Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (713 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Paired, segmented masses of mesenchyme located on either side of the developing spinal cord (neural tube). Somites derive from paraxial mesoderm and continue to increase in number during organogenesis. Somites give rise to skeleton (sclerotome); muscles (myotome); and dermis (dermatome).
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Somite.
Where it fits in the MeSH classification
- Broader topics
- Mesoderm
Related concepts
Research landscape
PubMed indexes 1,955 records tagged with the MeSH heading “Somites” (counts retrieved 2026-10-31). 190 of them (9.7%) were published from 2020 onward, and the busiest period so far is 2000-2009 with 903 records.
Reviews account for 259 records (13.2%) and meta-analyses for 0. Randomized controlled trials number 1 (0.1%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 245 |
| 2000-2009 | 903 |
| 2010-2019 | 617 |
| 2020 onward | 190 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 259 | 13.2% |
| Meta-analyses | 0 | 0.0% |
| Randomized controlled trials | 1 | 0.1% |
Method: PubMed query "Somites"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Setting the tempo in development: an investigation of the zebrafish somite clock mechanism | 2007 | Research article Design not recorded in structured metadata | 148 | cc by PMID 17535112 · DOI · PMC1877819 |
| Periodic formation of epithelial somites from human pluripotent stem cells | 2022 | Research article Design not recorded in structured metadata | 126 | cc by PMID 35484123 · DOI · PMC9050736 |
| Diverse Routes toward Early Somites in the Mouse Embryo | 2021 | Research article Design not recorded in structured metadata | 80 | cc by PMID 33308481 · DOI · PMC7808755 |
| Modelling co-development between the somites and neural tube in human trunk-like structures | 2025 | Research article Design not recorded in structured metadata | 13 | cc by PMID 41402467 · DOI · PMC12717004 |
Setting the tempo in development: an investigation of the zebrafish somite clock mechanism [1]
Abstract reading summary — source excerpts
- Opening excerpt
- The somites of the vertebrate embryo are clocked out sequentially from the presomitic mesoderm (PSM) at the tail end of the embryo.
- Closing excerpt
- In general, the findings strongly support the mathematical model of how the somite clock works, but they do not exclude the possibility that other oscillator mechanisms may operate upstream from the her7/her1 oscillator or in parallel with it.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (271 words)
The somites of the vertebrate embryo are clocked out sequentially from the presomitic mesoderm (PSM) at the tail end of the embryo. Formation of each somite corresponds to one cycle of oscillation of the somite segmentation clock--a system of genes whose expression switches on and off periodically in the cells of the PSM. We have previously proposed a simple mathematical model explaining how the oscillations, in zebrafish at least, may be generated by a delayed negative feedback loop in which the products of two Notch target genes, her1 and her7, directly inhibit their own transcription, as well as that of the gene for the Notch ligand DeltaC; Notch signalling via DeltaC keeps the oscillations of neighbouring cells in synchrony. Here we subject the model to quantitative tests. We show how to read temporal information from the spatial pattern of stripes of gene expression in the anterior PSM and in this way obtain values for the biosynthetic delays and molecular lifetimes on which the model critically depends. Using transgenic lines of zebrafish expressing her1 or her7 under heat-shock control, we confirm the regulatory relationships postulated by the model. From the timing of somite segmentation disturbances following a pulse of her7 misexpression, we deduce that although her7 continues to oscillate in the anterior half of the PSM, it governs the future somite segmentation behaviour of the cells only while they are in the posterior half. In general, the findings strongly support the mathematical model of how the somite clock works, but they do not exclude the possibility that other oscillator mechanisms may operate upstream from the her7/her1 oscillator or in parallel with it.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 17535112 · DOI · PMC1877819
Periodic formation of epithelial somites from human pluripotent stem cells [2]
Abstract reading summary — source excerpts
- Opening excerpt
- During embryonic development, epithelial cell blocks called somites are periodically formed according to the segmentation clock, becoming the foundation for the segmental pattern of the vertebral column.
- Closing excerpt
- Somitoids provide a novel platform to study human somitogenesis.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (150 words)
During embryonic development, epithelial cell blocks called somites are periodically formed according to the segmentation clock, becoming the foundation for the segmental pattern of the vertebral column. The process of somitogenesis has recently been recapitulated with murine and human pluripotent stem cells. However, an in vitro model for human somitogenesis coupled with the segmentation clock and epithelialization is still missing. Here, we report the generation of human somitoids, organoids that periodically form pairs of epithelial somite-like structures. Somitoids display clear oscillations of the segmentation clock that coincide with the segmentation of the presomitic mesoderm. The resulting somites show anterior-posterior and apical-basal polarities. Matrigel is essential for epithelialization but dispensable for the differentiation into somite cells. The size of somites is rather constant, irrespective of the initial cell number. The amount of WNT signaling instructs the proportion of mesodermal lineages in somitoids. Somitoids provide a novel platform to study human somitogenesis.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 35484123 · DOI · PMC9050736
Diverse Routes toward Early Somites in the Mouse Embryo [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Somite formation is foundational to creating the vertebrate segmental body plan.
