颅眶区结构的显微解剖学研究

Microanatomical study on the structure of the cranioorbital region

目的 通过显微解剖研究颅眶区的骨性结构、肌肉、神经及动脉等解剖结构,为该区域的手术提供解剖学依据.方法 选取8具(16侧)成人尸头标本,经额颞眶颧入路行弧形切口逐层显露颅眶区解剖,观察颅眶交界区解剖结构、测量眶上裂相关数据;观察眼眶区的骨性结构、肌肉、神经走行、眼动脉的解剖结构及其位置关系,并测量经眶上裂进入眼眶的神经直径.结果 颅眶交界区位于前床突下方,视神经管沟通颅内与眼眶,眶上裂连接眼眶和中颅窝,8具尸头标本的眶上裂外侧缘、内侧缘、上缘长度分别为(18.4±6.2)mm、(7.7±1.6)mm、(16.4±5.6)mm,左、右侧眶上裂宽度分别为(3.64± 0.86)mm、(3.69±0.88)mm.眶壁由额骨、颧骨、筛骨、泪骨、蝶骨、腭骨和上颌骨7块骨性结构构成;眼眶处存在顶壁、底壁、内侧壁和外侧壁,除内侧壁外,其他各壁的骨性结构呈对称排列.眼眶肌肉由上睑提肌、上斜肌、下斜肌、上直肌、下直肌、内直肌和外直肌7条肌肉构成.眼眶内神经主要由视神经、滑车神经、眼神经的3个分支(额神经、泪腺神经、鼻睫神经)、外展神经、动眼神经(上、下支)共7根神经构成;除视神经由视神经管进入眼眶外,其他6根神经的7个分支均由眶上裂进入眼眶,依上述次序直径分别为(0.86±0.42)mm、(1.51±0.53)mm、(0.71±0.36)mm、(0.82±0.47)mm、(1.23±0.41)mm、(1.29±0.48)mm、(1.82±0.48)mm.眼动脉在视神经下方同视神经一起由视神经管入眶,8具标本中共观察到16支眼动脉,其中1具为双干眼动脉,其上、下干的距离为11.2mm;其余7具均为单干眼动脉,并根据其在眼动脉眶内走行中的眼动脉角和眼动脉弯将眼动脉眶内段依次分为3段.颅眶区的骨性结构、肌肉、神经走行、眼动脉位置关系基本固定.结论 颅眶区域解剖复杂,空间狭小,熟悉该区域显微解剖及其位置关系,有利于临床医生在外科手术中对重要解剖结构的保护,尤其存在双干眼动脉时对其下干的保护.

ObjectiveTo study the spatial structures among the bony structures,muscles,nerves,and arteries in the cranio-orbital region by microdissection,and to provide anatomical basis for neurosurgery in this area.MethodsA total of 8 adult(16 sides)cadaveric head specimens were selected.The cranio-orbital region was exposed layer by layer using a curved incision via the frontotemporal orbito-zygomatic approach.The anatomical structure of the cranio-orbital junction region was observed and the data related to the supraorbital fissure were documented.The bone structures,muscles,nerve courses ophthalmic arteris anatomy and their position relationship were obserred.The diameters of the nerves entering the orbit through the supraorbital fissure were measured as well.ResultsThe cranio-orbital junction region was located below the anterior clinoid process.The optic canal connected the cranial fossa and the orbit.The supraorbital fissure connected the orbit to the middle cranial fossa.The lengths of lateral,medial,and superior margins of the supraorbital fissure in the eight cadaveric head specimens were 18.4±6.2 mm,7.7±1.6 mm,16.4±5.6 mm respectively.The widths of the supraorbital fissure on the left side and right side were 3.64±0.86 mm and 3.69±0.88 mm respectively.The widths of the left and right supraorbital fissures were 3.64±0.86 mm and 3.69±0.88 mm respectively.The orbital wall consisted of 7 bony structures:frontal bone,zygomatic bone,ethmoid bone,lacrimal bone,pterygoid bone,palatine bone and maxillary bone.The orbit had a roof,a floor,a medial wall and a lateral wall.Except for the medial wall,the other walls had symmetrically arranged bony structures.The extraocular muscles included 7 muscles:levator palpebrae,rectus superioris,rectus inferioris,rectus medialis,rectus externus,obliquus superioris and obliquus inferioris.The intraorbital nerves mainly consisted of 7 nerves:the optic nerve,the trochlear nerve,three branches of the ophthalmic nerve(frontal,lacrimal and nasociliary nerves),the abducens nerve and the oculomotor nerve(upper and lower branches).Except the optic nerve passing through the optic canal,other 6 nerves(7 branches in total)entered the orbit through the supraorbital fissure and their diameters were 0.86±0.42 mm,1.51±0.53 mm,0.71±0.36 mm,0.82±0.47 mm,1.23±0.41 mm,1.29±0.48 mm and 1.82±0.48 mm respectively.The ophthalmic artery which was located below the optic nerve entered the orbit through the optic canal.A total of 16 ophthalmic arteries were observed in 8 specimens.In 1 case there was a duplicated trunk and the distance between the upper and lower trunks was 11.2 mm.In the remaining 7 cases,there were single-trunk ocular arteries.The intraorbital segment of ophthalmic artery was divided into 3 segments according to the angle and curvature of ophthalmic artery.The spatial correlations of the bony structures,muscles nerve courses,and ophthalmic arteries were basically constant.ConclusionsThe anatomy of the cranioorbital region is complicated and its space is narrow.Proficiency in the microanatomy and spatial correlations of the region would help physicians protect important anatomical structures during surgery and particularly lower duplicate ophthalmic artery.