BLOOD SUPPLY OF BONE

• A bone receives blood supply from several arteries in the periosteum.
• The shaft of the long bone contains a nutrient foramen through which a large nutrient artery enters the bone.
• The nutrient artery are usually directed away from the growing end of the bone.
• In bones where both ends are growing the nutrient canal is directed away from the actively growing end.

'to the elbow I go , from the knee I flee'

• The shoulder end of the humerus and the wrist end of the radious and ulna grow more than the elbow end.
• So elbow is less growing in nature,thus nutrient artery directed towards the elbow.
• In the lower limb the knee end of both the femur and tibia grow more than hip and ankle.
• Thus knee is actively growing end and the nutrient artery is directed away from knee end.

Main artaries and branches that supply long bones.

• Periosteal branches: 
• enters the shaft at multiple points and supply the compact bone.
• Nutrient artery:
• main artery of the shaft.
• they are the medullary artery that enters the medullary cavity through the nutrient canal and divides into proximal and distal branch .
• Each proximal and distal branch gives out several branches which supply the marrow,the compact bone and the metaphyseal area.
• Branches from adjacent articular arteries: 
• Arteries which anastomose around the joint gives out smaller twigs;these twigs are epiphyseal twigs and metaphyseal twigs and supply to the epiphysis and metaphysis .