Applied microanatomy of petrous portion and mastoidea of temporal bone

Abstract

Objective To explore the regional anatomic of petrous bone and mastoideus and to provide the anatomic base for microsurgery for the lesion in the petroclivial region.Method 10 skull specimens(20 sides)and 10 fresh specimens were observed.Measurement of the distance within the asterion,the angle of parietomastoid sutures with STP ( sigmoid - transverse - superior petrosal ) were carried out.The body landmark of upper curvature of sigmoid sinus sulcus was observed.Results The configuration of the groove of sigmoid sinus (GSS) was “Z” - shape; the extracranial mark spot of upper limb of the “Z” was angle of parietomastoid sutures in 80％ of all; the extracranial mark spot of the lower part of the “Z” about 4.67 mm below the front of the asterion in 75％ of all.Conclusions The angle of parietomastoid sutures and the asterion are two keyholes for the combind transpetrosal approach.The appropriate use of the two keyholes may reduce collateral damage during operation and postoperative complications. Key words: Temporal bone; Dissection; The angle of parietomastoid sutures ; Asrerion; Grove of sigmoid sinus