03-06: The Elbow Joint Flashcards
Bones of the Elbow Joint
Humerus, Radius, Ulna
Ligaments of the Elbow Joint
Medial Collateral Ligament, Lateral Collateral Ligament, Annular Ligament
Function of Medial Collateral Ligament
Prevents excessive valgus formation, distal end of arm moves outward
Function of Lateral Collateral Ligament
Prevents excessive varus formation
Function of Annular Ligament
Stabilizes proximal radial head so forearm can spin
Medial Collateral Ligament
- Connects humerus to ulna
- Triangle shaped ligament (3-4 bands): Anterior, tranverse, posterior/intermediate band
Stability of Anterior MCL
Stable with elbow in full extension
Stability of Posterior MCL
Stable with elbow in 90˚ flexion
Stability of Intermediate/Transverse MCL
Always taut, acts as stabilizing valgus force
Lateral Collateral Ligament
- Connects humerus to radius
- One band
Annular Ligament
- Lateral aspect of ulma and radial head connects to medial ulna
- Encompasses radial head
Interosseous Membrane
- Connects radius to ulna
- Provides more surface area for attachment to forearm and wrist muscles
Joints of Elbow Joint (4)
Radial humeral, Ulnar humeral, Proximal radioulnar joint, Distal radioulnar joint
Motions of Elbow Joint (4)
Flexion/Extension - Elbow joint motion
Pronation/Supination - Forearm motion
Joint motion of proximal RU joint
- Vex (Radius) on Cave (Ulna)
- Radius spinning on ulnar side (rolls anteriorly, glides posteriorly)
Joint motion of distal RU joint
- Cave (Radius) on Vex (Ulna)
- Distal radius guides anteriorly
Bony landmark of scapula
Supraglenoid tubercle, infraglenoid tuberlce, coracoid process
Brachialis
O: Anterior lower 1/2 of humerus
I: Coronoid process and ulnar tuberosity of the ulna
A: Prime elbow flexor (primarily in pronated position)
N: Musculocutaneous (C5 Root)
Brachioradialis
O: Supracondylar ridge of humerus
I: Styloid process of radius
A: Elbow flexion (neutral forearm), primarly in neutral position
N: Radial Nerve (C7 Root)
Biceps Brachii
O: Long Head - Supraglenoid tubercle of humerus, Short Head - Coracoid process of scapula
I: Radial Tuberosity, Licertus FIbrosis (Biciptal Aponeurosis)
A: Prime forearm supination, Assists in elbow flexion, Assists in shoulder flexion
N: Musculocutaneous (C5 Root)
Long Head of Biceps Brachii/Labrum
Surrounded by labrum; tendon attaches to superior aspect of labrum
Triceps Brachii
O: Long Head - Infraglenoid tubercle of scapula, Lateral Head - Posterior aspect of proximal humerus lateral to radial groove, Medial Head - Posterior aspect of distal humerus medial to radial groove
I: Olecranon process of ulna
A: Primary elbow extensor, Long Head - shoulder extension, external rotation
N: Radial Nerve (C7)
Anconeus
O: Lateral epicondyle of humerus
I: Posterior ulna adjacent to olecranon
A: Assists with elbow extension
N: Radial Nerve (C7)
Pronator Teres
O: Medial epicondyle of the humerus and coronoid process of the ulna
I: Lateral aspect of the radius
A: Forearm pronation, Assists in elbow flexion
N: Median Nerve (C6, C7)
Pronator Quadratus
O: Anterior distal 1/3 of ulna
I: Anterior distal 1/3 of radius
A: Forearm pronation
N: Median Nerve (C6, C7)
Supinator
O: Lateral epicondyle of humerus and adjacent ulna
I: Anterior proximal radius
A: Forearm supination, Assist in elbow extension
N: Radial Nerve (C7)
Muscle Actions (Flexion)
Biceps Brachii, Brachialis, Brachioradialis, Assist from Pronator Teres
Muscle Actions (Extension)
Triceps Brachii, Assist from Anconeus
Muscle Actions (Pronation)
Pronator Teres, Pronator Quadratus
Muscle Actions (Supination)
Biceps Brachii, Supinator
Innervation (Musculocutaneous)
Biceps brachii, Brachialis
Innervation (Radial)
Brachioradialis, Triceps Brachii, Anconeus, Supinator
Innervation (Median)
Pronator Teres, Pronator Quadratus
