kin 191 b – wrist, hand and finger anatomy

KIN 191B – Advanced Assessment of Upper

Extremity Injuries

Wrist, Hand and Finger Anatomy

Anatomy

Bony anatomy

Articulations and ligamentous support

Muscular anatomy

Neurovascular anatomy

Carpal tunnel

Bony Anatomy

Bony Anatomy

Distal radius and ulna

Carpal bones

Metacarpals

Phalanges Proximal, middle and distal

Bony Anatomy

Distal Radius and Ulna

Distal radius broadens Ulnar notch articulates with ulnar head (distal

radioulnar joint) Radial styloid process (thumb side)

Distal ulna terminates at ulnar head Ulnar head has circular appearance Ulnar styloid process (little finger side)

Carpal Bones

Total of eight bones – 2 rows of 4 Irregular shapes and surfaces

Proximal row Articulate with distal radius (radiocarpal joint)

Distal row Articulate with proximal aspect of metacarpals

Carpal Bones

Proximal row (lateral to medial) Scaphoid Lunate Triquetrum Pisiform

“Some Lovers Try Positions”

Distal row (lateral to medial) Trapezium Trapezoid Capitate Hamate

hook

“That They Can’t Handle”

Metacarpals

Numbered 1 through 5 (lateral to medial)

Represent most of length of hand – all have base, shaft and head from proximal to distal

Proximal aspects articulate with distal row of carpals – carpometacarpal joints

Distal aspects articulate with proximal aspect of proximal phalanges of fingers

Phalanges

Each phalange has base, shaft and head from proximal to distal

All fingers (2nd through 4th digits) have proximal, middle and distal phalanges

Thumb (1st digit) has only proximal and distal phalanges

Bony Anatomy

Articulations and Ligamentous Support

Articulations

Distal radioulnar joint Radiocarpal joint Intercarpal joints Carpometacarpal joints Metacarpophalangeal joints Interphalangeal joints (proximal and distal) Retinaculum and palmar aponeurosis

Distal Radioulnar Joint

Head of ulna articulating with ulnar notch on distal radius

Contributes to forearm pronation and supination ROM (with proximal radioulnar joint)

Radiocarpal Joint

Comprised of 2 articulations Laterally – distal radius with scaphoid and

lunate bones Medially – triangular fibrocartilaginous disc

(TFCC) with lunate and triquetrum

Allows for flexion/extension and radial/ulnar deviation movements

Radiocarpal Joint

Radiocarpal Joint

Radial collateral ligament Radial styloid process to scaphoid and trapezium Limits ulnar deviation, terminal wrist flexion and

extension

Ulnar collateral ligament Ulnar styloid process to triquetrum and pisiform Limits radial deviation, terminal wrist flexion and

extension

Radiocarpal Joint

Palmar (volar) radiocarpal ligament Most important stabilizer of wrist Anterior distal radius to capitate, triquetrum and

scaphoid Collectively limits wrist hyperextension

Dorsal radiocarpal ligament Only major stabilizer on dorsal wrist Posterior distal radius to lunate and triquetrum Limits wrist hyperflexion

Radiocarpal Joint

Intercarpal Joints

Individual ligaments connecting adjacent carpal bones (named as such) within proximal and distal rows

Contribute to significant stability of bones

Subtle gliding motions allowed between adjacent bones, but no collective gross movements allowed

Carpometacarpal Joints

First 3 metacarpals articulate with single carpal bone each 1 – trapezium 2 – trapezoid 3 – capitate

4th and 5th metacarpals articulate with same bone - hamate

Carpometacarpal Joints

1st and 5th carpometacarpal joints allow for flexion/extension and abduction/adduction movements 1st also has accessory rotation to

accommodate opposition/reposition

2nd through 4th carpometacarpal joints allow only flexion/extension movements

Metacarpophalangeal (MP) Joints

Articulations between convex metacarpal heads and corresponding concave base of proximal phalanges

Allow for flexion/extension and abduction/adduction movements 2nd through 5th digits have more

abduction/adduction ROM when extended

Hand Articulations

Metacarpophalangeal (MP) Joints

MP joint ligamentous support Varus/valgus forces resisted by radial (lateral) and

ulnar (medial) collateral ligaments – tighter in flexion than extension

Palmar (volar) aspect reinforced by thick, fibrocartilaginous palmar (volar) ligament

Dorsal aspect reinforced by extensor tendinous structure and deep transverse metacarpal ligament – limits abduction/adduction

Interphalangeal (IP) Joints

IP joint only at thumb due to only 2 phalanges Proximal interphalangeal (PIP) joints between

proximal and middle phalanges of 2nd through 5th digits

Distal interphalangeal (DIP) joints between middle and distal phalanges of 2nd through 5th digits

Varus/valgus forces resisted by radial (lateral) and ulnar (medial) collateral ligaments

