The olecranon joint (located at the elbow) is a synovial hinge joint, similar to the ankle and knee joints. Two or more bones form hinge joints that move along an axis, rather than rotate like the hip joint. The distal humerus and proximal ulna are the primary elbow joint bones. In addition, the hinge joint allows the elbow to bend and straighten. It also helps with hand motion by allowing the forearm to rotate.
The elbow consists of three articulations, which are:
- The ulnohumeral joint.
- The radiohumeral joint.
- The proximal radioulnar joint.
A fracture to a joint is either a complete or partial break in the continuity of bone tissue. Fractures can occur in any bone in the human body, such as the knee, arms, hands, and in these cases, the olecranon joint. An olecranon fracture (also known as an elbow fracture) is an injury that occurs from a break or crack in one or a combination of bones that make up the olecranon joint. The ultimate cause of an olecranon fracture is trauma, such as falling on the elbow or on an outstretched hand.
There are also other types of olecranon fractures, which include:
- Extra-articular fractures – Extra-articular fractures are fractures that occur outside of the joint. These fractures can occur from blunt trauma or forcible blow to the end of the toes.
- Intra-articular fractures – These types of fractures happen when the fracture line crosses into the surface of a joint resulting in some degree of cartilage damage. The fractures can vary from hairline fractures to displaced fractures.
- Radial head and neck fractures – Fractures in the hard portion of the radius bone are referred to as radial head and neck fractures.
- Distal humerus fractures – Distal humerus fractures often occur in children and the elderly. Nerves and arteries in the olecranon joint may sometimes be injured in these fractures.