The relationship of the posterior inferior cerebellar artery to cranial nerves VII-XII

The posterior inferior cerebellar artery (PICA) is the largest branch of the vertebral artery. It usually arises at the anterolateral margin of the medulla oblongata close to the lower cranial nerves. The PICA had the most complex relationship to the cranial nerves of any artery and it is frequently exposed in approaches directed to the fourth ventricle. The aim of this article is to describe the anatomical relationship of the PICA to the lower cranial nerves. In this study, 12.5% of PICAs passed between the glossopharyngeal and vagus nerves, 20% between the vagus and accessory nerves, and 65% through the rootlets of the accessory nerve. The lateral medullary segment of the PICA showed a lateral loop which in 20% specimens pressed against the inferior surfaces of the facial and vestibulocochlear nerves. The lateral medullary segment of the PICA in 20% specimens passed superior to the hypoglossal nerve, in 47.5% through the rootlets of the hypoglossal nerve, and in 30% inferior to the hypoglossal nerve. The findings on the relationship of the PICA to the lower cranial nerves could be helpful in microsurgery of this region.     

小脑下后动脉在枕骨大孔区的解剖学研究

目的对颅后窝枕骨大孔区小脑下后动脉进行观察与测量,并探讨其临床意义。方法选取成人颅底标本15例,观察枕骨大孔区小脑下后动脉位置、走行、毗邻关系及其分布,测量相关数据并进行统计学处理。结果颅后窝枕骨大孔区小脑下后动脉左右两侧起始部外径:左侧为1.32~1.49 mm,平均(1.41±0.05)mm;右侧为1.27~1.49 mm,平均(1.39±0.07)mm,左右管径比较差异无统计学意义(P>0.05);小脑下后动脉走行呈“S”形,与第Ⅸ、Ⅹ、Ⅺ对脑神经的位置关系密切。结论小脑下后动脉在枕骨大孔区起点走行、分布具有特有的解剖特点,在临床中枕骨大孔区小脑下后动脉相关疾病的手术时应避免医源性损伤。     

The course of the posterior inferior cerebellar artery may be related to its level of origin

The course of the posterior inferior cerebellar artery (PICA) was analyzed with reference to its origin and relationships with the medullary and cerebellar surfaces and the adjacent cranial nerves in 40 brains after the injection with acrylic resins of the vertebrobasilar system. In 42.5% of instances, the PICA originated from the lateral medullary segment of the vertebral artery (VA), in 32.5% from its premedullary segment, in 22.5% from the basilar artery (BA), and in 2.5% it was absent. With reference to the level of origin, three patterns of course for the lateral medullary segment of the PICA can be outlined. (1) When it arises from the lateral medullary segment of the VA, it passes below the hypoglossal nerve, and the lateral medullary segment may form a loop with an anterosuperior convexity towards the pontomedullary sulcus (41%), or it may follow a rectilinear course (41%). It passes at the level of the accessory nerve. The tonsillomedullary (TM) segment shows a caudal loop and the telovelotonsillary (TVT) has a cranial loop. (2) When the PICA arises from the BA, it passes above the hypoglossal nerve. The lateral medullary segment forms a loop with lateral convexity (78%) and passes above or through the glossopharyngeal nerve, frequently showing a recurrent course among the roots of the IX, X, or XI cranial nerve. The TM and the TVT segments do not have loops. (3) When the PICA arises from the premedullary segment of the VA, it passes above, below, or through the rootlets of the hypoglossal nerve. In the lateral medullary segment, it follows a rectilinear course (54%) and passes the plane formed by the IX, X, and XI cranial nerves at an intermediate level with respect to the other two patterns. The TM and the TVT segments show caudal and cranial loops. The different origins and courses of the PICA derive from the selection of different branches of the primitive vertebrobasilar plexus during the development of the cerebellum. The existence of an embryologic correlation between the course of the PICA and its level of origin may be useful in the evaluation of its angiographic anatomy.     

Endovascular treatment of ruptured distal posterior inferior cerebellar artery aneurysms: report of 11 cases

Objective

To investigate the clinical characteristics and endovascular treatment of ruptured distal posterior inferior cerebellar artery (PICA) aneurysms.

