Volar Pad
Definition
A transient cushion of mesenchymal tissue on the volar surface of each developing digit, present from approximately gestational week 6 to 7 and regressing from week 10 to 12. The size and position of the pad at its maximum, and the timing of its regression, determine the eventual fingerprint pattern type.
- Tissue type
- Transient mesenchymal cushion
- Location
- Volar surface of each developing digit
- Appears
- About gestational week 6 to 7
- Regresses
- About gestational week 10 to 12
- Determines
- Final fingerprint pattern type
Common questions
Why does the volar pad's timing and size, rather than genetics alone, shape the fingerprint pattern?+
As the pad grows and then regresses, the friction ridges that form over it follow the pad's changing surface contour and its position relative to the digit. A larger, more symmetrical, later-regressing pad tends to produce a whorl, while a smaller or asymmetric pad tends toward a loop or arch, so pattern type is largely a mechanical consequence of pad development rather than a directly inherited trait.
Does this mean identical twins should have identical fingerprints?+
No. Volar pad growth and regression are influenced by local factors in the womb such as finger position and pressure that differ even between genetically identical fetuses, which is why identical twins share overall pattern class tendencies but not matching minutiae detail.
Related terms
- ACE-V
- Analysis, Comparison, Evaluation, Verification: the four-stage method for latent print examination used by accredited forensic fingerprint laboratories. Analysis examines the latent in...
- Eccrine Sweat Gland
- A coiled secretory gland in the deep dermis that opens via a straight duct to a pore on the friction ridge crest....
- Friction Ridge Skin
- Specialised volar skin on fingers, palms, and soles characterised by parallel ridges and furrows, absence of hair follicles, and a high density...
- Individuality
- The claim that no two persons share an identical friction ridge configuration at any corresponding digit. Supported empirically by the absence of...
- Monozygotic Twin Distinction
- Despite sharing a genome, monozygotic twins develop different ridge configurations at the minutia level, demonstrating that ridge individuality arises from non-genetic developmental...
- NAS 2009 Report
- The National Academy of Sciences report 'Strengthening Forensic Science in the United States: A Path Forward' (2009), which critiqued the scientific foundations...
- Papillary Dermis
- The uppermost layer of the dermis, characterised by dermal papillae projecting into the epidermis. In friction ridge skin, the pattern of these...
- Persistence
- The property that friction ridge configuration remains stable from birth through death and into decomposition, as long as the papillary dermis survives....
- Ridge Formation Window
- The period from approximately gestational weeks 10 to 17 during which friction ridges form by epidermal thickening and proliferation, propagating outward from...