Hand and Wrist Anatomy

1
Hand and Wrist Anatomy

• 14 phalanges
• 2 sesamoid bones (thumb)
• 5 metacarpals
• 8 carpal bones
• Distal Radius
• Forms small ulnar notch to accept the ulnar head
• Radial styloid process
• Distal Ulna
• Ulnar styloid process arises from medial surface
• Ulnar head

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• Carpals(flat bones aligned in 2 rows)
• Proximal
• Scaphoid-most commonly fractures
• Lunate-most commonly dislocated
• Triquetrum
• Pisiform-acts as sesmoid bone
• Distal
• Trapezium(aligns with 1st metacarpal)
• Trapezoid(2nd metacarpal)
• Capitate(3rd metacarpal)
• Hamate(4th and 5th metacarpal)

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Articulations

• Distal Radioulnar
• Formed by ulnar head and ulnar notch
• Allows 1 degree freedom of movement
• Pronation/supination
• Radius glides around the ulna

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• Radiocarpal joint
• Reinforced by ligamentous thickening
• Formed by distal radius articulating with
  scaphoid, lunate and triangular fibrocartilage
  disk(TFCC)
• Ellipsoid joint (2 degrees freedom)
• Flexion/extension
• Radial/ulnar deviation

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• Intercarpal Joints
• Palmar/dorsal/interosseous ligaments between each
  carpal
• Very little gliding

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• Midcarpal Joints
• Proximal/distal carpal row separated by a single
  joint cavity with small fibrous projections
  connecting the rows
• Limited mobility in flex/ext, radial/ulnar
  deviation

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• Carpometacarpal Joint (CMC)
• MC1/trapezium
• MC2/trapezoid
• MC3/capitate
• MC4and 5/hamate (forms 1 articulation)

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• 1st CMC (thumb)
• Saddle joint
• 2 degrees of freedom(3)
• Flexion/extension
• Abduction/adduction
• Accessory rotation
• Allows for opposition

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• 2-4 CMC
• Plane/synovial joint
• 1 degree freedom
• Flexion/extension
• 5th CMC
• 2 degree freedom
• Flexion/extension
• Abduction/adduction

10

• Metacarpophalangeal Joint (MCP)
• Two degrees freedom of movement
• Flexion/extension
• Abduction/adduction
• Thumb can abduct at any point/fingers only when
  extended
• Collateral ligaments
• Varus/valgus force
• When fingers are in flexion they tighten and
  limit abduction/adduction

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• Interphalangeal Joint
• One degree freedom of movement
• Flexion/extension
• Collateral ligaments

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Muscular Anatomy

• Wrist Extensors (innervated by radial n.)
• Superficial
• Extensor carpi radialis brevis/longus
• Extensor carpi ulnaris
• Extensor digitorium
• brachioradialis
• Deep compartment
• Extensor pollicus longus/brevis
• Abductor pollicus longus
• Extensor indices
• supinator
• Secured by extensor retinaculum

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• Wrist flexors (median n.)
• Superficial
• Flexor carpi radialis
• Palmaris longus
• Flexor carpi ulnaris
• Flexor digitorium superficialis
• Pronator teres
• Deep
• Flexor digitorium profundus
• Flexor pollicis longus
• Pronator quadratus

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• Palmar (intrinsic)
• Thenar
• Abductor pollicis brevis
• Flexor pollicis brevis
• Opponens Pollicis
• Tendon FPL
• Adductor pollicis

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• Hypothenar
• Abductor digiti minimi
• Opponens digiti minimi
• Flexor digiti minimi brevis

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• Central
• Tendons FDS/FDP
• Superficialis (PIP)
• Profundus (DIP)
• Lumbricales
• Radial side profundus tendon(extensor hood)
• Flex MP/ext PIP/DIP
• Palmar aponeurosis
• Interossei
• 4 palmar/4 dorsal

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Carpal Tunnel

• Fibro-osseous structure
• Floor is proximal carpal bones
• Roof is transverse carpal ligament
• Tunnel contains 10 structures
• Median n., flexor pollicis longus tendon, 4 slips
  of flexor digitorium superficialis, flexor
  digitorium profundus
• Compression results in paresthesia 2-4 fingers
  and decrease grip

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• Wrist and Hand Evaluation

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History

• Location of pain
• Mechanism of injury
• Relevant sounds/sensations
• Duration of symptoms
• Description of symptoms
• Previous history
• General medical health

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Inspection

• General
• Posturing of hand
• Gross deformity
• Palmar Creases
• Areas of lacerations or scars
• Wrist
• Continuity of distal radius and ulna
• Continuity of carpals/metacarpals
• Lunate dislocation
• Alignment of MCP joint
• Posture of wrist and hand
• Ganglion cyst
• Volkmans Contracture
• Finger Deformities