Methods

11 consecutive patients (7 women, 4 men, mean age of 49.2 years) with ruptured distal PICA aneurysms were studied retrospectively. All had onset of acute intraventricular or cerebellar haemorrhage, and subarachnoid hemorrhage (SAH). Hunt-Hess (HH) grades were H-H I in 1 patient, H-H II in 5 patients, H-H 111 in 4 patients and H-H IV in 1 patient on admission.

Results

All patients were treated by endovascular treatment, seven cases got endosaccular coiling and four cases got parent artery occlusion at the same time. All the patients were followed up one to four years. Recurrences occurred in 1 patient two years post-treatment, and were successfully retreated by endosaccular coiling and parent artery occlusion. The occluded PICA was recanalized one year post-treatment but without any growth of the aneurysm in one case. One year post-treatment, 2 patients had a modified Rankin Scale (mRS) score of 0, 8 patients had a mRS score of 1 and 1 patient had a mRS score of 2.

Conclusions

Coiling of ruptured distal PICA aneury, with or without parent vessel occlusion, was feasible, relatively safe and effective in preventing early/medium-term rebleeding. A strict angiographic follow-up, however, was necessary to detect recurrence.     

小脑动脉与三叉神经根毗邻关系的应用解剖

目的观察小脑动脉的起始位置、行程特点及其与三叉神经根的毗邻关系,为三叉神经微血管减压术提供解剖学依据。方法采用12个福尔马林固定的成人头部标本,在手术显微镜下分别解剖小脑上动脉、小脑下前动脉、小脑下后动脉及三叉神经等结构。观察相关动脉、神经的位置、走行特点,测量上述动脉的起始段外径及其与三叉神经根最近距离等相关数据。结果共发现小脑上动脉27支,2支压迫三叉神经根,5支与神经根接触,其余无接触压迫者与三叉神经的最近距离为(3.87±1.58)mm(0.55～6.30 mm);小脑下前动脉23支,压迫神经根1例,与之接触者2例,其余20支小脑下前动脉与三叉神经根最近距离为(4.67±1.77)mm(2.65～9.50 mm);小脑下后动脉21支,与三叉神经根最近距离为(17.12±3.86)mm(10.45～25.70 mm),未发现与之接触或压迫者。结论小脑上动脉与三叉神经关系密切,常与三叉神经接触并压迫神经,成为三叉神经痛发生的主要结构。小脑下前动脉与三叉神经相距稍远,也可与三叉神经接触或压迫神经。小脑下后动脉与三叉神经相距较远,但偶尔也会压迫三叉神经根导致三叉神经痛。     

小脑动脉与三叉神经根毗邻关系的应用解剖

目的　观察小脑动脉的起始位置、行程特点及其与三叉神经根的毗邻关系,为三叉神经微血管减压术提供解剖学依据。 方法　采用12个福尔马林固定的成人头部标本,在手术显微镜下分别解剖小脑上动脉、小脑下前动脉、小脑下后动脉及三叉神经等结构。观察相关动脉、神经的位置、走行特点,测量上述动脉的起始段外径及其与三叉神经根最近距离等相关数据。 结果　共发现小脑上动脉27支,2支压迫三叉神经根,5支与神经根接触,其余无接触压迫者与三叉神经的最近距离为（3.87±1.58） mm（0.55~6.30 mm）;小脑下前动脉23支,压迫神经根1例,与之接触者2例,其余20支小脑下前动脉与三叉神经根最近距离为（4.67±1.77）mm（2.65~9.50 mm）;小脑下后动脉21支,与三叉神经根最近距离为（17.12±3.86） mm（10.45~25.70 mm）,未发现与之接触或压迫者。 结论　小脑上动脉与三叉神经关系密切,常与三叉神经接触并压迫神经,成为三叉神经痛发生的主要结构。小脑下前动脉与三叉神经相距稍远,也可与三叉神经接触或压迫神经。小脑下后动脉与三叉神经相距较远,但偶尔也会压迫三叉神经根导致三叉神经痛。     

