41. Septal defects ( ventricular septal defects and atrial septal defects ) are also common, as are patent foramina ovalia. 42. Unlike other early archosauromorphs, they do not have parietal foramina , which in many reptiles holds a parietal eye. 43. There are broad and shallow foramina in front of the orbits indicate that the rostrum had a rich blood supply. 44. The foramen spinosum is often used as a landmark in neurosurgery, due to its close relations with other cranial foramina . 45. There are two pairs of distinct foramina anterior and posterior to the dorsal transverse suture; modern placentals only bear one. 46. The skull is delicate and the incisive foramina ( openings in the front part of the palate ) are short and narrow. 47. It can also be caused by a foramina stenosis, a narrowing of the nerve opening, as a result of arthritis. 48. From here, the CSF passes through the interventricular foramina to the third ventricle, then the cerebral aqueduct to the fourth ventricle. 49. Each nerve emerges in two divisions : one division through the anterior sacral foramina and the other division through the posterior sacral foramina. 50. Each nerve emerges in two divisions : one division through the anterior sacral foramina and the other division through the posterior sacral foramina .
