Structure and Growth of Fingernails and Toenails (2024)

The parts of the nail, whether at your fingers or toes, follow a basic structure. This nail anatomy serves to protect against infections or injury, while adding functional ability (like scratching) and improving sensation and dexterity (self-defense and other skill with your hands).

The structure is divided into three main parts: the nail itself, the underlying structure that supports nail growth, and the skin tissue that surrounds it.

This article explains each of these features of nail anatomy. It also discusses certain conditions that affect the health of your nails and those for which nail changes can be a sometimes surprising sign, such as liver or kidney failure.

Structure and Growth of Fingernails and Toenails (1)

Nail Anatomy

The nail structure is divided into different components that make up the nail itself, or the surrounding skin and structure. Each of the elements has a specific function, and if disrupted, it can affect the nail's appearance and health.

Parts of the Nail

Your nail plate is the actual fingernail, and it's made of translucent keratin. Keratin is a protein found in your nails, hair, and skin, that works to protect against infection (among other things). The pinkish appearance of the nail comes from blood vessels that are underneath it.

The underside of the nail plate has grooves that run along the length of the nail and help anchor it to the nail bed, while the free edge is the part of the nail plate extending from the finger (the white tip that you trim).

Part of the nail root appears as a visible white crescent, known as the lunula. The root portion at the base of your nail lies below the skin, underneath the nail, and extends several millimeters into the finger. Itproduces most of the volume of the nail and the nail bed.

The germinal matrix (the nail matrix) and the nail root are related. The matrix lies beneath the skin, at the inner edge of the nail plate, and is responsible for most of a nail's growth. It's where new cells grow and then advance forward to form the nail, until it reaches the outer edge and ultimately is removed. Without it, no nail plate growth is possible.

Underlying Structures

The nail bed is also referred to as the sterile matrix. It extends from the edge of the nail root, or lunula, to the tissue known as hyponychium.

The nail bed contains blood vessels, nerves, and melanocytesthat produce melanin. As the root grows, the nail streams down along the nail bed and adds material to the underside of the nail to make it thicker. When the nail grows properly, the nail bed is smooth, but if the nail doesn't grow correctly, the nail may split or develop ridges that may be considered cosmetically unattractive.

Structure and Growth of Fingernails and Toenails (2)

Surrounding Tissues

Theeponychiumtissue produces the cuticle. The cuticle is found between the skin of the finger and the nail plate. It fuses these structures together and provides a waterproof barrier. It includes the proximal (nearest to your body) fold of the skin, at the cuticle.

The paronychium is the skin that overlaps onto the sides of the nail plate, also known as the paronychial edge of the lateral fold. The paronychium is the site of conditions including hangnails, ingrown nails, and paronychia, a skin infection.

The hyponychium is the area between the free edge of thenail plate and the skin of the fingertip. It also provides a waterproof barrier.

What Causes White Spots on Nails and How to Treat Them

How Do Nails Grow?

About 80% of your fingernail arises from the nail root (which determines length) and the other 20% comes from the nail bed (which determines thickness). On average, a healthy person's fingernails grow about 3 to 3.5millimeters per month.

Nails are constantly growing, but their growth rate slows down due to poor circulation and aging. The rate of growth also varies between its fingers and toes, and even between your different fingers.

Nail Functions

Fingernails serve a number of helpful functions, whether helping people to grip an item, used for scratching or grooming, or as a part of self-defense. For example, the DNA collected from fingernails when used to fight off an attack can be presented as evidence within the criminal justice system.

Nails aren't merely tools, with their presence boosting the ability to handle objects or feel pressure. They also serve to protect against infection, which can occur when the nail plate and other structures are damaged or brittle.

Conditions That Affect the Nails

There are a number of health conditions that can affect your nails, and in some cases (like chemotherapy), the treatments for certain diseases can affect your nail health.

A simple fungal infection can affect fingernails and toenails, while melanoma cancer can occur because melanocytes grow in the nail bed. Other conditions include:

  • Trauma or injury
  • Nail psoriasis
  • Discoloration (melanonychia)that can be a sign of other illnesses

Certain other conditions, like clubbing, can be associated with lung disease or other conditions. Your nails also can provide information about digestive conditions, heart health, diabetes, or kidney function.

Summary

The structure of your fingernails and toenails is designed to provide protection and additional function to your hands and feet. The parts of the nail include the nail itself, the underlying support of the nail, and the skin tissue around it.

