经脉络膜裂房部至四叠体池的显微解剖

Microsurgical anatomy from atrial portion of choroid fissure to quadrigeminal cistern

目的研究经脉络膜裂房部至四叠体池的解剖特点,为经脉络膜裂入路治疗四叠体池周围区域病变提供解剖学依据。方法经10%甲醛固定的完整成人湿性尸头标本10例(20侧),观察脉络膜裂房部的神经血管结构,显微镜下模拟经脉络膜裂房部到四叠体池手术入路。结果脉络膜裂房部是位于侧脑室房部内侧壁穹窿伞和丘脑枕之间的一条自然裂隙,其后缘为丘脑枕处,此处到侧脑室三角区后缘的距离为(15.9±3.3)mm,到中线的垂直距离为(21.6±2.8)mm,距室间孔后缘的脉络膜裂起点的裂长度为(31.4±3.5)mm。经此裂隙可进入四叠体池,池的前壁内侧为松果体和四叠体,脉络膜裂房部后缘到松果体的距离为(10.8±2.1)mm。脉络膜后外动脉通过脉络膜裂进入侧脑室,分布于颞角后部、房部、体部后部的脉络丛,脉络膜后内动脉经四叠体池进入三脑室顶壁,分布于中间帆内的脉络丛。房内侧静脉为位于侧脑室房部和枕角内侧壁呈放射状向脉络膜裂汇聚的一组静脉,经穹窿内侧到达四叠体池,汇入大脑内静脉或大脑大静脉。模拟经脉络膜裂房部的手术入路,可显露的范围包括四叠体池和同侧环池的后部,对池内走行的大脑后动脉(P2和P3)、基底静脉等众多血管结构显露良好,分离这些血管可以显露位置较深的松果体,而对上下丘显露十分困难。结论脉络膜裂房部及四叠体池周围神经血管结构复杂,熟悉其解剖特点十分重要,经脉络膜裂入路为治疗四叠体池周围区域病变提供了一条良好的路径。

Objective To study the anatomic features from atrial portion of choroid fissure to quadrigeminal cistern in order to provide an anatomic evidence for treating pathological changes around quadrigeminal cistern via choroidal approach in surgery. Methods Ten normal adult cadaveric heads（ 20 sides） fixed with 10% formaldehyde were enrolled in the study. The neurovascular structures around atrial portion of choroid fissure were observed,then the simulated surgical approach from atrial portion of choroid fissure to quadrigeminal cistern was performed under microscope. Results The atrial portion of choroid fissure was a strip of natural fissure that located between fimbria fornicis and pulvinar,in the medial wall of atrial portion of lateral ventricle. The pulvinar was posterior border of atrial portion of the fissure. The distance from pulvinar to trailing edge of trigone of lateral ventricles and central line was（ 15. 9 ± 3. 3） mm and（ 21. 6 ± 2. 8） mm,respectively. Moreover,the length of the fissure from pulvinar to the starting point locating behind foramen of monro was（ 31. 4 ± 3. 5） mm. The quadrigeminal cistern could be accessed through choroid fissure in atrial portion. The anterior medial wall of the cistern was pineal body and quadrigeminum,and the distance from posterior border of the fissure to pineal body was（ 10. 8 ± 2. 1） mm. The lateral posterior choroidal artery distributed to the choroid plexus locating in temporal horn,atrial portion and body portion of lateral ventricle via choroid fissure. The medial posterior choroidal artery distributed to the choroid plexus locating in interpositum of hanging wall of the third ventricle via quadrigeminal cistern. The medial atrial vein was a group of veins locating in the medial wall of atrial portion and occipital horn of lateral ventricle. This group of veins aggregated in choroid fissure and entered into internal cerebral vein or Galen＇s vein in quadrigeminal cistern via medial portion of fornix to form a simulated transchoroidal approach,with exposure range including quadrigeminal cistern and posterior part of ipsilateral ambient cistern. The most of blood vessels passing through quadrigeminal cistern could be well exposed,including P2 and P3 segment of posterior cerebral artery and basilar vein. The pineal body could be exposed after removing these blood vessels,however,the superior and inferior colliculus were difficult to be seen. Conclusion The neurovascular structures are complicated in atrial portion of choroid fissure and quadrigeminal cistern,so it is quite important to have an intimate knowledge for the related anatomical structures,and transchoroidal approach provides an natural pathway to treat the lesions around quadrigeminal cistern.