HUMAN GERMINAL MATRIX - VENOUS ORIGIN OF HEMORRHAGE AND VASCULAR CHARACTERISTICS

PURPOSE: To examine the vascular supply and architecture of the germin al matrix in the preterm neonatal brain and to determine whether veins or arterioles are the source of germinal matrix hemorrhage, METHODS: Brains from eight preterm neonates (24 to 35 weeks' gestation) and two full-term infants were fixed in alcohol, embedded in celloidin, secti oned at 100- and 500-mu m thicknesses, stained for alkaline phosphatas e, and examined with light microscopy, High-resolution contact radiogr aphs of 500-mu m-thick sections were also mounted on glass slides for microscopic examination. RESULTS: The upper and middle regions of the germinal matrix are supplied by branches of the lateral striate arteri es, whereas the inferior part is supplied by branches of the recurrent artery of Heubner. In brain sections from four of the preterm infants , we found 15 circumscribed hemorrhagic foci within the germinal matri x. The largest was 5 mm in diameter; the smallest, 1 mm, All hemorrhag es but one were closely associated with veins, with significant involv ement of the perivenous space, The other hemorrhage appeared to be ass ociated with an arteriole, In term and preterm infants, we found no ar teriolar-to-arteriolar shunts, precapillary arteriolar-to-venules shun ts, or vascular rete, At all gestational ages, the terminal vascular b ed had only conventional branchings and connections. CONCLUSION: In pr eterm neonates, staining for endogenous alkaline phosphatase allows vi sual differentiation between afferent and efferent vessels. Germinal m atrix hemorrhage in preterm neonates is primarily venous in origin. A hemorrhage can tunnel along the venous perivascular space, collapsing the vein and rupturing the tethered connecting tributaries. Extravasat ion of blood from the arterial circulation appears to be much less com mon.