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Objective: To describe the road map of the lateral and endoscopic ventral approaches for the pharyngeal segment of the internal carotid artery, propose a sub-segmentation scheme, systematically and comprehensively understand its anatomical details and relationships with the surrounding structures. Methods: Five fresh cadaveric head specimens（10 sides in total） were dissected through lateral and endoscopic ventral approaches to evaluate the anatomical details of the parapharyngeal internal carotid artery and its relationship with the surrounding structures. Results: From the bifurcation of the common carotid artery to the vertical part of the internal carotid artery, alongside the direction of blood flow, the parapharyngeal internal carotid artery passes through four distinct anatomical tissues. Based on this, the parapharyngeal internal carotid artery can be divided into four sub-segments: nerve, muscle, fascia and osseous sub-segments. The boundaries and important adjacent structures of each segment are described in detail. Conclusion: The anatomical road map of the parapharyngeal internal carotid artery and the sub-segmentation scheme serving as a practical guide to navigate modular endoscopic skull base surgery of the parapharyngeal space while reduce the risk of internal carotid artery injury., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

Objective: To study the microanatomy of the perforating arteries in the superior space of the internal carotid artery visualized through a pterional approach., Methods: Twelve (24 sides) perfused cadaver heads were dissected via the pterional approach, and the perforating arteries in the superior space of the internal carotid artery were studied under microscope. The diameter, course and distribution in the anterior perforated substance of the perforating arteries were recorded., Results: All the perforating arteries exposed lied on the side of the brain tissue. The carotid bifurcation on 8 sides had perforating arteries, and 11 sides showed medial lenticulostriate artery of the middle cerebral arteries, with short course and overlapped with another perforating arteries upon entry into the anterior perforated substance. On 4 sides, the medial lenticulostriate artery coincided with the perforating arteries in A1. All 24 sides showed middle lenticulostriate artery and lateral lenticulostriate artery of the middle cerebral arteries. Most of the lenticulostriate arteries originated from the anterior segment of the bifurcation of the middle cerebral arteries. The earlier bifurcation occurred in M1 of the middle cerebral arteries, the more perforating arteries originated. On 22 sides, the anterior cerebral arteries had perforating arteries with many branches, and fewer perforating arteries in a main artery were associated with greater diameter of them., Conclusion: The superior space of the internal carotid artery allows a space for operation, and in some cases, part of the medial leticulostriate arteries and A1 perforating arteries can be severed to obtain larger space for the operation.

Objective: To explore the arterial origin of the facial nerve and the site of the arteries joining it in cerebellopontine angle (CPA), in order to provide anatomical data for clinical application., Methods: The nutrient arteries were observed on 22 fresh adult head specimens fixed and perfused with formalin and gelatin under operation microscope., Results: Of all the nutrient arteries of facial nerve motor root,31 were derived from the artery loops in CPA space (50.82%) and 17 from the branch of anterior inferior cerebellar artery (27.88%). Eight of them originated from the labyrinthine artery (13.1%), 3 from posterior inferior cerebellar artery (4.92%) and 2 from basilar artery (3.28%) respectively. Forty-seven nutrient arteries (77.05%) entered the proximal 1/3 segment of facial nerve motor root. Thirty-six nutrient arteries of nervus intermedius raised from the artery loops in CPA space (73.47%), 7 from the branch of anterior inferior cerebellar artery (14.29%) and 6 from labyrinthine artery (12.24%) respectively., Conclusions: The observation of the arterial origin of the facial nerve and the site of the arteries joining it in cerebellopontine angle provided an anatomic basis for the etiology of hemifacial spasm and the microsurgical operation in CPA.

Objective: In order to improve the safety of skull base surgery and to completely resect the skull base tumors, the anatomical landmarks of skull base were studied., Methods: 29 cases of skull base surgery were performed between 1992 and 2002, and their clinical data were retrospectively analysed. The anatomical landmarks of cranial base, such as comb, pterygoid process, spine of temporal bone, styloid process, and internal caroid artery, were analysed in preoperative diagnosis and operative treatment of various kinds of skull base tumors., Results: In the early stages, because of lacking the knowledge of anatomical landmarks of the skull base, the surgery lasted longer, part of skull base tumors remained and operative blood lose was much more than that in later stage. In the later stage, no operative death and severe complications were found in 26 cases which underwent various kinds of skull base surgery. The survival rates at 3 and 5 years were 72.2% and 35.7% respectively for malignant tumors., Conclusions: Comb, pterygoid process, spine of temporal bone, styloid process, internal caroid artery and their adjacent structures were important anatomical landmarks for operative treatment of anterior, middle and lateral cranial base tumors. It was important to know the anatomical landmarks to ensure the safety of the skull base surgery.

