Atlas of Genetics and Cytogenetics in Oncology and Haematology OPEN ACCESS JOURNAL AT INIST-CNRS Educational Items Section Embryology, Semiology, Dysmorphology Jean-Loup Huret Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France (JLH) Published in Atlas Database: July 2000 Online updated version : http://atlasgeneticsoncology.org/educ/polyembryoeng.html DOI: 10.4267/2042/37685 This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 France Licence. 2000 Atlas of Genetics and Cytogenetics in Oncology and Haematology HANDS The palm is characterized by: - flexion creases: generated by mouvements of the skin in relation to joints motility. - dermatoglyphics: dermal ridges on fingers, on the palm, and on the planta. CREASES: - fingers: 2 flexion creases for each finger (except the thumb: only 1 crease). - finger-palm creases. - palm : 3 normal creases: longitudinal radial crease (LRC in the Figure). proximal transverse crease (PTC). distal transverse crease (DTC). Fusion of (complete fusion or bridge between) the 2 transverse creases is called single transverse crease, transverse palmar crease, or simian crease. DERMATOGLYPHICS: Triradius: point of convergence of ridges from 3 different directions. Normally, there is: - 1 axial triradius: normally in t, close to the wrist. - 4 subdigital triradii (a.b.c.d.). - On the pad of the distal phalanx, sometimes on thenar or hypothenar eminences, are triradii, accompanied with the following patterns: worl: 2 triradii. loops and equivalents (ulnar or radial orientated): 1 triradius. arches: 0 triradius. From each palmar triradius a, b, c, d, and t, is drawn the 3 lines separating the ridges at this convergence point. The longest is the main line (-- A B C D & T), ending at a side of the palm numbered from 1 to 14 (see Figure). - T normally ends in 13. - transversality index = A+B+C+D = 27 on the Figure. On the fingers may be counted the number of ridges from the center of the pattern to the triradius. (example here: n = 4); in case of an arch, n=0. For the 10 fingers, males have 140-145 ridges, and female have 120-130 ridges, according to the formula: n = 187 - (30 * no of X) - (12 * no of Y); this may be very useful in the Underground to determine the sex of the person next to you, and to pass the time. METACARPO- OR METATARSO- PHALANGEAL ANOMALIES NUMERICAL ANOMALIES: - Polydactyly: existence of supernumerary fingers. example: palmar and/or plantar hexadactyly trisomy 13. - Syndactyly: union of 2 or more fingers or toes (more or less complete, only involving the skin or with bone fusion). SIZE ANOMALIES: - Brachydactyly: short fingers. Various types according to which phalanx is involved (e.g. brachymesophalangy: short medial phalanx). - Brachymetacarpy: short metacarp(s) (example: in Turner syndrome). SHAPE ANOMALIES: - Clinodactyly: bend of fingers (often the 5th, as in trisomy 21). - Camptodactyly: irreductible flexion of the 2nd phalanx on the 1st (without bone involvment). - Arachnodactyly: long and slender fingers. Atlas Genet Cytogenet Oncol Haematol. 2000; 4(4) 237
As isolated signs, these anomalies are often transmitted as autosomal dominant traits. Atlas Genet Cytogenet Oncol Haematol. 2000; 4(4) 238
FACE: Semiology and Embryology Atlas Genet Cytogenet Oncol Haematol. 2000; 4(4) 239
Atlas Genet Cytogenet Oncol Haematol. 2000; 4(4) 240
HEART: Embryology and Malformations Atlas Genet Cytogenet Oncol Haematol. 2000; 4(4) 241
Atlas Genet Cytogenet Oncol Haematol. 2000; 4(4) 242
GENITALIA: Embryology This article should be referenced as such:. Embryology, Semiology, Dysmorphology. Atlas Genet Cytogenet Oncol Haematol. 2000; 4(4):237-243. Atlas Genet Cytogenet Oncol Haematol. 2000; 4(4) 243