Head Of The First Rib

Description

Head of the first rib occupies the posteromedial end of the bone, where its single, rounded articular facet meets the superior costal facet on the body of the first thoracic vertebra (T1). From this medial head, the neck extends laterally and slightly anteriorly toward the rib’s tubercle, which aligns with the transverse process of T1 at the costotransverse joint. Along the superior surface of the first rib, the scalene tubercle lies anterior to the groove for the subclavian artery, while the broader groove for the subclavian vein sits more anterior and inferior, helping orient the proximal rib when the thoracic cage is in anatomical position. Orientation matters. That solitary facet is the teaching point: rib 1 articulates only with T1, unlike the typical ribs that share demifacets across adjacent vertebral bodies. For clinicians, degenerative change or inflammatory arthropathy at the T1 costovertebral and costotransverse joints can refer pain to the upper thorax and posterior shoulder girdle, and a first-rib fracture can transmit force to these joints while also raising concern for nearby neurovascular structures at the thoracic inlet. The tight juxtaposition of the head and neck to the sympathetic chain and apex of the lung makes this anatomic neighborhood worth getting right in a single, fixed frame. Use this illustration in thoracic wall and osteology teaching, in exam-prep materials that contrast atypical ribs with ribs 3 to 9, and in surgical education around first-rib resection for thoracic outlet syndrome where bony landmarks guide exposure near the scalene attachments and subclavian groove. Anatomical accuracy verified by SciePro's Medical Advisory Board.