1how is the wrist oriented?
flexion and ulnar deviation
2the radiocarpal joint is made up of the articulation between
distal radius, ulna, TFCC, and the proximal carpal row
3the TFCC is firmly attached to the
Radioulnar ligaments
4the TFCC moves with the
radius during pronation and supination
5the TFCC increases what for the radiocarpal joint?
joint congruency, large space between triquetrum and ulna
6the TFCC absorbs
forces trasmitted through the wrist on the medial side
7the TFCC is an attachment for the
ECU tendon
8midcarpal row is the articulation between
proximal row and the distal row of carpal bones
9the central pillar and axis of rotation of the wrist is the
capitate
10the distal carpal joint is the articulation between the
distal carpal row and proximal metacarpals 2-5
11arthrokinematics of all the wrist joints
proximal radiocarpal - convex on concave
midcarpal - convex on concave
distal - concave on convex
12Important intercarpal ligaments and their function
scapholunate and lunotriquestral
keep the proximal row together so that they move as a unit
13wrist extensor prime movers
Extensor Carpi Radialis Longus and Brevis, Extensor Carpi Ulnaris
Assistors - ED
14wrist flexor prime movers
Flexor carpi radialis, flexor carpi ulnaris, palmerus longus
Assistors - FDS and FDP and FPL
15Radial Deviators
Prime - Extensor Carpi radialis longus and flexor carpi radialis
Assistors - APL, EPL and brevis
16Ulnar Deviators
Prime - FCU, ECU
17arthrokinematics of MCP, DIP, and PIP
concave on convex
18MCP degrees of Freedom
2
19arthrokinematics at the thumb (ab/adduction vs flexion/extension)
ab/adduction - convex on concave
flexion/extension - concave on convex
20Gripping Muscles - Main extensor
ECRB - extends the wrist, followed by ECU and ECRL when force increases
21maximal grip force is produced at what position of the wrist?
20-30 degrees of wrist extension
22finger flexors (extrinsic and intrinsic)
Extrinsic - FDS and FDP (with ED and ECRB)
Intrinsic - Interossei and Lumbricals
23How does finger flexion work?
active contraction: interossei and finger flexors
passive tension: lumbricals (flexion torque)
synergy: ECRB to offset flexion moment + optimize length tension of long finger flexors
Stabilize: ED at MCP
24Finger extensors (extrinsic and intrinsic)
extrinsic - ED, EI, EDM
Intrinsic - Interossei and Lumbricals
all are actively contracting!
25How does finger extension work?
ED extends the wrist and flexes the fingers - don't want finger flexion!
fix - contract lumbricals and interossei to pull on the extensor hood and not allow MCP hyperextension
Combat Wrist Extension - use FCR