A study of articular surfaces and synovial fossae of the pectoral limb of swine.

Articular surfaces of the pectoral limb were studied in 50 swine and are described in detail. Synovial fossae were not present at birth but were found commonly on the articular surface of the scapula, distal humerus, proximal radius, distal radius and distal surfaces of the intermediate carpal bone after four to five months of age. When present, they were bilaterally symmetrical and were located at the depth of a concavity of the articular surface. Microscopically, synovial fossae appeared as an invagination of articular cartilage extending into subchondral bone. Evidence of endochondral bone formation was less apparent at the depth of synovial fossae than in areas of weight bearing cartilage.