Supramastoid Crest, Safety Landmark for Craniotomy?
Pichayen Duangthongpon MD*, Chaiwit Thanapaisal MD*, Amnat Kitkhuandee MD*, Kowit Chaiciwamongkol MD**, Vilaiwan Morthong MD**
Affiliation : * Division of Neurosurgery, Department of Surgery, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand ** Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
Background : Bony landmarks are important in identifying and avoiding various structures, and thus, decreasing surgical
morbidity. Knowledge of frontal bone was studied to help surgeons with safe craniotomy as temporooccipital region study was
rare.
Objective : To identify usefulness of supramastoid crest and relationship to venous and Labbe’s vein.
Material and Method: Twenty fresh cadaveric heads, the vessels were injected with colorized silicone, were studied on both
sides, yielded 40 sides. The relationship of the supramastoid crest to the transverse, sigmoid sinus, Labbe’s vein was also
determined and measured. The following distances were measured utilizing the digital caliper for all measurements.
Results : Supramastoid crest was found in all cadavers (100%) and skull opened along supramastoid crest 100% safe from
injury to venous sinus. Anterior border of supramastoid crest was close in relation to middle cranial fossa floor, 85% on right
side and 90% on left side and the same level of middle cranial. The authors defined supramastoid point with turning of
supramastoid crest and found distance from supramastoid point to nearest venous sinuse (always transverse sinus) 1.0-
22.41 mm in range and average 12.94 mm on right side and 11.87 mm on left side. The last distance, from supramastoid point
to nearest Labbe’s vein, was measured and found to be 5.94-24.97 mm in range and average 17.23 mm on both sides.
Conclusion : Supramastoid crest is bony landmark and easy to identify in the adult cadaver and craniotomy along supramastoid
crest and always safe from injuring the venous sinus and Labbe’s vein. 87.5% anterior border of supramastoid crest is the
same level for middle cranial fossa floor.
Keywords : Supramastoid crest, Safty landmark
