First thoracic vertebra: anatomy, location and function

Also called

T1

What it is

The first of the twelve thoracic vertebrae, labelled T1, which articulate with ribs.

Location

Lies at the top of the thoracic spine between C7 and T2.

Function

Supports the trunk, forms the posterior part of the rib cage by articulating with ribs, and protects the spinal cord.

Body system

Skeletal · single, midline structure

FMA ID

FMA9165 (Foundational Model of Anatomy)

Key facts

• Has a complete costal facet on its upper body for the head of rib 1 and a demifacet below for rib 2.
• Its spinous process is long and nearly horizontal, and is often as prominent as that of C7.
• Its transverse processes articulate with the tubercles of rib 1; the T1 nerve leaves below it and is the lowest root of the brachial plexus.

The nearest named structures in the 3D model, measured from the centre of each part:

• Seventh cervical vertebra · skeletal
• Semispinalis cervicis · muscular
• Second thoracic vertebra · skeletal
• Intervertebral disk of first thoracic vertebra · skeletal
• Intervertebral disk of seventh cervical vertebra · skeletal
• Splenius cervicis · muscular
• Spinalis · muscular
• Inferior oblique part of longus colli · muscular
• Longissimus cervicis · muscular
• Sixth cervical vertebra · skeletal