突发性聋与小脑下前动脉血管袢及颈静脉球形态学关系的研究

目的　探讨小脑下前动脉血管袢及颈静脉球的形态特点与突发性聋的关系。 方法　选取单侧起病突发性聋患者80例（80耳），36例健康成人（72耳），分别设为突聋组（80耳）和对照组（72耳），回顾分析其内耳MRI扫描及三维重建图像，观察以下指标：（1）小脑下前动脉血管袢是否突入内听道；（2）小脑下前动脉血管袢与面神经及前庭蜗神经的位置关系；（3）颈静脉球与周围结构的位置关系。 结果 （1）小脑下前动脉血管袢突入内听道：突聋组35耳（43.8%）、对照组29耳（40.3%），P=0.665，差异无统计学意义。（2）小脑下前动脉血管袢与面神经及前庭蜗神经的位置关系分型：突聋组上位型9耳（11.3%）、中间型53耳（66.3%）、下位型11耳（13.8%）、前位型7耳（8.8%）、后位型0耳，对照组上位型8耳（11.1%）、中间型46耳（63.9%）、下位型11耳（15.3%）、前位型7耳（9.7%）、后位型0耳。P=0.771，差异无统计学意义。（3）颈静脉球位置分型：突聋组I型2耳（2.5%）、Ⅱ型40耳（50.0%）、Ⅲ型36耳（45.0%）、Ⅳ型2耳（2.5%），对照组I型0耳、Ⅱ型19耳（26.4%）、Ⅲ型46耳（63.9%）、Ⅳ型7耳（9.7%)。P<0.001，差异有统计学意义。 结论　突发性聋与颈静脉球的位置相关，与小脑下前动脉血管袢是否突入内听道无关，与面神经及前庭蜗神经的位置无关。颈静脉球Ⅱ型（后上型）较其它类型人群患突发性聋的比例更高。     

突发性聋与小脑下前动脉血管袢及颈静脉球形态学关系的研究

目的　探讨小脑下前动脉血管袢及颈静脉球的形态特点与突发性聋的关系。 方法　选取单侧起病突发性聋患者80例（80耳）,36例健康成人（72耳）,分别设为突聋组（80耳）和对照组（72耳）,回顾分析其内耳MRI扫描及三维重建图像,观察以下指标：（1）小脑下前动脉血管袢是否突入内听道;（2）小脑下前动脉血管袢与面神经及前庭蜗神经的位置关系;（3）颈静脉球与周围结构的位置关系。 结果 （1）小脑下前动脉血管袢突入内听道：突聋组35耳（43.8%）、对照组29耳（40.3%）,P=0.665,差异无统计学意义。（2）小脑下前动脉血管袢与面神经及前庭蜗神经的位置关系分型：突聋组上位型9耳（11.3%）、中间型53耳（66.3%）、下位型11耳（13.8%）、前位型7耳（8.8%）、后位型0耳,对照组上位型8耳（11.1%）、中间型46耳（63.9%）、下位型11耳（15.3%）、前位型7耳（9.7%）、后位型0耳。P=0.771,差异无统计学意义。（3）颈静脉球位置分型：突聋组I型2耳（2.5%）、Ⅱ型40耳（50.0%）、Ⅲ型36耳（45.0%）、Ⅳ型2耳（2.5%）,对照组I型0耳、Ⅱ型19耳（26.4%）、Ⅲ型46耳（63.9%）、Ⅳ型7耳（9.7%)。P<0.001,差异有统计学意义。 结论　突发性聋与颈静脉球的位置相关,与小脑下前动脉血管袢是否突入内听道无关,与面神经及前庭蜗神经的位置无关。颈静脉球Ⅱ型（后上型）较其它类型人群患突发性聋的比例更高。     

Magnetic resonance imaging based classification of anatomic relationship between the cochleovestibular nerve and anterior inferior cerebellar artery in patients with non-specific neuro-otologic symptoms

