Elbow Flashcards
Humeroulnar Close Packed
Elbow: full extension
Forearm: supinated
Humeroulnar Resting
Elbow: 70 deg flexion
Forearm: 10 deg supination
Humeroulnar and Radiohumeral Capsular Pattern
Flexion more limited than extension
Rotations full range and painless
Radiohumeral Close Packed
Elbow: 90 deg flexion
Forearm: 5 deg supination
Radiohumeral Resting
Elbow: 70 deg flexion
Forearm: 10 deg supination
Proximal R/U Close Packed
Elbow: N/A
Forearm: 5 deg supination
Proximal R/U Resting
Elbow: 70 deg flexion
Forearm: 35 deg supination
Superior R/U Capsular Pattern
Equal limitation of pronation and supination
Normal ROM for Flex/Ext, Pro/Sup:
● Flexion/Extension- 10-0-150
● Pronation- 0-75
● Supination- 0-85
What percentage of the axial load goes through each articulation at the elbow?
Radiohumeral- 60%
Humeroulnar- 40%
What structure helps transmit this load from radius to ulna in UE weightbearing?
Interosseus membrane
When pulling a door open, what structure helps transmit force from radius to ulnar prior to reaching elbow joint?
Oblique cord
Where does the axis for flexion/extension lie at the elbow? How does this affect motion at the joint?
Bisects the trochlea (obliquely). The motion does not take place in a strictly sagittal direction (some rotation and add/abduction accompany flexion/extension).
Where does the axis for pronation/supination lie? How does this affect motion at the joint?
Through the heads of each bone (not along the longitudinal axis of radius). Open chain motion: radius will roll on ulna. Closed chain motion: ulna will rotate around radius.
Normal Limitations to Extension at Elbow
● restriction by olecranon against fossa
● occasionally anterior capsule tension
Abnormal Limitations to Extension at Elbow
● short brachialis
● passive insufficiency of biceps
Normal Limitations to Flexion at Elbow
● mass of biceps
● posterior capsule tension
● impaction of bony surfaces (radial head or coronoid in fossa)
Abnormal Limitations to Flexion at Elbow
● passive insufficiency of triceps
Normal Limitations to Pronation at Elbow
● bony (shaft of ulna contacting radius)
● tension in posterior R/U ligament
● possibly posterior MCL
Abnormal Limitations to Pronation at Elbow
● passive insufficiency of supinators
● shoulder/elbow position will not affect range if supinator is tight, but will affect it if biceps is tight
Normal Limitations to Supination at Elbow
● oblique cord
● anterior ligament of inferior R/U joint
● interosseus membrane
Abnormal Limitations to Supination at Elbow
● passive insufficiency of pronators
● elbow position will not affect range if pronator quadratus is tight
What force(s)/motions does MCL resist?
resists valgus forces overall
What force(s)/motions does LCL resist?
resists varus forces overall
What force(s)/motions does Annular ligament resist?
prevents radial head from dislocating. Resists distraction of the RH joint.
What force(s)/motions does Interosseous membrane resist?
prevents proximal displacement of radius on ulna
Proximal Radioulnar Joint: Open chain pronation…OK? AK? (roll + slide)
OK: Roll ant.
AK: Glide post.
Proximal Radioulnar Joint: Open chain supination….OK? AK?
OK: Roll post.
AK: Glide ant.
Proximal Radioulnar Joint: Closed chain pronation…OK? AK? (roll + slide)
OK: Roll ant.
AK: Glide ant.
Proximal Radioulnar Joint: Closed chain supination…OK? AK? (roll + slide)
OK: Roll post.
AK: Glide post.
Which muscles produce Flexion?
Biceps (active with flexion and supination)
Brachialis (largest/strongest flexor)
Brachioradialis (longest flexor)
Which is greater? Flexion torque or extension torque? Flexion force or extension force?
Flexion torque is 70% greater
Flexion force is 25% greater in supination (blame biceps)
Which muscles produce Extension?
Triceps
Anconeus
Which muscles produce Pronation?
Pronator teres
Pronator quadratus
Which muscles produce Supination?
Supinator (recruited first)
Biceps
Brachioradialis (supinates to neutral)
Anconeus
PA: post side of lateral epicondyle of humerus
DA: between olecranon process and proximal surface of post side of ulna
Action: elbow extension; longitudinal and M-L stability along humeroulnar joint
Biceps Brachii
PA: Long Head: supraglenoid tubercle of scapula
Short Head: apex of coracoid process of scapula
DA: bicipital tuberosity of radius
Action: shoulder flexion, elbow flexion, forearm supination
Brachialis
PA: distal anterior surface of humerus
DA: coronoid process and tuberosity on proximal ulna
Action: elbow flexion
Brachioradialis
PA: upper ⅔ lateral supracondylar ridge of humerus
DA: near styloid process at distal radius
Action: elbow flexion, rotation of forearm (depending on position in reference to neutral forearm)
Pronator Quadratus
PA: anterior surface of distal ulna
DA: anterior surface of distal radius
Action: forearm pronation
Pronator Teres
PA: Humeral head: medial epicondyle
Ulnar head: medial to tuberosity of ulna
DA: lateral surface of middle radius
Action: forearm pronation, elbow flexion
Supinator
PA: lateral epicondyle of humerus, radial collateral ligament, annular ligament, superior crest of ulna
DA: lateral surface of proximal radius
Action: forearm supination
Triceps Brachii
PA: Long Head: infraglenoid tubercle of scapula
Lateral Head: post humerus, superior and lateral to radial groove
Medial Head: post humerus, inferior and medial to radial groove
DA: olecranon of ulna
Action:
● Long Head: shoulder extension, shoulder adduction, elbow extension
● Lateral Head: elbow extension
● Medial Head: elbow extension (also drawing elbow capsule taut during extension)
