圖1.1。A，顱後窩的上視圖。後窩的骨壁由枕骨、顳骨和蝶骨形成。前顱窩以蝶背、蝶骨後部和枕骨斜坡部分為界;後麵在枕骨鱗狀部分的下部後麵;兩側分別是顳骨的岩狀和乳突部分，以及枕骨的外側部分。顳骨上方的一小部分是由頂骨的下角形成的。B，後顱窩的神經和動脈。12對顱神經中隻有2對完全走行於顱後窩外。天幕沿岩石脊附著，覆蓋後顱窩。 A., artery; Ac., acoustic; A.I.C.A., antero- inferior cerebellar artery; Bas., basilar; CN, cranial nerve; For., foramen; Int., internal; Jug., jugular; Occip., occipital; P.C.A., posterior cerebral artery; P.I.C.A., posteroinferior cer- ebellar artery; S.C.A., superior cerebellar artery; Temp., tem- poral; Tent., tentorial; Vert., vertebral.

圖1.2。小腦幕、枕下和岩側表麵。A，幕表麵麵對幕的下表麵。前側蚓部是小腦幕表麵的最上部分。這個表麵向下傾斜到它的後緣和側緣。這個表麵的蚓類分支比它們相應的半球部分要好。右側列出了用於蠕蟲
和小腦幕表麵半球細分的經典命名法
，左側列出了我們的簡化命名法。幕尖小葉和四角小葉對應小腦幕表麵的前部，幕尖小葉、單葉和部分上半月形小葉對應小腦幕表麵的後部。在我們的術語中，將小腦幕表麵分為前後兩部分的裂縫被稱為小腦幕裂，但在舊的術語中，它是主要的裂縫。這個裂縫將半球表麵在四邊形和簡單的小葉和蚓部之間分開。 The anterior part of the superior surface of the cerebellum surrounds the posterior half of the midbrain to form the cerebellomesencephalic fissure. B, suboccipital surface. The suboccipital surface is located below and between the sigmoid and lateral sinuses and is the surface that is exposed in a wide bilateral suboccipital craniectomy. The classical nomenclature applied to this surface is shown on the right, and our simplified nomenclature is on the left. The vermis sits in a large median depression, the posterior cerebellar incisura, between the cerebellar hemispheres. According to classical nomenclature, the portions of the vermis within the incisura from above to below are the folium, tuber, pyramid, and uvula. The parts of the hemispheric surface from above to below are the superior and inferior semilunar and biventral lobules and the tonsils. These lobules extend beyond the suboccipital surface to the other surfaces of the cerebellum. The prebiventral fissures between the inferior semilunar and the biventral lobules separate the hemispheres into superior and inferior parts, and the prepyramidal fissure between the pyramid and tuber separates the vermis into superior and inferior parts. We refer to the union of the prebiventral and the prepyramidal fissures that divide the suboccipital surface into superior and inferior parts as the suboccipital fissure. From below to above the corresponding vermian and hemispheric parts are the uvula and the tonsils, the pyramid and the biventral lobules, the tuber and inferior semilunar lobules, and the folium and the superior semilunar lobules. The petrosal (horizontal) fissure, the most prominent fissure on the petrosal surface, extends onto the suboccipital surface and divides the superior half of the suboccipital surface between the superior and inferior semilunar lobules. The cerebellomedullary fissure extends superiorly between the cerebellum and medulla. C, petrosal surface. The petrosal surface faces forward toward the petrous temporal bone and is the surface that is retracted to surgically expose the cerebellopontine angle. The classical nomenclature applied to this surface is shown on the right, and our simplified nomenclature is on the left. The petrosal fissure divides the petrosal surface into superior and inferior parts. The superior part is formed by the quadrangular, simple, and a small part of the superior semilunar lobules. The inferior part is formed by the inferior semilunar and biventral lobules and the tonsil. The cerebellopontine fissures are V-shaped fissures formed where the cerebellum wraps around the pons and the middle cerebellar peduncles. These fissures have a superior and an inferior limb, which meet at a lateral apex. The petrosal fissure extends laterally from the apex of the cerebellopontine fissures. Ant., anterior; Cer.Med., cerebellomedullary; Cer.Pon., cerebellopontine; CN, cranial nerve; Fiss., fissure; Horiz., horizontal; Inf., inferior; Pet., petrosal; Post., posterior; Quad., quadrangular; Suboccip., suboccipital; Sup., superior; Tent., tentorial.

