Muscles Of The Hand Flashcards
What is the difference between the extrinsic and intrinsic muscles of the hand?
Extrinsic- located in the anterior and posterior compartments of the forearm, they control crude movements and produce a forceful grip
Intrinsic- located within the hand itself, they are responsible for the fine motor functions of the hand
How many intrinsic muscles of the hand are there? Name them
6: Adductor pollicis Palmaris Blevins Interossei Lumbricals Thenar Hypothenar
What nerve innervates the thenar muscles?
Median
How many muscles make up the thenar eminance, name them?
3:
Opponens pollicis
Abductor pollicis Brevis
Flexor pollicis Brevis
Where does the opponens pollicis lie in relation to the other thenar muscles in the hand?
Largest and lies underneath them
What are the attachments of the opponens pollicis, one of the thenar muscles in the hand?
Originates from the tubercle of the trapezium and associated flexor retinaculum
Inserts into the lateral margin of the metacarpal of the thumb
What is the action of the opponens pollicis, one of the thenar muscles in the hand?
Opposed the thumb, by medially rotating and flexing the metacarpal on the trapezium
What nerve innervates the opponens pollicis, one of the thenar muscles in the hand?
Median nerve
In relation to the other thenar muscles of the hand, where is the abductor pollicis Brevis ?
Found anteriorly to the opponens pollicis and proximal to the flexor pollicis brevis
What are the attachments of the abductor pollicis brevis, one of the thenar muscles in the hand?
Originates from the tubercles of the scaphoid and trapezium and from the associated flexor retinaculum
Attaches to the lateral side of proximal phalanx of the thumb
What is the action of the abductor pollicis brevis, one of the thenar muscles in the hand?
Abducts the thumb
What nerve innervates the abductor pollicis brevis, one of the thenar muscles in the hand?
Median
Where is the flexor pollicis brevis muscle in relation to the other thenar muscles of the hand?
Most distal of the muscles
What are the attachments of the flexor pollicis brevis, one of the thenar muscles in the hand?
Originates from the tubercle of the trapezium and from the associated flexor retinaculum
Attaches to the base of the proximal phalanx of the thumb
What is the action of the flexor pollicis brevis, one of the thenar muscles in the hand?
Flexes the metacarpophalangeal (MCP) join of the thumb
What nerve innervates the flexor pollicis brevis, one of the thenar muscles in the hand?
Median
How many muscles make up the hypothenar eminence? Name them
3:
Opponens digiti minimi,
Abductor digiti minimi and flexor digiti minimi brevis
In relation to the other hypothenar muscles, where is the opponens digiti minimi muscle of the hypothenar eminence in the hand?
Lies deep to the others
What are the attachments of the opponens digiti minimi muscle of the hypothenar eminence in the hand?
Originates from the hook of hamate and associated flexor retinaculum
Inserts into the medial margin of metacarpal V
What is the action of the opponens digiti minimi muscle of the hypothenar eminence in the hand?
Rotaries the metacarpal of the little finger towards the palm, producing opposition
What nerve innervates the opponens digiti minimi muscle of the hypothenar eminence in the hand?
Ulnar
In relation to the other muscles of the hypothenar, where is the abductor digiti minimi muscle of the hypothenar eminence in the hand?
Most superficial muscle
What are the attachments of the abductor digiti minimi muscle of the hypothenar eminence in the hand?
Originates from the pisiform and the tendon of the flexor carpi ulnaris
Attaches to the base of the proximal phalanx of the little finger
What is the action of the abductor digiti minimi muscle of the hypothenar eminence in the hand?
Abducts the little finger
What nerve innervates the abductor digiti minimi muscle of the hypothenar eminence in the hand?
Ulnar
In relation to the other. Hypothenar muscles, where is the flexor digiti minimi brevis muscle of the hypothenar eminence in the hand?
Lies laterally to the abductor digiti minimi
What are the attachments of the flexor digiti minimi brevis muscle of the hypothenar eminence in the hand?
Originates from the hook of hamate and adjacent flexor retinaculum
Inserts into the base of the proximal phalanx of the little finger
What is the action of the flexor digiti minimi brevis muscle of the hypothenar eminence in the hand?
Flexes the MCP joint of the little finger
What nerve innervates the flexor digiti minimi brevis muscle of the hypothenar eminence in the hand?
The ulnar nerve
How many lumbricals are there in the hand and what are each associated with?
4, 1 for each finger
What do the lumbricals in the hand link?
The extensor tendons to the flexor tendons
Denervation of the lumbricals of the hand is the basis for what conditions?
Ulnar claw
Hand of benediction
What are the attachments of the lumbricals of the hand?
Each originates from a tendon of the flexor digitorum profundus
Insert into extensor hood
What root do the lumbricals take along the fingers?
Travel dorsally and laterally to the finger
What is the action of the lumbricals of the hand?
Flexion at the MCP joint and extend at the IP joints of each finger
What nerve innervates the lumbricals of the hand?
Two medial lumbricals- ulnar nerve
Two lateral lumbricals- median nerve
Where are interossei muscles found?
Between the metacarpals
What are the 2 interossei muscle groups called?
Dorsal interossei
Palmar interossei
What are the attachments of the dorsal interossei muscles of the hand?
Each originates from the lateral and medial surfaces of the metacarpals
Attach into the extensor hood and proximal phalanx of each finger
What is the action of the dorsal interossei muscles of the hand?
Abducts the fingers at the MCP joint
And assists the lumbricals in flexion at MCP joints and extension at the IP joints
What nerve innervates the dorsal interossei of the hand?
Ulnar nerve
How many dorsal interossei muscles are there?
4
How many palmar interossei muscles are there?
3
What are the attachments of the palmar interossei muscles of the hand?
Each originates form the medial or lateral surface of a metacarpal
Attaches to the extensor hood and proximal phalanx
What are the actions of the palmar interossei muscles of the hand?
Adduction of the fingers at the MCP joint
And assists the lumbricals in flexion at MCP joints and extension at the IP joints
What nerve innervates the palmar interossei?
Ulnar nerve
Name the two other muscles found in the hand that are neither lumbricals, interossei, hypothenar nor thenar muscles
Palmaris brevis and adductor pollicis
What is the palmaris brevis?
Small, thin muscles found very superficially in the subcutaneous tissue of the hypothenar eminence
What are the attachments of the palmaris brevis muscle in the hand?
Originates from the palmar aponeurosis and flexor retinaculum
Attaches to the dermis of the skin on the medial margin of the hand
What is the action of the palmaris brevis in the hand?
Wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand, improving grip
What nerve innervates the palmaris brevis muscle of the hand?
Ulnar nerve
What is the adductor pollicis muscle of the hand?
Large triangular muscle with two heads- forms the deep Palmar arch
What is the interaction of the radial artery and the adductor pollicis?
The radial artery passes anteriorly through the space between the two heads
What are the attachments of the adductor pollicis muscle of the hand?
One head- from metacarpal 3
One head- from capitate and adjacent areas of metacarpals 2 and 3
Attach into the base of the proximal phalanx of the thumb
What is the action of the adductor pollicis muscle of the hand?
Adductor of the thumb
What nerve innervates the adductor pollicis?
Ulnar nerve
What nerve innervates the hypothenar eminence?
The ulnar nerve