In development

Carnegie-stage timeline

CS1–CS23 (embryonic) · PCW 9–20 (fetal) · click a stage to inspect

Click a stage to inspect; per-source coverage is shown below. Mouse equivalents are approximate. 3-D model thumbnails: HDBR Atlas, CC BY-NC-SA 4.0.

CS23

56–60 d· End of embryonic period (~8 weeks)

The head is rounded; limbs are well-formed. End of the embryonic period; the fetal period begins.

56–60days p.f.
~E15mouse equiv.
Stereo-seq · 38Stereo-seq (BGI) — DNB-array spatial transcriptomics with subcellular ~500 nm resolution, capturing the whole transcriptome in physical tissue coordinates. The HESTA human atlas aligns serial Stereo-seq sections into whole-embryo and per-organ cell-resolved maps.HREM · 1High-Resolution Episcopic Microscopy — block-face imaging of a resin-embedded embryo: each section surface is photographed before microtoming, yielding a perfectly-aligned, isotropic 3D volume. The HDBR human 3-D models are reconstructed from HREM.

Virtual Human Embryo (Cork) registered serial sections at CS23 — reconstructed 3-D volumes; open to scrub through any plane.

Cell-segmented Stereo-seq organ atlases at CS23 — single-cell resolution, spatial. Each card shows this stage's section; open the viewer and use the stage selector to step through the other developmental stages.