In this study, we aimed to assess anatomical relationship between the anterior inferior cerebellar artery (AICA) and cochleovestibular nerve (CNV) in patients with non-specific cochleovestibular symptoms using magnetic resonance imaging (MRI). One-hundred and forty patients with non-specific neuro-otologic symptoms were assessed using cranial and temporal MRI. Classification was performed according to four different types of anatomical relationship observed between the AICA and CVN. In type 1 (point compression), the AICA compresses only a limited portion of the CVN. In type 2 (longitudinal compression), the AICA approaches the CVN as both traverse parallel to each other. In type 3 (loop compression), the vascular loop of the AICA encircles the CVN. In type 4 (indentation), the AICA compresses the CVN so as to make an indentation in the nerve. The anatomical relationship between the CVN and AICA was encountered in 19 out of 140 (13.6%) patients (20 ears). The VCC was unilateral in 18 patients (94.7%) and bilateral in one patient (5.3%). There was no other vascular structure causing VCC to the CVN except for vertebral artery that was seen in 2 out of 140 patients (1.4%). These were unilateral cases. There were tinnitus, vertigo or dizziness, hearing loss, and both hearing loss and vertigo in 5 (25%), 13 (65%), 1 (5%) and 1 (5%) ears of 20 patients, respectively. There was no relationship between the cochleovestibular symptoms and type of compression (p>0.05). Neurovascular relationship between the CVN and AICA can be imaged properly using MR and MR based classification may help reporting this relationship in a standard way. Although, MR images can show the anatomical relationship accurately, diagnosis of vascular conflict should not be based on imaging findings alone.     

面听神经血管压迫综合征患者小脑下前动脉血管袢与患者典型面听神经症状的MRI研究

目的 探讨小脑下前动脉前(AICA)血管袢的位置对面听神经血管压迫综合征患者典型面、听神经症状的影响。方法 回顾性研究。纳入兰州大学第二医院核磁共振科311例患者(622侧耳)内耳MR可变翻转角三维快速自旋回波(3D-SPACE)序列影像资料,其中男113例、女198例,年龄22~77(48±10.8)岁。统计AICA血管袢发生率及其Chavda分型占比。311例中,单侧面肌痉挛患者107例,比较其患侧(107侧)与健侧(107侧)AICA血管袢发生率、Chavda分型占比,以及AICA走行全程与神经有无接触。自血管袢阳性患者中选择90例(148侧)为血管袢组,比较不同Chavda分型AICA血管袢患者临床表现的差异;将ChavdaⅡ型及Ⅲ型的63侧耳纳入内耳道内血管袢组,将内耳道中的神经分布分为4个象限,观察AICA血管袢与面、听神经接触的位置象限不同的患者间典型面、听神经症状的差异。结果 本组311例622侧患者AICA血管袢的发生率为65.43%(407/622),其中双侧AICA血管袢形成144例、单侧119例,ChavdaⅠ型170侧(41.77%)、Ⅱ型189侧(46.44%)、Ⅲ型48侧(11.79%)。107例单侧面肌痉挛患者健侧AICA血管袢发生率为71.96%(77/107)、患侧70.09%(75/107),两侧比较差异无统计学意义(P＞0.05);健侧和患侧神经血管接触率分别为57.9%(62/107)、43.9%(47/107),差异有统计学意义(χ²=4.207, P＜0.05)。血管袢组90例(148侧)中,不同Chavda分型患者面肌痉挛、听力下降、耳鸣症状的发生率比较,差异均无统计学意义(P值均＞0.05);内耳道内血管袢组共63侧,内耳道内AICA血管袢所处象限不同患者的典型面、听神经症状比较,差异均无统计学意义(P值均＞0.05)。结论 内耳MR 3D-T₂-SPACE成像可清晰显示AICA血管袢及其与内耳道的位置关系,血管袢深度、位置对面听神经压迫综合征典型面、听神经症状无明显影响。     

