Elbow, Wrist and Hand Flashcards
describe the makeup of the elbow’s joint capsule
- large loose and weak (A/P)
- reinforced laterally by collateral ligaments
what is the normal carrying angle of the elbow?
8-15 degrees
what is the purpose of the carrying angle at the elbow?
allows for a person to carry an object away from side of the thigh
list the passive structures that reinforce the elbow joint
- medial (ulnar) collateral ligaments
- A/P Transverse
- Lateral (radial) collateral ligaments
- lateral ulnar collateral ligament
- annular ligament
what does the A/P transverse ligament do at the elbow?
stabilizes against valgus torque at the elbow and limits elbow extension at end ROM
what is the role of the annular ligament?
stabilizes against varus torque at the elbow and combined varus and supination torques
what osteokinematic motions are available at the humeroulnar and humeroradial joint?
flexion/extension
describe the arthrokinematics at the humeroulnar and humeroradial joint
concave on convex
roll and slide in same direction
At the humeroulnar joint, what is the:
closed pack position
open pack position
capsular pattern
closed = full extension and supination
open = flexed 70 degrees, supinated 10 degrees
capsular pattern = flexion > extension
at the humeroradial joint, what is the following:
closed pack position
open pack position
capsular pattern
closed = 90 degrees of elbow flexion and 5 degrees of supination
open = full extension and supination
capsular pattern = flexion > extension
what types of joints are the proximal and distal radioulnar?
synovial pivot
how is the arthrokinematics different at the proximal and distal radioulnar?
proximal = convex on concave
distal = concave on convex
describe the following for the proximal radioulnar joint:
closed pack position
open pack position
capsular pattern
closed pack = 5 degrees supination
open = 70 degrees flexion and 35 degrees supination
capsular pattern: supination = pronation
describe the following for the distal radioulnar joint:
closed pack position
open pack position
capsular pattern
closed = 5 degrees supination
open = 10 degrees supination
capsular pattern: supination = pronation
how do we produce the most torque for elbow flexion at the elbow?
supinated position
increased flexor moment arm of biceps and brachioradialis when forearm is supinated
what is the workhorse of the elbow?
brachialis
can produce equal force regardless of position
describe the synergy between the triceps and anterior deltoid
ant deltoid synergizes with triceps during elbow extension
this will counter shoulder extension potential of triceps