Cranial Anatomy & Mechanics: Understanding the Human Skull

The human skull is made up of 22 bones — 8 forming the cranial vault that surrounds the brain, and 14 forming the facial structure. These bones meet at joints called sutures.

Cranial sutures

Sutures aren’t simply seams where growth stopped. They are complex, biologically active interfaces with their own biomechanical properties, and they remain a genuine subject of anatomical and biomechanical research. The degree to which adult sutures retain flexibility — and how much that matters clinically — is still debated among researchers.

The cranium is not perfectly rigid

Studies using biomechanical loading have documented small, measurable deflections in the living adult skull — on the order of a few micrometers in some studies. That is a very small amount of movement, and researchers disagree about its clinical significance. What it does tell us is that the skull isn’t simply a single, fused, motionless bone.

The meninges and dura

The brain and spinal cord are surrounded by protective membranes called the meninges, including the dura mater. These membranes have attachments throughout the cranium and down into the spinal canal.

My clinical model is that restrictions in cranial movement may create mechanical tension involving these membranes, which in turn may relate to the neuromuscular changes I sometimes observe during an examination. This is a clinical model based on my experience — not a fully established physiological mechanism.

Cranium, face and jaw

The cranium doesn’t function in isolation. It has a close anatomical and mechanical relationship with the facial bones, the jaw, and the upper cervical spine. That relationship is part of why I look at the whole head and neck — not just the area where someone feels a symptom.