The blood of a long bone is derived from the following sources:
Nutrient artery enters the shaft through the nutrient foramen, runs obliquely through the cortex, and divides into ascending and descending branches in the medullary cavity.
Each branch divides into a number of small parallel channels which terminate in the adult metaphysic by anastomosing with the epiphysial, metaphysial and periosteal arteries. The nutrient artery supplies medullary cavity, inner two thirds of cortex and metaphysic.
The nutrient foramen is directed away from the growing end of the bone; their directions are indicated by a jingle
Periosteal arteries are especially numerous beneath the muscular and ligamentous attachments. They ramify beneath the periosteum and enter the Volkmann’s canals to supply the outer one third of the cortex.
Epiphysial arteries are derived from periarticular vascular arcades (circulus vasculosus) found on the nonarticular bony surface. Out of the numerous vascular foramina in this region, only a few admit the arteries (epiphysial and metaphysial), and the rest are venous exits.
The number and size of these foramina may give an idea of the relative vascularity of the two end of a long bone.
Metaphysial arteries are derived from the neighbouring systemic vessels. They pass directly into the metaphysis and reinforce the metaphysial branches from the primary nutrient artery. For anatomical basis of osteomyelitis see under ‘metaphysis’.
In miniature long bones, the infection begins in the middle of the shaft rather than at the metaphysis because, the nutrient artery breaks up into a plexus immediately upon reaching the medullary cavity. In the adults, however, the chances of infection are minimized because the nutrient artery is mostly replaced by the periosteal vessels.
Short bones are supplied by numerous periosteal vessels which enter their nonarticular surfaces. In a vertebra, the body is supplied by anterior and posterior vessels, and the vertebral arch by large vessels entering the bases of transverse processes. Its marrow is drained by two large basivertebral veins. A rib is supplied by:
a The nutrient artery which enters it just beyond the tubercle; and
b The periosteal arteries.
Veins are numerous and large in the cancellous, red marrow bone (e.g., basivertebral veins). In the compact bone, they accompany arteries in the Volkmann’s canals.
Lymphatics have not been demonstrated within the bone, although some of them do accompany the periosteal blood vessels, which drain to the regional lymph nodes.