Skeletal Anatomy: Cranial Bones, Sutures, Vertebral Column, and Intervertebral Discs

Cranial bones

The group of $8$ bones that enclose, protect, and stabilize the brain.

Frontal bone

Cranial bone ($1$) forming the anterior and superior portion of the cranium, the roof of the anterior cranial fossa, and the superior part of the orbits.

Parietal bones

Paired cranial bones ($2$) that form the greater part of the sides and the roof of the cranium.

Temporal bones

Paired cranial bones ($2$) forming the inferior sides of the cranium and part of the cranial floor.

Occipital bone

Cranial bone ($1$) forming the posterior part and most of the base of the cranium; contains the foramen magnum and external occipital protuberance.

Foramen magnum

Large opening located in the occipital bone that connects the medulla oblongata with the spinal cord.

Sphenoid bone

Cranial bone ($1$) situated in the middle part of the base of the skull that articulates with all other cranial bones and holds them together.

Ethmoid bone

Light, spongy cranial bone ($1$) forming part of the anterior cranial fossa, the medial walls of the orbits, the superior portion of the nasal septum, and the sidewalls and roof of the nasal cavity.

Cranial sutures

Immovable joints that hold the bones of the skull together.

Coronal suture

Immovable joint located between the frontal bone and the parietal bones.

Sagittal suture

Immovable joint located between both parietal bones.

Lambdoid suture

Immovable joint located between the parietal bones and the occipital bone.

Squamous suture

Immovable joint located between the parietal bone and the temporal bone.

Vertebral column

A flexible skeletal structure composed of a series of bones called vertebrae that forms the skeleton of the trunk, encloses and protects the spinal cord, supports the head, and serves as an attachment point for the ribs, pelvic girdle, and back muscles.

Vertebral column height proportion