Fingernails and toenails can be directly affected by a number of health conditions, like fungal infections, but changes also can be signs of more serious health issues, including cancer. Contact your healthcare provider to discuss any concerns with your nails and their appearance.

14 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Munteanu O, Filipoiu FM, Cirstoiu MM, Băloiu AI, Petrescu IA, Bohiltea RE. A Comprehensive Study Regarding the Intrauterine Development of Nails. Organogenesis. 2021 Apr 3;17(1-2):14-19. doi:10.1080/15476278.2021.1899739.

  2. Iorizzo M, Starace M, Pasch MC. Leukonychia: What Can White Nails Tell Us? Am J Clin Dermatol. 2022 Mar;23(2):177-193. doi:10.1007/s40257-022-00671-6.

  3. RegisteredNurseRN.com. Nail anatomy.

  4. Piipponen M, Li D, Landén NX.The immune functions of keratinocytes in skin wound healing.International Journal of Molecular Sciences. 2020; 21(22):8790. doi:10.3390/ijms21228790

  5. Liu TH, Hsieh MC, Chou PR, Huang SH. Reconstruction for Defects of Total Nail Bed and Germinal Matrix Loss with Acellular Dermal Matrix Coverage and Subsequently Skin Graft. Medicina (Kaunas). 2020 Jan 3;56(1):17. doi:10.3390/medicina56010017.

  6. Higashi T, Aso S, Horisaki H, Ito T, Tanaka S, Nishimoto-Kusunose S, et al. Evaluation of thumbnail clipping as a specimen for retrospectively assessing average production of testosterone. Clin Chim Acta. 2023 Jan 1;538:157-163. doi:10.1016/j.cca.2022.11.019.

  7. Singal A, Arora R.Nail as a window of systemic diseases.Indian Dermatol Online J. 2015;6(2):67-74. doi:10.4103/2229-5178.153002

  8. Voegel CD, Hofmann M, Kraemer T, Baumgartner MR, Binz TM. Endogenous steroid hormones in hair: Investigations on different hair types, pigmentation effects and correlation to nails. Steroids. 2020 Feb;154:108547. doi:10.1016/j.steroids.2019.108547.

  9. Johannessen H, Gill P, Shanthan G, Fonneløp AE. Transfer, persistence and recovery of DNA and mRNA vaginal mucosa markers after intimate and social contact with Bayesian network analysis for activity level reporting. Forensic Sci Int Genet. 2022 Sep;60:102750. doi:10.1016/j.fsigen.2022.102750.

  10. Chessa MA, Iorizzo M, Richert B, López-Estebaranz JL, Rigopoulos D, Tosti A, et al. Pathogenesis, Clinical Signs and Treatment Recommendations in Brittle Nails: A Review. Dermatol Ther (Heidelb). 2020 Feb;10(1):15-27. doi:10.1007/s13555-019-00338-x.

  11. Robert C, Sibaud V, Mateus C, et al.Nail toxicities induced by systemic anticancer treatments.Lancet Oncol. 2015;16(4):e181-e189. doi:10.1016/S1470-2045(14)71133-7

  12. Lee DK, Lipner SR. Optimal diagnosis and management of common nail disorders. Ann Med. 2022 Dec;54(1):694-712. doi: 10.1080/07853890.2022.2044511.

  13. Mount Sinai.Clubbing of the fingers or toes.

  14. Meegada S, Verma R. Terry's nails. Clin Case Rep. 2020 Jan 17;8(2):404-405. doi:10.1002/ccr3.2671.

By Heather L. Brannon, MD
Heather L. Brannon, MD, is a family practice physician in Mauldin, South Carolina. She has been in practice for over 20 years.

See Our Editorial Process

Meet Our Medical Expert Board

Was this page helpful?

Thanks for your feedback!

What is your feedback?

Structure and Growth of Fingernails and Toenails (2024)

References

Top Articles
Latest Posts
Recommended Articles
Article information

Author: Dong Thiel

Last Updated:

Views: 6007

Rating: 4.9 / 5 (79 voted)

Reviews: 86% of readers found this page helpful

Author information

Name: Dong Thiel

Birthday: 2001-07-14

Address: 2865 Kasha Unions, West Corrinne, AK 05708-1071

Phone: +3512198379449

Job: Design Planner

Hobby: Graffiti, Foreign language learning, Gambling, Metalworking, Rowing, Sculling, Sewing

Introduction: My name is Dong Thiel, I am a brainy, happy, tasty, lively, splendid, talented, cooperative person who loves writing and wants to share my knowledge and understanding with you.