Costotransverse ligament

At a glance

English

Costotransverse ligament

Latin (TA2)

Ligamentum costotransversarium

System

Ligament

Region

Thorax

Side

Paired, left and right

About the costotransverse ligament

Each typical rib meets the vertebral column at two joints: its head articulates with the vertebral bodies, and its tubercle with the transverse process of its own numbered vertebra. The second of these, the costotransverse joint, has a thin capsule and depends on a group of ligaments for its strength. The costotransverse ligament in the strict sense is the one that fills the gap between the back of the rib neck and the front of the transverse process.

It is a short band of tough fibres packed into the narrow costotransverse foramen between the two bones, running from the back of the rib neck to the front of the transverse process beside it. Two companions are usually described with it. The lateral costotransverse ligament passes from the tip of the transverse process to the rough outer part of the rib tubercle that bears no facet, behind and lateral to the joint. The superior costotransverse ligament runs from the upper border of the rib neck up to the underside of the next transverse process above, and the posterior intercostal vessels and the ventral ramus of the spinal nerve pass in front of it. Some accounts add small inferior and posterior bands.

Together these ligaments hold the rib firmly against the transverse process, prevent it slipping or dislocating, and confine the costotransverse joint to a small gliding movement. That gliding, combined with rotation at the joint of the rib head, lets the rib neck turn about its own axis and so raises the rib in breathing: the bucket-handle movement of the lower ribs and the pump-handle movement of the upper ones.

The eleventh and twelfth ribs have no costotransverse joints, and these ligaments are weak or missing at those levels. Their back surfaces give attachment to the deep extensor muscles of the back. Strain of the ligaments after twisting injuries can cause localised pain beside the thoracic spine that worsens with deep breaths.

Attachments and function

Attaches from

The back of the rib neck.

Attaches to

The front of the transverse process on the vertebra sharing the rib's number.

Function

Binds the rib to the transverse process, prevents dislocation of the costotransverse joint and limits it to a slight gliding movement during breathing.

Nerve supply

Branches of the dorsal rami of the thoracic spinal nerves.

Blood supply

Dorsal branches of the posterior intercostal arteries.