Blood supply of the inferior turbinate and its clinical applications

One of the most effective treatments of inferior turbinate (IT) hypertrophy is surgical reduction. Bleeding from the IT branch of the posterior lateral nasal artery (ITB) may interfere with the outcome of IT surgery. The aim of this study is to define the anatomic localization of the ITB and its variations and to investigate its clinical importance. Anatomic relations of the ITB were determined by microdissecting 20 adult, sagittally cross‐sectioned head specimens. Branching characteristics of the ITB and its anatomical relations were evaluated. The most consistent two markers to define the ITB on the lateral nasal wall were the posterior attachment of the IT (PAIT) and the posterior attachment of the middle turbinate (PAMT). Mean horizontal distances of the ITB from the PAIT and the PAMT were 7.2 mm ± 2.8 mm (2.5–11.8 mm) and 8.2 mm ± 2.8 mm (4–14.6 mm), respectively. ITB was the only major artery that supplied the IT in 85% of the specimens, and, in 15%, there was more than one artery. ITB was located lateral to the IT in 95% and medial to the IT in 5%. The ITB coursed on the lateral nasal wall, vertically between the middle and ITs and always anterior to the PAIT. All the variations of blood supply to the IT were within a one square centimeter area, ～1‐cm anterior to the PAIT. Successful cauterization of this particular area may be an alternative cauterization site in IT surgery. Clin. Anat. 23:770–776, 2010. © 2010 Wiley‐Liss, Inc.     

Variations in the origin and course of the posterior interventricular artery in relation to the crux cordis and the posterior interventricular vein: An anatomical study

Corrosion castings of 60 human hearts were used to demonstrate that the point of origin of the posterior interventricular artery (PIA), in relation to the crux cordis, is responsible for its subsequent course with respect to the posterior interventricular vein (PIV). In seven cases (12%), the PIA appeared as the continuation of the left circumflex, descending rightwards and on a deeper level of the PIV. In 53 cases (88%), the PIA arose from the right coronary artery (RCA) and 50 of these were selected to be classified into three groups, according to the PIAs origin and course. In group A (29 cases, 58%) and B (seven cases, 14%), the PIA emerged before the crux cordis and descended to the right or left of the PIV, respectively. In group C (14 cases, 28%), it originated at, or beyond, the crux cordis and descended along the left side of the PIV. Among the 50 cases, the PIA was found to be long in 34 (68%), large in 32 (64%), and long and large in 29 cases (58%). In 18 of the latter 29 cases (62%) or 36% of the 50 cases in total, the PIA arose as a continuation of the RCA (group A) and therefore these cases were easily accessible to interventional cardiologists and also to surgeons, since the PIA lay on the same or on a superficial level in relation to the PIV. This work describes and explains the variations of the PIA and concludes that at least 36% of these may be helpful in coronary artery angioplasty and bypass surgery. Anat. Rec. 252:413–417, 1998. © 1998 Wiley-Liss, Inc.     

An anatomic investigation of the serratus posterior superior and serratus posterior inferior muscles

In classical anatomy textbooks the serratus posterior superior muscle was said to elevate the superior four ribs, thus increasing the AP diameter of the thorax and raising the sternum. However, electromyographic and other studies do not support its role in respiration. In order to help resolve this controversy and provide some insight into their possible functionality, the present study aimed at examining the morphology, topography and morphometry of serratus posterior superior and inferior muscles in both normal specimens and those derived from patients with a history of chronic obstructive pulmonary disorder (COPD). These muscles were examined in 50 human cadavers with an age range of 58–82 years. In 18 of the cadavers their histories revealed that they were suffering from COPD. There was no significant difference between right and left sides, race, gender and age and positive COPD history in regard to dimensions and nerves supply of serratus posterior superior and inferior muscles (P > 0.05). Based upon our findings that no morphometric differences exist between the of serratus posterior superior and inferior muscles of COPD patients versus controls, we are suggesting that no respiratory function be attributed to either of the serratus posterior superior and inferior muscles.     

Microsurgical anatomy of the foramen of Luschka in the cerebellopontine angle,and its vascular supply

Cerebellopontine angle and vascular supply of adjacent brainstem and cerebellum are susceptible to compression and eventual damage by tumors. Delicate and complicated neurosurgical operations in the cerebellopontine angles of the brainstem, where lateral recesses of fourth ventricle empty, are abundant especially operations in which foramina of Luschka are used as possible access to the floor of the fourth ventricle. So awareness and knowledge of the normal anatomical features of the region is valuable for neurosurgeons. Arteries of 40 human cerebella were injected with colored gelatin to investigate the microsurgical anatomy around the foramen of Luschka in the cerebellopontine angle. Two compartments of the foramen of Luschka were distinguished, choroidal part and the patent part. Seventy-four (92.5%) of foramina were open and only 6 (7.5%) foramina were closed. The mean distance between the foramen of Luschka and the anterior inferior cerebellar artery was 3.90 mm on the left side and 3.89 on the right side. The distance from the posterior inferior cerebellar artery was 7.08 and 5.81 mm to the left and right foramina of Luschka, respectively. In ten cases, tortuous vertebral artery was occupying the left cerebellopontine angle space and the foramen of Luschka.     

