Elbow joint consists of three bones
1-Distal humerus
2- proximal radius
3-proximal ulna
•Distal humerus has 2 articular surfaces
○Trochlea located medially, articulates with ulna
○Capitellum located laterally, articulates with radius
○Trochlea and capitellum separated by intercondylar ridge
○Hyaline cartilage continuous across trochlea and capitellum
○At superior margin of trochlea, 2 fossae are present
-Posteriorly, olecranon fossa articulates with olecranon process of ulna
-Anteriorly, coronoid fossa articulates with coronoid process
-Anatomic variant is olecranon foramen, traversing humerus at site of olecranon and coronoid fossae
•Proximal radius
○Round, slightly concave articular surface (fovea) articulates with capitellum
•Proximal ulna
○Olecranon process articulates with trochlea and olecranon fossa
-Articular surface called trochlear notch
○Coronoid process: Triangular tip of anterior articular margin
○Sublime tubercle: Discrete projection of medial margin
-Insertion of ulnar collateral ligament (UCL)
•Ulnohumeral joint is pure hinge joint
○Flexion and extension only
•Radiocapitellar joint allows more complex motions
○Flexion, extension, pronation, supination
•Proximal radioulnar joint
○Hyaline cartilage surfaces on apposing surfaces of radius and ulna
○Allows pronation, supination
The proximal radius
consists of the radial head, neck and tuberosity. The radial head is cylindrical which articulates with the capitellum of the humerus. The head rotates within the annular ligament to produce supination and pronation of the forearm
The ulna
is one of two bones that make up the forearm, the other being the radius. It forms the elbow joint with the humerus and also articulates with the radius both proximally and distally. It is located in the medial forearm when the arm is in the anatomical position. It is the larger of the two forearm bones
The ulna forms the skeleton of the medial part of the forearm and is a long bone, consisting of an expanded proximal end, a shaft and a head at the distal end