眶经颅手术入路显微解剖学研究

目的研究经颅至眶部手术入路的显微解剖学及解剖参数,为临床手术入路提供形态学依据。方法应用10例成人头颅湿标本,在放大5-20倍显微镜下,对眶内手术入路进行显微解剖分析及测量。结果内侧入路是经上斜肌与提上睑肌之间的间隙,经此入路可切除眶尖区内侧病变。中央入路是经提上睑肌与上直肌之间的间隙,根据额神经牵向内侧还是牵向外侧分为两种术式;经此入路可行眶内段视神经中段病变的切除。外侧入路是经上直肌与外直肌之间的间隙,根据眼上静脉牵向内侧还是外侧也分为两种术式,经此入路可切除眶尖区上、下、外侧部及眶上裂区病变。结论3种手术入路为经颅至眶部手术避免损伤神经血管提供了显微解剖依据。     

经眶额颞入路鞍区手术间隙的应用解剖

目的研究眶额颞入路中鞍区4个手术间隙的显微解剖特征,探讨这些间隙在鞍区显微外科手术中的应用。方法在10例(20侧)成人尸头标本上,模拟眶额颞入路开颅,在显微镜下对鞍区手术常用的4个手术间隙及其内部结构进行解剖观察和测量。结果对视交叉前间隙、视神经-颈内动脉间隙、颈内动脉-小脑幕三角间隙及终板间隙的结构构成及其邻近血管神经进行描述测量。结论选择合适的手术入路、熟悉鞍区解剖间隙的显微解剖、保护穿通支是鞍区手术成功的关键。眶额颞入路兼有额下和翼点入路的优点,适合大型鞍区肿瘤的切除。     

内镜经鼻入路视神经管和眼眶的解剖学

目的通过研究对视神经管和眼眶的解剖研究,为内镜经鼻入路视神经管减压和治疗眼眶内病变提供解剖基础。方法国人尸头5例,采用大体解剖和内镜下经鼻入路两种方法,观察重要的解剖标志;使用内直肌内移技术,观察视神经管和眼眶内结构的暴露情况以及重要结构的位置、毗邻、走行等。结果钩突位于中鼻甲的前下方;筛泡在钩突的后方,切开筛泡可进入筛窦;筛前后动脉是筛窦内的重要解剖标志;视神经管隆突、颈内动脉隆突和视神经管颈内动脉隆突(OCR)是蝶窦内重要的解剖标志;纸样板位于筛窦的外侧壁,切开纸样板可暴露眶内容物;在眶内,可从内直肌与下直肌之间的通路暴露视神经。在本次10侧标本中,9侧眼动脉起自于颈内动脉的床突上段;1侧眼动脉起自于颈内动脉海绵窦段。7侧眼动脉在视神经管内走行于视神经的下外侧;2侧走行于视神经的正下方;1侧走行于视神经的下内侧。结论内镜下经鼻入路可以进行视神经管和眼眶内侧部分的暴露。钩突、筛泡、筛前后动脉及后组筛窦是本入路重要解剖标志。视神经管隆突、颈内动脉隆突及视神经管颈内动脉隆突(OCR)是进行视神经管减压的重要标志。眼动脉及其眼眶内分支、筛前后动脉和颈内动脉是重要的血管结构。眼内直肌内移技术可以有助于暴露眶内解剖结构。     

内镜下经鼻眶内手术入路的解剖

目的 观察内镜经鼻眶内手术的关键解剖标志并探讨其临床应用。方法 3例（6侧）新鲜尸头,颈总动脉、椎动脉以及颈内静脉硅胶灌注后,采用STORZ 内镜系统和内镜手术器械,行内镜经鼻入路眶内区的入路解剖,并应用Storz Image 1系统采集高清图像。选择两例患者采取此径路进行手术。结果 内镜经鼻入路可以暴露眶内侧壁和部分眶下壁骨质,以及深层的眶骨膜、肌锥外脂肪。并能深入暴露内直肌、上斜肌和下直肌。经内直肌和下直肌之间的潜在间隙进入肌锥内,去除眶脂体显露重要的血管神经结构：眼动脉及其分支下内侧肌干、视神经和动眼神经的分支。临床上采用内镜经鼻入路处理眶内病变,选择眶内肌锥内球后金属异物和累及翼腭窝和颞下窝的眶尖海绵状血管瘤,手术均顺利,达到了预期手术目的,术后恢复良好,无手术并发症。结论 深入把握眶内关键解剖结构,选择恰当病例进行内镜下经鼻入路治疗,具有安全、有效及微创性。     

