The Wrist ComplexPRESENTED BY : USMAN FAROOQ

The Wrist Complex

The wrist (carpus) consists of two compound joints:

The radiocarpal and the

midcarpal joints,

referred to collectively as the wrist complex

Wrist Complex

The shoulder serves as a dynamic base of support; the elbow allows the hand to approach or extend away from the body; and the forearm adjusts the approach of the hand to an object.

The major contribution of the wrist complex seems to be to control length-tension relationships in the multi articular hand muscles and to allow fine adjustment of grip.

The wrist has been called the most complex joint of the body, from both an anatomic and physiologic perspective.

The wrist complex as a whole is considered to be biaxial, with motions of

extension/flexion around a coronal axis

ulnar deviation/radial deviation around an anteroposterior axis.

Normal ranges are cited as

Wrist flexion, 65 to 85

extension 60 to85 ,

radial deviation 15 to 21

ulnar deviation 20 to 45

Radiocarpal Joint Structure

The radiocarpal joint is formed by the radius and radioulnar disk as part of the triangular fibrocartilagecomplex (TFCC) proximally and by the scaphoid, lunate, and triquetrum distally

Triangular fibrocartilagecomplex (TFCC)

The TFCC is essentially comprised of the fibrocartilage disc interposed between the medial proximal row and the distal ulna within the medial aspect of the wrist

The primary function of the TFCC is to improve joint congruency and to cushion against compressive forces

The TFCC transmits about 20% of the axial load from the hand to the forearm

Anatomy

The Wrist

Comprised of the distal radius and ulna, eight carpal bones, and the bases of five metacarpals

The carpal bones lie in two transverse rows

The proximal row contains (lateral to medial) the scaphoid (navicular), lunate, triquetrum, and pisiform

The distal row holds the trapezium, trapezoid, capitate, and hamate

Anatomy

Mid Carpal Joints

The midcarpal joint lies between the two rows of carpals

A ‘compound’ articulation because each row has both a concave and convex segment

The proximal row of the carpals is convex laterally and concave medially.

The scaphoid, lunate, trapezium trapezoid, and triquetrum present with a concave surface to the distal row of carpals

Anatomy

Carpal Ligaments

The major ligaments of the wrist include the palmarintrinsic ligaments, and the dorsal extrinsic and intrinsic ligaments

The extrinsic palmar ligaments provide the majority of the wrist stability

The intrinsic ligaments serve as rotational restraints, binding the proximal row into a unit of rotational stability

Anatomy

Radiocarpal Joint

Formed by the large articular concave surface of the distal end of the radius, the scaphoid and lunate of the proximal carpal row, and the TFCC

Anatomy

Antebrachial Fascia

A dense connective tissue ‘bracelet’ that encases the forearm and maintains the relationships of the tendons that cross the wrist

Anatomy

The Extensor Retinaculum

This retinaculum serves to prevent the tendons from ‘bow-stringing’ when the tendons turn a corner at the wrist

Anatomy

The extensor retinaculum compartments, from lateral to medial, contain the tendons of:

Abductor pollicis longus and extensor pollicis brevis

Extensor carpi radialis longus and brevis

Extensor pollicis longus

Extensor digitorum and indicis

Extensor digiti minimi

Extensor carpi ulnaris

Anatomy

The Flexor Retinaculum

Transforms the carpal arch into a tunnel, through which pass the median nerve and some of the tendons of the hand

Proximally, the retinaculum attaches to the tubercle of the scaphoid and the pisiform

Distally it attaches to the hook of the hamate, and the tubercle of the trapezium

In the condition known as ‘carpal tunnel syndrome’ the median nerve is compressed in this relatively unyielding space

Anatomy

Carpal Tunnel

Serves as a conduit for the median nerve and nine flexor tendons

The palmar radiocarpal ligament and the palmar ligament complex form the floor of the canal

The roof of the tunnel is formed by the flexor retinaculum (transverse carpal ligament)

The ulnar and radial borders are formed by carpal bones (trapezium and hook of hamate respectively)

Within the tunnel, the median nerve divides into a motor branch and distal sensory branches

Anatomy

Tunnel of Guyon

A depression superficial to the flexor retinaculum, located between the hook of the hamate and the pisiform bones

The palmar (volar) carpal ligament, palmaris brevismuscle, and the palmar aponeurosis form its roof

Its floor is formed by the flexor retinaculum(transverse carpal ligament), pisohamate ligament, and pisometacarpal ligament

The tunnel serves as a passage way for the ulnar nerve and artery into the hand

Biomechanics

The wrist contains several segments whose combined movements create a total range of motion that is greater than the sum of its individual parts

Biomechanics

Pronation

Approximately 90° of forearm pronation is available

During pronation, the concave ulnar notch of the radius glides around the peripheral surface of the relatively fixed convex ulnar head