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Inspection

• Hand
• Alignment of knuckles
• Depressed(metacarpal fracture)
• Alignment of fingernails
• Spiral fracture
• Boutonniere deformity
• Flex PIP, ext MP/DIP
• Mallet finger
• Inability to extend distal phalanx
• Avulsion of extensor tendon 25-35 flexion DIP
• Jersey Finger
• Ruptured FDP-inability to flex DIP

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Palpation

• Anteromedial
• Ulnar head
• Ulnar styloid process
• UCL-(styloid, triquetrum and pisiform)
• Pisiform
• Triquetrum
• Hamate
• Wrist flexor group
• Flexor Carpi Ulnaris
• Flexor Digitorium Profundus
• Palmaris Longus
• Flexor carpi radialis
• Carpal Tunnel

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• Posterolateral
• Radial shaft
• Distal radius and styloid process
• Radial collateral ligament
• Scaphoid(Anatomical snuff box)
• Extensor Carpi Radialis Longus
• Extensor Digitorium
• Extensor Carpi Ulnaris
• Thumb extensors (EPL, EPB)

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• Bony
• Carpals
• scaphoid
• Metacarpals
• Phalages
• Ulna
• Radius
• Listers Tubercle

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Palpation

• Hand
• Collateral ligaments of MCP(1-5)
• Phalanges
• Collateral ligaments of IP joints
• Thenar compartment
• Thenar webspace
• Central compartment
• Hypothenar eminence

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• Wrist AROM (2 degrees)
• PROM
• RROM
• Ligamentous/Capsular Testing
• Neurologic Testing
• Special Tests

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Wrist Goniometry

• Flexion and Extension
• Patient
• Forearm pronated with hand off edge of table
• Fulcrum
• Over lateral joint line of wrist
• Stationary Arm
• Centered midline of ulnar shaft
• Movement Arm
• Centered on midline of 5th metacarpal

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• Radial and Ulnar Deviation
• Patient
• Forearm is pronated with hand resting on table
• Fulcrum
• Aligned with the center of distal radioulnar
  joint just proximal to capitate
• Stationary Arm
• Centered over midline of forearm
• Movement Arm
• Centered over 3rd metacarpal

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• Wrist AROM
• 2 degrees
• Sagittal plane
• Flexion (80-90)
• Extension (75-85)
• Fingers relaxed to ensure maximum ROM
• Frontal plane (in neutral)
• Radial (20)
• Ulnar deviation (35)

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• PROM
• Flexion firm end point
• Extension firm end point
• Radial deviation hard (scaphoid/styloid)
• Ulnar deviation firm end point

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• RROM
• Flexion/extension
• Radial/ulnar deviation

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• Finger A/P/RROM MCP joint
• Flexion/extension MCP (105-135)
• Flexion hard end feel
• Extension firm
• Abduction/adduction MCP (20-25)
• Abduction firm
• Flexion/extension IP
• Test each finger individually

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Wrist Special Tests

• Valgus and Varus Test
• Patient
• Sitting with elbow flexed to 90 deg, forearm
  pronated
• Examiner
• One hand grips distal forearm other grasps hand
  across metacarpals
• Procedure
• UCL Valgus stress is applied (radially deviated
  wrist)
• RCL Varus stress is applied (ulnarly deviate
  wrist
• Positive Test
• Pain or laxity
• Implications

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• Wrist Glide
• Patient
• Sitting, elbow flexed to 90 deg, forearm pronated
• Examiner
• One hand grasps distal radius, other grasps
  proximal carpal row
• Procedure
• Shear force is applied to wrist by gliding distal
  segment in a radial and ulnar direction and then
  in a volar and dorsal direction
• Positive Test
• Pain or significant change in glide
• Implications

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• Ligamentous/capsular testing for fingers
• Valgus/Varus
• Full extension IP
• MCP-thumb
• Ulnar colateral (valgus)
• RCL of little finger

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• Murphys sign
• Patient makes a fist
• If the head of the third metacarpal is level with
  the 2nd and 4th metacarpal, sign is positive for
  lunate dislocation

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• Finkelsteins test
• Patient
• Seated or standing
• Procedure
• Tucks thumb under fingers by making a fist
• Ulnarly deviate wrist
• Positive test
• Increased pain over radial styloid process and
  length of extensor pollicis brevis and abductor
  pollicis longus
• Implication
• deQuervians syndrome

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• Neurologic Testing
• Special tests
• Drop wrist syndrome
• Inability to extend wrist (radial n.)
• Tinels sign

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• Phalens Test
• Patient
• Standing or seated
• Procedure
• Examiner applies overpressure during passive
  wrist flexion and holds for 1 minute
• Positive Test
• Tingling in distribution of median n.
• Implications
• Median Nerve Compression

40

• Vascular Occlusion
• Allens test