The Study Of Microsurgical Anatomy Of The Parapharyngeal Space And Infrotemporal Fossa

Objective To understand the microsurgical anatomy of the parapharyngealspace(PPS) and infrotemporal fossa(ITF) and to provide anatomical basis for the operation of the region.Methods (1) Direct foraminal measurements were made in twenty dry skulls (40 sides),and the relationship of these foramina to each other and various landmarks were determined in the the parapharyngeal space and infrotemporal fossa.(2) Ten adult cadaveric heads (20 sides) fixed in 10% formalin were examined using microsurgical techniques and instruments, including the operating microscope.Subtemporal preauricular infratemporal fossa and mandibular swing approaches were selected to study.The anatomic relationships of the muscles, nerves, arteries, and veins were carefully recorded, with special emphasis regarding the relative relationship of these structures.Results (1) The distances from the root of styloid process to the foramen oval,foramen lacerum,exocranial entrance to the hypoglossal canal,exocranial entrance to the carotid canaljugula rfossa were 25.25?.38mm,17.90?.54mm, 17.88 ?.52mm,10.25?.34mm,3.32?.75mm;and the angles were!49.48?.85? 54.00?4.83?85.48?.780,119.95?0.780,86.05?.52?respectiveiy.The distances from the articular tubercle to them were 29.88?.78mm,28.02?.01 mm, 48.12?.71mm,32.86?.21mm,3.75?.74mm,respectively.(2) The shortest distance from the tragal pointer to the trunk of facial nerve was 10.80?.10mm.The temporal branches of facial nerve had three rami.They crossed the zygomatic arch to the temporal region,and ran between the superficial temporal fascia and the superficiallayer of the deep temporal fascia .The superficial temporal vessels were enwarpped with the superficia temporal fascia.The anterior temporal branch of the facial nerve crossed zygomatic arch at the distance of 31.30?.64mm before the tragus,the middle temporal branch 21.50?.51mm,and the posterior temporal branch 16.32?.43mm.(3) The mandibular nerve was the largest branch of the trigeminal.Its main branches included masseteric,deep temporal,buccal,auriculotemporal,lingual and inferior alveolar nerve.60% of the anterior deep temporal nerve had a common trunk with the buccal nerve.They crossed between the superior and inferior head of lateral pterygoid before entering the deep layer of temporal muscle.The posterior deep temporal nerve accompanying the masseteric nerve accounted for 55%,and they ran laterally on the roof of the ITF before they passed posterior to the infrotemporal crest and entered the deep layer of temporal muscle.The deep temporal artery accompanying with nerve ran between temporal muscle and periosteum,and supplied temporal muscle.(4) The lower cranial nerves(IX-XII), internal jugular vein, internal carotid artery sat medial to the styloid diaphragm,and ran between the styloid process and the transverse process of the atlas(TPA).The lower cranial nerves fanned out at front of the TPA.The glossopharyngeal nerve and the hypoglossal nerve coursed anteriorly .The vagus nerve continued its vertical course.and the spinal accessory nerve coursed posteriorly.(5) After the glossopharyngeal nerve exited jugular foramen,it coursed medial to the styloid process.lt curved around the posterior border of the stylopharyngeal muscle(SPM)and traveled over its lateral surface.Then it ran anteriorly to enter medial to the posterior border of the hyoglossus,At which the distance from the hypoglossal nerve was 19.45?.54mm.(6) The lingual nerve ran inferolateraly to cross the submandibular duct,and curved around it to travel medial to it so that two crossings were formed.Conclusions (1) The root of styloid process and the articular tubercle are two reference guides during the operation of the PPS and the ITF.(2) The tragal pointer is a key landmark to find the extratemporal portion of the facial nerve. The temporal branch of the facial nerve lies between the superficial temporal fascia and the superficial layer of the deep temporal fascia in the temporal region It is safe to dissectin the plane between the deep layer of the deep temporal fascia and the...