Elbow Complex

Question 1

What bones make up the humeroulnar and humeroradial joints?

Answer 1

Humeroulnar - trochlear notch of ulna and trochlea of humerus
Humeroradial - head of radius and capitulum of humerus

Question 2

What type of joints are they?

Answer 2

Modified hinge

Question 3

Describe the makeup of the joint capsule at the elbow.

Answer 3

Joint Capsule - Elbow (radioulnar and radiohumeral) and proximal radioulnar joint enclosed in a single joint capsule

• Large, loose and weak anteriorly and posteriorly
• Reinforced laterally by collateral ligaments

Question 4

What is the normal carrying angle?

Answer 4

8-15

Question 5

What is the purpose of the carrying angle, how does it help us functionally?

Answer 5

• Results in valgus angulation of the forearm

- Function: allows for a person to carry object away from side of

Question 6

What structures provide support to the elbow joint?

Answer 6

1. Medial (ulnar) collateral lig - (ant/post/transverse) stabilizes against valgus torque
   - Limits ext at end ROM
2. Lateral (radial) collateral lig complex: stabilizes against varus torque
   - Lateral (radial) collateral lig
   - Lateral ulnar collateral lig
   - Annular lig

Question 7

Describe the osteo of the humeroulnar

Answer 7

Flex/ext

Question 8

Describe the arthrokinematics of the humeroulnar

Answer 8

-Concave surface of trochlear notch on convex trochlea of humerus
Flex: roll anterior, glide anterior
Ext: posterior roll, posterior glide

Question 9

Describe the osteo humeroradial joints.

Answer 9

Flex/ext

Question 10

Describe the arthrokinematics humeroradial joints.

Answer 10

-Concave surface of head of radius on convex capitulum of humerus
Flex: roll anterior, glide anterior
Ext: roll posterior, glide posterior

Question 11

What is the open pack position and capsular pattern for the humeroulnar and humeroradial joints?

Answer 11

Humeroulnar:
Open pack = Flexed 70, supinated 10
Humeroradial:
Open pack = full extension and supination

Capsular pattern = flex > ext

Question 12

What bones make up the proximal and distal radioulnar joints?

Answer 12

Proximal = ulnar radial notch (concave) and head of radius (convex) with annular lig
Distal = ulnar notch or radius (concave) with head of ulna (convex) with articular disc

Question 13

What type of joints are they?

Answer 13

Pivot joint

Question 14

Describe the osteo of the proximal radioulnar joint

Answer 14

supination/pronation

Question 15

Describe the arthrokinematics of the proximal radioulnar joints.

Answer 15

-Rotation of convex head of radius on concave ulnar radial notch within annular lig
Supination - posterior spin with anterior glide
Pronation - anterior spin with posterior glide

Question 16

Describe the osteo distal radioulnar joints.

Answer 16

Supination/pronation

Question 17

Describe the arthrokinematics distal radioulnar joints.

Answer 17

-Concave ulnar notch of radius on convex head ulna
Supination - spin and glide posteriorly
Pronation - spin and glide anteriorly

Question 18

What is the open pack position and capsular pattern for the proximal joints?

Answer 18

open pack = 70 flexion and 35 supination

Capsular pattern = supination = pronation

Question 19

What is the open pack position and capsular pattern for the distal radioulnar joints?

Answer 19

Open pack = 10 supination

Capsular pattern = supination = pronation

Question 20

How can we produce the most torque for elbow flexion at the elbow?

Answer 20

• 20-25% greater with the elbow in a supinated position compared to pronated position
• Increased flexor moment arm of biceps and brachioradialis when supinated

Question 21

Which muscle is considered the workhorse of the elbow and can produce equal force regardless of supination and pronation?

Answer 21

Brachialis

Question 22

Describe the synergy between the triceps and anterior deltoid.

Answer 22

Anterior deltoid counter shoulder extension potential of triceps

Question 23

Which muscle is primarily activated during low level supination?

Answer 23

Supinator

Question 24

Which two muscles are primarily activated to produce forceful supination?

Answer 24

Biceps and supinator

Question 25

What role does the tricep play during forceful supination?

Answer 25

Triceps must co-contract to prevent biceps from actually flexing the elbow and shoulder during supination effort

Question 26

Which muscle is primarily activated during low level pronation?

Answer 26

Pronator quadratus

Question 27

Which two muscles are primarily activated to produce forceful pronation?

Answer 27

Pronator quadratus and pronator teres

Question 28

What role does the tricep play during forceful pronation?

Answer 28

triceps act as counter tendency of pronator teres to also flex the elbow