Anatomy

Thymus Gland

A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.

National Library of MedicineMedical Subject Headings2026

Structured Summary

Abstract

A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.

MeSH Record

Classification

Broader headings

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See Also

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Synonyms

4 entry terms
  • Thymus
  • Gland, Thymus
  • Glands, Thymus
  • Thymus Glands

MeSH Record

Aspects Covered

24 allowable subheadings

Indexed with the subheadings abnormalities, anatomy & histology, blood supply, chemistry, cytology, diagnostic imaging, drug effects, embryology, enzymology, growth & development, immunology, injuries, innervation, metabolism, microbiology, parasitology, pathology, physiology, physiopathology, radiation effects, surgery, transplantation, ultrastructure, virology.

MeSH Record

Indexing Annotation

diseases: coordinate IM with LYMPHATIC DISEASES (IM); / surg: probably THYMECTOMY; agenesis, aplasia, dysplasia = DIGEORGE SYNDROME; cyst = THYMIC CYST see MEDIASTINAL CYST; THYMOCYTES is available

MeSH Hierarchy

Tree Numbers

  1. A10w.549w.750w
  2. A15.382w.520w.604w.750w

MeSH Record

NLM Classification

WK 400

AMA Style

References

  1. National Library of Medicine. Thymus Gland. Medical Subject Headings (MeSH). 2026. Unique ID D013950. http://id.nlm.nih.gov/mesh/2026/D013950
  2. Thymus Gland. In: Wikipedia. https://en.wikipedia.org/wiki/Thymus
  3. Thymus Gland. In: Wikidata. https://www.wikidata.org/wiki/Q163987