MSK Session 6 Flashcards
What gives the power grip?
Muscles in the forearm
What allows for the precision grip?
Muscles of the hand
How is blood supplied to the hand?
Ulnar artery branches into deep and superficial palmar arches
Radial anastomoses
What is the venous drainage of the hand?
Veins follow arteries in the dorsal venous network
What are the five intrinsic muscle groups of the hand?
Thenar Lumbricals Pollicis Interossei Digiti minimi
What causes Hand of Benediction?
Damage of the median nerve at the wrist of elbow
What causes wrist drop?
Damage of radial nerve at axilla/radial groove/deep superficial branch
Which muscles of the hand are innervated by the median nerve?
Lateral 2 lumbricals
Opponens pollicis
Abductor policis
Flexor pollicis brevis
What is the main action of opponens pollicis?
Oppose thumb by drawing 1st metacarpal medially to centre of Palm and rotating it medially
What is the main action of abductor pollicis brevis?
Abducts thumb
Assists opposition
What is the main action of flexor pollicis brevis?
Flex thumb
What is the main action of adductor pollicis brevis?
Addicts thumb toward lateral border of palm
What innervates adductor pollicis?
Ulnar nerve
What is the main action of abductor digiti minimi?
Abduct 5th digit
Assist flexion of proximal phalanx of 5th digit
What is the main action of flexor digiti minimi brevis?
Flex proximal phalanx of 5th digit
What is the main action of opponens digiti?
Draw 5th metacarpal anterior
Rotate 5th metacarpal bringing it into opposition w/thumb
What innervates the hypothenar muscles - ADM, FDMB and OD?
Ulnar nerve
What is the main action of the 1st-4th lumbricals?
Flex metacarpophalangeal joints
Extend interphalangeal joints of 2nd-5th digits
What is the main action of the dorsal interossei 1st-4th?
Abduct 2nd-4th digits from axial line
Act w/lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints
What is the main action of the palmar interossei 1st-3rd?
Adduct 2nd, 4th and 5th digits towards axial line
Assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints
Extensor expansions of 2nd-4th digits
What innervates the 3rd and 4th lumbricals and both dorsal and palmar sets of interossei?
Ulnar nerve
What is ulnar claw?
Damage of the ulnar nerve at the elbow or wrist
How do you test for Hand of Benediction?
Ask to make a fist - first three digits paralysed so only 4th and 5th bend
How do you test the function of the dorsal interossei?
Ask patient to spread fingers and resist closure
How do you test the function of the palmar interossei?
Ruler b/w fingers and pull
Where is cutaneous sensation loss tested for in radial nerve damage?
Anatomical snuffbox
What are the contents of the carpal tunnel?
4 tendons of flexor digitorum superficialis
4 tendons of flexor digitorum profundus
Median nerve
How is the location of the carpal tunnel found by surface anatomy?
Most distal crease of wrist when slightly flexed
What forms the roof of the carpal tunnel?
Flexor retinaculum
What is carpal tunnel syndrome?
Pain and paresthesia due median nerve compression
What can carpal tunnel syndrome lead to?
Thenar muscle atrophy
Describe the pain experienced in carpal tunnel syndrome.
Radiates to forearm
Worse at night and in morning
What is found in Guyon’s canal?
Palmaris longus tendon
Ulnar artery
Ulnar nerve
What is Tinel’s sign?
Tap median nerve to elicit carpal tunnel symptoms
What is Phalen’s manoeuvre?
Hold wrist in flexion (palms/dorsal aspects pressed together) for 60s to elicit carpal tunnel syndrome symptoms
What are the treatments for carpal tunnel syndrome?
Splint to hold in dorsi-flexion overnight
Corticosteroid injections into tunnel
Surgical decompression
What forms the carpal tunnel?
Deep carpal arch
Superficial flexor retinaculum
What forms the carpal arch?
Laterally by scaphoid and trapezium
Medially by hook of hamate and pisisform
Describe the path of the superficial flexor retinaculum.
Originates in lateral side and inserts on medial side of carpal arch
What happens to the median nerve once it passes through the carpal tunnel?
Divides into recurrent branch and palmar digital nerve branch
What does the palmar digital nerve give sensory innervation to?
Palmar skin
Dorsal nail beds of lateral 3.5 digits
What surrounds the 8 tendons of the flexor digitorum profundus and superficialis?
Synovial sheath
What is the flexor carpi radialis tendon associate with?
Flexor retinaculum
