Elbow

Question 0

Elbow: Articulating Surfaces

Answer 0

Trochlear Ridge (Ulna) - Trochlear Groove (Humerus)
Radial Head - Capitulo-trochlear groove
Full Flexion:
Rim of Radial Head - Radial Fossa
Coronoid Process - Coronoid Fossa (Humerus)
Full Extension:
Olecranon Process in Olecranon Fossa

Question 1

Elbow

~ Joint Specifics

Answer 1

Compound Joint (3 bones articulate)
Uniaxial: Flexion / Extension around x-axis
Hinge Joint
ROM 140-150 Flexion / 0 Extension

Question 2

Elbow:

Ligaments

Answer 2

1. Medial Collateral (aka Ulnar Collateral): resists valgus/medially directed forces
2. Lateral Collateral (aka Radial Collateral): resists varus/laterally directed forces

Carrying Angle: 10-15 (Cubital valgus)

Question 3

Radioulnar Joint

Articulating Surfaces, ROM

Answer 3

1. Proximal: Radial Head pivots in radial notch
2. Distal: Sigmoid Notch (aka Ulnar Notch) moves over Ulnar Head

Uniaxial Pivot joint: Supination, Pronation: y-axis
ROM 80-90. Forearm Neutral 0

Question 4

Radioulnar Joint

Ligaments

Answer 4

Proximal:
Annular
Quadrate
Oblique

Distal:
Anterior and Posterior R-U Ligaments
Interosseous Membrane

Question 5

Elbow Muscles:
Flexors (4)
Extensors (2)

Weak Flexors (4)
Extensors

Answer 5

Flexors:
  Biceps
  Brachialis (workhorse)
  Brachioradialis
  Pronator Teres

Extensors
Triceps
Anconeous

Weak Forearm Flexors
  Flexor Carpi Radialis
  Palmaris Longus
  Flexor Carpi Ulnaris
Extensors:
  Extensor Carpi Radialis Longus
  Extensor Carpi Radialis Brevis

Question 6

Brachialis

Answer 6

Anterior Distal 2/3 of Humerus - Ulnar Tuberosity

One Joint - Spurt Muscle (Mobility)

Question 7

Biceps Brachii

Answer 7

Long Head: Supraglenoid Tubercle of Scap
Short Head: Coracoid Process of Scap
Insert: Radial Tuberosity, Bicipital Aponeurosis
Two-joint Muscle: Flexes Elbow and Shoulder
Less active when forearm is pronated
Active Insufficiency: flexed elbow and shoulder
Shunt @ Shoulder, Spurt @ Elbow

Question 8

Brachioradialis

Answer 8

Lateral Supracondylar Ridge - Radial Tuberosity
Shunt Muscle (origin close to joint, insertion further away = stability)
Elbow Flexor, but better when forearm neutral

Question 9

Pronator Teres

Answer 9

Two Heads:
  Medial Supracondylar Head
  Coranoid Process of Ulna
Attaches Anterior Surface, but Lateral Side of Radius
Elbow Flexion + Pronation

Question 10

Triceps

Answer 10

Long: Infraglenoid Tubercle
Lateral: Proximal 2/3 of Humerus
Medial: Distal 2/3 of Humerus
Posterior Olecranon of Ulna
Active Insufficiency: Elbow + Shoulder Extension

Question 11

Anconeous

Answer 11

Posteriorly Situated: Stabilizes Joint
In Extension, pulls on Joint Capsule to get it out of the way
Lateral Humeral Condyle - courses medially to - Lateral Portion of Olecranon Process, and adjacent proximal quarter of posterior ulna.

Question 12

Pronator Quadratus

Answer 12

Primary Pronator
O: Distal Anterior 1/4 Ulna
I: Distal 1/4 of Radius

Question 13

Supinators: Biceps + Supinator

Answer 13

Supinator: 2 Heads
Lateral Epicondyle
Supinator Crest (Posterior Dorsal Ulna)
Insertion: lateral Proximal Portion of Radius
Supinators are stronger than Pronators
Test Supinator: Elbow complete extension (removes biceps)
Biceps most powerful when elbow @ 90

Question 14

Synergies (2)

Answer 14

1. Biceps + Pronator Teres w/ Triceps: Stabilize @ elbow, so elbow flexion does not occur
2. Biceps @ elbow only, not Shoulder - Posterior Deltoid contracts to prevent shoulder flexion.