Feet (anatomy)

The foot is an anatomical structure found in many animals. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws or nails.

General forms of the foot


The feet of land vertebrates are characterized as either plantigrade, digitigrade, or unguligrade. In plantigrade animals, such as humans, frogs or bears, the bottom of the entire foot supports the weight of the animal. In digitigrade animals, such as cats, wolves or birds, the toes bear the animal's weight, while the upper regions of the foot, the ankle and wrist, remain elevated. Finally, in unguligrade animals, such as cows or horses, even the toes are elevated, the animal standing only atop its nails, which have evolved to bear weight and are called hooves.

Anatomy
The human foot is of the plantigrade form. The major bones in the human foot are:
 * Phalanges: The bones in the toes are called phalanges.
 * Metatarsals: The bones in the middle of the foot are called metatarsal bones.
 * Cuneiforms: There are three bones in the middle of the foot, towards the centre of the foot between the navicular bone and the 1-3 metatarsal bone( the three bones are the intermediate, lateral, medial cuneiform bones.)
 * Cuboid: The bone sitting adjacent to the cuneiforms on the outside of the foot is called the cuboid.
 * Navicular: This bone sits behind the cuneiforms.
 * Talus: Also called the ankle bone, the talus sits directly behind the navicular.
 * Calcaneus: Also called the heel bone, the calcaneus sits under the talus and behind the cuboid.

The foot also contains sesamoid bones in distal portion of the first metatarsal bone.

Anthropometry
An anthropometric study of 1197 North American adult Caucasian males (mean age 35.5 years) found that mean foot length was 26.3 cm with a standard deviation of 1.2 cm.

In culture
Worldwide, different cultures treat and perceive feet very differently:
 * Many societies have "foot taboos":
 * In countries strongly influenced by Buddhism (e.g., Thailand, Nepal), feet are the least respected parts of the body and strong taboos obtain against touching with feet, pointing with feet, or exposing the sole of the foot toward someone. In Thai custom, feet should not be in a higher position than someone's head and must never face someone or an image of the Buddha. In Nepal, sleeping on the floor with someone's feet oriented toward another sleeper is considered entirely unacceptable.
 * Traditional Arab culture also has the same anti-foot bias as in the Nepal or Thailand cultures.
 * In traditional China (10th through 20th Centuries), the practice of female foot binding stunted the growth of the feet of young girls, resulting in a very tiny, intensely painful, and aesthetically desirable (though deformed) foot- this was often nicknamed 'Pink Socking' as it left the foot bright pink.
 * Within several Christian denominations, foot washing is a religious ritual possibly originating in the hospitality customs of the Levant.
 * Foot fetishism is a sexual interest and preoccupation with feet and hosiery. Playing footsie is also a term dealing with rubbing each other's feet, and can have sexual connotations, while a foot job is a sex act involving the feet.

Footwear customs
Customs about footwear while indoors vary significantly from place to place and usually depend on climate, weather, and other factors:
 * It is customary to remove one's footwear when entering a home:
 * in some homes in Europe and Canada, and in many homes in New Zealand and Australia.
 * in some homes in the United Kingdom
 * in some homes in the United States
 * in Korea and Japan the custom is so widespread that floors are often made of materials that are too soft to survive being walked on with shoes.
 * In some cultures, bare feet may be considered unsightly or offensive. In Arab countries and in Thailand, it is considered extremely offensive to show someone the sole of your foot, although the practice of going barefoot is common, due to various reasons including hot climate and tradition.
 * In many religious subgroups of Uzbekistan, touching another's foot is a sign of affection. However, more conservative families consider this to be an act of promiscuity.
 * The feet are one of the most common places to be tickled on the human body. The soles generally tend to be sensitive to tickling.

Customary measurement
One way to measure short distances on the ground is by placing one foot directly in front of the other; this led to the adoption of the foot as a unit of length, even though not all human feet correspond to this measure.

Myths
It is a myth that the Imperial "foot" (304.8 mm) is about the length of the average European male foot. The average today is less than 280 mm and 90% of the population is within 20 mm of that. Although many men today have feet that are 11.5 inches long (size 12-13): most are less than size 11. In the past, the average length would have been even less. The overall length of most shoes however, is above one "foot". Tradition has it that the Imperial foot was based upon the size of Hercules' foot or the size of the king of England.

Medical aspects
Due to their position and function, feet are exposed to a variety of potential infections and injuries, including athlete's foot, bunions, ingrown toenails, Morton's neuroma, plantar fasciitis, plantar warts and stress fractures. In addition, there are several genetic conditions that can affect the shape and function of the feet, including a club foot or flat feet.

This leaves humans more vulnerable to medical problems that are caused by poor leg and foot alignments. Also, the wearing of shoes, sneakers and boots can impede proper alignment and movement within the ankle and foot. For example, high heels are known to throw off the natural weight balance (this can also affect the lower back). For the sake of posture, flat soles and heels are advised.

A doctor who specializes in the treatment of the feet practices podiatry and is called a podiatrist. A pedorthist specializes in the use and modification of footwear to treat problems related to the lower limbs.