肌锥间隙的断层解剖

目的：为眶区影像诊断和手术治疗提供断层解剖学资料。方法：应用36例成人头颅湿标本，制成0．5mm冠状位火棉胶连续切片，用双目解剖镜对眶区结构进行形态观察，并采用计算机图像分析系统对标本上的肌锥间隙、视神经进行了测量。结果：肌锥间隙自眼球后极层面，自前向后，面积随眶腔减小，但不同层面肌锥间隙占眶腔的比例基本一致。眶内段视神经从前向后，横径和面积先逐渐减小，而后逐渐增大，垂直径逐渐减小，其与4条直肌的距离逐渐减小。结论：熟悉肌锥间隙的显微解剖，对影像诊断，麻醉及手术均有重要意义。     

内窥镜辅助眶上锁孔入路的应用解剖

目的：为眶上锁孔入路提供临床解剖学基础。方法：在21例福尔马林固定尸头上测量各有关解剖结构距离及夹角，在9例新鲜尸头上进行模拟手术，进一步验证其观察及操作范围。结果：提供了角突及眶上孔至盲孔、视神经管颅口、前床突尖、后床突尖距离，两点与上述结构连线与中线的成角，视交叉前缘至鞍结节距离，视神经颅内段长度，颅口处视神经内侧缘之间距离，第一间隙面积，颈内动脉床突上段长度等数据及入路的观察、操作范围。结论：眶上锁孔入路有广泛的视野及充足的操作空间，熟悉入路到各结构的距离对术中定位有重要意义。     

眶上外侧-纵裂入路处理前交通动脉瘤的临床应用解剖

目的　研究经眶上外侧-纵裂入路至前交通动脉复合体区的显微解剖,为临床应用该入路夹闭前交通动脉瘤提供解剖学依据。 方法　选取20具（40侧）成人尸头模拟经眶上外侧-纵裂入路,显微镜下观察前交通动脉复合体区的暴露情况,测量并记录相关数据。 结果　经眶上外侧-纵裂入路可较好地暴露前交通动脉复合体,尤其是前交通动脉的上区和后上区,且在暴露时对同侧额叶及直回的牵拉明显减轻。前交通动脉长度为（2.80±1.12）mm,中间外径为（1.79±0.82）mm,其距视交叉前缘中点距离为（4.59±2.22）mm。 结论　眶上外侧-纵裂入路具有手术视野好、脑组织损伤小等特点,对于上突型和后上突型前交通动脉瘤的暴露十分有益。     

垂体腺瘤经颅手术的显微解剖及临床应用

目的探讨一种可一次全切巨大型侵袭性垂体腺瘤的手术入路,并在临床上应用以验证其实际意义。方法采用15例经福尔马林固定的国人成人头颅湿标本共30侧,模拟额颞眶颧手术人路并逐步对相关的解剖标志进行详细地显微解剖。结合该区域的显微解剖,笔者回顾性总结了近几年收治的采用额颞眶颧入路治疗5例巨大型侵袭性垂体腺瘤的临床资料。结果在硬膜下阶段,根据垂体腺瘤生长的不同方向,可从多个间隙切除肿瘤。联合经硬膜外的海绵窦外侧壁入路可达到一次全切巨大型侵袭性垂体腺瘤的目的。5例巨大型侵袭性垂体腺瘤中,3例全切除,1例为次全切除,1例大部分切除。结论巨大型侵袭性垂体腺瘤可采用额颞眶颧入路进行手术治疗,根据需要可对该人路进行适当裁剪。     

前颅底手术入路应用解剖

目的：为前颅底手术的前方入路和眶外侧入路提供相关的解剖依据。方法：通过对４０例颅骨的测量，确定鼻根点和眶额颧点至前颅底上下方各结构的距离和夹角。结果：鼻根点至视交叉沟前缘、视神经管颅口、颈内动脉沟前端、蝶骨小翼后缘、筛前孔和筛后孔的距离分别为（４９．７±２．７）ｍｍ、（４９．９± ２．６）ｍｍ、（５３．５ ± ２．３）ｍｍ、（５１．３ ± ３．０）ｍｍ、（２５．３ ± ２．２）ｍｍ、（３３．０ ± ２． ２）ｍｍ；眶额颧点至盲孔、视神经管颅口、眶上裂内、外端和眶下裂内、外端的连线长度和各连线与正中矢状面成角分别为（４８．０±２．２）ｍｍ和９１．０°±３．０°、（５２．５±２．９）ｍｍ和４３．６°±３．５°、（５１．０±２．２）ｍｍ和４０．４°±４．２°（３４．５±２．７）ｍｍ和３６．６°±５．７°、（５０．３±２．３）ｍｍ和３７．８±４．３°、（２５．８±２．３）ｍｍ和２４．７°±３．３°。结论：两种手术入路有关测量结果，有助于手术入路设计，并可为术中准确定位有关结构提供参考依据。     

