Elbow Complex Flashcards
What bones make up the humeroulnar and humeroradial joints?
Humeroulnar - trochlear notch of ulna and trochlea of humerus
Humeroradial - head of radius and capitulum of humerus
What type of joints are they?
Modified hinge
Describe the makeup of the joint capsule at the elbow.
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
What is the normal carrying angle?
8-15
What is the purpose of the carrying angle, how does it help us functionally?
- Results in valgus angulation of the forearm
- Function: allows for a person to carry object away from side of
What structures provide support to the elbow joint?
- Medial (ulnar) collateral lig - (ant/post/transverse) stabilizes against valgus torque
- Limits ext at end ROM - Lateral (radial) collateral lig complex: stabilizes against varus torque
- Lateral (radial) collateral lig
- Lateral ulnar collateral lig
- Annular lig
Describe the osteo of the humeroulnar
Flex/ext
Describe the arthrokinematics of the humeroulnar
-Concave surface of trochlear notch on convex trochlea of humerus
Flex: roll anterior, glide anterior
Ext: posterior roll, posterior glide
Describe the osteo humeroradial joints.
Flex/ext
Describe the arthrokinematics humeroradial joints.
-Concave surface of head of radius on convex capitulum of humerus
Flex: roll anterior, glide anterior
Ext: roll posterior, glide posterior
What is the open pack position and capsular pattern for the humeroulnar and humeroradial joints?
Humeroulnar:
Open pack = Flexed 70, supinated 10
Humeroradial:
Open pack = full extension and supination
Capsular pattern = flex > ext
What bones make up the proximal and distal radioulnar joints?
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
What type of joints are they?
Pivot joint
Describe the osteo of the proximal radioulnar joint
supination/pronation
Describe the arthrokinematics of the proximal radioulnar joints.
-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
Describe the osteo distal radioulnar joints.
Supination/pronation
Describe the arthrokinematics distal radioulnar joints.
-Concave ulnar notch of radius on convex head ulna
Supination - spin and glide posteriorly
Pronation - spin and glide anteriorly
What is the open pack position and capsular pattern for the proximal joints?
open pack = 70 flexion and 35 supination
Capsular pattern = supination = pronation
What is the open pack position and capsular pattern for the distal radioulnar joints?
Open pack = 10 supination
Capsular pattern = supination = pronation
How can we produce the most torque for elbow flexion at the elbow?
- 20-25% greater with the elbow in a supinated position compared to pronated position
- Increased flexor moment arm of biceps and brachioradialis when supinated
Which muscle is considered the workhorse of the elbow and can produce equal force regardless of supination and pronation?
Brachialis
Describe the synergy between the triceps and anterior deltoid.
Anterior deltoid counter shoulder extension potential of triceps
Which muscle is primarily activated during low level supination?
Supinator
Which two muscles are primarily activated to produce forceful supination?
Biceps and supinator
