Wrist
Wrist is a joint complex consisting of radio-carpal joint and many relationships between the carpal bones
Review of carpals Proximal row = Pisiform, Triquetrum, Lunate,
and Scaphoid* Distal row = Hamate, Capitate, Trapezoid, and
Trapezium *Scaphoid has a notoriously poor blood supply
and recovers poorly following injury
Wrist
All carpal bones articulate via gliding or plane joints
A more or less joint exists between proximal row and distal row of bones called mid-carpal – truly is a series of gliding joints
Scaphoid, Lunate and Triquetrum with Trapezium, Trapezoid, Capitate and Hamate
Pisiform is not involved
Wrist
True Wrist = Radio-Carpal• “Ulnar-Carpal” = interposed disc
Distal radius with proximal carpals Condyloid joint – 2 degrees of freedom Major Ligaments Palmar radio-carpal, palmar ulnocarpal,
dorsal radio-carpal, dorsal ulno-carpal, radial and ulnar collateral
Wrist
Mid-Carpal Proximal row of carpals with distal row A series of gliding joints – 3 DOF MAJOR Ligaments – Capsule plus Pisohamate, pisometacarpal,
capitotriquetral, palmar and dorsal carpometacarpal
Wrist
Movements Flexion/Extension – about 70-80 degrees of ROM
• Radiocarpal v. Mid Carpal
• Flexion is initiated in mid carpal joint and 60% occurs there
• Extension is also initiated at mid carpal but most occurs in radio-carpal. Need 35 degrees for good function – at least 10 for any significant function.
Abduction/Adduction – about 15 to 20 degrees• Intercarpal – proximal row slides over distal row
Carpo-Metacarpal Joints
2-5• Hamate with 4 and 5
• Capitate with 3
• Trapezoid with 2
Gliding joints with limited range – mostly passive
Palmar and Dorsal carpometacarpal ligaments
Metacarpal – Phalangeal Joints
Ellipsoid 2 DOF Passive rotation Collateral Ligaments Deep Transverse Metacarpal Ligaments Palmar Ligaments (Plates)
Definition of Finger Movements
Reference is imaginary line through the middle of long (3rd) finger
Adduction of 2-5 = towards that point Abduction = away –1, 4, and 5 Thumb
• Flexion
• Extension
• ABD
• ADD
• Rotation
• Opposition = flexion with adduction and rotation
Flexor Tendons
Tenosynovium (AKA Fibro-Osseous Tunnels)
Anular Pulleys AKA Vaginal Ligaments• Anular and Cruciform
• Relationship to Palmar Plates
Dorsal Hood Mechanism
Insertion of Long Extensor Tendons• Ext. Dig. Communis
• Ext. Indicis Proprius
• Ext. Digiti Minimi
Extensor Expansion – MP Joints Central Band – Middle Phalanx Lateral Band –Distal Phalanx Relationship to Intrinsic Muscles
Intrinsic Muscles
Thenar Eminence - median Hypothernar Eminence - ulnar Intermediate – ulnar and some median There are NO muscles in the hand
innervated by the Radial nerve
Blood Supply
Ulnar aa• Superficial Palmar Arch
• Common Palmar aa
• Proper palmar digital aa Radial aa
• Deep Palmar Arch
• Dorsal digital aa
• Princeps Pollicus
• Radialis Indicis
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