The arterial anatomy of the human carpus. Part II: The intraosseous vascularity.

The intraosseous vascular anatomy of the carpal bones of 25 fresh cadaver limbs was studied by injection and Spalteholz clearing techniques. The carpal bones were classified into three general groups based on the size and location of nutrient vessels, the presence or absence of intraosseous anastomoses, and the dependence of large areas of bone on a single intraosseous vessel. Group I included the scaphoid, capitate, and 20% of the lunates in this series. Each had large areas of bone dependent on a single intraosseous vessel and was considered at greater risk to develop avascular necrosis following fracture. Group II included the trapezoid and hamate, both of which have two areas of vessel entry but lack intraosseous anastomoses. Group III included the trapezium, triquetrum, pisiform, and 80% of the lunates in this series, which receive nutrient arteries through two nonarticular surfaces, have consistent intraosseous anastomoses, and have no large areas of bone dependent upon a single vessel. The clinical incidence of avascular necrosis in groups II and III is low.