Functional anatomy of hand and wrist Flashcards
What comprises the wrist joint?
Distal radius (NOT ulna), triangular fibrocartilage complex (TFCC), scaphoid + lunate
What type of joint is the wrist joint?
Ellipsoid synovial = allows movement in 2 axes (flex, ext., adduct, abduct = circumduction)
What 4 ligaments stabilise the wrist joint?
Dorsal + palmar radiocarpal ligaments = attach radius to carpal
Ulnar + radial collateral ligaments
How many carpal, metacarpals + phalanges?
8
5
14 (proximal, middle + distal, ONLY proximal + distal on thumb)
What are the 8 carpal bones in the proximal and distal rows from radial (lateral) to ulnar?
Some Lovers Try Positions That They Can’t Handle
PROXIMAL = Scaphoid, Lunate, Triquetrum, Pisiform DISTAL = Trapezium, trapezoid, capitate hamate
What is the blood supply of the scaphoid?
Dorsal carpal branch of radial artery
Retrograde
Describe the articulations of the 5 metacarpals (radial to ulnar)
1 = trapezium + prox. phalanx thumb 2 = trapezoid + prox. phalanx index 3 = capitate + prox. phalanx middle finger 4 = hamate + prox. phalanx ring 5 = hamate + prox. phalanx little
What are the 4 compartments of hand muscles?
Thenar compartment
Adductor compartment
Hypothenar compartment
Central compartment
Generally, describe the thenar compartment
Cause thenar eminence = prominence on radial palm Median nerve (exc. deep head flexor pollicis brevis = ulnar) Opponens pollicis, abductor pollicis brevis, flexor pollicis brevis
Describe opponens pollicis
From trapezium + flex. retinaculum to lateral border 1st metacarpal
Opposes thumb
Describe abductor pollicis brevis
Scaphoid/trapezium/flexor retin. to lat. border of proximal phalanx thumb
Palmar abduction of thumb
Describe flexor pollicis brevis
SUPERFICIAL HEAD = trapezium + flex. retin.
DEEP HEAD = trapezoid + capitate
Ulnar aspect base of proximal phalanx thumb
Flex MCPJ
What compartment is adductor pollicis in? Describe the muscle
Adductor
Ulnar nerve
TRANSVERSE HEAD = shaft of 3rd metacarpal
OBLIQUE HEAD = capitate, base of 2nd + 3rd metacarpals
Ulnar aspect base of prox. phalanx thumb
Adducts thumb
Describe the hypothenar compartment
Causes hypothenar eminence = ulnar aspect
Ulnar nerve
Opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis
Describe opponens digit minimi
Hook of hamate/flex. retin. to ulnar margin 5th metacarpal
Rotates 5th metacarpal to palm = allows opposition against thumb
Describe abductor digiti minimi
Pisiform + tendon of flexor carpi ulnaris to base prox. phalanx little finger
Abducts little finger (only in coronal plane)
Describe flexor digiti minimi brevis
Hook of hamate/flex. retin. to base prox. phalanx little finger
Flex MCPJ little finger
Describe the central compartment
Palmaris brevis, palmar + dorsal interossei + 4 lumbricals
Radial 2 lumbricals = median nerve
Ulnar 2 lumbricals = ulnar nerve
Palmaris brevis + interossei = ulnar nerve
Describe palmaris brevis
From palmar aponeurosis + flex. retin. to dermis of skin on medial margin
Wrinkles skin of hypothenar eminence = deepens curvature of palm, improves grip
What is the role of the lumbricals?
Link flexor digitorum profundus tendon on palmar surface to ext. digitorum tendon on dorsum
Contract = flex fingers @ MCPJ, extend @ IPJ
Which lumbricals are bipennate and which are unipennate? What innervates them?
Unipennate = index, middle = median nerve Bipennate = ring, little = ulnar nerve
Describe lumbricals I and II (index + middle)
I = FDP from index finger to extensor digitorum of index II = FDP from middle to ED of middle
Describe lumbricals III and IV (ring + little)
III = FDP from middle + ring to ED of ring IV = FDP from ring + little to ED of little
Where are the interossei? What are the actions for the dorsal and palmar interossei? What innervates the interossei?
Between metacarpals DAB = dorsal abduct PAD = palmar adduct (assist lumbricals in flex./ext. @ MCPJ + IPJ) Ulnar nerve
