Sistematização, descrição e território das artérias cerebral caudal, cerebral média, cerebroetmoidal e cerebelar ventral caudal na superfície do encéfalo em avestruz (Struthio camelus)

Abstract

Nesta tese foi descrito e sistematizado a distribuição e território das artérias cerebrais média e caudal, artéria cerebroetmoidal e artéria cerebelar ventral caudal na superfície do encéfalo de 30 avestruz ((Struthio camelus), 17 machos e 13 fêmeas, jovens e adultos. Os 30 espécimes foram injetados com látex corado em vermelho através das artérias (Aa.) carótidas internas. As artérias carótidas do cérebro e seus ramos foram sistematicamente descritas. A artéria (a.) cerebral caudal foi, à direita, dupla (73,4%), tripla (23,3%) e quádrupla (3,3%); à esquerda, dupla (76,7%), tripla (20%) e quádrupla (3,3%). A a. tectal mesencefálica dorsal foi ímpar em 96,7% e originada como ramo colateral da a. cerebral caudal. A a. tectal mesencefálica dorsal originou a a. cerebelar dorsal à direita (40%) e à esquerda (63,3%). Os ramos hemisféricos occipitais mediais foram quatro (46,7%) e três (20%) à direita e, quatro (30%) e três (26,7%) à esquerda. A a. pineal foi dupla (50%), única (23,3%), tripla (20%) e quádrupla (6,7%) à direita e, dupla (50%), única (23,3%), tripla (16,7%) e quádrupla (10%) à esquerda. A a. diencefálica esteve presente à direita (40%) e à esquerda (60%). A a. inter-hemisférica esteve presente à direita (60%) e à esquerda (40%), lançando quatro (40%) troncos hemisféricos dorsais, três (40%), dois (10%), cinco (6,7%) e um (3,3%) e, um único ramo hemisférico dorsal (26,7%). As Aa. cerebrais caudais foram classificadas em: tipo I (56,7%) com subtipos IA (36,7%) e IB (20%), tipo II (40%) com subtipos IIA (20%) e IIB (20%) e exceção no tipo III (3,3%). A artéria (a.) cerebral média, um vaso sempre único e de grosso calibre, lançou, à direita, dois ramos hemisféricos mediais desenvolvidos (46,6%), três (26,7%) e um (26,7%); à esquerda, um (36,7%), dois (33,3%) e três (30%). A a. cerebral média emitiu, à direita, oito ramos hemisféricos laterais desenvolvidos (40%), nove (20%), sete (16,7%), onze (6,7%), dez (6,7%), 12 (3,3%), seis (3,3%) e cinco (3,3%); à esquerda, sete (46,7%), nove (13,3%), oito (13,3%), seis (10%), cinco (10%) e dez (6,7%). Ramos perfurantes diretos da a. cerebral média foram emitidos, à direita, dois (33,3%), quatro (20%), três (20%), um (16,7%) e cinco (10%); à esquerda, três (33,3%), dois (30%), um (13,4%), seis (10%), quatro (10%) e cinco (3,3%). A artéria cerebroetmoidal, foi um vaso único de grosso calibre, que se projetou rostromedialmente, emitindo logo após sua formação a artéria cerebral rostral. A a. cerebral rostral foi um vaso único (90%) e duplo (10%) à direita e, único (96.7%) e duplo (3,3%) à esquerda. A a. etmoidal foi sempre um vaso único, de médio a grosso calibre, sendo a continuação natural da artéria cerebroetmoidal, logo após a emissão da artéria cerebral rostral. A artéria (a.) tectal mesencefálica ventral, um vaso sempre único e de médio calibre, foi, à direita, ramo colateral do ramo caudal da a. carótida do cérebro (53,4%), ramo direto da a. carótida do cérebro (43,3%) e ramo direto da a. basilar (3,3%) e, à esquerda, ramo colateral do ramo caudal da a. carótida do cérebro (66,7%), ramo direto da a. carótida do cérebro (30%) e ramo direto da a. basilar (3,3%). Vascularizava apenas a hemiface ventral do lobo óptico, não participando da vascularização do cerebelo à direita (93,3%) e à esquerda (80%) e, estendeu-se até os lóbulos mais ventrorrostrais do cerebelo vascularizando-os à direita (6,7%) e à esquerda (20%). A a. cerebelar ventral caudal foi um vaso único em à direita (96,7%) e à esquerda (93,3%). Seu primeiro ramo foi um tronco comum: espinal dorsal-cerebelar caudal à direita (60%) e à esquerda (56,6%). Seu segundo ramo foi a a. cerebelar caudal à direita (76,7%) e á esquerda (86,7%). Seu terceiro ramo foi o segundo componente da a. cerebelar caudal à direita (6,7%) e à esquerda (3,3%). O mesencéfalo foi vascularizado pelas Aa. tectal mesencefálica dorsal e tectal mesencefálica ventral. A primeira supre a hemiface dorsal e, a segunda a hemiface ventral do lobo óptico. O cerebelo foi vascularizado pelas ramificações da a. cerebelar ventral caudal, que suprem toda a extensão da face rostral do vérmis, flóculo até os lóbulos mais ventrocaudais; e pela a. cerebelar dorsal, que suprem a face rostral e os lóbulos mais ventrorrostrais.

