Elbow Flashcards
Humeroulnar joint - what articulates
Distal humerus (trochlea) with proximal end of ulna
Humeroradial joint - what articulates
Distal end of humerus (capitulum) with concave facet of radius
Proximal radioulnar joint - what articulates
Medial radius with radial notch of ulna
Distal radioulnar joint - what articulates
Convex ulna with concave radius
Flexors
Biceps
Brachialis
Brachioradialis
Extensors
Triceps
Pronators
Pronator teres
Pronator quadratus
Supinators
Biceps
Supinator
Innervation of biceps
Musculocutaneous
Innervation of triceps
Radial
Innervation of brachialis
musculocutaneous
Innervation of supinator
Radial
Innervation of pronators
Median
Capsule - continues medially with ___
Ulnar collateral ligament
Capsule - continues laterally with ___
Radial collateral ligament
Ulnar collateral ligament
Three parts
Reinforces humeroulnar joint medially
Radial collateral ligament
Fan shaped from lateral epicondyle to annular ligament
Reinforces humeroradial joint laterally
Annular ligament
Osteofibrous ring attached to medial ulna and encircles the radial head
Protects radial head
Taut in extreme pronation and supination
Quadrate ligament
Radial notch of ulna to the neck of the radius
Reinforces inferior joint capsule
Distal radioulnar ligament
Ant and Post parts
Both strengthen capsule
Bursa
Olecranon bursa - located on post aspect elbow over olecranon process
Main contributors to elbow bony stability
Trochlea of humerus and trochlear fossa of ulna
Medial collateral ligament provides resistance to
valgus forces
Lateral vs. medial collateral ligament
Lateral does not have to be as strong
Tensile forces usually placed medially
Compressive forces usually laterally
Biomechanics - what does ulna do with flex and ext
Ulna pronates slightly with ext
Supinates slightly with flex
Biomechanics - during extension, proximal elbow
glides medially
Biomechanics - during flexion, proximal elbow
glides laterally
Biomechanics - Flex/Ext of elbow is accompanied by
screw home mechanism with conjunct rotation of ulna
Biomechanics - screw home mechanism
Ulna ER (supinates) during elbow flexion Ulna IR (pronates) during elbow extension