Elbow joint

Question 1

articulating surface of the elbow joint

Answer 1

Humerus
1. capitulum
2. trochlea
Radius:
1. head of radius (fossa)
2. head of radius (side)
ulna:
1. olecranon fossa
2. radial notch

Question 2

Is the humerus convex or concave in the sagittal plane

Answer 2

convex

Question 3

Elbow classification

Answer 3

compound synovial joint (3 joints - 1 capsule)
-humeroulnar
-humeroradial
-proxmial radioulnar

Question 4

Humeroulnar joint

Answer 4

-diarthrrosis
-uniaxial hinge (still has rolling and gliding)
- humerus is convex and ulna is concave
trochlear + trochlear notch

Question 5

Humeroradial joint

Answer 5

-humerus with radius
- diarthrosis
-triaxial ball and socket
-allows flexion/extension and supination/pronation
-could do abd/add but ulna restricts it
-spins during pronation/supination

Question 6

Proximal radioulnar joint

Answer 6

diarthrosis
uniaxial pivot joint
pivot allows of pronation and supination (spins)

Question 7

Elbow range of motion

Answer 7

-flexion: active 0-145*
-hyperextension : 0-5*
-pronation: 0-90*
-supination: 0-90*

Question 8

Elbow ligaments

Answer 8

Anterior oblique
annular ligament
ulnar collateral (medial)
Radial collateral (lateral)
quadrate ligament
oblique cord

Question 9

Anterior oblique

Answer 9

thickening of the joint capsule for reinforcement

Question 10

annular ligament

Answer 10

attaches head of radius to ulna

Question 11

Ulnar collateral ligament

Answer 11

3 division:
-anterior: more tension in extension
-transverse (oblique): depends the socket
-posterior: medial epicondyle to trochlear notch and tensioned more in flexion
resists valgus stress

Question 12

Radial collateral ligament

Answer 12

lateral epicondyle to annular ligament and supinator crest (blends in to reinforce the annular ligament)

Question 13

quadrate ligament

Answer 13

Runs from inferior to radial fossa to head of radius to control radial rotation

Question 14

Oblique cord

Answer 14

prevents radius from being retracted distally

Question 15

Flexion/extension arthrokinematics at the elbow

Answer 15

Roll and glide in the same the direction during open chain activities

Question 16

pronation/supination arthrokinematics at the elbow

Answer 16

spin or pivot at both the radius and the ulna joint and the radius and humeral joint

Question 17

Accessory structures at the elbow joint

Answer 17

olecranon bursa over the olecranon process

Question 18

Elbow flexors

Answer 18

Brachioradialis: mid pronation works best

Biceps brachii: supination is the best

Brachialis: pronation and flexion is the best

Question 19

Muscles extensors

Answer 19

-triceps brachii
-medial head helps contribute the most force due to no influence of shoulder position

Question 20

What limits joint motion in extension

Answer 20

-olecranon process/fossa = bony end field
-tight elbow flexors
-being immobilized = tight anterior joint capsule
-mostly anterior structures

Question 21

What limits motion in flexion

Answer 21

-tricep length
-coronoid pocess
-posterior capsule

Question 22

What limits motion in from a valgus force

Answer 22

-medial ligaments such as ulnar collateral ligaments (in flexion, the anterior portion is more tensed and in extension the posterior portion is more tensed)
–as you approach closed pack position it puts more tension on ligaments

Question 23

What limits motion in a varus force

Answer 23

lateral ligaments such as radial collateral ligaments
-olecranon process fits tightly in the fossa in full extension
-as you approach open pack position it puts more tension on ligaments

Question 24

What is the carrying angle

Answer 24

Men: 10-15
women: 20-25

Question 25

interossesous memebrane

Answer 25

-joins radius and ulna
-transmits load from radius to ulna to hummus
-radius is more distal than the ulna so if the force went straight up the radius and was not transmitted, the capitulum would shatter