Wrist Flashcards
Allows the wrist and hand to rotate on the radius farther into ulnar deviation than into radial deviation
Ulnar tilt
What is the normal degree for ulnar tilt?
25 degrees
The distal articular surface of the radius is angered about ___ degrees in the palmar direction. This _______ accounts, in part, for greater amounts of flexion than extension in the wrist
10; palmar
Which row of carpal bones is relatively loose? which row is bound tightly by strong ligaments?
proximal; distal (creates a stable base for metacarpal bones)
Arches over the concave carpal bones to form tunnel
Transverse carpal ligament
What is contained in the carpal tunnel?
- median nerve
- 4 tendons of flexor digitorum superficialis
- 4 tendons of flexor digitorum profundus
- tendon of pollicis longus
What prevents contained ligaments from bowstringing anteriorly and out of the carpal tunnel during grasping actions performed with a partially flexed wrist?
transverse carpal ligament
Where is the axis of rotation in the wrist?
Head of capitate (firmly articulated with 3rd metacarpal)
- for both medial-lateral and anterior-posterior
What is the ROM for wrist flexion? extension?
70-85
60-75
- flexion normally exceeds extension by 10-15 degrees
Why does flexion normally exceed extension?
Palmar tilt of radius
What is the ROM for ulnar deviation? Radial deviation?
35-40
15-20
- ulnar deviation usually 2x more than radial deviation due to ulnar tilt of radius
What is the average wrist ROM needed for ADL’s?
40 degrees flexion
40 degrees extension
10 degrees radial deviation
30 degrees ulnar deviation
What is the “position of function” of the wrist (the average position of the wrist during daily activities)?
10-25 degrees extension
10 degrees ulnar deviation
The “position of function” is the position the wrist would be fused or splinted. Why would you fuse the wrist or any joint?
stability and relief of pain
What is the capsular pattern for the radiocarpal joint?
Equal amounts of flexion and extension
What is the close packed position for the radiocarpal joint? open pack?
Extension, radial deviation;
neutral, slight ulnar deviation
Arthrology of the radiocarpal joint: [concave/convex] radius and disc on [concave/convex] scaphoid and lunate
Concave; convex
__% of total force passes through the scaphoid and lunate to the radius
__% of force passes through the articular disc
80%; 20%
Where is the mid carpal joint?
Between proximal and distal rows of carpal bones
The wrist is a double-joint system and motion occurs simultaneously at both radiocarpal and mid carpal joints. Where does the majority of wrist flexion occur? wrist extension?
Midcarpal joint; radiocarpal joint
Formed by the distal radius, lunate, capitate, and 3rd metacarpal
central column of wrist
in wrist extension, the ____ ligaments becomes slackened and the ____ ligaments become taut
dorsal radiocarpal; palmar radiocarpal
Extension occurs as the convex surface of the lunate rolls ___ on the radius and simultaneously slides ____. At the mid carpal joint, the head of the capitate rolls ___ on the lunate and simultaneously slides in a ____ direction
dorsally; palmarly; dorsally; palmarly
Ulnar deviation (for both the mid carpal and radiocarpal joint) involves the scaphoid, lunate, and triquetrum rolling _____ and slide a significant distance ____.
Ulnarly; radially
- both joints contribute to fairly equal overall wrist motion
The amount of radial deviation at the _____ joint is limited as the radial slide of the carpus impinges agains the styloid process of the radius. Therefore, the majority of radial deviation occurs at the _____ joint.
radiocarpal; mid carpal
During radial deviation, the proximal row of carpal bones ____ 20 degrees. During ulnar deviation, the proximal row of carpal bones ____ 20 degrees.
Flexes; extends
What is the primary cause of carpal instability? what are the two common types?
Laxity or rupture of ligaments
- Rotation collapse of wrist (zig zag deformity; DISI or VISI)
- Ulnar translocation of carpus
How can you tell if a rotational collapse of the wrist is a DISI or a VISI?
The direction the distal end of the lunate faces
What does the ulnar tilt of the radius create?
a translation force in the ulnar direction
What is an excessive ulnar translocation of the carpus result in?
altered biomechanics of the wrist and hand; radial side = stretched ligaments; ulnar side = compressed ligaments
What are the primary wrist extensors?
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor carpi ulnaris
Prevents the tendons from “bowstringing” up and away from the radiocarpal joint during active extension
Extensor retinaculum
Compartment I (containing tendons of extensor pollicis previous and abductor pollicis longus) are particularly susceptible to inflammation, a condition called
de Quervain’s tenosynovitis
If you have a radial nerve disruption in the upper arm, what wrist deformity could it cause?
DISI
What is the main function of the wrist extensors?
to position and stabilize the wrist during activities involving active flexion of the fingers
The wrist extensor muscles must counterbalance the significant ___________ torque produced by the [extrinsic] finger flexor muscles
wrist flexion
What position must the wrist be in to produce maximal grip force? why?
30 degrees wrist extension
- optimizes the length-tension relationship [active insufficiency)
- overstretched finger extensors create a passive extensor torque at the fingers
Finger flexion needs a counterbalance of wrist extension. Activities that require repetitive forceful grasp, such as hammering or playing tennis, may stress the proximal attachment site of the wrist extensor muscles, often leading to a painful condition. What is this condition called?
Lateral epicondylitis/ epicondylagia
- AKA tennis elbow
- may not be inflammatory but rather degenerative
What are the primary wrist flexors?
- Flexor carpi radialis
- Flexor carpi ulnaris
- Palmaris longus
Which muscle produces the greatest wrist flexion toque potential of the three primary wrist flexors?
flexor carpi ulnaris
Do wrist flexors or wrist extensors have a larger cross0sectional area?
flexors (2x)
wrist flexor muscles produce about __% greater isometric torque than the wrist extensor muscles
70
distal radius fracture; growth plate fracture that causes ulnar tilt to be significantly less
Cole’s fx
What action could cause a scaphoid fracture?
Punching a wall
- scaphoid provides stability for lunate
Synovial fluid buildup in sheath or joint; pin in dorsal of the wrist
ganglion cysts