圖1.3。小腦幕表麵和小腦間裂。首先，幕部表麵正對著被移除的幕部。表麵從頂端向下傾斜到後緣和側緣。小腦幕表麵上部包圍中腦後半部分，形成小腦後裂後唇。小腦前切跡，即腦幹與小腦幕表麵前部相吻合的切跡，位於小腦前切跡，即小腦鐮與小腦相吻合的切跡，位於小腦後切跡。B，小腦脊髓裂放大圖，該裂向下延伸至中腦和小腦之間。後唇的淺部由中線的唇峰和外側的四角小葉組成。四叉腦池向尾部從鬆果體延伸至小腦裂。C，嘴部被切除，露出中央小葉和它的翅膀，它們構成小腦裂後唇的一部分。 D, the central lobule and its wings, the lingula, the superior medullary velum, and medial part of the superior cerebellar peduncles have been removed to expose the fourth ventricle. The lower half of the roof is formed in the midline by the nodule and laterally by the inferior medullary velum, which passes laterally above, but is separated from the rostral pole of the tonsils by the cerebellomedullary fissure. E, some of the middle peduncle has been removed to expose the choroid plexus extending through the lateral recess into the cerebellopontine angle below the facial and vestibulocochlear nerves. F, oblique view of the lower half of the roof formed by the inferior medullary velum and the tela choroidea in which the choroid plexus arises. The inferior medullary velum arises on the surface of the nodule and extends laterally to blend into the flocculus and, with the flocculus and nodule, forms the flocculonodular lobe of the cerebellum. A.I.C.A., anteroinferior cerebellar artery; Cent., central; Cer., cerebellar; Cer.Mes., cerebellomesencephalic; Chor., choroid; CN, cranial nerve; Coll., colliculus; Dent., dentate; Fiss., fissure; Flocc., flocculus; Inf., inferior; Lat., lateral; Mid., middle; Med., median, medullary; Nucl., nucleus; Ped., peduncle; Plex., plexus; Post., posterior; Quad., quadrangular; Sulc., sulcus; Sup., superior; Tent., tentorial; Vel., velum; Vent., ventricle.

圖1.4小腦幕表麵及小腦脊裂。A，小腦幕麵麵對著小腦幕，從位於小腦幕頂下方的小腦幕頂向下傾斜。小腦間裂向前延伸，位於小腦和中腦之間。枕下表麵，蚓部是最高的部分，與枕下表麵不同，枕下表麵蚓部在小腦半球之間折疊成一個很深的裂縫，即切骨。直竇和小腦幕邊緣均被保留。SCA出於小腦裂，供應十麵。B，切除小腦裂後唇右半部分。裂隙的前壁在中線由小腦丘板和舌骨形成，外側由上小腦蒂形成。小腦中部的花梗包裹在上花梗的外側表麵。滑車神經起源於下丘下麵。 C, the right half of the lingula and superior medullary velum have been removed to expose the fourth ventricle. Additional white matter has been removed below the right superior peduncle to expose the dentate nucleus in which the superior peduncular fibers arise. D, enlarged view. The dentate nucleus appears to wrap around the rostral pole of the tonsil. E, oblique view into the fourth ventricle. Additional cerebellum has been removed to expose the nodule and rostral pole of the tonsil. The dentate nucleus wraps around the rostral pole of the tonsil. The upper half of the roof is formed by the superior medullary velum, which has the lingula layered on its outer surface. The upper part of the lower half of the roof is formed by the nodule in the midline and by the inferior medullary velum laterally. The inferior medullary velum, an almost transparent membrane, stretches laterally across the upper pole of the tonsil. F, the left half of the upper part of the roof has been removed. The velum arises on the nodule and sweeps laterally above both tonsils. The SCA courses within the cerebellomesencephalic fissure. A.I.C.A., anteroinferior cerebellar artery; Cer.Mes., cerebellomesencephalic; Chor., choroidal; CN, cranial nerve; Coll., colliculus; Dent., dentate; Fiss., fissure; Inf., inferior; Lat., lateral; Med., medullary; Mid., middle; Nucl., nucleus; Ped., peduncle; S.C.A., superior cerebellar artery; Str., straight; Sup., superior; Tent., tentorial; Vel., velum; Vent., ventricle.

