eponychium

eponychium

English

Cross-section showing eponychium, labelled

Etymology

From Ancient Greek ἐπί (epí, “on top of”) + ὀνῠ́χιον (onúkhion, “little claw”, diminutive of ὄνυξ (ónux)).

Noun

eponychium (plural eponychia)

1. (anatomy) The thickened layer of skin adjoining fingernails and toenails, particularly at the base of the nail.
   • 2008, Peter M. Antevy, Richard A. Saladino, 103: Management of Finger Injuries, Christopher King, Fred M. Henretig (editors), Textbook of Pediatric Emergency Procedures, page 947,

     The nail is replaced to provide a physiologic dressing and to splint open the eponychium so that a new nail will grow in place.

   • 2011, Maura Scali-Scheahan, Milady Standard Professional Barbering, Cengage Learning, 5th Edition, page 673,

     The cuticle (KYOO-tih-kul) is the crescent of dead, colorless tissue attached to the nail plate around the base of the nail. It forms a seal between the eponychium and the nail plate to prevent the entry of foreign materials and microorganisms and to help prevent injury and infection.

   • 2015, Milady (Cengage Learning), chapter I, in Milady Standard Cosmetology‎, page 200:

     Every nail has a lunula, but some lunulas are short and remain hidden under the eponychium.

   • 2015, Nicole Z. Sommer, M. Colin Rymer, Ryan W. Schmucker, 3: Injuries to the Nail Apparatus, Leo M. Rozmaryn (editor), Fingertip Injuries: Diagnosis, Management and Reconstruction, page 69,

     The eponychium overlies and protects the proximal portion of the nail and the germinal matrix.

2. (zoology, veterinary medicine) The protective capsule that surrounds the hoof of foetuses and neonates of hoofed animals, which disappears soon after birth, but remnants of which remain as part of the permanent hoof.
   • 2012, Paul McGreevy, Equine Behavior: A Guide for Veterinarians and Equine Scientists, 2nd Edition, page 163,

     The hooves are tipped with collagenous eponychia, which prevents damage to the amnion and beyond.

   • 2014, Kevin T. Corley, Jonna M. Jokisolo, Chapter 172: Evaluation of the Compromised Neonatal Foal, Kim A. Sprayberry, N. Edward Robinson, Robinson's Current Therapy in Equine Medicine, 7th Edition, page 720,

     The presence of eponychium (also called “foal slippers”) on the feet (Figure 172-3) is indicative that the foal has not yet stood.

   • 2015, Donald M Broom, Andrew F Fraser, Domestic Animal Behaviour and Welfare, 5th Edition, page 196,

     In ungulates, this is apparently exaggerated by the presence of the eponychia, or collagenous pads over the sole of the fetal hoof.

Usage notes

• (layer of skin): Sometimes confounded with cuticle. Properly, the cuticle is a layer of dead skin connecting the eponychium to the nail and forming a seal. The eponychium is living tissue.

Synonyms

• (layer of skin): medial nail fold, proximal nail fold

Related terms

• eponychial
• hyponychium
• paronychium
• perionychium

See also

• nail fold
• nail fold on Wikipedia.Wikipedia