The Hand Flashcards
which muscle of the forearm (not found in everyone) is continuous with the fascia of the palm shown?
palmaris longus
working from superficial to deep, there are 5 compartments of the hand:
- thenar compartment
- hypothenar compartment
- lumbricals and long flexor tendons - central compartment
- adductor compartment
- interosseous compartment
what do the thenar muscles of the hand form?
the fleshy muscle belly (thenar eminence) on the lateral aspect of the palm
Name the three Thenar muscles
short ones
- abductor pollicis brevis (APB)
- flexor pollicis brevis (FPB)
- opponens pollicis (OP) lies immediately deep to the above muscles.
label the thenar muscles
which nerve segment from the brachial plexus serves to provide the majority of the innervation to the thenar muscles?
C6-T1, median nerve,can contain fibres from C5 in some individuals
what do the hypothenar muscles form?
the fleshy muscle belly (hypothenar) eminence on the medial aspect of the palm
what are the three hypothenar muscles called?
- abductor digiti minimi
- flexor digit minimi
- opponens digiti minimi
label the hypothenar muscles
which nerve innervates the hypothenar muscles?
ulnar nerve
which nerve root from the brachial plexus serves to provide the majority of the innervation to the hypothenar muscles?
C8-T1, ulnar nerve
what does opponens mean in relation to muscles?
- contraction of the muscle results in the movement of either the thumb (pollicis), or little finger (digiti minimi) towrads the other fingers
lying deep to the thenar and hypothenar eminence is which compartment?
central compartment
what does the central compartment of the hand contain?
Flexor tendons passing distally from the forearm to the digits, with their respective synovial sheathes:
- flexor digitorum superficialis
- flexor digitorum profundus
- flexor pollicis longus
Additionally, 4 small muscles of the hand originate here called the Lumbricals.
what do the lumbricals arise from?
They arise from the medial and lateral aspects of the FDP tendon, between the 1st to 5th metacarpals.
what is the action of the lumbricals?
The lumbricals flex the fingers at the metacarpophalangeal joint and extend the interphalangeal joint of 2nd to 5th digits.
what is the innervation of the lumbricals?
- medial two lumbricals are innervated by the ulnar nerve
- lateral two are innervated by the median nerve
The adductor pollicis lies deep in the hand below the neurovascular structures and has 2 heads. Label these heads.
which nerve innervates adductor pollicis?
ulnar nerve C8-T1
describe the Interossei muscles
These muscles are deepest in the hand and lie between the metacarpal bones. There are 4 doarsal and 3 palmar interossei.
what is the action of the dorsal interossei muscles?
DAB
Dorsal interossei ABduct the fingers
what is the action of the palmar interossei muscles?
PAD
Palmar interossei ADduct the fingers
which nerve innervated the dorsal and palmar interossei muscles?
ulnar nerve
which spinal segment contributes the most to the innervation of the interossei?
C8-T1, ulnar nerve
what is the blood supply to the hand composed of?
The ulnar and radial arteries provide the blood supply to the hand. Once they reach the palm they form the superficial and deep palmar arch.
These arches anastomose with each other, therefore if one artery becomes blocked the other can maintain blood supply via. its collateral circulation.
which artery is the main contributor of the superficial palmar arch?
ulnar artery
which artery is the main contributor of the deep palmar arch
radial artery
which nerves supply the muscles of the hand?
median and ulnar nerves
the ulnar nerve is a branch of which cord of the brachial plexus?
medial cord
how would we test the motor and sensory function of the axillary nerve?
motor: abduct the shoulders (deltoid)
sensory: outer aspect of shoulder
how would we test the motor and sensory function of the musculocutaneous nerve?
motor: flex the elbow (biceps, brachialis)
sensory: lateral aspect of forearm
how would we test the motor and sensory function of the radial nerve?
motor: extend your wrist (posterior compartment of forearm)
sensory: posterior arm, forearm and dorasl aspect of lateral 3 and a half fingers
how would we test the motor and sensory function of the ulnar nerve?
motor: spread your fingers (intrinsic muscles of the hand)
sensory: palmar and dorsal aspect of the medial 1 and a half fingers
how would we test the motor and sensory function of the median nerve
motor: move youir thumb towards your nose (abductor pollicis brevis)
sensory: palmar aspect of lateral 3 and a half fingers
