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Corn (Medicine) | |
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Painful corns |
A corn or clavus (plural clavi or clavuses) is an often painful, cone-shaped, inwardly directed callus of dead skin that forms at a pressure point near a bone, or on a weight-bearing part of the body. When on the feet, corns can be so painful as to interfere with walking. The visible portion of the corn tends to be more-or-less round, but corns are defined by having a hard tapering root that is directed inward, and pressure on the corn pushes this root deeper into the flesh (thus the Latin term clavus meaning "nail"). Pressure corns usually occur on thin or glabrous (hairless and smooth) skin surfaces, especially on the dorsal surface of toes or fingers, but corns triggered by an acute injury (such as a thorn) may occur on the thicker skin of the palms (palmar corns) or bottom of the feet (plantar corns).
Pressure corns form when chronic pressure on the skin against an underlying bone traces a usually elliptical path during the rubbing motion. The corn forms at the center of the pressure point and gradually widens and deepens.
Corns from an acute injury, such as from a thorn in the sole of the foot, may form due to the weight of the body, when the process that creates the usually evenly developing plantar callus is concentrated at the point of the healing injury, as an internal callus may be triggered by pressure on the transitional scar tissue. Once formed, the corn itself becomes the pressure point that generates the callus. Plantar corns have appearance superficially similar to plantar warts, but the cause and treatment are very different.
The modern medical word for a corn is Greek heloma (plural helomas or helomata); Latin "clavus" is somewhat dated. Another term is tyloma 'callus' (plural tylomas or tylomata), which tends to be more common in the United States. A hard corn is called a heloma durum or clavus durus, while a soft corn is called a heloma molle or clavus mollis. [1]
Other types of corn include,
Although an excised corn resembles a barleycorn in shape, the two words 'corn' are unrelated. The word 'corn' for a callus derives from the Latin cornus 'horn', and is related to the Greek keras (whence keratin). The 'corn' of 'barley corn' descends from the Indo-European word for 'grain'. The similarity in form is a historical accident.
Many languages have metaphoric phrases for corns. Several are based on the word for 'eye': e.g. German Hühnerauge and Mandarin 雞眼jīyǎn, both 'chicken eye', or Japanese uo-no me, Malay mata ikan and Thai ตาปลาtaa plaa, all 'fish eye'. German also has Krähenauge 'crow's eye', Hornauge 'horned eye' and Leichdorn 'body/corpse thorn'; similar phrases are used in other Germanic languages (e.g. Dutch eksteroog 'magpie eye' and likdoorn, Swedish liktorn). Romance languages tend to use cognates of 'callus' (French cal, Spanish callo and Italian callo), 'cornus' (French cor, Italian corno), but Catalan uses ull de poll meaning 'chick's eye'. Medically hyperkeratosis (Fr. hyperkératose, Sp. hiperqueratosis, It. ipercheratosi).
The hard part at the center of the corn resembles a barleycorn or shoe tack, that is, a cone or funnel shape with a broad top and a pointed tip at bottom. Because of their shape, corns intensify the pressure at the tip and can cause deep tissue damage and ulceration. [2] Hard corns are especially problematic for people with insensitive skin due to damaged nerves (e.g., in people with diabetes mellitus), as they more readily become infected and potentially lead to gangrene. In others they may interfere with walking and lead to the medical complications of a lack of movement and exercise.
The location of soft corns tends to differ from that of hard corns. Hard corns occur on dry, flat surfaces of skin. Soft corns (frequently found between adjacent toes) stay moist, keeping the surrounding skin soft. The corn's center is not soft, however, but indurated.
To exclude other differential diagnoses, a skin biopsy may be taken. [2] Imaging studies can be used in order to detect any underlying bony abnormalities that cause abnormal pressure on the overlying skin. [2] For this purpose, a plain radiograph usually suffices, but, occasionally, CT scanning is used. [2]
Treatment of pressure corns includes paring of the lesions, which immediately reduces pain. [2] Another popular method is to use a corn plaster, a felt ring with a core of salicylic acid that relieves pressure and erodes the hard skin. However, if an abnormal pressure source remains, the corn generally returns. If the source of any abnormal pressure is detected, this may be avoided, usually through a change to more comfortable footwear or with various types of shoe inserts or footwear with extra toe space. In extreme cases correcting gait abnormalities may be required. [2] If no other treatment is effective, surgery may be performed. [2]
Corns formed around an acute injury occur in deeper tissue than pressure corns, they can usually be excised without cutting into the dermis, leaving only a thin layer of epidermis behind. The resulting hole in the sole of the foot may however form its own internal callus which triggers a new corn before it can fully heal, so it may be necessary to excise the corn more than once before the spot returns to an even plantar callus.
The leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula.
The heel is the prominence at the posterior end of the foot. It is based on the projection of one bone, the calcaneus or heel bone, behind the articulation of the bones of the lower leg.
Toes are the digits of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being digitigrade. Humans, and other animals that walk on the soles of their feet, are described as being plantigrade; unguligrade animals are those that walk on hooves at the tips of their toes.
A callus is an area of thickened and sometimes hardened skin that forms as a response to repeated friction, pressure, or other irritation. Since repeated contact is required, calluses are most often found on the feet and hands, but they may occur anywhere on the skin. Some degree of callus, such as on the bottom of the foot, is normal.
A plantar wart is a wart occurring on the bottom of the foot or toes. Its color is typically similar to that of the skin. Small black dots often occur on the surface. One or more may occur in an area. They may result in pain with pressure such that walking is difficult.
