Nosaiba Al-Ryalat; Osama Samara; Azmy Hadidy; Mahasen Al-Najjar; Nida’ Mubarak; Hamsa Abdulmunem; Fadi Alhadidi & Saif Aldeen AlRyalat

External occipital protuberance (EOP) is a midline bony protrusion in the occipital bone, the significance of which has gained recent attention in the medical community. Our present study aims to assess the average size of EOP in a Jordanian cohort and its relation to age and sex, while determining the frequency of enlarged EOP in this cohort. The present study was a cross-sectional study that was carried out in a referral hospital in Jordan. We reviewed thousands of CT scans taken with dedicated bone window imaging during the last two years, beginning January 2018. Measurements were taken by trained radiology residents and were then further reviewed by radiology specialists. An EOP was classified as enlarged (EEOP) if it exceeded 10 mm.A total of 4409 patients, 2265 (51.4 %) females and 2144 (48.6 %) males, met our inclusion criteria. Their mean age was 54.1 ± 22.2 years. The mean size of the EOP in these patients was 8.4 ± 4.2 mm (range: 0-56 mm). Out of the 4409-study population, 1210 (27.4 %) presented with EEOP. The prevalence of an EEOP was significantly higher in the male population (33.6 %) when compared with the female population (21.6 %) (P < 0.001). The size of the EOP was also significantly related to the age of the patient, with EEOP increasing with increasing age. The mean size of EOP in our Jordanian cohort was 8.4 ± 4.2 mm. The frequency of enlarged EOP was found to be 27.4 % in our cohort, and was significantly more common in males and in older patients.

KEY WORDS: External occipital protuberance; CT scan; Bony protrusion; Headache.

AL-RYALAT, N.; SAMARA, O.; HADIDY, A.; AL-NAJJAR, M.; MUBARAK, N.; ABDULMUNEM, H.; ALHADIDI, F. & ALRYALAT, S. A. Frequency of enlarged external occipital protuberance and its association with age and sex: A cross-sectional CT scan study. Int. J. Morphol., 39(5):1274-1277, 2021.