Elbow/Forearm Biomechanics

Question 1

What type of joint is the elbow? ROM?

capsular pattern?

Answer 1

Hinge joint (1 dof)
0 degrees extension, 145 flexion
flexion > extension

Question 2

what are the three parts of the MCL?

Answer 2

Anterior: valgus restraint

posterior: taut in flexion
tranverse: no role

Question 3

What are the three parts of the LCL complex?

Answer 3

LCL: restrain varus/supination
LUCL: second restraint to varus/sup.
Annular: secondary restraint to varus/sup.

Question 4

What is the axis of motion for the elbow and the carrying angle?

Answer 4

center or trochlea/capitellum 
13 degrees (higher in females)

Question 5

What are the limits of extension in the elbow?

Answer 5

Anterior capsule
bone (olecranon)
flexor muscles

Question 6

What are the limits of flexion in the elbow?

Answer 6

soft tissue
posterior capsule
extensor muscles
bone (radial head and coronoid process)

Question 7

What is the open and close pack position of the HU joint?

Answer 7

open: 70 flex, 10 sup
closed: full extension and supination

Question 8

What is the open and closed position of the HR joint?

Answer 8

open: full extension/supination
closed: 90 flex, 5 sup

Question 9

What type of joint is the RU joint? ROM? capsular pattern is?

Answer 9

pivot (pro/sup)
75 pronation
85 supination
PRO> SUP

Question 10

What are the limits to supination?

Answer 10

pronator teres
pronator quadratus
TFCC
palmar DRUJ ligament 
IOM

Question 11

What are the limits to pronation?

Answer 11

supinator
biceps
TFCC
dorsal DRUL ligament