A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious organisms including bacteria and fungi, as well as other materials such as foreign objects, keratin, and suture fragments.
Diabetic neuropathy includes various types of nerve damage associated with diabetes mellitus. The most common form, diabetic peripheral neuropathy, affects 30% of all diabetic patients. Symptoms depend on the site of nerve damage and can include motor changes such as weakness; sensory symptoms such as numbness, tingling, or pain; or autonomic changes such as urinary symptoms. These changes are thought to result from a microvascular injury involving small blood vessels that supply nerves. Relatively common conditions which may be associated with diabetic neuropathy include distal symmetric polyneuropathy; third, fourth, or sixth cranial nerve palsy; mononeuropathy; mononeuropathy multiplex; diabetic amyotrophy; and autonomic neuropathy.
An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. "Palpebral" means relating to the eyelids. Its key function is to regularly spread the tears and other secretions on the eye surface to keep it moist, since the cornea must be continuously moist. They keep the eyes from drying out when asleep. Moreover, the blink reflex protects the eye from foreign bodies. A set of specialized hairs known as lashes grow from the upper and lower eyelid margins to further protect the eye from dust and debris.
Diseases of the foot generally are not limited, that is they are related to or manifest elsewhere in the body. However, the foot is often the first place some of these diseases or a sign or symptom of others appear. This is because of the foot's distance from the central circulation, the heart and its constant exposure to pressures from the ground and the weight of the body.
Ainhum, also known as dactylolysis spontanea, is a painful constriction of the base of the fifth toe frequently followed by bilateral spontaneous autoamputation a few years later.
An ingrown nail, also known as onychocryptosis from Greek: ὄνυξ 'nail' and κρυπτός 'hidden', is a common form of nail disease. It is an often painful condition in which the nail grows so that it cuts into one or both sides of the paronychium or nail bed. While ingrown nails can occur in the nails of both the hands and the feet, they occur most commonly with the toenails, and for the most part are only problematic and painful on the big toe.
Hyperkeratosis is thickening of the stratum corneum, often associated with the presence of an abnormal quantity of keratin, and is usually accompanied by an increase in the granular layer. As the corneum layer normally varies greatly in thickness in different sites, some experience is needed to assess minor degrees of hyperkeratosis.
The gastrocnemius muscle is a superficial two-headed muscle that is in the back part of the lower leg of humans. It is located superficial to the soleus in the posterior (back) compartment of the leg. It runs from its two heads just above the knee to the heel, extending across a total of three joints.
Plantar fascial fibromatosis, also known as Ledderhose's disease, Morbus Ledderhose, and plantar fibromatosis, is a relatively uncommon non-malignant thickening of the feet's deep connective tissue, or fascia. In the beginning, where nodules start growing in the fascia of the foot, the disease is minor. Over time, walking becomes painful. The disease is named after Georg Ledderhose, a German surgeon who described the condition for the first time in 1894. A similar disease is Dupuytren's disease, which affects the hand and causes bent hand or fingers.
Tarsal tunnel syndrome (TTS) is a nerve compression syndrome or nerve entrapment syndrome causing a painful foot condition in which the tibial nerve is entrapped as it travels through the tarsal tunnel. The tarsal tunnel is found along the inner leg behind the medial malleolus. The posterior tibial artery, tibial nerve, and tendons of the tibialis posterior, flexor digitorum longus, and flexor hallucis longus muscles travel in a bundle through the tarsal tunnel. Inside the tunnel, the nerve splits into three segments. One nerve (calcaneal) continues to the heel, the other two continue on to the bottom of the foot. The tarsal tunnel is delineated by bone on the inside and the flexor retinaculum on the outside.
A neuroma is a growth or tumor of nerve tissue. Neuromas tend to be benign ; many nerve tumors, including those that are commonly malignant, are nowadays referred to by other terms.
A horse hoof is the lower extremity of each leg of a horse, the part that makes contact with the ground and carries the weight of the animal. It is both hard and flexible. It is a complex structure surrounding the distal phalanx of the 3rd digit of each of the four limbs, which is covered by soft tissue and keratinised (cornified) matter.
Clavus may refer to:
A breast mass, also known as a breast lump, is a localized swelling that feels different from the surrounding tissue. Breast pain, nipple discharge, or skin changes may be present. Concerning findings include masses that are hard, do not move easily, are of an irregular shape, or are firmly attached to surrounding tissue.
Stasis papillomatosis is a disease characterized by chronic congestion of the extremities, with blood circulation interrupted in a specific area of the body. A consequence of this congestion and inflammation is long-term lymphatic obstruction (lymphedema). It is also typically characterized by the appearance of numerous papules. Injuries can range from small to large plates composed of brown or pink, smooth or hyperkeratotic papules. The most typical areas where injuries occur are the back of the feet, the toes, the legs, and the area around a venous ulcer formed in the extremities, although the latter is the rarest of all. These injuries include pachydermia, lymphedema, lymphomastic verrucosis and elephantosis verrucosa. The disease can be either localized or generalized; the localized form makes up 78% of cases. Treatment includes surgical and pharmaceutical intervention; indications for partial removal include advanced fibrotic lymphedema and elephantiasis. Despite the existence of these treatments, chronic venous edema, which is a derivation of stasis papillomatosis, is only partially reversible. The skin is also affected and its partial removal may mean that the skin and the subcutaneous tissue are excised. A side effect of the procedure is the destruction of existing cutaneous lymphatic vessels. It also risks papillomatosis, skin necrosis and edema exacerbation.