Intracapsular and intraosseous vascular supply to the mature dog's coxofemoral joint.

The intracapsular and intraosseous arterial supply to the mature dog's coxofemoral joint was investigated using a vascular injection, tissue-clearing technique in 6 mixed-breed dogs. Ascending arteries of the femoral neck, arising from an extracapsular vascular ring at the base of the femoral neck, penetrated the articular capsule and traveled subsynovially over the surface of the femoral neck. These intracapsular arteries formed an incomplete intracapsular vascular ring at the junction of the femoral head and neck. Bony components of the acetabulum, ie, ilium, ischium, and acetabular bones, received intraosseous vascular supply from the nutrient artery of the ilium and minute vessels entering nutrient foramina around the rim of the acetabulum. The femoral head received branches (epiphyseal arteries) from the ascending arteries of the femoral neck at the intracapsular vascular ring. Epiphyseal arteries formed anastomosing vascular arches of decreasing caliber up to the subchondral bone of the femoral head. The proximal femoral metaphysis, particularly the femoral neck, received vascular supply from 4 sources: (i) branches from the epiphyseal arteries on the surface of the physeal scar which descended, penetrating the physeal scar, (ii) distally directed branches from the intracapsular vascular ring, (iii) ascending nutrient vessels from the trochanteric fossa, and (iv) terminal branches of the ascending nutrient artery of the femur.