This theses was described and systematized the distribution and territory of the middle and caudal cerebral arteries, cerebroethmoidal and caudal ventral cerebellar arteries at the surface of the brain of 30 young and adult ostrich (Struthio camelus), 17 males and 13 females. The brain specimens from 30 ostriches were injected with red-dyed latex via the internal carotid arteries. The carotid arteries of the brain and their branches were systematically described. On the right side, the caudal cerebral artery was double-, triple- and quadruple-branched in 73.4%, 23.3% and 3.3% of cases, respectively; on the left side, it was double-, triple- and quadruple-branched in 76.7%, 20% and 3.3% of cases, respectively. The dorsal tectal mesencephalic artery appeared as a single vessel in 96.7% of cases, emerging as a collateral branch of the caudal cerebral artery. The dorsal mesencephalic tectal artery originated from the right dorsal cerebellar artery in 40% of cases and from the left side in 63.3% of cases. On the right side, there were four and three medial occipital hemispheric branches in 46.7% and 20% of cases, respectively; on the left side, there were four and three branches in 30% and 26.7% of cases. On the right side, the pineal artery was double-, single-, triple- and quadruple-branched in 50%, 23.3%, 20% and 6.7% of cases, respectively; on the left side, this artery was double-, single-, triple- and quadruple-branched in 50%, 23.3%, 16.7% and 10% of cases, respectively. The diencephalic artery was on the right side in 40% of cases and on the left side in 60% of cases. The interhemispheric artery was on the right side in 60% of cases and on the left side in 40% of cases; four, three, two five and one dorsal hemispheric trunks branched off of the interhemispheric artery in 40%, 40%, 10%, 6.7% and 26.7% of cases, respectively. The caudal cerebral artery was classified as type I in 56.7% of cases (subtype IA in 36,7% of cases and IB in 20% of cases), type II in 40% of cases (subtype IIA in 20% of cases and IIB in 20% of cases) and type III in 3.3% of cases. The middle cerebral artery, a single vessel of large-caliber, launched, the medial hemispheric branches developed, on the right side, was two-, three-, one-branches in 46.6%, 26.7% and 26.7% respectively; on the left side, one-, two-, three-branches in 36.7%, 33.3% and 30%, respectively. The middle cerebral artery, launched, the lateral hemispheric branches developed, on the right side, was eight-, nine-, seven-, eleven-, ten-, twelve-, six- and five-branches in 40%, 20%, 16.7%, 6.7%, 6.7%, 3.3% and 3.3%, respectively. On the left side, seven-, nine-, eight-, six-, five- and ten-branches in 46.7%, 13.3%, 13.3%, 10%, 10% and 6.7% respectively. Direct perforating branches of the middle cerebral artery was launched, on the right side, two-, four-, three-, one-, five-branches in 33.3%, 20%, 20%, 16.7% and 10% respectively. On the left side, three-, two-, one-, six-, four-, five-branches in 33.3%, 30%, 13.4%, 10%, 10% and 3.3% respectively. The cerebroetmoidal artery was a single vessel large-caliber, which was designed rostromedialmente, launching shortly after its formation the rostral cerebral artery. The cerebral rostral artery appeared as a single vessel in 90% of cases on the right side and 96.7% on the left side, as a double vessel in 10% of cases on the right side and 3.3% on the left side. The ethmoidal artery was always a single vessel, medium to large-caliber, being the natural continuation of cerebroetmoidal artery, immediately after issuance of the rostral cerebral artery. The ventral tectal mesencephalic artery, one vessel always single, medium to large-caliber, was, on the right side, collateral branches of caudal branches of cerebral carotid artery in 53.4% of cases, direct branches of cerebral carotid artery in 43.3% and direct branches of basilar artery in 3.3%. On the left side, collateral branches of caudal branches of cerebral carotid artery in 66.7% of cases, direct branches of cerebral carotid artery in 30% and direct branches of basilar artery in 3.3%. Irrigated only hemiface ventral optic lobe, not participating in the vascularization of the cerebellum, on the right side in 93.3% and on the left side in 80% of cases, extended up to the most ventrorrostrais lobes of the cerebellum vascularizing them, on the right side in 6.7% and on the left side in 20%. The caudal ventral cerebelar artery was a single vessel on the right side in 96.7% of cases and on the left side in 93.3%. His first branch was one common trunk: dorsal espinal-caudal cerebelar on the right side in 60% of cases and on the left side in 56.6%. His second branch was the caudal cerebelar artery in 76.6% of cases on the right side and 86.7% on the left side. His third component was the second component of the caudal cerebral artery in 6.7% of cases on the right side and 3.3% on the left side. The midbrain was vascularized by dorsal tectal mesencephalic arteries and ventral tectal mesencephalic arteries. The first vascularize the dorsal hemiface and the second the ventral hemiface of the optic lobe. The cerebelum was vascularized by ramification of caudal ventral cereblar artery, providing whole length of the cerebellar vermis, flóculo, until even the most ventrocaudal wolves, and by dorsal cerebelar artery, that supply the rostral face and more ventrorrostrais lobes.