Your nails serve several purposes: to support the tissues of the fingers and toes; to protect the upper surface of the fingertips from injury; to assist you in picking up small objects; and to help you to grasps, scratch and pinch.
Nails also provide external stability to the softer skin that is found around the fingertip. Your nails are made up of several components - some visible, others not. Their basic ingredient is keratin, a fibrous protein that gives nails their tough, hard quality. Keratin is also responsible for human hair, the claws of animals, the horn of a rhinoceros, and the feathers and beaks of birds.
Nails are translucent, usually a faint pinkish colour due to the network of blood vessels beneath them. This colour varies and may lighten when you are cold and the blood vessels become constricted.
PARTS OF THE NAIL
Half-moon
The whitish, half-moon visible at the base of your nail is the lunula. Its pale appearance arises from the fact that it does not adhere so closely to the underlying tissue. It forms a bridge between the living matrix and the nail plate.
It size, shape and brightness varies from person to person and finger to finger, often being more pronounced on the thumb.
Nail matrix
Nail growth begins in the nail matrix. Also known as the nail root, it is the living part of the nail hidden under the cuticle. Nail keratin is created here. The matrix contains nerves, lymph vessels and blood vessels vital for nourishing the fingernails. Nail cells divide in the matrix, lengthening the nail plate and pushing it forwards over the nail bed.
Nail bed and nail plate
The most visible part of the nail is called the nail plate - a hard, smooth, slightly convex covering to the fingertip. This is the part we usually think of as the fingernail.
The nail bed is the finger tissue directly under the nail plate; its network of small blood vessels provides nutrition to the nail. While the nail bed supports the nail, it does not contribute to nail growth. As keratin forms in the nail matrix, it pushes forward onto the nail bed to harden and become the expose nail plate.
The tough nail plate is no longer living tissue, nor does it contain any of the nerves or blood vessels that can be found in the nail bed.
Nail fold
This is the layer of skin covering the edge of the nail plate on all sides except the tip, holding the nail in place. It is usually where nail fungus infections occur.
Cuticle
The cuticle is the thin tissue that grows from the finger to overlap and protect the nail plate and form a rim around the base of the nail. It is the most important part of the nail, protecting both the nail matrix with its delicate tissues and the cells below the nail plate, which are actively forming the hard nail.
Its purpose is to protect against debris, micro-organisms and bacteria that can damage the matrix and nail bed. Gentleness is the key to cuticle care, as vigorous trimming or pushing back of the cuticles, as well as chemical solvents, may cause ridges in the nail.
In addition, you need to be aware that once the cuticle is damaged, the watertight space under the nail fold is laid open to moisture and becomes a potential breeding ground for bacteria, which can lead to a number of unwanted infection.
STRUCTURE OF THE PALM OF THE HAND
BonesAnatomically the bones of the hand can be divided into three parts:
- The carpus, or wrist, is a flexible joint composed of eight small bones held together by ligaments. The bones of the hand are connected to those of the lower arm by tendons.
- The metacarpus, or palm, is the main part of the hand and has five long metacarpal bones.
- The phalanges, or fingers, are formed by 14 phalangeal bones. Each finger has three phalanges whereas the thumb has only two.
This complex framework of bones allows a range of fine and gross movements in your hands, which can perform huge tasks, as well as the most delicate and precise functions.
Muscles
The hand has many small muscles that overlap from joint to joint, giving flexibility and strength. When the hands are properly cared for, these muscles will remain supple and graceful.
Abductors separate the fingers and adductors draw the fingers together. Both of these types of muscles are located at the base of the thumb and fingers. Opponent muscles in the palm of the hand bring the thumb toward the fingers, giving rise to the grasping action of the hand.
Nerves
Three major nerves in the hand allow you to feel sensation, experience motion and participate in fine, delicate movement.
The median nerve is the main nerve for precision grip; it controls finger flexion (bending fingers into the palm) and wrist flexion (bending the wrist down). It also controls sensation in the palm side surface of the thumb, index and middle fingers, and half of the ring finger. In addition, it supplies stimulus to the muscles that bring the thumb toward the fingers to enable you to grasp an object.
The ulnar nerve works with the median nerve to innervate the muscles responsible for the fine movements of the hand, such as typing, writing or sewing. The third major nerve, the radial nerve, supplies sensation to the back of the hand, affecting the muscles that extend the arm, forearm, hand and fingers.
Our hands-complex structures of bones, muscles and nerves-are vital tools throughout our lives.
Muscles, Tendons And Ligaments
The muscles of the hand cannot work alone but function as an interactive group, together with ligaments and tendon, which consist of tough elastic and connective tissue.
Ligaments are dense fibrous bands that provide stability and connect one bone to another, while still allowing some movement and providing guidance, coordination and restrain. Tendons connect muscle contracts, the strong, cable-like tendon pulls the bone to which it is attached. All movements are balanced between the opposing forces of each of the muscles.
There are 20 small muscle groups for independent finger movements, plus an extra 14 muscle groups in the forearm. Nine muscles contribute to the flexibility and movement of the thumb,allowing it greater mobility and range of movement than the other fingers as it requires more strength in order to oppose the pressure exerted by four fingers.
The muscle groups in the hands are joined by more than 20 long tendons, which enter the hand under a larger 'wristband' tendon and go forward to form a criss-cross pattern around each finger. Each muscle, tendon, ligament, nerve and blood vessels is surrounded by connective tissue, which consists of bundles of collagen and elastin. These bundles have three major functions: to separate or connect structures; to cushion and protect; and to help maintain the shape of the hands, palms and fingers.
Circulatory System
Oxygen and nutrients are transported in the blood to the tissues of the hand by a complex network of arteries, veins and capillaries.
Nutrient-and-oxygen-rich blood is carried from your heart through the brachial artery of the upper arm and then through either the radial or ulnar arteries, which carry the main blood supply for the hand and arm. The ulnar artery and its branches supply the outer side of the arm and the palm of the hand, while the radial artery and its branches supply the inner side of the arm and the back of the hand.
Any blockage in the arteries affects your circulation and may result in swelling and pain, or even a mottled, blue discolouration of the hands.
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