Wrist

Question 1

Allows the wrist and hand to rotate on the radius farther into ulnar deviation than into radial deviation

Answer 1

Ulnar tilt

Question 2

What is the normal degree for ulnar tilt?

Answer 2

25 degrees

Question 3

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

Answer 3

10; palmar

Question 4

Which row of carpal bones is relatively loose? which row is bound tightly by strong ligaments?

Answer 4

proximal; distal (creates a stable base for metacarpal bones)

Question 5

Arches over the concave carpal bones to form tunnel

Answer 5

Transverse carpal ligament

Question 6

What is contained in the carpal tunnel?

Answer 6

• median nerve
• 4 tendons of flexor digitorum superficialis
• 4 tendons of flexor digitorum profundus
• tendon of pollicis longus

Question 7

What prevents contained ligaments from bowstringing anteriorly and out of the carpal tunnel during grasping actions performed with a partially flexed wrist?

Answer 7

transverse carpal ligament

Question 8

Where is the axis of rotation in the wrist?

Answer 8

Head of capitate (firmly articulated with 3rd metacarpal)

- for both medial-lateral and anterior-posterior

Question 9

What is the ROM for wrist flexion? extension?

Answer 9

70-85
60-75
- flexion normally exceeds extension by 10-15 degrees

Question 10

Why does flexion normally exceed extension?

Answer 10

Palmar tilt of radius

Question 11

What is the ROM for ulnar deviation? Radial deviation?

Answer 11

35-40
15-20
- ulnar deviation usually 2x more than radial deviation due to ulnar tilt of radius

Question 12

What is the average wrist ROM needed for ADL’s?

Answer 12

40 degrees flexion
40 degrees extension
10 degrees radial deviation
30 degrees ulnar deviation

Question 13

What is the “position of function” of the wrist (the average position of the wrist during daily activities)?

Answer 13

10-25 degrees extension

10 degrees ulnar deviation

Question 14

The “position of function” is the position the wrist would be fused or splinted. Why would you fuse the wrist or any joint?

Answer 14

stability and relief of pain

Question 15

What is the capsular pattern for the radiocarpal joint?

Answer 15

Equal amounts of flexion and extension

Question 16

What is the close packed position for the radiocarpal joint? open pack?

Answer 16

Extension, radial deviation;

neutral, slight ulnar deviation

Question 17

Arthrology of the radiocarpal joint: [concave/convex] radius and disc on [concave/convex] scaphoid and lunate

Answer 17

Concave; convex

Question 18

__% of total force passes through the scaphoid and lunate to the radius
__% of force passes through the articular disc

Answer 18

80%; 20%

Question 19

Where is the mid carpal joint?

Answer 19

Between proximal and distal rows of carpal bones

Question 20

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?

Answer 20

Midcarpal joint; radiocarpal joint

Question 21

Formed by the distal radius, lunate, capitate, and 3rd metacarpal

Answer 21

central column of wrist

Question 22

in wrist extension, the ____ ligaments becomes slackened and the ____ ligaments become taut

Answer 22

dorsal radiocarpal; palmar radiocarpal

Question 23

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

Answer 23

dorsally; palmarly; dorsally; palmarly

Question 24

Ulnar deviation (for both the mid carpal and radiocarpal joint) involves the scaphoid, lunate, and triquetrum rolling _____ and slide a significant distance ____.

Answer 24

Ulnarly; radially

• both joints contribute to fairly equal overall wrist motion

Question 25

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.

Answer 25

radiocarpal; mid carpal

Question 26

During radial deviation, the proximal row of carpal bones ____ 20 degrees. During ulnar deviation, the proximal row of carpal bones ____ 20 degrees.

Answer 26

Flexes; extends

Question 27

What is the primary cause of carpal instability? what are the two common types?

Answer 27

Laxity or rupture of ligaments 1. Rotation collapse of wrist (zig zag deformity; DISI or VISI) 2. Ulnar translocation of carpus

Question 28

How can you tell if a rotational collapse of the wrist is a DISI or a VISI?

Answer 28

The direction the distal end of the lunate faces

Question 29

What does the ulnar tilt of the radius create?

Answer 29

a translation force in the ulnar direction

Question 30

What is an excessive ulnar translocation of the carpus result in?

Answer 30

altered biomechanics of the wrist and hand; radial side = stretched ligaments; ulnar side = compressed ligaments

Question 31

What are the primary wrist extensors?

Answer 31

1. Extensor carpi radialis longus 2. Extensor carpi radialis brevis 3. Extensor carpi ulnaris

Question 32

Prevents the tendons from “bowstringing” up and away from the radiocarpal joint during active extension

Answer 32

Extensor retinaculum

Question 33

Compartment I (containing tendons of extensor pollicis previous and abductor pollicis longus) are particularly susceptible to inflammation, a condition called

Answer 33

de Quervain's tenosynovitis

Question 34

If you have a radial nerve disruption in the upper arm, what wrist deformity could it cause?

Answer 34

DISI

Question 35

What is the main function of the wrist extensors?

Answer 35

to position and stabilize the wrist during activities involving active flexion of the fingers

Question 36

The wrist extensor muscles must counterbalance the significant ___________ torque produced by the [extrinsic] finger flexor muscles

Answer 36

wrist flexion

Question 37

What position must the wrist be in to produce maximal grip force? why?

Answer 37

30 degrees wrist extension - optimizes the length-tension relationship [active insufficiency) - overstretched finger extensors create a passive extensor torque at the fingers

Question 38

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?

Answer 38

Lateral epicondylitis/ epicondylagia - AKA tennis elbow - may not be inflammatory but rather degenerative

Question 39

What are the primary wrist flexors?

Answer 39

1. Flexor carpi radialis 2. Flexor carpi ulnaris 3. Palmaris longus

Question 40

Which muscle produces the greatest wrist flexion toque potential of the three primary wrist flexors?

Answer 40

flexor carpi ulnaris

Question 41

Do wrist flexors or wrist extensors have a larger cross0sectional area?

Answer 41

flexors (2x)

Question 42

wrist flexor muscles produce about __% greater isometric torque than the wrist extensor muscles

Answer 42

70

Question 43

distal radius fracture; growth plate fracture that causes ulnar tilt to be significantly less

Answer 43

Cole's fx

Question 44

What action could cause a scaphoid fracture?

Answer 44

Punching a wall | - scaphoid provides stability for lunate

Question 45

Synovial fluid buildup in sheath or joint; pin in dorsal of the wrist

Answer 45

ganglion cysts