Wrist / Hand Complex Flashcards
Wrist (Carpus) Complex
The radiocarpal and midcarpal joints
Major contribution of the Wrist Complex
-Control length-tension relationship in the multiarticular hand muscles
-Allow fine adjustment of grip
Wrist muscles designed for …
balance and control vs force production
Radiocarpal joint composed of:
Proximally:
Radius
Radioulnar disc
Distally:
Scaphoid
Lunate
Triquetrum
Radiocarpal joint articulation
Scaphoid w/ lateral radial facet
Lunate w/ medial radial facet
Triquetrum w/ triangular fibrocartilage complex TFCC)
Midcarpal joint composed of:
Scaphoid
Lunate
Triquetrum
Trapezium
Trapezoid
Capitate
Hamate
Wrist complex
Biaxial
Flexion/extension around coronal axis
Radial / Ulnar Deviation around A-P axis
Radiocarpal joint surface is…
Oblique and angles slightly volarly and ulnarly
Normal angle inclination: 23 deg (Ulnar)
11 deg (Volar)
Palmer / Volar Ligaments
-Palmer Radiocarpal Ligament
-Radial Collateral Ligament
-Palmer Intercarpal Ligament
-Transverse Carpal Ligament
Dorsal Ligaments
-Dorsal Radiocarpal Ligament
-Dorsal Intercarpal Ligament
-Ulnar Collateral Ligament
Importance of the Scaphoid
-Greatest mobility of the proximal carpal bones
-Acts as a link between the proximal and distal carpal rows
Triangular Fibrocartilage Complex (TFCC)
-Articulates with triquetrum and partially with the lunate
-Radioulnar disc is a continuation or the articular cartilage of the radius
Wrist Movement
Open packed-neutral between flex/ ext
Closed packed-full ext and radial deviation
Wrist flexion Normal Range
65-85 deg
Wrist Extension Normal Range
60-85 deg
Radial deviation Normal Range
15-21 deg
Ulnar deviation Normal Range
20-45 deg
Volar Wrist Musculature
6 muscles cross volar surface of wrist and contribute to wrist flexion
PL, FCR, FCU, FDS, FDP, FPL
Carpal Tunnel
FDS tendons
FDP tendons
FPL tendon
Median nerve
Dorsal Wrist Musculature
9 muscles cross the dorsal aspect of wrist and contribute to wrist extension
Extensor retinaculum provides 6 distinct compartments for these muscles
Compartment 1 and 2
(dorsal)
- APL, EPB
- ECRB, ECRL
Compartment 3 and 4
(dorsal)
- EPL
- ED, EI
Compartment 5 and 6
(dorsal)
- EDM
- ECU
Flexion/Extension
Carpals on radius = convex on concave
Opposite roll and glide
Flexion; scaphoid tends to move with the distal carpal row with the proximal row following
Extension initiated by distal carpal row