Wrist

Question 1

how many degrees of freedom in the wrist and how many AOR?

Answer 1

2 DOF and biaxial

Question 2

where are the wrist AOR

Answer 2

radiocarpal (proximal) and midcarpal (distal)

Question 3

where does the 1st MC articulate?

Answer 3

the trapezium

Question 4

what is the most commonly fracture carpal?

Answer 4

scaphoid (60-70%)

Question 5

which carpal is the most frequently dislocated

Answer 5

lunate

Question 6

what is the largest metacarpal

Answer 6

capitate

Question 7

why is the capitate important (2)

Answer 7

• creates a rigid column for the hand

- AOR for all wrist movement passes through it

Question 8

what forms the structure for the carpal tunnel?

Answer 8

proximal carpals

Question 9

where is the majority of motion in the wrist?

Answer 9

medial mid carpal joint

Question 10

what are the two major wrist tilts and their degrees

Answer 10

ulnar (25) and palmar (10)

Question 11

where do the four motions of the wrist pass through?

Answer 11

the capitate bone

Question 12

describe wrist extension in open chain

Answer 12

convex on concave

- capitate on lunate on radius

Question 13

describe wrist flexion in open chain

Answer 13

convex on concave

- capitate on lunate on radius

Question 14

describe the frontal plane arthokinematics at the wrist

Answer 14

convex on concave

- capitate on (scaphoid, lunate, and triquetrum in succession and reversed in the opposite direction)

Question 15

how do the four wrist motions change in closed chain?

Answer 15

concave on convex

Question 16

how does RA changes the wrist position?

Answer 16

chronic inflammation > bone and ligament deformity > ulnar deviation

Question 17

all wrist flexors pass under the flexor retinaculum except which muscles? where do they attach?

Answer 17

PL (flex ret and palm apon) and FCU (pisiform)

Question 18

what are the primary wrist extensors

Answer 18

ECRL/ECRB + ECU

Question 19

what muscle is implicated in tennis elbow and why

Answer 19

ECRB - a hard squeeze encourages wrist extension which leads to stress on the ECRB

Question 20

when is grip strength strongest? why?

Answer 20

about 30 deg wrist extension - minimized active/passive insufficiencies of long finger flexors and wrist extenders

Question 21

what kind of patients require tenodesis grip?

Answer 21

tetraplegic patients with C6 intact

Question 22

describe tenodesis grip

Answer 22

wrist extension promotes finger flexion via exploiting passive insufficiency of long finger flexors