Date of Graduation


Document Type


Degree Name

Master of Science in Kinesiology (MS)

Degree Level



Health, Human Performance and Recreation


Kaitlin Gallagher

Committee Member

Claire Terhune

Second Committee Member

Abigail Schmitt


Bony Growth, Enlarged External Occipital Protuberance, External Occipital Protuberance, Head Circumference, Neck Circumference, Neck Strength, Young Adults


Overview: Enlarged external occipital protuberances (EEOPs) are found in 41% of young adults. These EEOPs have the potential to lead to pain throughout life and possibly surgery. Little is known of the pathophysiology or characteristics that could lead to these EEOPs. Purpose: The purpose of this study is to use radiographic measurements to investigate how anthropometrics, neck posture and neck strength in flexion and extension differ between those with and without an EEOP. Methods: 80 radiographs from three different studies were digitized and the marking of landmarks performed in ImageJ. The cut-off for an EEOP was established as any EOP greater than or equal to 10 mm. Neck strength and anthropometrics have been previously collected while all neck posture variables were measured using models in Microsoft Excel. Outcome measures were (1) body mass, (2) head circumference, (3) neck circumference, (4) neck length, (5) gravitational moment arm, (6) intervertebral joint angles, (7) skull angle, (8) forward head protraction, and (9) isometric neck strength. A two-way ANCOVA was ran with between factors of sex and EEOP occurrence on each variable and a covariate of neck length. A Tukey post hoc test was run on any significant main effects, and simple effects was run on any significant interactions. Significance level was set at p < .05. Results: There were no significant differences in neck posture, age, body mass, height, or neck strength between the those with and without EEOPs. Neck circumference was significantly different in those with EEOPs, where participants with EEOPs present had larger neck circumferences. Conclusion: EEOP occurrence does not seem to be due to differing neck postures in neutral, but a larger neck circumference may indicate larger neck muscle volume which may point to muscle size and strength as possible influences. Future work should look at neck muscle volume and strength between those with and without EEOPs, focusing on even sample sizes within each age distribution and treatments groups.