Measurement of bony landmarks in the posterior part of the lateral cranial base and body surface location of the transverse sinus and sigmoid sinus

Objective To study the body surface location of the transverse sinus and sigmoid sinus to provide the anatomic information to location of the bone window for petrous bone-associated operation. Methods Thirty dry and 15 fresh cadaver heads were chosen for study. The distances between marker points were measured. Corresponding relationships were observed between the bony landmarks of the posterior part of the lateral cranial base and locations of the sigmoid sulcus and transverse sinus sulcus. Results ① The junction of temporo-squamosal -parietomastoid sutures was projected to the anterosuperior border of the superior flexion of the sigmoid sinus sulcus, accounting for 86.7% of the sum, and 28 cases showed that internal occipital protuberance corresponds to the inferior part of the transverse sinus sulcus, accounting for 93.3%. ②The superior border of the transverse sinus corresponds to the line connecting external occipital protuberance with the junction of temporo-squamosal-parietomastoid sutures, and its inferior border to the line connecting internal occipital protuberance with O point. The anterior border of the sigmoid sinus corresponds to the line connecting the mastoid tip with the junction of temporo-squamosal -parietomastoid sutures, and its posterior border to the line connecting the mastoid tip with O point. Conclusion Surface location of the transverse sinus and sigmoid sinus could be performed by touching the crest of the external auditory canal,mastoid tip and external occipital protuberance, which contribute to provide a craniotomy approach with safety and wide surgical view without injury to the venous sinus to the maximum extent.