肘前内侧血管神经间隙入路的临床解剖学

目的　对肘前内侧血管神经等相关结构进行解剖研究,为肘关节相关手术提供更佳的手术入路。 方法　 福尔马林防腐动脉灌注红色乳胶成人尸体上肢标本20侧,按层次解剖,从肱桡肌及旋前圆肌间隙进入,通过正中神经与肱、尺动脉之间的血管神经间隙,显露肘前侧解剖结构。观察肱动脉、桡动脉和尺动脉向内、外侧的分支,测量分支到桡、尺动脉分叉处的距离,分支管径;观察正中神经及分支走行情况,测量神经与血管伴行无相互交叉分支距离。 结果　血管神经无互相交叉分支伴行长度平均为6.04 cm,两者之间无重要分支相交叉,易于向两侧分开,能够清楚地提供肘关节相应部位的暴露。动脉向内侧分支较向外侧分支少且细,易于向外侧牵拉。神经肌支,基本上向内侧发出,以极小的锐角从主干发出,几乎与主干平行,易于向内侧牵拉。 结论　肘前内侧血管神经间隙入路,可保护血管神经,能清楚显露肘关节前侧解剖结构,易于操作。     

Bilateral supernumerary rectus muscles of the orbit

A bilateral anomaly of the rectus muscles and a unilateral variation of the levator palpebrae muscle were found in the right and left orbits of an 84-year-old man. The anomaly was in the form of a supernumerary rectus muscle lying on a sagittal orientation between the optic nerve and lateral rectus muscle (in the right orbit) and adjacent to the inferior rectus muscle (in the left orbit). In each orbit the anomalous muscle originated occipitally from the common tendinous ring and frontally—near the eyeball—joined the terminal part of the inferior rectus. On its superior margin the anomalous muscle had, in the right orbit, a broad (4 mm), and in the left orbit a slender (2 mm) muscular bridge to the superior rectus muscle. Because of their connection to the superior rectus and their innervation by N.III the accessory orbital muscles are not deemed to be vestiges of the retractor bulbi muscle which, with the exception of the primates, is a typical occurrence in vertebrates and is always innervated by N.VI. Our anomalous orbital muscle must be explained as a supernumerary rectus muscle. A further variation occurred in the right orbit: an isolated medial part or belly of the levator palpebrae muscle (the so-called M. gracillimus). In primates this variation is known as a remnant of the membrana nictitans (third eyelid of the amniotes). Ignorance of anomalies in the orbital muscles may lead to confusion and error in diagnostic identification and surgical exposure. Clin. Anat. 11:271–277, 1998. © 1998 Wiley-Liss, Inc.     

Microsurgical anatomy of the ocular motor nerves

This study was designed to provide anatomic data to help surgeons avoid damage to the ocular motor nerves during intraorbital operations. The microsurgical anatomy of the ocular motor nerves was studied in 50 adult cadaveric heads (100 orbits). Dissections were performed with a microscope. The nerves were exposed and the neural and muscular relationships of each portion of the nerve were examined and measured. The superior division of the oculomotor nerve coursed between the optic nerve and the superior rectus muscle after it left the annular tendon, and its branches entered into the superior rectus muscle and levator muscle. A mean of five fibers (range 3–7) innervated the superior rectus muscle, and a mean of one fiber (range 1–2) followed a medial direction (84%) or went straight through the superior rectus muscle (16%). The inferior division of the oculomotor nerve branched into the medial rectus, inferior rectus and inferior oblique muscles. The trochlear nerve ended on the orbital side of the posterior one-third of the superior oblique muscle in 76 specimens. The abducens nerve ended on the posterior one-third of the lateral rectus muscle in 86 specimens. If the belly of the lateral rectus muscle was divided into three superior–inferior parts, the nerve commonly entered into the middle one-third in 74 specimens. Based on the observed data, microanatomical relationships of the orbital contents were revised.     

