Regional Anatomy and Normal Variants

A normal variant is an anatomical feature that differs from the textbook pattern but is not itself a disease, and the core skill is telling a harmless variant from genuine pathology.

Variants are common: accessory ossicles, unfused ossification centres, extra muscles, and variations in nerves and vessels. Most are found by chance and mean nothing. A minority become symptomatic, and some are mistaken for fractures, leading to needless immobilisation, scans or surgery.

This page covers the variants a sports clinician meets most often around the foot, ankle, knee, shoulder and spine, how to weigh a variant against an acute injury, and when a variant is the source of pain.