| Objective:The ACP(anterior clinoid process), the SOF(superior orbital fissure) and the optic canal were important anatomical landmarks of the cranial-orbital conjunctive region.To get detialed dates of ACP, SOF,the optic canal and its surrounding structures by observation an measurement. To provide the anatomical reference for operations in these areas by statistics and analysis. To explore the methods and significance of anterior clinoidectomy, and optic canal ectomy.Methods:The osseous structures of anterior clinoid process, superior orbital fissure and the optic canal were observed and measured in10cases (20sides) of dry adult cadaveric skull specimens.Adult cadaveric heads specimens were fixed by Formalin10cases(20sides),after displacement with alcohol and perfusion of the arteries and veins with colored silicone, were dissected layer by layer under microscope via orbitalzygomatic approach. To get detialed dates of ACP, SOF,the optic canal and its surrounding structures by observation measurement and photo. All date were statistically processed by SPSS13.0and presented in the mean (range and measured value) style.Results:1The temporal branch of the facial nerve run the course in temporal fascia fat layer(between the first layer and the second layer of fat pad) between the fronto-temporal branch of the superficial temporal artery and the edge of zygomatic arch. On the upper edge of the zygomatic arch and the line of ear-superciliary arch, the distance between the superficial temporal artery and the temporal branch of the facial nerve were5.61±0.93(3.60-8.72)mm,6.16±0.62(3.80-6.88)mm respectively.2MacCarty keyhole was located in the fronto-sphenoid suture. It was located posterior to frontal-zygomatic-sphenoid intersection.The distance of the MacCarty keyhole posterior to the frontal-zygomatic-sphenoid intersection is4.64mm.3Anterior clinoid process was a taper structure, posterior and medial continuation of the lesser wing of sphenoid bone. The length, width and thickness of the ACP were9.21±0.54(7.98-10.14)mm,11.87±0.44(11.12-12.88)mm,5.62±0.30(5.05-5.98)mm respectively. Bone bridges could be found between the ACP and both middle or posterior clinoid processes,its frequency is8%. ACP pneumatization was found in10%of all sides.4Clinoid space was taper lacuna after anterior clinoid process was stripped, it could provide about0.8～1.0cm3additional operating space.The length of posteriormedialis,lateral,anteriomedialis of the Dolenc’s triangle were9.91±0.98(7.69-13.42)mm,10.34±1.36(7.32-15.18)mm,6.41±0.70(4.24-8.60)mm respectively.5The additional length of optic nerve and the internal carotid artery after stripping the anterior clinoid process were9.95mm,5.32mm respectively.6The distal and the proximal ring crouses from upper and lower of The clinoid process. The distal dural ring was a thick and firm membrane, which the thickness of0.48±0.07mm; The proximal dural ring was loosely memebrace,which the thickness of the proximal dural ring was0.26±0.05mm.7The clinoid segment of the ICA was between the distal dural ring and the proximal dural ring, with the length of5.66±0.34mm.8There were four walls and two openings for optic canal.The length of internal, lateral,superior and inferior walls were10.72±1.17(8.48-12.14)mm,8.99±0.97(7.44-10.78)mm,9.37±1.04(7.66-11.02)mm,5.08±1.01(3.28-7.32) mm respectively. The area of crinal opening,middle and orbital opening of optic canal were19.5±3.83mm2,16.17±1.67mm2,1.25±2.44mm2.The area of crinal opening,middle and orbital opening of optic canal were10.39±2.17mm2,9.17±2.93mm2,8.26±1.64mm2.9Dural fold formed falciform ligament at superior wall of Posterior to optic canal, with the width(anteroposterior diameter)was2.77±0.83(0.98-5.46) mm.There were85%approximately optic nerve impression. 10The superior orbital fissure(SOF) was a triangular cleft and the length of the superior side, the medial side and the lateral side of the SOF were18.23±1.28(15.32-19.98)mm,5.83±0.58(4.96-6.98)mm,19.10±1.30(16.78-22.24) mm respectively. The SOF was divided into three areas by the annular tendon. Nerves and vasculars of SOF were relatively fixed structure.The diameter of inferior branch of oculomotor nerve was the larges (1.64±0.05)mm, in contrast the lacrimal nerve was the smallest(0.53±0.05)mm.11Ophthalmic artery originated from the medial third of supraclinoid segment of internal carotid artery.None of them arosed from the cavernous sinus and run into orbit via superior orbital fissure. The ophthalmicartery commonly courses beneath the optic nerve in the dura. From cranial opening to orbital opening, most of it courses from inside to outside under the optic nerve.90%Ophthalmic artery originated from the upper inner1/3of internal carotid artery.60%of them located lower inner of optic nerve,35%of them located benath of optic nerve, and35%of them located lower outer quadrantConclusions:1The temporal branch of the facial nerve courses in front of the fronto-temporal branch of the superficial temporal artery,and they have had relatively fixed anatomy relationship.Put fronto-temporal branch of the superficial temporal artery as anatomical landmarks fasciotomy,it is a simple and effective way to protect the temporal branch of the facial nerve. MacCarty keyhole is located in the fronto-sphenoid suture.It is located posterior to the frontal-zygomatic-sphenoid intersection.The distance of the MacCarty keyhole posterior to the frontal-zygomatic-sphenoid intersection is4.64mm.2Anterior clinoid process have a high degree of variability. Preoperative imaging examination is necessary to evaluate pneumatization of the ACP and bone bridge between the ACP and middle or posterior clinoid processes.3It is more safer epidural anterior clinoidectomy than intradural. Removal the anterior clinoid process should be start from the middle of the ACP. Anterior clinoidectomy should be confined to the upper limited of distal ring, the lower limited of the oculomotor nerve sheath,and within limited optic struck.In this way,accidental injury may reduce largely.4Anterior clinoidectomy is very important for improving the exposure of seller region and upper clivus. Clinoid space is the essential pathway into cavernous sinus from superior approach, via which the paraclinoid segment of ICA and ophthalmic artery origin can be exposed thoroughly.5The falciform ligment, sheath of optic nerve, anular tendon and the middle of optic canal should be incised in optic canal decompression. The incision shuoud be located on the supralateral wall of the sheath of optic nerve to avoid destroy ophthalmic artery.6The superior orbital fissure(SOF) was a triangular cleft The cleft have complex nerves and vasculars structures. We should dissected dura along direction of the ridge of sphenoid to small wing of sphenoid bone and along the direction of greater wing of sphenoid to the anterior clinoid outside, finally open the FTDF.It is safer and effective way to open FTDF by this way... |
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