The arterial flow enters the marrow through the nutrient artery. 

The nutrient artery bifurcates into ascending and descending arterial branches from which originate the radial arteries that either anastomose with the very small vessels in the bony cortex or terminate to form the primary venous sinuses.

The venous sinuses anastomose with one another forming secondary and tertiary sinuses, ultimately becoming larger collecting sinuses that drain into the very large diameter central sinus. Thereafter, blood flows out emissary veins through the cortical foramen to enter the systemic venous circulation.

Hematopoiesis occurs in the intersinusoidal spaces, sometimes referred to as the hematopoietic cords. Newly formed mature blood cells penetrate the sinus wall to enter the blood.