Fragmented medial coronoid processThe most common form of elbow dysplasia is the fragmented medial coronoid process of the ulna. The elbow joint is made up of the radial head, responsible for 80% of weight bearing, the medial and lateral coronoid processes of the ulna,which bears the remaining 20%. From about 12 to 20 weeks of age the medial coronoid process undergoes ossification (turning cartilage in bone). FCP is Fragmented coronoid processthe result of unequal growth rates of the radius and ulna, either individually or together. The joint space between the ulna and humerus is narrower than the joint space between the radius and humerus. The resulting uneven pressure on the medial coronoid process can develop cracks or fragments of the coronoid process. Left untreated these loose bits of bone will lead to pain during movement and arthritis.