Parietal Margin Of The Greater Wing Of The Sphenoid Bone, Anatomy

Description

Parietal margin of the greater wing of the sphenoid forms a serrated, bevelled suture line at the superolateral aspect of the sphenoid, where it meets the anteroinferior edge of the parietal bone at the pterion. Along this superior border, the greater wing lies inferior to the parietal squama, posterior to the frontal bone, and anterior to the squamous part of the temporal bone, creating the four-bone junction classically used as a surface landmark. The contour of the margin tracks laterally toward the sphenoid’s temporal surface, with the suture teeth interdigitating in a pattern typical of cranial vault articulations rather than the smoother margins seen around the orbit. Small adjacent portions of the sphenoid crest and the root of the zygomatic process of the temporal bone may be appreciated as nearby reference points. Bone only. Pterion anatomy is not trivia. A blow to the thin bone at this junction can fracture the greater wing and tear the anterior division of the middle meningeal artery as it courses deep to the pterion, producing an epidural hematoma with rapid neurologic deterioration. For neurosurgeons planning a pterional craniotomy, the parietal margin of the greater wing helps define the superior extent of the sphenoid component of the bone flap and the relationship of the sphenoid ridge to the lateral fissure region. The fixed viewpoint and emphasis on the serrated border make the suture morphology easy to teach, including how sutural interdigitation differs between individuals and across age groups as synostosis progresses. Neuroanatomy, head and neck anatomy, and neurosurgical approaches courses can use this illustration to anchor teaching of cranial sutures, surface landmarks, and trauma mechanisms, and it also suits radiology or forensic texts discussing pterion variability on CT and skeletal remains. Anatomical accuracy verified by SciePro's Medical Advisory Board.