Eponychium

In human anatomy, the eponychium [Greek epi (on, upon) + onychion (little claw)], is the thickened layer of skin surrounding fingernails and toenails. It can also be called the medial or proximal nail fold. Its function is to protect the area between the nail and epidermis from exposure to bacteria. The vascularization pattern is similar to that of perionychium.

In hoofed animals, the eponychium is the deciduous hoof capsule in fetuses and newborn foals, and is a part of the permanent hoof in older animals.

See Also

References

Nail

Nail or Nails may refer to:

In biology

Objects

Arts and entertainment

People

Businesses

Nail (unit)

A nail, as a unit of cloth measurement, is generally a sixteenth of a yard or 2¹⁄₄ inches (5.715 cm). The nail was apparently named after the practice of hammering brass nails into the counter at shops where cloth was sold. On the other hand, R D Connor, in The weights and measures of England (p 84) states that the nail was the 16th part of a Roman foot, i.e., digitus or finger, although he provides no reference to support this.Zupko's A dictionary of weights and measures for the British Isles (p 256) states that the nail was originally the distance from the thumbnail to the joint at the base of the thumb, or alternately, from the end of the middle finger to the second joint.

An archaic usage of the term nail is as a sixteenth of a (long) hundredweight for mass, or 1 clove of 7 pound avoirdupois (3.175 kg).

The nail in literature

Thou yard, three-quarters, half-yard, quarter, nail
Thou flea, thou nit, thou winter cricket thou:―
Brav'd in mine own house with a skein of
thread!

Explanation: Katherine and Petruchio are getting married. At the tailor shop, they examine the wedding dress, which is nearly finished. Petruchio is concerned that it has too many frills, wonders what it will cost, and suspects that he has been cheated. Katherine says she likes it, and complains that Petruchio is making a fool of her. The taylor repeats Katherine's words: Sir, she says you're making a fool of her. This is where Petruchio launches into the above-quoted tirade. Monstrous may be a double-entendre for cuckold. The half-yard, quarter and nail were divisions of the yard used in cloth measurement.

Nail (fastener)

In woodworking and construction, a nail is a pin-shaped object of metal (or wood, called a treenail or "trunnel") which is used as a fastener, as a peg to hang something, or sometimes as a decoration. Generally nails have a sharp point on one end and a flattened head on the other, but headless nails are available. Nails are made in a great variety of forms for specialized purposes. The most common is a wire nail. Other types of nails include pins, tacks, brads, and spikes.

Nails are typically driven into the workpiece by a hammer, a pneumatic nail gun, or a small explosive charge or primer. A nail holds materials together by friction in the axial direction and shear strength laterally. The point of the nail is also sometimes bent over or clinched after driving to prevent pulling out.

History

The history of the nail is divided roughly into three distinct periods:

Cuticle

A cuticle /ˈkjuːtɪkəl/, or cuticula, is a term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non-homologous, differing in their origin, structure, function, and chemical composition.

Human anatomy

In human anatomy, cuticle (sometimes confused with eponychium) refers to several structures. It refers to the layers of epidermal cells or keratinocytes that produce the horn protein keratin, and also to the superficial layer of overlapping cells covering the hair shaft (cuticula pili) that locks the hair into its follicle (See also Cuticle (hair)).

Invertebrate zoology

In zoology, the invertebrate cuticle or cuticula is a multi-layered structure outside the epidermis of many invertebrates, notably roundworms and arthropods, in which it forms an exoskeleton (see arthropod exoskeleton).

The main structural components of the nematode cuticle are proteins, highly cross-linked collagens and specialised insoluble proteins known as "cuticlins", together with glycoproteins and lipids.

Arthropod cuticle

The cuticle forms the major part of the integument of the Arthropoda. It includes most of the material of the exoskeleton of the insects, Crustacea, Arachnida, and Myriapoda.

Morphology

In arthropods, the integument, the external "skin", or "shell", is the product of a single layer of ectodermal epithelium. That layer is attached to the external or distal surface of the deepest layer, the non-cellular internal membrane of the integument. That non-cellular membrane is called the basement membrane. The layer of epithelium on the basement membrane produces the cuticle, which begins as a tough, flexible layer of chitin. Such thin, flexible chitin is the major structural part of the integument where flexibility is necessary, such as in bodily parts that must stretch to contain accumulated liquids, or that form joints between rigid parts of the exoskeleton. In other parts of the cuticle the function of the integument demands more rigid materials, such as armoured regions or the biting parts of the jaws, or where the exoskeleton forms the tubular limbs of most Arthropoda. To achieve such rigidity the outer chitin layer of the cuticle is impregnated, thickened, and reinforced with harder, more brittle materials such as sclerotinised proteins or calcite. This main chitinous layer of the cuticle is called the procuticle.

Cuticle (disambiguation)

Cuticle, or cuticula (Latin for "covering"), may refer to: