- Lateral to flexor pollicis brevis
What is the origin of abductor pollicis brevis?
Tubercules of scaphoid and trapezium and associated flexor retinaculum
Where does abductor pollicis brevis insert?
Lateral side of proximal phalanx
What are the actions of abductor pollicis brevis?
Abduction of the thumb
What is the origin of flexor pollicis brevis?
Tubercle of the trapezium and associated flexor retinaculum
Where does flexor pollicis brevis insert?
Base of the proximal phalanx of the thumb
What are the actions of flexor pollicis brevis?
Flexion of the metacarpophalangeal joint of the thumb
What is the arterial supply to the thenar muscles?
Superficial palmar arch
What are the THREE hypothenar muscles? What do they produce?
- Opponens Digiti Minimi
- Abductor Digiti Minimi
- Flexor Digiti Minimi Brevis
Produce the hypothenar eminence - muscle bulge on medial palm, at the base of 5th digit
What is the origin of opponens digiti minimi?
Hook of the hamate and its associated flexor retinaculum
Where does opponens digiti minimi insert?
Medial margin of the 5th metacarpal
What are the actions of opponens digiti minimi?
- Opposition of the little finger
rotates 5th metacarpal towards the palm
What is the origin of abductor digiti minimi?
- Pisiform
- Tendon of the flexor carpi ulnaris
Where does abductor digiti minimi insert?
Base of the proximal phalanx of the 5th digit
What are the actions of abductor digiti minimi?
Abduction of the 5th digit
What is the origin of flexor digiti minimi brevis?
Hook of the hamate and the adjacent flexor retinaculum
Where does flexor digiti minimi brevis insert?
Base of the proximal phalanx of the 5th digit
What are the actions of flexor digiti minimi brevis?
Flexion of the MCP joint of the little finger
Which nerve innervates the hypothenar muscles?
Ulnar nerve
What is the arterial supply of the hypothenar muscles?
Ulnar artery
How many lumbrical muscles are there? Which are unipennate and which are bipennate?
- 4, each associated with a finger
- 1 and 2 = unipennate (tendon on one side)
- 3 and 4 = bipennate (muscle on both sides of a tendon)
Where do the lumbricals originate?
Each come from a tendon of the flexor digitorum profundus
Where do the lumbricals insert?
Extensor hood of each finger
after passing around dorsally and laterally
What is the innervation of the lumbricals?
- Medial two (4th and 5th digits) = ulnar nerve
- Lateral two (2nd and 3rd digits) = median nerve
What is the arterial supply of the lumbricals?
- Superficial palmar arch
- Common palmar digital artery
- Deep palmar arch
- Dorsal digital artery
What are the actions of the lumbricals?
- Flexion of the metacarpophalangeal (MCP) joints
- Extension of the interphalangeal joints
Where are the interossei muscles located?
Between the metacarpals
What is the origin of the dorsal interossei muscles?
Each one originates from the lateral and medial surfaces of the metacarpals
Where do the dorsal interossei muscles insert?
- The extensor hood of their corresponding finger
- The proximal phalanx of their corresponding finger
What innervates the interossei muscles?
Ulnar nerve
What is the arterial supply of the dorsal interossei muscles?
Dorsal and metacarpal palmar artery
What are the actions of the dorsal interossei muscles?
- Abduction of the fingers at the MCP joints
- Assist lumbricals with flexion of MCP joints and extension of IP joints
What are the origins of the palmar interossei muscles?
Medial OR lateral surface of a metacarpal
Where do the palmar interossei muscles insert?
The extensor hood and proximal phalanx of their corresponding finger
What is the arterial supply of the palmar interossei muscles?
Palmar metacarpal artery of the deep palmar arch
What is the action of the palmar interossei muscles?
- Adduction of the fingers at the MCP joint
- Assist lumbricals with flexion of MCP joints and extension of IP joints
What is the origin of palmaris brevis?
Palmar aponeurosis and flexor retinaculum
Where does palmaris brevis insert?
Dermis of the skin on the medial margin of the hand
What is the innervation of palmaris brevis?
Ulnar nerve
What is the arterial supply of palmaris brevis?
Palmar metacarpal artery
What are the actions of palmaris brevis?
- Wrinkles skin of hypothenar eminence
- Deepens curvature of the hand
(Improves grip)
What is the origin of ambdductor pollicis?
- One head = metacarpal 3
- Other head = capitate
(along with adjacent areas of metacarpal 2&3)
Where does adductor pollicis insert?
Proximal phalanx of the thumb
What is the innervation of adductor pollicis?
Ulnar nerve
What is the arterial supply of adductor pollicis?
Deep palmar arch
What are the actions of adductor pollicis?
Adduction of the thumb