圖1.5。小腦枕下表麵和小腦延髓裂。A，枕下表麵位於乙狀竇和側鼻竇之間的下方，是寬枕骨下骨瓣切除術暴露的表麵。蚓部位於兩個半球之間的凹陷處，即小腦後切骨。小腦延髓裂沿室頂下半部分在小腦和延髓之間向上延伸。小淋巴管在扁桃體之間向上延伸，並通過馬琴蒂孔與第四腦室相通。異食癖支配著枕下表麵。B,放大圖。蚓部腦室後麵的下部是錐體和小舌。C，切除右側扁桃體，露出由下髓膜和脈絡膜形成的頂部下部。 The nodule on which the velum arises is hidden in front of the uvula. The uvula hangs downward between the tonsils, thus mimicking the situation in the oropharynx. The choroid plexus arises on the inner surface of the tela and extends through the foramen of Luschka behind the glossopharyngeal and vagus nerve. The inferior medullary velum arises on the surface of the nodule, drapes across the superior pole of the tonsil, and blends into the flocculus laterally. D, both tonsils have been removed to expose the inferior medullary velum and tela choroidea bilaterally. The telovelar junction is the junction between the velum and tela. The cerebellomedullary fissure extends upward between the rostral pole of the tonsil on one side and the tela choroidea and inferior medullary velum on the opposite side. The segment of the PICA passing through this cleft is called the telovelotonsillar segment. The rhomboid lip is a sheet-like layer of neural tissue attached to the lateral margin of the ventricular floor, which extends posterior to the glossopharyngeal and vagus nerves and joins the tela choroidea to form a pouch at the outer extremity of the lateral recess. E, the right half of the tela has been removed to expose the ventricle and the lateral recess. The inferior medullary velum extends laterally to form a peduncle, the peduncle of the flocculus, which blends into the flocculus at the outer margin of the lateral recess. F, the tela has been removed on both sides. The lateral wall of the upper half of the ventricle is formed by the superior cerebellar peduncles. The inferior cerebellar peduncles ascend along the dorsolateral medulla and form the anterior and rostral margins of the lateral recess. Cer.Med., cerebellomedullary; Chor., choroid; CN, cranial nerve; Fiss., fissure; Flocc., flocculus; For., foramen; Inf., inferior; Lat., lateral; Med., medullary; Ped., peduncle; P.I.C.A., posteroinferior cerebellar artery; Plex., plexus; Suboccip., suboccipital; Sup., superior; Telovel., telovelar; Vel., velum.

圖1.6。枕下表麵和小腦延髓裂。A、小腦延髓
裂在扁桃體和
延髓之間向上延伸。通過
切開扁桃體的蒂，切除了兩個扁桃體。切除
扁桃體暴露出下髓膜
和形成
室頂下部的脈絡膜。下小腦
梗沿後外側
髓質上升。脈絡膜叢起於脈絡膜叢的內
表麵。帶絛蟲
是脈絡膜的附著點
沿著腦室的下外側邊緣
底。延髓連接處是
下髓膜與
脈絡膜連接的部位。這個結節，
下髓膜在其上升起，隱藏在小舌深
處。 B, the tela, in which the choroid
plexus arises, has been removed to expose both
lateral recesses. The superior cerebellar
peduncle forms the lateral wall of the upper half of the ventricle. The inferior cerebellar peduncle forms the anterior and upper margin of the lateral recess. The middle cerebellar peduncle, which forms a large prominence on the lateral surface of the pons, is separated from the ventricular surface by the superior and inferior cerebellar peduncles. C, lateral surface of the left tonsil. All of the tonsillar surfaces, except at the superolateral margin, are free surfaces. The peduncle of the tonsil, located along the superolateral margin of the tonsil, attaches the tonsil to the remainder of the cerebellum. The posterior surface of the tonsil faces the cisterna magna. The medial surface faces the other tonsil. The anterior surface faces the posterior medulla. The rostral pole faces the inferior medullary velum and tela choroidea. The lateral surface below the peduncle of the tonsil faces the biventral lobule. D, posterior view of the left tonsil. The peduncle of the tonsil is located along the superolateral margin. Dividing the narrow peduncle allows the tonsil to be separated from the remaining cerebellum. Bivent., biventral; Inf., inferior; Lat., lateral; Med., medullary; Ped., peduncle; Post., posterior; Rost., rostral; Sup., superior; Telovel., telovelar; Vel., velum.

