Thoracic vertebra T1

Function

Anchors the first pair of ribs — the superior aperture of the thoracic cage — and marks the level where the brachial plexus emerges between the scalene muscles.

Landmarks

• Body with complete costal facets
• Transverse process with facet
• Long inferiorly-angled spinous process

Articulations (joints)

• C7 above
• T2 below
• First and second ribs (superior and inferior costal facets)

Clinical relevance

T1 root injury wastes the intrinsic hand muscles (Klumpke palsy); apical lung tumours (Pancoast) invade the T1 nerve root causing similar hand wasting with Horner syndrome.