Systematization, distribution and territory of the caudal cerebral artery on the brain's surface of the turkey (Meleagris gallopavo)

Abstract

Thirty Meleagris gallopavo heads with their neck segments were used. Animals were contained and euthanized with the association of mebezonium iodide, embutramide and tetracaine hydrochloride (T 61, Intervet ) by intravenous injection. The arterial system was rinsed with cold saline solution (15°C), with 5000IU heparin and filled with red-colored latex. The samples were fixed in 20% formaldehyde for seven days. The brains were removed with a segment of cervical spinal cord and after, the dura-mater was removed and the arteries dissected. The cerebral carotid arteries, after the intercarotid anastomosis, were projected around the hypophysis, until they reached the tuber cinereum and divided into their terminal branches, the caudal branch and the rostral branch. The rostral branch was projected rostrolateralwards and gave off, in sequence, two collateral branches, the caudal cerebral and the middle cerebral arteries and the terminal branch was as cerebroethmoidal artery. The caudal cerebral artery of one antimere formed the interhemispheric artery, which gave off dorsal hemispheric branches to the convex surface of both antimeres. Its dorsal tectal mesencephalic branch, of only one antimere, originated the dorsal cerebellar artery. In the interior of the cerebral transverse fissure, after the origin of the dorsal tectal mesencephalic artery, the caudal cerebral artery emitted occipital hemispheric branches, pineal branches and medial hemispheric branches, on both antimeres. The caudal cerebral artery's territory comprehended the entire surface of the dorsal hemioptic lobe, the rostral surface of the cerebellum, the diencephalic structures, the caudal pole and the medial surface of the cerebral hemisphere and in the convex surface, the sagittal eminence except for its most rostral third. Due to the asymmetry found in the caudal cerebral arteries' ramifications, the models were classified into three types and their respective subtypes.

Systematization, Description, and Territory of the Middle Cerebral, Rostral, and Cerebroethmoidal Arteries on the Surface of the Brain of the Ostrich (Struthio camelus)

“…In the ostrich, the hemispheric terminal branch of the middle cerebral artery projected ventrally onto the lateral side of the convex face of the cerebral hemisphere, toward the olfactory bulb, terminating, in most cases, by advancing slightly into the lateral territory of the olfactory bulb. In the turkey, the terminal hemispheric branch of the middle cerebral artery, called the rostral hemispheric branch, rose to the convex face to vascularize the most rostral third of the sagittal eminence, where its terminal branches were anastomosed “ in osculum ” with the terminal branches of the final dorsal hemispheric vessel, a branch of the interhemispheric artery (Carvalho and Campos, ). For Campos (), in Gallus gallus, the main terminal branch of the middle cerebral artery divided into two main trunks at the height of the olfactory bulb, called the medial and lateral rostral hemispheric branches.…”

“…In the turkey, the rostral cerebral artery in the right antimere displayed a medium development in 50% of cases to the right antimere and a small development in 43.3% of specimens in the left antimere. In cases in which the development was small, the vascular territorial area was compensated by the ventral hemispheric branches of the middle cerebral artery, which were more developed (Carvalho and Campos, ). Vitums et al () found that in sparrows, after originating in the middle and caudal cerebral artery, the rostral branch abruptly projected medially, approaching the brain's interhemispheric fissure in the pre‐optic groove, where the rostral branch gave rise to a cerebral rostral artery, continuing as an ethmoidal artery.…”

“…It projected medially and rostrally, following the brain's interhemispheric fissure, leaving the cranial cavity through the olfactory foramen along with the homonymous nerve, crossing the orbital cavity, proceeding to be distributed into the nasal cavity. This behavior was similar to that shown by the turkey (Carvalho and Campos, ). Campos () reported duplicity of the left ethmoidal artery in 10% of cases.…”

“…In the turkey, the terminal hemispheric branch of the middle cerebral artery, called the rostral hemispheric branch, rose to the convex face to vascularize the most rostral third of the sagittal eminence, where its terminal branches were anastomosed "in osculum" with the terminal branches of the final dorsal hemispheric vessel, a branch of the interhemispheric artery (Carvalho and Campos, 2014). For Campos (1990), in Gallus gallus, the main terminal branch of the middle cerebral artery divided into two main trunks at the height of the olfactory bulb, called the medial and lateral rostral hemispheric branches.…”

“…In Struthio camelus , the middle cerebral artery was a medium to large single vessel, as occurred in Meleagris gallopavo (Carvalho and Campos, ). It projected in an arc (Westpfahl, ) in a lateral‐rostral‐medial direction across the ventral surface of the cerebral hemisphere until it reached the lateral face of the olfactory bulb (Kitoh, ; Richards, ; Campos, ; Carvalho and Campos, ). On the convex face of the cerebral hemisphere, the ostrich's middle cerebral artery went beyond the telencephalic vallecula, reaching rostrally the lateral two‐thirds of the sagittal eminence.…”