圖1.7。腦幹、岩麵、橋小腦裂。一個,斜視圖。小腦的岩麵向前朝向岩骨，是縮回露出橋小腦角的表麵。橋小腦裂，也可稱為橋小腦角，是小腦包裹橋小腦和小腦中腳梗形成的v型裂。上、下肢在岩裂隙的前端橫向會合，岩裂隙將岩麵分為上、下兩部分。小葉和脈絡膜叢從裂下肢上方的Magendie孔向外側延伸。基底溝是位於腦橋前表麵的淺縱溝，容納基底動脈。B,放大圖。 The petrosal fissure extends laterally from the apex of the cerebellopontine fissure. The abducens nerve arises in the medial part of the pontomedullary sulcus rostral to the medullary pyramids. The facial and vestibulocochlear nerves arise just rostral to the foramen of Luschka near the flocculus at the lateral end of the pontomedullary sulcus. The hypoglossal nerves arise anterior to and the glossopharyngeal, vagus, and accessory nerves arise posterior to the olives. Cho- roid plexus protrudes from the foramen of Luschka behind the glossopharyngeal and vagus nerves. C, enlarged view of another brain- stem. The facial and vestibulocochlear nerves join the brainstem 2 or 3 mm rostral to the glossopharyngeal nerve on a line drawn dorsal to the olive along the origin of the rootlets of the glossopharyngeal, vagus, and accessory rootlets. The rhomboid lip, a thin neural membrane in the ventral margin of the lateral recess, extends laterally behind the glossopharyngeal, vagus, and accessory nerves with the choroid plexus. D, enlarged view of another cerebellopontine fissure. The cerebellopontine angle is the area situated between the superior and inferior limbs of the cerebellopontine fissure. The glossopharyngeal, vagus, and accessory nerves arise near the inferior limb, dorsal to the olive, and anterior to the choroid plexus protruding from the foramen of Luschka. The facial and vestibulocochlear nerves arise in the midportion of the fissure and the trigeminal nerve near the superior limb of the fissure. The hypoglossal rootlets arise in front of the olive and the cranial rootlets of the accessory nerve. Bas., basilar; Cer.Pon., cerebellopontine; Chor., choroid; CN, cranial nerve; Fiss., fissure; Flocc., flocculus; For., foramen; Inf., inferior; Mid., middle; Ped., peduncle; Pet., petrosal; Plex., plexus; Sup., superior.

圖1.8。f。腦幹，第四腦室，岩側小腦麵。逐步前曝光。A，岩麵向前麵對顳骨的後表麵。第四腦室位於腦橋和髓質後麵。中腦和腦橋由腦橋腦溝隔開，腦橋和延髓由腦橋腦溝隔開。三叉神經起源於腰橋。外展神經起源於橋髓溝的內側，靠近髓錐體。麵神經和前庭耳蝸神經起源於橋延髓溝的外側端，緊靠盧施卡孔。 The hypoglossal nerves arise anterior to the olives and the glossopharyngeal, vagus, and accessory nerves arise posterior to the olives. Choroid plexus protrudes from the foramen of Luschka behind to the glossopharyngeal and vagus nerves. B, right cerebellopontine angle following removal of some of the medulla. The foramen of Luschka opens into the cerebellopontine angle below the junction of the facial and vestibulocochlear nerves with the lateral end of the pontomedullary sulcus. Choroid plexus protrudes from the lateral recess and fora- men of Luschka behind the glossopharyngeal, vagus, and accessory nerves. The cerebellopontine fissure, a V-shaped fissure formed by the cerebellum wrapping around the pons and middle cerebellar peduncle, has a superior and inferior limb that define the margins of the cerebellopontine angle. The superior limb extends above the trigeminal nerve and the inferior limb passes below the flocculus and the nerves that pass to the jugular foramen. C, the part of the pons and medulla forming the left half of the floor of the ventricle has been removed to expose the fastigium, which divides the ventricular roof into superior and inferior parts. D, the right half of the pons has been removed to expose the upper half of the roof. The superior part of the roof is formed by the superior medullary velum. The rostral part of the lower half of the roof is formed by the nodule and inferior medullary velum and the caudal part is formed by the tela choroidea, a thin arachnoid-like membrane, in which the choroid plexus arises. E, the cerebellopontine fissure has upper and lower limbs, which meet at a later apex located at the medial end of the petrosal fissure, also called the horizontal fissure, which divides the petrosal surface into upper and lower halves. The junction of the pons and medulla, which forms the anterior wall of the left lateral recess, has been removed to expose the choroid plexus protruding through the lateral recess into the cerebellopontine angles. F, enlarged view. The choroid plexus protrudes laterally through the foramen of Luschka into the cerebellopontine angle below the floc- culus. Cer.Pon., cerebellopontine; Chor., choroid; CN, cranial nerve; Fiss., fissure; Flocc., flocculus; For., foramen; Inf., infe- rior; Lat., lateral; Med., medial, medullary; Mid., middle; Ped., peduncle; Pet., petrosal; Plex., plexus; Pon.Med., pontomedul- lary; Pon.Mes., pontomesencephalic; Seg., segment; Sulc., sulcus; Sup., superior; Vel., velum.

