Is external occipital protuberance normal?

External Occipital Protuberance (EOP) is a normal anatomical structure located on the posterior surface of the occipital bone, at the level of the superior nuchal line. It is the insertion site of the nuchal ligament1.

What is enlarged external occipital protuberance?

Occipital spurs, also called as occipital knob, occipital bun, chignon or inion hook, is an exaggerated external occipital protuberance (EOP). It is a frequent finding among males and hence a prominent occipital spur is often used in gender determination in forensic investigations.

Is external occipital protuberance bad?

Besides, the aforementioned “horns” are actually bone spurs on the external occipital protuberance at the base of the skull, which we all have to some degree. While bone spurs on the external occipital protuberance are unlikely to cause symptoms, poor posture is known to contribute to neck and back pain in many people.

How do you palpate external occipital protuberance?

The external occipital protuberance, the C2 spinous process, and the C1 vertebral arch are palpated. The latter structure is located by rolling a fingertip off the cranial edge of the C2 spinous process and palpating firmly, feeling for a transverse bony ridge (the C1 vertebral arch).

What muscles attach to external occipital protuberance?

The inion is the most prominent projection of the protuberance which is located at the posterioinferior (rear lower) part of the human skull. The nuchal ligament and trapezius muscle attach to it.

How many people have external occipital protuberance?

To avoid ambiguity, the threshold for recording the size of an EOP was set at 5 mm, and an EOP was classified as enlarged if it exceeded 10 mm. Reliability testing was also undertaken. Results indicated that an EEOP was present in 41% of the total population, with 10% of all participants presenting with an EOP ≥ 20 mm.

How common are external occipital protuberance?

External occipital protuberance is normal anatomical entity, rarely it may show hyperostosis and may get prominent and causing pain and examination reveals presence of tender bony swelling. However, such occurrence is extremely uncommon.

Is occipital bun painful?

Pain may be present at rest and during neck movements. It often presents in late adolescence due to the growth spurts, and as the protuberance grows in size it causes subperiosteal stretching resulting in tenderness. Some patients, especially those with short hair, may complain that it looks unaesthetic.

What muscles attach to the external occipital protuberance?

To it is attached, the splenius capitis muscle, the trapezius muscle, and the occipitalis. From the external occipital protuberance a ridge or crest, the external occipital crest also called the median nuchal line, often faintly marked, descends to the foramen magnum, and affords attachment to the nuchal ligament.

What is the most prominent point of the external occipital protuberance?

the inion
Near the middle of the squamous part of occipital bone is the external occipital protuberance, the highest point of which is referred to as the inion. The inion is the most prominent projection of the protuberance which is located at the posterioinferior (rear lower) part of the human skull.

What is the protuberance of the occipital?

Anatomical terminology. Near the middle of the squamous part of occipital bone is the external occipital protuberance, the highest point of which is referred to as the inion. The inion is the most prominent projection of the protuberance which is located at the posterioinferior (lower rear) part of the human skull.

What is obosseous proliferation at the posterior occipital region?

Osseous proliferation at the posterior occipital region is related to prominent external occipital protuberance. External occipital protuberance is a midline bony prominence in the occipital bone that ligamentum nuchae and trapezius muscle attach to its tip.

What is an occipital spur?

Occipital spurs, also called as occipital knob, occipital bun, chignon or inion hook, is an exaggerated external occipital protuberance (EOP). It is frequently discussed in anthropological literature as a Neanderthal trait but hardly reported and considered as a normal variant in medical literature.

What are the major features of the occipital region?

The major features of this region include: Located on the midline of the external surface, the external occipital protuberance is a prominence that can be felt on touching. It acts as a site of attachment for the trapezius muscle.