Second to Twelfth Ribs

costae II-XII

Ribs 2-12 form the lateral thoracic cage, each with a head (two articular facets for adjacent vertebral bodies), neck, tubercle (for costotransverse joint), and shaft. The typical ribs (3-9) have all these features; floating ribs (11-12) have no tubercle or costotransverse joint. Each rib contains a neurovascular bundle (intercostal nerve, artery, vein) in the subcostal groove along the inferior inner border, 'Remember VAN': Vein superior, Artery middle, Nerve inferior.

Anatomical Data

Structure & Landmarks

Articulations	Two adjacent vertebral bodies (head, ribs 2-9 each) Transverse process of the corresponding vertebra (tubercle, ribs 1-10) Costal cartilage (anterior end, ribs 1-10 to sternum or each other)
Landmarks	Angle of the rib (posterior angulation point, the posterior reference for intercostal nerve block) Subcostal groove (neurovascular bundle. Injection must be below the rib to avoid the VAN) Rib head (costovertebral joint)
Ossification	Primary shaft centres at 8-9 weeks fetal. Tubercle and head epiphyses appear at puberty and fuse at skeletal maturity.

Clinical Relevance

Clinical Notes

Intercostal nerve blocks are placed at the rib angle with the needle directed slightly cephalad to stay in the subcostal groove above the nerve. Rib fractures produce pleuritic chest pain. Three or more consecutive fractures produce flail chest requiring mechanical ventilation. Epidural analgesia or thoracic paravertebral block provides superior pain control for multiple rib fractures compared to systemic analgesia.

Pathology

Common Injuries & Conditions

Rib Fracture

Blunt trauma commonly fractures the ribs, causing pain on breathing and risk of pneumothorax.

Flail Chest

Multiple adjacent ribs fractured in two places create a segment that moves paradoxically with breathing.

Rib Stress Fracture

Repetitive muscle loading, as in rowing, causes stress fractures, usually of the middle ribs posterolaterally.

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