Objective: To observe and measure the inside diameter of basicranial arteries, the angulation of main arteries, the three dimensional image characteristic of internal carotid arteries and the anatomical variation of Willis circle., Methods: The arteries of 30 formalin-fixed adult heads were injected with latex after which the caliber and characteristic of cerebral arteries were observed and measured. The three dimensional image characteristic of internal carotid arteries and its branches were measured using 3D-DSA., Results: (1) Main artery caliber: origin of internal carotid artery (Left 5.12 +/- 1.48 mm; Right 5.11 +/- 1.42 mm); origin of middle cerebral artery (Left 2.93 +/- 1.44 mm; Right 2.92 +/- 1.46 mm); origin of anterior cerebral artery (Left 2.63 +/- 1.33 mm; Right 2.61 +/- 1.32 mm); origin of vertebral artery (Left 4.37 +/- 1.21 mm; Right 3.22 +/- 1.64 mm); origin of basilar artery (4.45 +/- 1.28 mm); origin of posterior cerebral artery (Left 2.62 +/- 1.36 mm; Right 2.61 +/- 1.22 mm). (2) The angulation of main arteries: C1, 2 of ICA and C4, 5 of ICA (Left 32 +/- 22 degrees; Right 36 +/- 28 degrees ); ICA and ACA (Left 43 +/- 26 degrees; Right 46 +/- 28 degrees). (3) The results show that anatomical and three dimensional image characteristic of internal carotid arteries have no difference (P > 0.05). (4) The anatomical variation of Willis circle: Type O (56.7%); Type A (16.7%); Type P (20.0%); Type AP (6.7%)., Conclusions: It is helpful to measure the inside diameter of basicranial arteries for the selection of various catheter in interventional neuroradiology, to observe the angulation of main arteries and the three dimensional image characteristic of internal carotid arteries for the moulding of various catheter in endovascular therapy and to master the anatomical variation of Willis circle for decreasing complications of endovascular treatment and judging prognosis of cerebrovascular diseases.

The anatomical relationships and morphologic features of the optic canal and the internal carotid artery to the lateral wall of the most posterior ethmoidal cell and the sphenoid sinus in 100 half-skulls swan middle-saggitally were investigated. The results showed: (1) The whole optic canals neighboured with the most ethmoidal cell in 39 cases, with the sphenoid sinus in 43 cases and with both of them in 18 cases; (2) The bulgings of the optic canal formed on the lateral wall of the most posterior ethmoidal cells and the sphenoid sinus were demonstrated in 48 and 47 cases respectively; (3) The marks of the internal carotid artery formed on the lateral wall of the sphenoid sinus were demonstrated in 53%-77% of all cases. The height and the thickness of the bony wall of the bulgings and marks of the optic canal and the internal carotid artery were measured. From our observation it was suggested that the variations of development and composition of the sphenoid-ethmoid sinuses, the bulging or mark of the optic canal and the internal carotid artery on the lateral wall of the most posterior ethmoidal cell and the sphenoid sinus might be the anatomical factors of severe complications in endoscopic ethmoid-sphenoid surgery.

Sixty-three sphenoid sinuses were examined in cadavers, with special attention to the neural and vascular structures on the lateral wall of the sinus. There are three structures producing prominences on the lateral wall of the sinus, 1) The carotid artery, including its presellar segment, infrasellar segment and retrosellar segment. The means of length, thickness and the distance to the middle line of the presellar one are 6.8 mm, 1.0 mm and 6.2 mm respectively. The means lf length, thickness and the distance to the middle line of the infrasellar one are 6.6 mm, 1.0 mm and 5.0 mm respectively. The means of length, thickness and the distance to the middle line of the retrosellar one are 6.6 mm, 1.8 mm and 7.1 mm respectively. 2) The bulge of optic canal, the means of its length, thickness and the distance to the middle line in sphenoid sinus are 4.8 mm, 1.0 mm and 5.5 mm respectively. 3) The maxillary branches of the trigeminal nerve, the mean of its length, thickness and the distance to the middle line in sphenoid sinus are 5.3 mm, 1.2 mm and 8.5 mm respectively.

The optic nerve in relation to the internal carotid artery was anatomically and pathologically studied in 51 adult brain specimens. There were obvious impressions on the optic nerves from compression by the sclerosed internal carotid arteries, and pathological changes in the optic nerves, such as atrophy, were observed in 6.9% of the specimens. This fact suggests that clinical visual defects of unknown explanation may be caused by the indurative internal carotid artery compressing the optic nerve.

The high-resolution real-time sonographic images in 186 carotid bifurcations (CB) of 93 selected normal persons were quantitatively analysed for 9 parameters including the diameters of the internal carotid arteries (CCA), the bifurcating angles of the ICA and ECA, and the angles between the ICA and ECA. The results of all the measurements were analysed with the relevant statistical methods. The normal field (99% limit) of CB in every age group was shown in this paper. The normal range of the measured values of the carotid bifurcations in each age group was calculated, and the laws governing their changing trends and their clinical significance were discussed.