圖1.8。G-J。腦幹，第四腦室，岩側小腦麵。G，左側髓質已被切除。屋頂的上半部由上髓膜形成，外側有蚓舌層。上蓋的下半部分由起源於結節表麵的下髓膜和起源於脈絡膜叢的脈絡膜層組成。脈絡膜叢由成對的l形條紋組成，有內、外側兩段。外側段向外側延伸通過Luschka孔，內側段向縱向延伸通過Magendie孔。H，切除右側脈絡膜層和脈絡膜叢，露出右側扁桃體上極。我，右小腦扁桃體被切除了。 All of the surfaces of the tonsils are free surfaces except the superolateral margin, the site of the tonsillar peduncle, a bundle of white matter, which attaches the tonsil to the remainder of the cerebellum. The inferior medullary velum is a thin membranous layer of neural tissue that arises on the nodule and extends laterally above the rostral pole of the tonsil to blend into the flocculus and form the flocculonodular lobe of the cerebellum. The cranial loop of the PICA courses between the rostral pole of the tonsil and the inferior medullary velum. J, both tonsils have been removed. The inferior medullary velum sweeps laterally from the surface of the nodule.

圖1.9。f。後的觀點。逐步解剖檢查下髓膜、齒狀核、扁桃體、小腦髓裂和小腦脊髓裂的關係。A, pica繞過後延髓到達小腦延髓裂的下緣。左異食癖在扁桃體下極周圍活動。右側異食癖在沿扁桃體內側表麵上升之前，先下降到扁桃體下方的枕骨大孔處。B, pica在扁桃體和延髓之間上升，到達扁桃體和小舌之間的間隙，並供應枕骨下表麵。C，右異食癖的後髓段分為支配蚓部和蚓旁區的內側幹和支配半球的外側幹。D，小腦斜冠狀麵切片顯示扁桃體嘴側極與下髓膜和齒狀核的關係。 The dentate nucleus is located above the posterolateral part of the ventricular roof, near the fastigium, where it wraps around, and is separated from, the rostral pole of the tonsil by the inferior medullary velum. The left tonsil has been removed while preserving the left half of the inferior medullary velum. The SCAs course in the cerebellomesencephalic fissure. The PICA passes between the walls of the cerebellomedullary fissure formed above by the inferior medullary velum and below by the upper pole of the tonsil. E, both tonsils have been removed. The PICAs ascend through the cleft between the inferior medullary velum and rostral pole of the tonsil. F, the superior part of the ventricular roof has been removed and the nodule and the inferior medullary velum has been folded downward to expose the floor. A., artery; Cer. Med., cerebellomedullary; Cer.Mes., cerebellomesencephalic; CN, cranial nerve; Dent., dentate; Fiss., fissure; Inf., inferior; Lat., lateral; Med., medial, medullary; Nucl., nucleus; Ped., peduncle; P.I.C.A., posteroinferior cerebellar artery; S.C.A., superior cerebellar artery; Suboccip., suboccipital; Telovel. Ton., telovelotonsillar; Vel., velum; Vent., ventricle; Vert., vertebral.

