# What is the thymus?

It is called the thymus. Gray's Anatomy (1918) describes it as a soft, lobed lymphoid organ.

## What it means

- A soft, lobed lymphoid organ.
- Prominent in children and adolescents; shrinks after puberty.
- Where T-lymphocytes mature.

## Action steps

1. In the upper chest, behind the sternum.
2. In front of the great vessels and the heart.
3. Extends up into the lower neck in children.

## Sources

- [Gray's Anatomy of the Human Body (1918)](https://www.bartleby.com/107/)

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