Movement of the Hand Flashcards
Define ‘opposition’ of the hand
Combination of flexion, medial rotation and abduction whereby the little finger and thumb are brought together in the middle of the palm
How do the joints of the thumb differ from the other digits?
Thumb only has one interphalangeal joint, other digits have two.
What is flexion of the thumb?
moves thumb across palm of hand
What is extension of the thumb?
normal position of the thumb (extended laterally)
What is abduction of the thumb?
takes the thumb away from the palm at right angles with the thumb aiming towards the ceiling when the palm is flat
What is adduction of the lumb?
return from abduction to resting position
What action does closing the hand involve?
Flexion
Describe what is meant by the ‘flexor digitorum’
Name for a group of muscles that have 4 tendons and flex the digits of the hand (not the thumb). The tendons enter the common flexor sheath deep to the flexor retinaculum where the muscles split into different synovial sheaths.
Name the two flexor digitorum muscles
Flexor digitorum superficialis and flexor digitorum profundus
What is the role of flexor digitorum profundus?
flexes the metacarpophalangeal joint, the proximal and distal interphalangeal joints too
What is the role of flexor digitorum superficialis?
flexes the metacarpophalangeal joint and the proximal interphalangeal joint
What is the name of the muscle that flexes the thumb?
flexor pollicis longus
Describe the role of the flexor pollicis longus muscle
It is the long flexor of the thumb which has 1 tendon and causes flexion of the MCP and IP joints of the thumb
What is meant by ‘thenar’ muscles?
Intrinsic muscles of the hand that act on the thumb
What is meant by ‘hypothenar’ muscles?
Intrinsic muscles of the hand that act on the little finger
What is the function of sheaths?
To allow free movement of tendons but reduce friction to prevent damage
What is the carpal tunnel?
A tunnel full of synovial fluid which holds all of the tendons together to support and protect them
What is meant by ‘trigger finger’
If tendons of the flexor digitorum superficialis or profunda enlarge close to the sheath, the tendon can become trapped and cause an individual to have an inability to extend their finger
Where are the muscles that open the hand located?
posterior side of the forearm
Name the muscles that open/extend the hand
extensor digitorum communis (has 4 tendons), extensor indicis (to index finger) and extensor digiti minimi (to little finger)
What is the fascia of the hand continuous with?
antebrachial fascia
How does the fascia differ across the hand?
fascia is thin over thenar and hypothenar muscles and thick in the centre of the palm (palmar aponeurosis)
What movements are possible at the metacarpophalangeal joint?
At the knuckles/MCP flexion, extension, adduction and abduction is possible
What movements are possible at the interphalangeal joints?
at DIP and PIP flexion and extension is possible
Where do the wrist flexors share a common origin?
medial epicondyle
Where do the wrist extensors share a common origin?
lateral epicondyle
Name the three main muscles that flex the wrist
Flexor carpi radialis, palmaris longus and flexor carpi ulnaris
Name the 3 main intrinsic muscles of the hand
Lumbricals, dorsal interossei and palmar interossei
What is the role of the lumbrical muscles in the hand?
to flex the metacarpophalangeal joint and extend the interphalangeal joints of the digits beside the thumb
What is the role of the dorsal interossei muscles in the hand?
abduct the 2nd-4th digits as well as assisting the lumbricals
What is the role of the palmar interossei muscles in the hand?
adduct the 2nd-5th digits as well as assisting the lumbricals