Functional organization of the oculomotor nucleus in the baboon

The functional organization of the oculomotor nucleus was investigated using horseradish peroxidase (HRP) histochemistry. In a series of baboons, injections of HRP were made into the skeletal muscles supplied by the oculomotor nerve (medial rectus, superior rectus, inferior rectus, inferior oblique, and the levator palpebrae superioris). After a 48-hour survival time the animals were sacrificed via perfusion-fixation and the brains treated according to the tetramethylbenzidine (TMB)-HRP method of Mesulam (1978). The inferior oblique, inferior rectus, medial rectus, and levator palpebrae superioris muscles are supplied by cells located primarily in the homolateral oculomotor nucleus. Some fibers to the levator palpebrae superioris arise from cells in both caudal central nuclei. The superior rectus muscle receives fibers from cells in the contralateral oculomotor nucleus. The results were complied using a Lucite-plate reconstruction method that permits visualization of the three-dimensional configuration of the neuronal populations within the oculomotor nucleus. Oculomotor neurons are organized in a vertical column that may be anatomically divided into rostral, middle, and caudal thirds. A section through any of these levels may be further subdivided into dorsal, intermediate, and ventral zones. Each of the oculomotor skeletal muscles was found to have cells at almost all levels of the nucleus and in certain zones at each level. These functional cell groups intermingle with one another in the baboon and do not remain segregated into distinct subnuclei or subdivisions. Much overlap was evident between cells innervating the homolateral inferior rectus, homolateral inferior oblique, and the contralateral superior rectus muscles. There was also overlap between those cells supplying the homolateral levator palpebrae superioris and the homolateral medial rectus muscles.     

Specific force of the rat extraocular muscles, levator and superior rectus, measured in situ

Extraocular muscles are characterized by their faster rates of contraction and their higher resistance to fatigue relative to limb skeletal muscles. Another often reported characteristic of extraocular muscles is that they generate lower specific forces (sP(o), force per muscle cross-sectional area, kN/m(2)) than limb skeletal muscles. To investigate this perplexing issue, the isometric contractile properties of the levator palpebrae superioris (levator) and superior rectus muscles of the rat were examined in situ with nerve and blood supply intact. The extraocular muscles were attached to a force transducer, and the cranial nerves exposed for direct stimulation. After determination of optimal muscle length (L(o)) and stimulation voltage, a full frequency-force relationship was established for each muscle. Maximum isometric tetanic force (P(o)) for the levator and superior rectus muscles was 177 +/- 13 and 280 +/- 10 mN (mean +/- SE), respectively. For the calculation of specific force, a number of rat levator and superior rectus muscles were stored in a 20% nitric acid-based solution to isolate individual muscle fibers. Muscle fiber lengths (L(f)) were expressed as a percentage of overall muscle length, allowing a mean L(f) to L(o) ratio to be used in the estimation of muscle cross-sectional area. Mean L(f):L(o) was determined to be 0.38 for the levator muscle and 0.45 for the superior rectus muscle. The sP(o) for the rat levator and superior rectus muscles measured in situ was 275 and 280 kN/m(2), respectively. These values are within the range of sP(o) values commonly reported for rat skeletal muscles. Furthermore P(o) and sP(o) for the rat levator and superior rectus muscles measured in situ were significantly higher (P < 0.001) than P(o) and sP(o) for these muscles measured in vitro. The results indicate that the force output of intact extraocular muscles differs greatly depending on the mode of testing. Although in vitro evaluation of extraocular muscle contractility will continue to reveal important information about this group of understudied muscles, the lower sP(o) values of these preparations should be recognized as being significantly less than their true potential. We conclude that extraocular muscles are not intrinsically weaker than skeletal muscles.     

Contractile properties and temperature sensitivity of the extraocular muscles, the levator and superior rectus, of the rabbit.

1. Contractile and fatigue-resistance characteristics, temperature sensitivity (10-37 degrees C) of contraction, and histochemical fibre types were determined for two of the extraocular muscles, the superior rectus and levator palpebrae superioris (levator), of the rabbit. 2. The levator displayed similar contractile characteristics (time to peak, half-relaxation time of twitch response, and twitch-tetanus force ratio) to mammalian fast-twitch limb muscle at room temperature (20 degrees C). However, normalized twitch and tetanic force levels were significantly less than those found in limb muscle. The superior rectus displayed the characteristics of even faster contraction than the levator at 20 degrees C, but generated lower maximum force levels than the levator. 3. The twitch response of the superior rectus showed a biphasic relaxation phase. This response was not due to non-twitch (tonic) fibres present in the superior rectus as it was unaffected by propranolol application during muscle stimulation. 4. The superior rectus and levator displayed significantly less fatigue in the tetanic force response than fast-twitch limb muscles did in response to a fatiguing electrical stimulation protocol. The levator was significantly more fatigue resistant than the superior rectus. 5. The force responses of both extraocular muscles displayed a similar dependence on temperature (10-37 degrees C) to limb skeletal muscles. 6. The superior rectus and levator exhibited a high proportion of fast-twitch muscle fibres (type II) as shown by myosin ATPase staining. Succinate dehydrogenase activity indicated that these muscles showed a high oxidative capacity, with a staining intensity typical of type I or type II A fibres of limb muscles. 7. The results emphasize the morphological and functional complexity of mammalian extraocular muscles. The combination of very fast contractile properties with high oxidative capacity make these muscles well suited to their role in eye/eyelid movement.     

