Background: There are a wide variety of aesthetic skull shape deformations that can be divided into either deficiencies or excesses. The excess category may be called protrusions and some are seen in profile where they violate the ‘Golden Arc’ of the skull. This arc is the shape and distance of the head from the nasion (N) anteriorly across the top of the head all the way to the back of the head to the inion. (I) Along the way the arc crosses the bregma (B) and the lambda. (L) These landmarks along this line become linear distances that can be measured and compared by ratios (BI/NB and NI/BI) which ideally are 1.6 or the Golden Ratio.
But the connections of these skull lines and their measurements are not linear. They have a curved or arc shape which also contributes to the aesthetic appearance of the skull. While an arc is a non-straight connection between two end points and can be similar to a semi-circle, in the skull this arc is not a fully symmetric half-circle. Its front half is less round/full than the posterior half as the crown of the head is higher than the front of the skull.
But when the crown of the skull is excessively high it violates a pleasing arc shape. This is due to biparietal skull overgrowth whose reduction depends on how thick the bone is.
Case Study: This male desired to have his crown height reduced as he felt it made his head look too high. It was projected for him in profile how much skull reduction would likely be achieved.
Under general anesthesia and in the prone position a small curved scalp incision was made behind the crown area and the bone exposed. Depth cut were made through the outer cortex of the crown area in a radiating pattern with a high speed burr.
The bone between the radiating cuts was then reduced with high speed burring which always generates a large amount of bone dust in so doing. A large area of circumferential bone reduction over the crown area was achieved.
The scalp incision was then closed over a drain. The head dressing and drain were removed the following day.
The amount of crown skull area reduced could be seen in profile at the end of the surgery.
When seen three months later the reduction in his crown area could be seen.
An excessive protrusion of the skull can be visibly reduced provided the bone is thick enough to do so. Most patieents will require a preoperative CT scan to make that assessment.
Key Points:
1) The high crown of the skull is due to a thickened parietal skull bone and is clinically seen as an ascending line in profile from front to back with its maximum height posteriorly.
2) A small posterior scalp incision can be used in the prone position to remove the outer cortex of the thickened parietal bone.
3) Parietal or crown of the head reduction restores the normal curvature of the skull in profile and is a procedure which is associated with a rapid recovery.
Dr. Barry Eppley
World-Renowned Plastic Surgeon