Interphalangeal Joints

Flexor Retinaculum orTransverse Carpal Ligament

Palmar Aponeurosis

Muscular Anatomy

Muscular Anatomy

Extrinsic muscles acting on wrist, hand and fingers

Intrinsic muscles acting on wrist, hand and fingers

Extrinsic Muscles

Abductor pollicis longus Extensor pollicis brevis Extensor carpi radialis

longus Extensor carpi radialis

brevis Extensor carpi ulnaris Extensor digitorum

(communis) Extensor indicis

Extensor digiti minimi Flexor carpi radialis Flexor carpi ulnaris Flexor digitorum

superficialis Flexor digitorum

profundus Flexor pollici longus Palmaris longus

Extrinsic Muscles

Origin, insertion, innervation and action of each addressed with elbow presentation

Refer to 4 groups of 3 for review of extensor muscles (no brachioradialis, supinator or anconeus)

Refer to hand placement/layers for review of flexor muscles (no pronators)

Intrinsic Muscles

Abductor digiti minimi Abductor pollicis

brevis Adductor pollicis Flexor digiti minimi Flexor pollicis brevis

Opponens pollicis Opponens digiti

minimi Lumbricales Palmar interossei Dorsal interossei

Hand Eminences

Thenar eminence – thumb Abductor pollicis

brevis Flexor pollicis brevis Opponens pollicis Tendon of flexor

pollicis longus

Hypothenar eminence – little finger Abductor digiti minimi Flexor digiti minimi Opponens digiti minimi

Abductor Digiti Minimi

O: flexor carpi ulnaris tendon, pisiform

I: ulnar side of base of 5th proximal phalanx

N: ulnar A: abduction of 5th

finger

Abductor Pollicis Brevis

O: flexor retinaculum, trapezium, scaphoid

I: radial side of base of 1st proximal phalanx

N: median A: abduction of 1st

CMC and MP joints, opposition

Adductor Pollicis

O: capitate, 2nd and 3rd metacarpal bases

I: ulnar side of base of 1st proximal phalanx

N: ulnar A: adduction of 1st

CMC and MP joints, opposition

Flexor Digiti Minimi

O: hook of hamate I: ulnar side of 5th

proximal phalanx N: ulnar A: 5th MP joint flexion,

opposition

Flexor Pollicis Brevis

O: flexor retinaculum, trapezoid, captitate

I: radial side of base of 1st proximal phalanx

N: median, ulnar A: flexion of 1st CMC

and MP joints, opposition

Opponens Pollicis

O: flexor retinaculum, trapezium

I: 1st metacarpal shaft N: median A: thumb opposition

Opponens Digiti Minimi

O: flexor retinaculum, hook of hamate

I: ulnar side of shaft of 5th metacarpal

N: ulnar A: opposition of 5th

finger

Lumbricales

O: 1 & 2 - radial surface of flexor profundus tendons, 3 – adjacent sides of flexor profundus tendons of 3rd and 4th fingers, 4 – adjacent sides of flexor profundus tendons of 4th and 5th fingers

I: radial border of extensor tendons of respective fingers

N: 1 & 2 – median, 3 & 4 – ulnar A: flexion of MP joints, extension of PIP/DIP

joints

Lumbricales

Palmar Interossei

O: 1 – ulnar border of 2nd metacarpal, 2 – radial border of 4th metacarpal, 3 – radial border of 5th metacarpal

I: 1 – ulnar side of 2nd proximal phalanx, 2 – radial side of 4th proximal phalanx, 3 – radial side of 5th proximal phalanx

N: ulnar A: adduction of 2nd , 4th and 5th fingers (middle

finger is reference point)

Palmar Interossei

Dorsal Interossei

O: 1 – radial border of 2nd metacarpal, 2 – radial border of 3rd metacarpal, 3 – ulnar border of 3rd metacarpal, 4 – ulnar border of 4th metacarpal

I: 1 – radial side of 2nd proximal phalanx, 2 – radial side of 3rd proximal phalanx, 3 – ulnar side of 3rd proximal phalanx, 4 – ulnar side of 4th proximal phalanx

N: ulnar A: abduction of 2nd through 4th fingers (middle

finger is reference point)

Dorsal Interossei

Neurovascular Anatomy

Neurological Anatomy

Peripheral nerves Median Ulnar Radial

Nerve root level (brachial plexus) distribution Dermatomes Myotomes

Sensory Maps

Vascular Anatomy

Radial artery

Ulnar artery

Superficial and deep arch vessels in hand

Capillary refill

Vascular Supply

Radial artery lateral (thumb side) Common pulse point

Ulnar artery medial (little finger side)

Hand Vascular Supply

Carpal Tunnel

Carpal Tunnel

Floor – proximal row of carpal bones Roof – transverse carpal ligament Contents (10 structures)

Median nerve Flexor pollicis longus tendon 4 tendons of flexor digitorum superficialis 4 tendons of flexor digitorum profundus

Carpal Tunnel