Pronation is limited by the bony impaction between the radius and the ulna

Biomechanics

Supination

Approximately 85-90° of forearm supination is available

Supination is limited by the interosseous membrane, and the bony impaction between the ulnar notch of the radius, and the ulnar styloid process

Biomechanics

Wrist flexion and extension

The movements of flexion and extension of the wrist are shared among the radiocarpal articulation, and the intercarpal articulation, in varying proportions

Biomechanics

Wrist flexion and extension

During wrist flexion, most of the motion occurs in the midcarpal joint (60% or 40°versus 40% or 30° at the radiocarpal joint), and is associated with slight ulnar deviation and supination of the forearm

During wrist extension, most of the motion occurs at the radiocarpal joint (66.5% or 40°versus 33.5% or 20° at the midcarpal joint), and is associated with slight radial deviation and pronation of the forearm

Biomechanics

Radial Deviation

Radial deviation occurs primarily between the proximal and distal rows of the carpal bones

The motion of radial deviation is limited by impact of the scaphoid onto the radial styloid, and ulnar collateral ligament

Biomechanics

Ulnar deviation

Ulnar deviation occurs primarily at the radiocarpal joint

Ulnar deviation is limited by the radial collateral ligament

Clinical Examinationof the

Wrist Joint

HISTORY

Age

Chief complaint

Occupation

Previous injury

Previous surgery

What exacerbates

What improves

Frequency

Duration

HISTORY

4 principle mechanisms of injury

Throwing

Weight bearing

Twisting

Impact

PHYSICAL EXAM

Inspection

Palpation

Range of Motion

Neurologic Exam

Special Tests

Ganglion

Cystic structure that arises from synovial sheath

Discrete mass

Dull ache

Dorsal or Volar aspect

RANGE OF MOTION

Active range of motion

Passive range of motion if unable to actively move joint

Bliateral comparison

To determine degrees of restriction

RANGE OF MOTIONWrist

Flexion

Extension

Radial deviation

Ulnar deviation

Ulnar deviation is greater than radial

PALPATION of Wrist Dorsum

Radial Styloid

Scaphoid

1st MC/Trapezium jt

Lunate

Lister’s Tubercle

Ulnar Styloid

TFCC

Triquetrum

Pisiform

Hook of Hamate

Guyon’s Tunnel

Radial Styloid palpation Scaphoid Bone palpation

Radial styloid

Scaphoid Fracture

Most commonly fractured carpal bone

70-80% of all carpal bone injuries

8% of all sports related fractures

1 in 100 college football players

Most susceptible to injury

Bridges proximal and distal rows of the carpal bones

Load to the dorsiflexed wrist as in fall onto outstretched hand

Scaphoid Fracture

Painful, swollen wrist after a fall

Tenderness in snuffbox

High frequency of nonunion and avascular necrosis

Initial x-rays often unremarkable

1st MC/Trapezium joint palpation

Lunate Bone palpation

Scapholunate Dissociation

Diagnosis often missed

Pain, swelling, and decreased ROM

Pressure over scaphoid tuberosity elicits pain

Greatest pain over dorsal scapholunate area, accentuated with dorsiflexion

X-ray shows widening of scapholunate joint space by at least 3 mm

Ulnar Styloid palpationLister’s Tubercle palpation

Ulnar styloid

Triangular Fibro-Cartilage Complex palpation (TFCC)

Triangular Fibrocartilage Complex Injuries Thickened pad of connective tissue that functions as a cushion

for the ulnar carpus as well as a sling support for the lunate and triquetrum

Injury from compression between lunate and head of ulna

Breaking fall with hand

Rotational forces-racket and throwing sports

Triangular Fibrocartilage Complex Injuries

Ulnar sided wrist pain, swelling, loss of grip strength

“Click” with ulnar deviation

Point tenderness distal to ulnar styloid

TFCC load test

Carpal Tunnel

Deep to palmaris longus

Contains median nerve and finger flexor tendons

Most common overuse injury of the wrist

Carpal Tunnel Syndrome

Entrapment of the median nerve

Phalen’s and Tinel’s Test

2 point discrimination

Symptoms

Aching in hand and arm

Nocturnal or AM paresthesias

“Shaking” to obtain relief

Carpal Tunnel Tests

Neurologic exam

Median nerve sensation and motor

Phalen’s Test:both wrists maximally flexed for 1 minute

Tinel’s Test

NEUROLOGIC EXAM

Muscular assessment using grading system

Sensation testing

Bilateral comparison

NEUROLOGIC EXAMMuscle Testing

WRIST

EXT C6

FLEX C7

FINGERS

EXT C7

FLEX C8

ABD T1

ADD T1

Sensation TestingDorsal hand Radial hand