Scalene tubercle is a bony protrusion on the first rib, which is used as a reference point for medical conditions related to the upper thoracic region. Synonyms for scalene tubercle include tubercle of the first rib, anterior tubercle, costal tuberosity and costal tubercle. These terms are commonly used in medical literature and radiology reports as a means of communicating with professionals in the field. Due to its location and significance, the scalene tubercle is often referenced in the evaluation of thoracic outlet syndrome, cervical spine injuries, and other pathological conditions which may affect the upper extremities.