Wrist and Hand

Wrist Joint

Wrist Joint• Bones

– Radius, Ulna– Carpal bones

• Pisiform, Triquetrum, Lunate, Scaphiod, Hamate, Capitate, Trapezium, Trapeziod

Articulations

• Distal RadioUlnar Joint

• Radiocarpal Joint

• MidCarpal Joint

• Intercarpal Joint

Distal Radioulnar Joint

• Does not participate in wrist movements

• Ulna has no contact with carpals

• Seperated by fibrocartilagenous disk which allows ulna to glide during pronation and supination

Radiocarpal Joint• Movement of whole hand takes place here

• Articulation of:– Distal Radius– Scaphoid and lunate

• Condyloid-type

• Allows for flexion/extension• 40% of flexion occurs at radiocarpal joint• 60% of extension occurs at radiocarpal joint

Radiocarpal Joint

Midcarpal Joint• These joints allow for translation of joint

with wrist movements

• Contributes to wrist flexion/extension– 60% of flexion occurs here

• 40% occurs at radiocarpal joint

– 30% of extension occurs here• 60% of extension occurs at radiocarpal joint

Midcarpal Joint• Radial and Ulnar deviation

– Proximal and distal carpal rows slide across each other

– Radial deviation• Proximal towards ulna, distal to radius

– Ulnar deviation• Proximal towards radius, distal to ulna

Intercarpal joints

• Between carpal bones of proximal row

• Midcarpal joint is between two rows of carpal bones (site of hand flexion and abduction)

• Carpals united by anterior, posterior, and interosseous ligaments

Intercarpal Joints

Palmar Dorsal

Wrist Joint Ligaments

• Ulnar Collateral Ligament

• Radial Collateral Ligament

• Volar Radiocarpal• Dorsal Radiocarpal

Ligaments of Wrist

Palmar Dorsal

Flexor Retinaculum

Extensor Retinaculum

Vascular Anatomy

• Forearm Arteries

Nerve Innervation (palmar)

Nerve Innervation (dorsal)

Movements of Wrist

• Flexion, extension, abduction (radial deviation), adduction (ulnar deviation)– Motion occurs mostly in proximal carpal row &

distal radius– 70°-90° of flexion– 70°-85° of extension– 15°-25° of abduction (radial deviation)– 25°-40° of adduction (ulnar deviation)

• Flexion– flexor carpi radialis– flexor carpi ulnaris– palmaris longus– assisted by:

• flexor digitorum superficialis• flexor digitorum profundus

Movement of the wrist

Superficial Muscles of Forearm

common flexor group

• Extension– extensor carpi radialis longus– extensor carpi radialis brevis– extensor carpi ulnaris– assisted by:

• other wrist extensor muscles

Movement of the wrist

common extensor group

common extensor group

Hand and Fingers

Wrist & HandPalmar Aspect

PhalangesMetacarpals

Carpals

Carpometacarpal Joint• Last four have very little movement-mostly

gliding joint which moves with carpals

• More movement at 4th and 5th articulation– Up to 10-30 degrees of flexion/extension in

these fingers

Carpometacarpal Joint• Thumb articulation

– Saddle joint provides major portion of thumb ROM

– 30-90 degrees of flexion– 15 degrees of extension– Sits at an angle of approx 60 deg.

Carpometacarpal Joints

DorsalPalmar

Metacarpophalangeal Joint• Last 4 allows for flexion/extension

– Abduction/adduction

• Ligamentous support is excellent

• Can flex from 70-90 deg, with most at 5th joint

• Can extend about 25 deg from relaxed position

• About 20 deg of ab/adduction

Metacarpalphalangeal Joints

Volar plate Deep Transverse Metacarpal

Collateral

Interphalangeal Joint

• Hinge Joints

• Allow for flexion/extension

• Most dislocations occur at these joints

• Collateral Ligaments provide good stability

• ROM– Proximal joint--110 degrees– Distal joint--90 degrees

Interphalangeal Joints (PIP)

Collateral Volar Plate

Interphalangeal Joints (DIP)

Collateral Volar Plate

Joints & Movements• Fingers

– Metacarpophalangeal Joint (MCP)

• Condyloid• 0°-40° of extension• 85°-100° of flexion

– Proximal interphalangeal Joint (PIP)

• Ginglymus• Full extension to 90°-

120° of flexion– Distal interphalangeal Joint

(DIP)• Ginglymus• Flex 80°-90° from full

extension

Thumb Joints• 2 joints

– Metacarpophalangeal (MCP)• Ginglymus• Full extension into 40°-90° of flexion

– Interphalangeal (IP)• Ginglymus• Flex 80°-90°

• Carpometacarpal (CMC) joint• Saddle joint• 50°-70° of abduction• Flex 15°-45° & extend 0°-20°

Finger Movement• Middle phalange is reference

point to differentiate abduction & adduction– Thumb, index & middle fingers

abduct when they move laterally toward radial side of hand

– Ring & little fingers abduction when they move medially toward ulnar side of hand

– Medial movement of thumb, index & middle fingers toward ulnar side of hand is adduction

– Lateral movement of ring & little finger toward radial side of hand is adduction

Intrinsic Muscles of the Hand

• Thenar muscles

• Hypothenar muscles

• Midpalmar muscles

– Interossei

– Lumbrical

Palmar Interossei

Dorsal Interossei

Thenar muscles

• Adductor pollicis

• Flexor pollicis brevis

• Abductor pollicis brevis

• Opponen pollicis

Hypothenar muscles

• Flexor digiti minimi

• Abductor digiti minimi

• Opponen digiti minimi

Anatomical Snuffbox

• Extensor pollicis longus (medial side)

• Extensor pollicis brevis (lateral side)

• Abductor pollicis longus (lateral side)

MedialLateral

3 Types of Grips• Cylindrical--Holding a bat or golf club

– Ulnar deviation enhances force of grip

• Spherical--More spread of fingers– Holding a basketball

• Hook--Precision handling– Holding a coffee cup or scalpel