Accessory levator muscle of the upper eyelid: Case report and review of the literature

The authors describe a supernumerary muscle in each orbit of an elderly male subject. There appear to be no previous reports of this muscle; most reports of anomalies of extraocular muscles describe hypoplasia or aplasia. Thirty-five formalin-fixed cadavers assigned to medical students for dissection were studied. The orbits were dissected by a superior approach which involved removal of the orbital plate of the frontal bone and the superior orbital margin. A supernumerary extraocular muscle was seen in each orbit of one cadaver, located between the superior oblique and levator palpebrae superioris muscles. It originated on the inferior surface of the lesser wing of sphenoid bone and was inserted into the skin of the medial one-third of the upper eyelid. It was innervated by a branch from the superior division of the oculomotor nerve. The insertion of the muscle into the upper eyelid produced a crease running obliquely upwards and medially, from the junction of the medial one-third and lateral two-thirds of the lid margin, towards the medial part of the superior orbital fold. The authors suggest the name levator palpebrae superioris accessorius for this muscle in view of its topography and action as tested in the cadaver. The significance of the findings is discussed and the literature on the development of the muscles supplied by the oculomotor nerve is reviewed. Clin. Anat. 11:410–416, 1998. © 1998 Wiley-Liss, Inc.     

Intramesencephalic course of the oculomotor nerve fibers: microanatomy and possible clinical significance

Comprehension of the mesencephalic syndromes that affect oculomotor nerve fascicles requires a detailed knowledge of their relationship with the adjacent structures and the blood supply of the central midbrain region. This was the reasoning behind our study, which was performed in ten serially sectioned midbrains stained with cresyl violet and luxol fast blue, in three microdissected midbrains, and in two injected and cleared specimens. Three continuous groups of the intramesencephalic oculomotor nerve fascicles were distinguished: the caudal, intermediate and rostral. The caudal fascicles, which most likely innervate the superior rectus and the levator palpebrae superioris muscles, extend through the superior cerebellar peduncle just caudal to the red nucleus and close to the lateral lemniscus. The intermediate fascicles, devoted to the medial rectus and the inferior oblique muscles, always pass through the superior cerebellar peduncle, just medial to the caudal part of the red nucleus (60 %), and less frequently (40 %) through the nucleus itself. The rostral oculomotor fascicles, which terminate in the inferior rectus and sphincter pupillae muscles, course medial to the rostral part of the red nucleus. While the rostral and intermediate oculomotor fascicles are supplied only by the medial twigs of the paramedian mesencephalic perforating arteries, the caudal fascicles are also nourished by the lateral branches of the same perforating arteries. The data obtained form an important basis for the explanation of certain mesencephalic syndromes, and even anticipate some new syndromes not yet described in the literature.     

视觉假体微电极经眶外侧壁入路植入视神经的应用解剖

目的为经眶外侧壁入路植入视神经视觉假体微电极提供解剖学依据。方法选用经4%甲醛固定及动脉灌注红色乳胶的成人头湿性标本30例,观测眶内眼动脉及相关分支的起始、数量和外径与穿入视神经鞘膜动脉的起始、外径和穿入部位、视神经外径等参数。结果泪腺动脉1～2支,经外直肌上缘上方(3.83±1.43)mm前行。外直肌-视神经间隙的深度为(8.14±0.90)mm,内有睫状短神经5～10条,颞侧睫状后动脉1～2支。穿入视神经鞘膜动脉的方位,内侧20%,上方29.3%,外侧6.7%,下方44%。视网膜中央动脉主要经下方穿入视神经,穿入处距球后(0.85±0.28)cm,该处动脉外径为(0.40±0.09)mm。眼动脉斜跨视神经处远侧端距球后(1.44±0.22)cm。在球后与总腱环中点处,视神经左右径(3.96±0.35)mm,上下径(4.18±0.33)mm。结论宜经眶外侧壁入路植入视神经视觉假体微电极,植入微电极的部位以视神经球后4～8mm处的外侧较好,植入深度应小于1.5mm。