Coccyx at a Glance

Purpose or Learning Objective: (1) To demonstrate the ligamentous attachment, vertebral numbering, and coccygeal anatomy; (2) to display the various coccygeal angulation and curvature types using various imaging modalities; and (3) to describe a variety of coccygeal disorders, including primary and secondary coccydynia, as well as various coccygeal-based pathologies, such as trauma, coccygeal and para-coccygeal infections, and destructive coccygeal sinister pathology.

Methods or Background: The coccyx, often known as the tailbone, is the smallest rudimentary lowest part of the spine. It is normally made up of four vertebrae (Co1–Co4) that join to form a triangular structure resembling a short tail. The coccyx is considered one of the commonly missed lower back pain generators with a variety of linked pathologies that are infrequently discussed.

We address the normal coccygeal anatomy, angulation, and up to six curvature variations using various imaging modalities. We also provide a description of types of coccygeal pathology for patients who present with a unifying clinical history of lower back pain with variable radiologic findings using different imaging modalities.

Results or Findings: Thorough knowledge of the coccygeal architecture, ligamentous attachment, angulation, and variation is paramount to identify coccygeal anomalies and associated diseases. A review of coccygeal pathology, including the variable types of coccydynia, trauma, coccygeal/para-coccygeal infection, and sinister tumoral pathology, is presented in a multimodality case-based scenario starting with basic conventional radiography to more advanced computed tomography (CT) and magnetic resonance imaging (MRI) techniques to highlight the diversity of coccygeal diseases.

Conclusion: Coccygeal pathology, one of the infrequently diagnosed causes of unexplained lower back pain, requires specialized imaging techniques. MRI is the best suited imaging technique for a precise examination of soft tissue, ligamentous, and osseous structures based on its high sensitivity and specificity in addressing the various pathologies.

Publication History

Article published online:
26 May 2023