- Closing excerpt
- Our study highlights the concept of molecular flexibility during early cell-type specification, with broad relevance for pluripotent stem cell differentiation and disease modeling.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (147 words)
Somite formation is foundational to creating the vertebrate segmental body plan. Here, we describe three transcriptional trajectories toward somite formation in the early mouse embryo. Precursors of the anterior-most somites ingress through the primitive streak before E7 and migrate anteriorly by E7.5, while a second wave of more posterior somites develops in the vicinity of the streak. Finally, neuromesodermal progenitors (NMPs) are set aside for subsequent trunk somitogenesis. Single-cell profiling of T-/- chimeric embryos shows that the anterior somites develop in the absence of T and suggests a cell-autonomous function of T as a gatekeeper between paraxial mesoderm production and the building of the NMP pool. Moreover, we identify putative regulators of early T-independent somites and challenge the T-Sox2 cross-antagonism model in early NMPs. Our study highlights the concept of molecular flexibility during early cell-type specification, with broad relevance for pluripotent stem cell differentiation and disease modeling.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 33308481 · DOI · PMC7808755
Modelling co-development between the somites and neural tube in human trunk-like structures [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Human stem cell-based embryo models provide experimentally amenable in vitro systems for developmental research.
- Closing excerpt
- Together, our data highlight the value of modularity in embryo models, which we leverage to explore human trunk co-development.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (145 words)
Human stem cell-based embryo models provide experimentally amenable in vitro systems for developmental research. A key feature of embryo models is their multi-lineage differentiation, which allows for the study of tissue co-development. Here we develop human trunk-like structures that have morphologically organized somites and a neural tube that form through self-organized, endogenous signalling. Transcriptomic comparison with human embryo datasets suggests that human trunk-like structure cells approximate Carnegie stage 13-14 (28-35 days after fertilization). The absence of a notochord leads to a dorsal identity, but exogenous Sonic Hedgehog signalling activation ventralizes both the somites and the neural tube in a dose-dependent manner. We further identify reciprocal signalling: neural tube-derived cues induce medial ALDH1A2 in somites, which in turn generate retinoic acid signals that drive spontaneous neural-tube patterning. Together, our data highlight the value of modularity in embryo models, which we leverage to explore human trunk co-development.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41402467 · DOI · PMC12717004
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article The segmentation clock: converting embryonic time into spatial pattern [5]
- Research article Patterning embryos with oscillations: structure, function and dynamics of the vertebrate segmentation clock [6]
- Research article Segmental patterning of the vertebrate embryonic axis [7]
- Research article Somite development in zebrafish [8]
- Research article The making of the somite: molecular events in vertebrate segmentation [9]
- Research article Vertebrate somitogenesis [10]
References
- Giudicelli F, Ozbudak EM, Wright GJ, Lewis J. Setting the tempo in development: an investigation of the zebrafish somite clock mechanism. . 2007. PMID 17535112 · DOI · PMC1877819
- Sanaki-Matsumiya M, Matsuda M, Gritti N, Nakaki F, Sharpe J, Trivedi V, et al.. Periodic formation of epithelial somites from human pluripotent stem cells. . 2022. PMID 35484123 · DOI · PMC9050736
- Guibentif C, Griffiths JA, Imaz-Rosshandler I, Ghazanfar S, Nichols J, Wilson V, et al.. Diverse Routes toward Early Somites in the Mouse Embryo. . 2021. PMID 33308481 · DOI · PMC7808755
- Makwana K, Tilley L, Chakravarty P, Thompson J, Baillie-Benson P, Rodriguez-Polo I, et al.. Modelling co-development between the somites and neural tube in human trunk-like structures. . 2025. PMID 41402467 · DOI · PMC12717004
- Pourquié O. The segmentation clock: converting embryonic time into spatial pattern. Science. 2003. PMID 12869750 · DOI
- Oates AC, Morelli LG, Ares S. Patterning embryos with oscillations: structure, function and dynamics of the vertebrate segmentation clock. Development. 2012. PMID 22274695 · DOI
- Dequéant ML, Pourquié O. Segmental patterning of the vertebrate embryonic axis. Nat Rev Genet. 2008. PMID 18414404 · DOI
- Stickney HL, Barresi MJ, Devoto SH. Somite development in zebrafish. Dev Dyn. 2000. PMID 11066087 · DOI
- Saga Y, Takeda H. The making of the somite: molecular events in vertebrate segmentation. Nat Rev Genet. 2001. PMID 11715039 · DOI
- Pourquié O. Vertebrate somitogenesis. Annu Rev Cell Dev Biol. 2001. PMID 11687492 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
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