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# T2–T3 nucleus

The nucleus pulposus is the soft, gel-like centre of the [T2-T3](https://durgical.com/en/anatomy/t2-t3/) disc in the mid-back; it works like a water cushion that spreads the load.

Official name: T2-T3

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## What it is

The soft, gel-like centre (nucleus pulposus) of the T2–T3 disc.

## What it does

Works like a water cushion: it turns pressure from above into outward push on the fibre ring, spreading the load. It is under the most pressure when you bend forward and lift.

## Key points

- Herniation of the nucleus at this level is among the rarest in the [spine](https://durgical.com/en/anatomy/region/spine/); pain spreading into the armpit points to the T2 root

## Key facts

**Where**
Centre of the T2–T3 disc, slightly toward the back, inside the annulus fibrosus

**Function**
Notochord-derived gel (about 70–90% water, proteoglycans); turns axial load into annulus tension; small in thin thoracic discs, herniation rare

## Relations

**Behind**
Back of the annulus fibrosus and the [posterior longitudinal ligament](https://durgical.com/en/anatomy/posterior-longitudinal-ligament/), then the [spinal cord](https://durgical.com/en/anatomy/spinal-cord/)

## Examination

- Pinprick in the armpit and inner upper arm, compared side to side, screens the T2 band; a change here with normal hand strength points to T2 rather than C8–T1

## On imaging

A darker, drier nucleus is common in upper thoracic discs with age and is often an incidental MRI finding without symptoms.

## Common problems

- Squeezes out through a tear in the ring (herniation), usually backward and to one side, toward a nerve root.
- Loses water with age, so the disc gets thinner and stiffer.

## How it is diagnosed

On MRI a healthy nucleus is bright on T2 images; a worn one turns dark ('black disc').

## Treatment

- In a microdiscectomy only the loose piece that has pushed out is removed; most of the disc stays.

## Clinical notes

- When it does herniate, the main complaint is often pain between the shoulder blades; armpit pain alone is more often from the shoulder, [chest](https://durgical.com/en/anatomy/region/chest/) wall or lung apex
- Pain and numbness of the inner upper arm can also come from the intercostobrachial nerve itself, which is often cut during axillary lymph node surgery; the history separates it from a T2 root lesion

## Test yourself

Think of the answer, then tap the question to see it.

## Pain spreading into the armpit from a T2–T3 nucleus herniation points to which root?

The T2 root; herniation at this level is among the rarest in the spine.

## What does a darker, drier T2–T3 nucleus on MRI usually mean?

Age-related change: it is common in upper thoracic discs and often an incidental finding without symptoms.

## How does the T2–T3 nucleus pulposus handle load?

It turns axial load into tension on the annulus fibrosus, like a water cushion spreading the pressure.

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Educational information, not medical advice. For any symptom, see a health professional.

## Its names

**Official Latin (TA2)**
nucleus pulposus T2-T3 TA2 1686

**Official Spanish (DeCS)**
Núcleo pulposo T2-T3 DeCS D000070614

**English (TA2)**
T2-T3

## Related

- [T2–T3 disc](https://durgical.com/en/anatomy/t2-t3/)
- [T2 vertebra](https://durgical.com/en/anatomy/t2/)
- [T3 vertebra](https://durgical.com/en/anatomy/t3/)

Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=56248&filter=ths_termall&q=N%C3%BAcleo%20Pulposo); [Anatomy, Back, Nucleus Pulposus](https://www.ncbi.nlm.nih.gov/books/NBK535373/); [Anatomy, Back, Intervertebral Discs](https://www.ncbi.nlm.nih.gov/books/NBK470583/); [7.3 The Vertebral Column](https://openstax.org/books/anatomy-and-physiology-2e/pages/7-3-the-vertebral-column) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/anatomy/t2-t3-spine-and-pelvis/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/t2-t3-spine-and-pelvis/