圖1.9。G-J。後的觀點。G是脈絡膜總層，脈絡膜叢在其中產生，它向下折疊，露出了地板的下部。H，左側外側隱窩及Luschka孔放大圖。菱形唇是一層薄薄的神經組織，從外側隱窩的前緣向外側延伸，與脈絡膜一起在外側隱窩的外緣形成一個袋。脈絡膜叢通過側隱窩和Luschka孔延伸至橋小腦角。I，骨層已被切除，以暴露位於結節上方和下方的部分地板和下髓膜。J，結節和下髓膜已被切除，以暴露整個基底，其在中線被正中溝和顱底分為橋核部分、連接部分和髓質部分。上足梗和下足梗麵對心室表麵。 The middle cerebellar peduncle is separated from the ventricular surface by the superior and inferior peduncles. Chor., choroid; Dent., dentate; Inf., inferior; Lat., lateral; Med., median, medullary; Mid., middle; Nucl., nucleus; P.I.C.A., posteroinferior cerebellar artery; Ped., peduncle; Plex., plexus; Sup., superior; Vel., velum.

圖1.9。K、l驗視圖。K，第四腦室底部放大圖。中間溝以中線縱向分隔地板。地板的每一半都被一個不規則的溝縱向分割，溝限，加深到麵丘和舌下三角形成上凹和下凹。藍斑細胞的暗區位於局限性溝的嘴端。髓紋在外側隱窩處橫過地麵。舌下核、迷走神經核和舌後區在地板的下部一個疊在另一個上麵，形成筆尖的結構，因此，該區域被稱為scriptorius菖蒲。L，第四心室底層。小腦上梗成對的靜脈在上梗外表麵走行，並向上連接形成小腦腦裂靜脈。 The median posterior medullary vein ascends on the medulla and splits into the paired veins of the inferior cerebellar peduncle at the caudal margin of the floor. That left vein is hypoplastic. The left vein of the cerebellomedullary fissure passes along the lateral recess and ascends to join the petrosal group of veins in the cerebellopontine angle. Cer.Med., cerebellomedullary; Cer., cerebellar; CN, cranial nerve; Coll., colliculus; Emin., eminence; Fiss., fissure; Hypogl., hypoglossal; Inf., inferior; Med., median, medullary; Mid., middle; Ped., peduncle; Post., posterior; Striae Med., Stria medullaris; Sup., superior; V., vein.

圖1.10。模擬。腹側入路進入第四腦室。A，小腦延髓裂在扁桃體後方和延髓前部之間向上延伸。小淋巴管在扁桃體之間打開進入第四腦室。B，兩個扁桃體向外側收縮，露出構成室頂下部的下髓膜和脈膜層。蚓部的結節，下髓起源於此，隱藏於小舌深處。C，小腦延髓裂左側放大圖。脈絡膜動脈沿著脈絡膜總層走行，脈絡膜叢從這裏伸入第四腦室的頂部。小腦延髓裂靜脈穿過下髓膜，是小腦延髓裂內最大的靜脈。 The interrupted line shows the site of the incision in the tela to provide the exposure seen in the next step. The telovelar junction is the line of attachment of the tela to the velum. D, the tela choroidea has been opened extending from the foramen of Magendie to the junction with the inferior medullary velum. The uvula has been displaced to the right side to provide this view extending from the aqueduct to the obex. A., artery; Cer.Med., cerebellomedullary; Chor., choroidal; Fiss., fissure; For., foramen; Inf., inferior; Med., medul- lary; P.I.C.A., posteroinferior cerebellar artery; Telovel., telovelar; V., vein; Ve., vermian; Vel., velum.

圖1.10。情況。腹側入路進入第四腦室。E，位於第四腦室內的神經鉤的尖端通過薄如紙的下髓膜可見。F，下髓膜的左半部分被切開，露出上外側隱窩和由上、下梗形成的心室麵。G，小舌向右縮回，露出整個心室和大部分心室頂。H，右側小腦矢狀分割小腦蚓部，橫切小腦蒂。扁桃體被切除，下髓膜和PICA顱環被向下移位，以暴露出通往外側隱窩的開口。齒狀核在第四腦室頂上外側隱窩靠近下髓膜附著處形成一個突出，即齒狀結節。凹痕。, dentate; Inf., inferior; Lat., lateral; Med., medullary; Nucl., nucleus; P.I.C.A., posteroinferior cerebellar artery; Ped., peduncle; Sup., superior; Vel., velum.