Muscles of the Hand Flashcards
What are the two groups of muscles that act on the hand?
Intrinsic
Extrinsic
Where are the extrinsic muscles mainly found?
In the forearm
What do the extrinsic muscles do?
Offer the forceful grip of the hand
Where are the intrinsic muscles found?
Inside the hand
What do the intrinsic muscles do?
The finer movements of the hand eg writing
What are the muscles of the hand?
Adductor pollicis Interossei Thenar Palmaris brevis Lumbricals Hyperthenar muscles
Which muscles are responsible for the fine movement of the thumb?
The thenar muscles
Adductor pollicis
Which nerve innervates the thenar muscles?
The median nerve
What are the 3 thenar muscles?
Oppenens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Which is the largest of the thenar muscles?
Oppenens pollicis. It lies under the other two thenar muscles
What is the main action of the oppoenens pollicis?
Opposes the thumb by medially rotating and flexing the metacarpel on the trapezium
Where is the abductor pollicis brevis found?
Anteriorly to the oppoenens pollicis
Proximal to flexor pollicis brevis
What is the main action of the abductor pollicis brevis?
Abducts the thumb
What is the main action of the flexor pollicis brevis?
Flexes the metacarpel-phalangeal joint of the thumb.
What are the hypothenar muscles?
Opponens digiti minimi
Abductor digiti minimi
Flexor digiti minimi brevis
Where are the hypothenar muscles located?
At the base of the little finger
Medial side of the palm
What nerve innervates the hypothenar muscles?
The ulnar nerve
Where is the opponens digiti minimi?
Deep to the hypothenar muscles
What is the main action of the opponens digiti minimi?
Produces opposition by rotating the metacarpel of the little finger towards the palm
Where is the Abductor digiti minimi?
Superificial to the hypothenar muscles
What is the main action of Abductor digiti minimi?
Abducts the little finger
Where is the flexor digiti minimi brevis?
Lateral to the abductor digiti minimi
What is the main action of the flexor digiti minimi brevis?
Flexes the metacarpel-phalangeal joint of the little finger
What are the two muscles of the palm which do not fit into the hypothenar group or thenar group?
Adductor pollicis
Palmaris brevis
What is special about the Adductor pollicis?
It has two heads with the radial artery passing through them to form the deep palmar arch
What is the main action of the Adductor pollicis?
Adduction of the thumb
What nerve innervates the Adductor pollicis?
The ulnar nerve
Where is the palmaris brevis?
Superficial to the subsutaneous tissue of the hypothenar eminence
What is the main action of the palmaris brevis?
Deepens the curvature of the hand to improve grip
What nerve innervates the palmaris brevis?
The ulnar nerve
How many lumbrical muscles are there?
Four. One associated with each finger.
Why are the lumbricals essential for finger movement?
They link the extensor tendons with the flexor tendons
What happens with denerveration of the lumbricals?
Ulnar claw
Hand of Benediction
What is the main action of the lumbricals?
Flex at the metacarpal-phalangeal joint of the finger
Extend at the inter-phalangeal joint of the finger
What innervates the lumbricals?
Medial 2 lumbricals = Ulnar nerve
Lateral 2 lumbricals = Median nerve
Where are the interossei muscles?
Between the metacarpals
What are the two types of interossei?
Dorsal interossei
Palmar interossei
How many dorsal interossei are there?
Four
Where are the dorsal interossei located?
Superficially
What is the main action of the dorsal interossei?
Abduct the fingers at the metacarpal-phalangeal joint
What innervates the dorsal interossei?
The ulnar nerve
Where are the Palmar interossei located?
Anteriorly on the hand
How many palmar interossei are there?
Three
What is the main action of the palmar interossei?
Adducts the finger at the metacapal-phalangeal joint
What innervates the palmar interossei muscles?
The ulnar nerve