The right inferior phrenic artery: path of its ascending branch at the vena caval foramen

The ascending branch of the right inferior phrenic artery is generally understood to pass to the lateral side of the vena caval foramen, on the inferior surface of the diaphragm. A study of 16 cadavers shows that the artery may pass through the vena caval foramen to run on the superior surface of the diaphragm, before returning to the inferior surface by passing through the muscle of the diaphragm.     

Anastomosis between the inferior alveolar artery branches and submental artery in human mandible

The mental artery displays several branches internal to the anterior region of the mandible as confirmed by macroscopic observation and computed tomography. The inferior alveolar artery formed complex branches and divided into mental and incisive branches, which were found in the right internal side of the mandible of one male cadaver (88 years old). The branches of these two arteries ran through the bony lingual canal to the lingual foramen between the canine and premolar region of the inner surface of the mandible body, where they emerged to enter the mylohyoid and anterior belly of the digastric muscles and communicate with the submental artery. The observation of the anastomotic artery is considered important for surgical placement of dental implants in the mandibular region.     

三叉神经根与周围血管关系及其临床意义

目的：研究三叉神经与小脑动脉、岩静脉等之间的关系，为临床三叉神经痛诊治提供解剖学资基础。方法：解剖20例（40侧）湿整颅标本，打开颅盖，去除硬脑膜后，小心切除大脑组织保留小脑及脑干，打开小脑幕，观察三叉神经根和小脑动脉、岩静脉间的关系，并拍照，最后测量它们之间的距离。结果：有17．4％（8支）岩静脉主干或属支与三叉神经根接触，6．5％（3支）主干或属支压迫神经根，42．5％（17支）小脑上动脉与三叉神经根接触，12.5％（5支）压迫神经根，27．5％（11支）小脑下前动脉与三叉神经接触或压迫。结论：小脑上动脉、小脑下前动脉为造成三叉神经痛的主要责任动脉，而岩静脉不仅是造成三叉神经痛原因之一而且与临床手术关系密切。     

A morphometric study of the inferior orbital fissure using three‐dimensional anatomical landmarks: Application to orbital surgery

The inferior orbital fissure (IOF) is an important structure during orbital surgery, however, neither its anatomical features nor the procedures necessary to expose the IOF have been examined in detail. A morphometric analysis of the IOF was performed on 232 orbits using computer software. The longest and shortest borders of the IOF were 18.2 ± 4.9 and 1.9 ± 1.3 mm, respectively. The outer and the inner angles were 138.9 ± 32.7° and 38.4 ± 24.7°, respectively. The perimeter of the IOF was 50.6 ± 13.5 mm and its area was 61.3 ± 39.1 mm². Eight types of IOF were observed. Type 1 IOF was observed in 42.2% and the Type 2 IOF was identified in 15.9%. A statistically significant relation was found between the longest edge and area and the widest edge and area of the IOF. The findings of our study suggest that the removal of the lateral wall should begin inferiorly, just lateral to the IOF and extended superolaterally. These data may be useful during surgical approaches to the orbit. Clin. Anat. 22:649–654, 2009. © 2009 Wiley‐Liss, Inc.     

Arborization of the inferior laryngeal nerve and internal nerve on the posterior surface of the larynx

The morphological patterns of the inferior laryngeal nerve and internal laryngeal nerve display complex arborizations. This paper attempts to identify and clarify these patterns. Dissections were performed on 105 adult Japanese cadavers, and observations were made on 201 sides. Results showed that the communications between the inferior laryngeal nerve (ILN) and internal laryngeal nerve (ITLN) could be classified into two types and three subtypes. Also, the ITLN displayed three characteristic patterns at the arytenoid cartilage. These communications produce complex arborizations of the ILN as it enters the larynx. This may explain the variety of potential clinical symptoms observed after thyroid surgery or neck dissections. © 1995 WiIey-Liss, Inc.