Morphometric Variants of the Coccyx in an Eastern Indian Cohort: Analysis from a Tertiary Care Center

The coccyx, forming the terminal portion of the human spine, has anatomical variations among countries, populations, and ethnicities. Given its complex structure involving multiple ligaments, muscles, and neural elements, the study of anatomical variations can provide valuable insight into the mechanisms underlying idiopathic coccydynia. Due to limited existing research on the morphometry of the Indian population, this study aims to examine the morphometry observed in the eastern Indian population.

A cross-sectional study of coccyx morphometry was conducted on patients who visited the radiology department of a tertiary care hospital in eastern India. A total of 109 patients were included, who had a computed tomography scan of the abdomen and pelvis. Patients with complaints of tumors or trauma to the spine were excluded. The coccygeal images were evaluated using the modified classification by Nathan et al.

Among the 109 patients, Type I coccyx was the most common type, with four segments in the coccyx. The mean straight and curved sacral lengths are 10.38 cm and 11.08 cm, and the straight sacrococcygeal length is 11.9 cm. The mean sacrococcygeal angle and intercoccygeal angle are 116.2° and 38.99°, respectively. Coccygeal spicules were seen in 30.3% of patients. 74.3% of the population had no intercoccygeal or sacrococcygeal joint subluxation.

Our analysis showed Type I of the coccyx was the most prevalent type, with four segments being most common. Our study also indicated that our population has a straighter coccyx. Our study can be correlated with the Southeast Asian population and can act as a baseline study for future anthropometric studies.