Hand Joints

Wrist joint (radiocarpal articulation)

Classification:

Synovial ellipsoid joint

Articular surfaces:

Concave ellipsoid distal surface of radius and articular disc
Convex proximal surfaces of :

Triquetral(1)
Lunate(2)
Scaphoid(3) bones

Capsule:

Surrounds the joint and is thickened to form palmar, dorsal and collateralligaments

Innervation:

Posterior and anterior interosseous nerves

Blood Supply

Carpal rete: Ventral and dorsal network

Movements:

Flexion

Extension

radial abduction

ulnar adduction

Movements accompanied by those at midcarpal joint

Total range of flexion 80° , of extension 60°

More flexion at midcarpal joint while more extension at wrist joint

Range of abduction 15° , range of adduction 45° . Why the difference?

Movements produced by:

Movement	Muscle
Flexion	flexor carpi radialis, flexor carpi ulnaris, palmaris, flexors of Fingers and thumb
Extension	Radial extensors, ulnar extensor, extensors of fingers and thumb
Abduction	Flexor carpi radialis, two radial extensors, abductor pollicis longus
Adduction	flexor carpi ulnaris, extensor carpi ulnaris

Intercarpal joints

Synovial
Intercarpal ligaments connect the bones. Flexor retinaculum is an accessory intercarpal ligament
Thin capsule
Synovial cavity may communicate with radiocarpal joint
Midcarpal joint is a compound sellar joint between the proximal and distal row of carpal bones
Carpometacarpal joints often communicate with intercarpal joints

The 1 st carpometacarpal joint of the thumb is a saddle joint between trapezium and 1 st metacarpal. Opposition occurs here. It has a loose and lax capsule allowing ranges of movement

Metacarpophalangeal joints

Synovial joints allowing flexion, extension, abduction and adduction
Palmar ligaments limit extension
Transverse metacarpal ligaments are additional stability
Collateral ligaments flank the joints

Interphalangeal joints

Uniaxial
Capsule
Extension is limited by palmar and collateral ligaments

1st Carpometacarpophalangeal Joint

Classification

Synovial joint of sellar variety

Articular surfaces

1st metacarpal base and trapezium

Reasons for increased mobility

Extensive articular surfaces and their shape
Laxity of the capsule
Obliquity of ligaments

Capsular attachments

From: Circumference of metacarpal base

To: Rim of distal trapezial articular facet

Capsule is thickest laterally and dorsally

Ligaments

Lateral ligament: From lateral surface of trapezium to radial side of metacarpal base

Palmar and dorsal ligaments: From palmar and dorsal surfaces of trapezium to ulnar side of metacarpal base

Relations

Palmar surface:

Thenar muscles

Dorsal surface:

Long and short extensors

Medial:

1st dorsal interosseous
Tendon of flexor pollicis longus

Lateral

Tendons of abductor pollicis longus
Extensor pollicis brevis

Movements

Movement	Muscles	Innervation
Flexion	Flexor pollicis brevis Opponens brevis Flexor pollicis longus	Median nerve
Extension	Abductor pollicis longus Extensor pollicis brevis and longus	Radial N.
Abduction	Abductor pollicis longus and brevis	Radial N.
Adduction	Adductor pollicis	Radial N.
Opposition	Opponens pollicis	Ulnar N.
Circumduction	All above muscles	All nerves

Innervation

Radial n.
Median n.
Ulna n.

Blood supply

Branches of radial artery