This is an individual with a slipped femoral epiphysis from St. Giles, a Medieval hospital cemetery.
The head is flattened, elongated, and projecting distally due to the distal displacement of the epiphysis. The neck is shortened. The surface of the head is a mixture of large areas of eburnation and zones of pitting. There is gross osteophytosis of the head, especially proximally where the new bone is irregular and has large underlying cavities, which have smooth walls and bases. Distal to the proximal osteophytic growth, above the surface of the head, is a wide groove that when articulated with the os coxa joins with the superior border of the acetabulum supplying the joint a degree of stability by limiting inferior displacement of the hip.
Right Os coxa
The acetabulum is enlarged and grossly shallowed. There is osteophytosis of the acetabular rim and a large build-up of irregular new compact bone on the anterior margin and the superior ramus of the pubis. The articular surface of the acetabulum is heavily eburnated with zones of pitting and possible underlying subchondral cystic cavities.