Occipital Bone Unlabeled – Outer and Inner Surfaces to Label

All 19 parts on the diagram

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Outer surface 13

Foramen magnum The large opening in the base of the skull. The lowest part of the brainstem passes through it to become the spinal cord.
Occipital condyle One on each side of the foramen magnum. The two rest on the atlas, the first vertebra of the neck.
External occipital protuberance The bump in the middle of the outer surface. It can be felt at the back of the head.
Squamous part The largest part, the curved plate behind the foramen magnum. It meets the parietal and temporal bones.
Basilar part The thick bar in front of the foramen magnum. It runs forward to join the sphenoid bone.
Superior nuchal line A ridge curving out to each side from the protuberance. The trapezius and other neck muscles attach along it.
Inferior nuchal line A ridge halfway between the protuberance and the foramen magnum. Small deep muscles of the neck attach near it.
External occipital crest (median nuchal line) The ridge down the midline from the protuberance to the foramen magnum. The nuchal ligament attaches to it.
Highest nuchal line A faint line just above the superior nuchal line. The tendon sheet of the scalp attaches to it.
Jugular process A plate of bone that juts out sideways from each condyle. The notch in front of it helps form the jugular foramen.
Condylar fossa A hollow behind each condyle. The edge of the atlas fits into it when the head tips back.
Hypoglossal canal A short tunnel through the bone above each condyle. The hypoglossal nerve, which moves the tongue, leaves the skull through it.
Pharyngeal tubercle A small bump on the underside of the basilar part. The seam at the back of the throat hangs from it.

Inner surface 6

Internal occipital protuberance The knob where the ridges cross. The grooves for the large vein channels of the skull meet here.
Groove for the superior sagittal sinus The groove running up from the internal protuberance. It holds the vein channel that runs along the top of the brain.
Groove for the transverse sinus A groove running out to each side from the internal protuberance. It holds the transverse sinus, a large vein channel.
Internal occipital crest The ridge from the internal protuberance down to the foramen magnum. It runs between the two lower hollows.
Cerebellar fossa One of the two lower hollows of the inner surface. A half of the cerebellum rests in each.
Clivus The smooth upper face of the basilar part. It slopes up from the foramen magnum, and the brainstem rests against it.

How this list was compiled: Every name and detail line was checked on 2026-09-30 against Gray, Anatomy of the Human Body, 20th edition, 1918 (public domain), the section on the occipital bone, https://archive.org/details/anatomyofhumanbo00grayrich; TeachMeAnatomy, The Occipital Bone, https://teachmeanatomy.info/head/osteology/occipital-bone/; and Kenhub, Occipital bone, https://www.kenhub.com/en/library/anatomy/the-occipital-bone. The wording is in our own words. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry, after the layout of Gray's Anatomy (1918, public domain) figures 129 and 130; nothing traced. Licence: own work

How it works

Two blank drawings of the occipital bone: the outer surface seen from below and behind, then the inner surface. Tap or name each part, and the page fills in until you have the occipital bone labeled.

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Outside: ridges round a bump

Start at the external occipital protuberance in the middle. The highest and superior nuchal lines curve out from it, the external occipital crest drops from it to the foramen magnum, and the inferior nuchal line crosses the crest halfway. A condyle sits on each side of the opening, with the basilar part in front.

Inside: a cross

Four grooves and ridges meet at the internal occipital protuberance. The arm above holds the superior sagittal sinus, the side arms hold the transverse sinuses, and the crest below divides the two hollows for the cerebellum.

Four nuchal lines: highest and superior curve sideways, the median one runs down, the inferior crosses it.
The hypoglossal canal is above the condyle; the condylar fossa is behind it.

Questions and answers

Is there an occipital bone unlabeled sheet to print?

Yes. The blank sheet shows both drawings with numbered rings and a line for each name: 1 to 13 on the outer surface and 14 to 19 on the inner surface.

What are the parts of the occipital bone?

Three, arranged round the foramen magnum: the squamous part, the large plate behind the opening; the two lateral parts at its sides, which carry the condyles; and the basilar part, the thick bar in front.

What passes through the foramen magnum?

The lowest part of the brainstem, the medulla oblongata, which continues below as the spinal cord. The vertebral arteries and the spinal parts of the accessory nerves pass through with it.

What bone does the occipital bone sit on?

The atlas, the first vertebra of the neck. The two occipital condyles rest in its two upper facets, and nodding the head happens at that pair of joints.