HESTA · Adrenal Gland (human, per-organ)Stereo-seq
HESTA · Adrenal Gland (human, per-organ)
11,628 cells · 54,852 genes
Cell-resolved spatial · spans 4 stages
Open viewer →
HESTA · Blood Vessel (human, per-organ)Stereo-seq
HESTA · Blood Vessel (human, per-organ)
28,123 cells · 54,563 genes
Cell-resolved spatial · spans 6 stages
Open viewer →
HESTA · Bone (human, per-organ)Stereo-seq
HESTA · Bone (human, per-organ)
68,091 cells · 55,450 genes
Cell-resolved spatial · spans 4 stages
Open viewer →
HESTA · Brain (human, per-organ)Stereo-seq
HESTA · Brain (human, per-organ)
226,639 cells · 55,157 genes
Cell-resolved spatial · spans 7 stages
Open viewer →
HESTA · Choroid Plexus (human, per-organ)Stereo-seq
HESTA · Choroid Plexus (human, per-organ)
7,012 cells · 54,461 genes
Cell-resolved spatial · spans 3 stages
Open viewer →
HESTA · Connective Tissue (human, per-organ)Stereo-seq
HESTA · Connective Tissue (human, per-organ)
284,179 cells · 54,091 genes
Cell-resolved spatial · spans 6 stages
Open viewer →
HESTA · Cranial Skeleton (human, per-organ)Stereo-seq
HESTA · Cranial Skeleton (human, per-organ)
46,034 cells · 54,903 genes
Cell-resolved spatial · spans 4 stages
Open viewer →
HESTA · Epidermis (human, per-organ)Stereo-seq
HESTA · Epidermis (human, per-organ)
68,535 cells · 55,133 genes
Cell-resolved spatial · spans 6 stages
Open viewer →
HESTA · Eye (human, per-organ)Stereo-seq
HESTA · Eye (human, per-organ)
5,805 cells · 52,838 genes
Cell-resolved spatial · spans 6 stages
Open viewer →
HESTA · Ganglion (human, per-organ)Stereo-seq
HESTA · Ganglion (human, per-organ)
42,545 cells · 54,784 genes
Cell-resolved spatial · spans 7 stages
Open viewer →
HESTA · Gonad (human, per-organ)Stereo-seq
HESTA · Gonad (human, per-organ)
7,375 cells · 55,907 genes
Cell-resolved spatial · spans 4 stages
Open viewer →
HESTA · Gut (human, per-organ)Stereo-seq
HESTA · Gut (human, per-organ)
68,272 cells · 55,427 genes
Cell-resolved spatial · spans 5 stages
Open viewer →
HESTA · Heart (human, per-organ)Stereo-seq
HESTA · Heart (human, per-organ)
26,305 cells · 55,669 genes
Cell-resolved spatial · spans 7 stages
Open viewer →
HESTA · Inner Ear (human, per-organ)Stereo-seq
HESTA · Inner Ear (human, per-organ)
7,033 cells · 56,591 genes
Cell-resolved spatial · spans 6 stages
Open viewer →
HESTA · Jaw and Tooth (human, per-organ)Stereo-seq
HESTA · Jaw and Tooth (human, per-organ)
51,822 cells · 55,128 genes
Cell-resolved spatial · spans 4 stages
Open viewer →
HESTA · Kidney (human, per-organ)Stereo-seq
HESTA · Kidney (human, per-organ)
6,639 cells · 56,942 genes
Cell-resolved spatial · spans 3 stages
Open viewer →
HESTA · Liver (human, per-organ)Stereo-seq
HESTA · Liver (human, per-organ)
88,357 cells · 55,034 genes
Cell-resolved spatial · spans 7 stages
Open viewer →
HESTA · Lung (human, per-organ)Stereo-seq
HESTA · Lung (human, per-organ)
38,035 cells · 54,559 genes
Cell-resolved spatial · spans 4 stages
Open viewer →
HESTA · Meninges (human, per-organ)Stereo-seq
HESTA · Meninges (human, per-organ)
81,333 cells · 55,189 genes
Cell-resolved spatial · spans 7 stages
Open viewer →
HESTA · Optic Nerve (human, per-organ)Stereo-seq
HESTA · Optic Nerve (human, per-organ)
8,816 cells · 50,264 genes
Cell-resolved spatial · spans 1 stages
Open viewer →
HESTA · Pancreas (human, per-organ)Stereo-seq
HESTA · Pancreas (human, per-organ)
3,877 cells · 55,530 genes
Cell-resolved spatial · spans 4 stages
Open viewer →
HESTA · Pharyngeal (human, per-organ)Stereo-seq
HESTA · Pharyngeal (human, per-organ)
10,845 cells · 52,815 genes
Cell-resolved spatial · spans 2 stages
Open viewer →
HESTA · Skeletal Muscle (human, per-organ)Stereo-seq
HESTA · Skeletal Muscle (human, per-organ)
195,067 cells · 57,202 genes
Cell-resolved spatial · spans 4 stages
Open viewer →
HESTA · Thyroid (human, per-organ)Stereo-seq
HESTA · Thyroid (human, per-organ)
874 cells · 55,277 genes
Cell-resolved spatial · spans 2 stages
Open viewer →
HESTA · Trachea (human, per-organ)Stereo-seq
HESTA · Trachea (human, per-organ)
3,453 cells · 55,222 genes
Cell-resolved spatial · spans 2 stages
Open viewer →

Interactive HDBR models for CS23. Click to open the viewer.

3-D models: HDBR Atlas, CC BY-NC-SA 4.0.

gene expression · datasets · 3-D anatomy · disease · drag to rotate, scroll to zoom

Stage-anchored sub-graph, as on the mouse atlas — HDBR Expression gene markers, the HESTA Stereo-seq atlas, HDBR 3-D-model anatomy, and literature-extracted claims for this stage, plus the human disease/phenotype layer (HPO + OMIM) on the shared cross-species anatomy vocabulary.

CS22
Previous
CS2254–56 d
Eyelids and ears developed

The Carnegie staging system divides human embryonic development — the first ~8 weeks (56 days) post-fertilization — into 23 stages defined by morphological features rather than by size or age. Virtual Embryo aligns all imagery, anatomy, and spatial transcriptomics to this axis (extended into the fetal period by PCW).

Next
PCW 9PCW 9
Early fetal; ossification begins
PCW 9

Status: the human layer is under construction and currently serves as a reference index — it cites and links out to external resources rather than hosting their data. Any future in-platform integration would follow a formal data-sharing agreement with each originator and preserve full attribution and licence terms (non-commercial academic use). The HDBR 3-D model thumbnails shown are used under CC BY-NC-SA 4.0 with attribution. Carnegie-to-mouse stage equivalences are approximate.