Growth in width of the metacarpals — an investigation in human fetuses
Bibliographic record
Abstract
The process of growth in width of the human hand during fetal life has never been described. Do metacarpals grow concentrically and separation between the bones occurs through expansion of soft tissues? Or is growth eccentric, a process termed drift by Enlow, a relocation in space of organs? Hands of 10 spontaneously aborted fetuses (age range: between 14.5 and 24 weeks of gestation) were examined paying special attention to the bone bark. A thicker bone bark was taken as an indication of growth in that direction. The thickness of the bone bark was measured at the radial and ulnar sides at the level of the proximal and of the distal physes of the second to fifth metacarpals. A ratio of radial over ulnar bone bark thickness (R/U ratio) was calculated. The third metacarpal grew almost concentrically (R/U ratio 1.12 +/- 0.06). The second metacarpal grew in a radial direction (R/U ratio 3.29 +/- 0.19) and the fourth and more so the fifth metacarpal grew in an ulnar direction (R/U ratio 0.70 +/- 0.04 and 0.42 +/- 0.02, respectively). The differences in R/U ratios between every metacarpal were statistically significant for all comparisons P < or = 0.001. Fetal growth in width of the human metacarpals is eccentric and not concentric. It is concluded that during growth in width the metacarpals move away from the midline of the hand and that growth occurs through eccentric bone apposition rather than through soft tissue expansion.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".