Foot
The foot (pl.: feet) is an
Etymology
The word "foot", in the sense of meaning the "terminal part of the leg of a vertebrate animal" comes from Old English fot, from Proto-Germanic *fot (source also of Old Frisian fot, Old Saxon fot, Old Norse fotr, Danish fod, Swedish fot, Dutch voet, Old High German fuoz, German Fuß, Gothic fotus, all meaning "foot"), from PIE root *ped- "foot".[1] The plural form feet is an instance of i-mutation.[1]
Structure
The human foot is a strong and complex mechanical structure containing 26
The foot can be subdivided into the hindfoot, the midfoot, and the forefoot:
The hindfoot is composed of the talus (or ankle bone) and the calcaneus (or heel bone). The two long bones of the lower leg, the tibia and fibula, are connected to the top of the talus to form the ankle. Connected to the talus at the subtalar joint, the calcaneus, the largest bone of the foot, is cushioned underneath by a layer of fat.[2]
The five irregular bones of the midfoot, the
The forefoot is composed of five
Both the midfoot and forefoot constitute the dorsum (the area facing upward while standing) and the planum (the area facing downward while standing).
The instep is the arched part of the top of the foot between the toes and the ankle.
Bones
There can be many sesamoid bones near the metatarsophalangeal joints, although they are only regularly present in the distal portion of the first metatarsal bone.[4]
Arches
The human foot has two longitudinal arches and a transverse arch maintained by the interlocking shapes of the foot bones, strong ligaments, and pulling muscles during activity. The slight mobility of these arches when weight is applied to and removed from the foot makes walking and running more economical in terms of energy. As can be examined in a footprint, the medial longitudinal arch curves above the ground. This arch stretches from the heel bone over the "keystone" ankle bone to the three medial metatarsals. In contrast, the lateral longitudinal arch is very low. With the cuboid serving as its keystone, it redistributes part of the weight to the calcaneus and the distal end of the fifth metatarsal. The two longitudinal arches serve as pillars for the transverse arch which run obliquely across the tarsometatarsal joints. Excessive strain on the tendons and ligaments of the feet can result in fallen arches or flat feet.[5]
Muscles
The muscles acting on the foot can be classified into
Extrinsic
All muscles originating on the lower leg except the popliteus muscle are attached to the bones of the foot. The tibia and fibula and the interosseous membrane separate these muscles into anterior and posterior groups, in their turn subdivided into subgroups and layers.[6]
Anterior group
Extensor group: the
Peroneal group: the
Posterior group
The superficial layer of posterior leg muscles is formed by the triceps surae and the plantaris. The triceps surae consists of the soleus and the two heads of the gastrocnemius. The heads of gastrocnemius arise on the femur, proximal to the condyles, and the soleus arises on the proximal dorsal parts of the tibia and fibula. The tendons of these muscles merge to be inserted onto the calcaneus as the Achilles tendon. The plantaris originates on the femur proximal to the lateral head of the gastrocnemius and its long tendon is embedded medially into the Achilles tendon. The triceps surae is the primary plantar flexor. Its strength becomes most obvious during ballet dancing. It is fully activated only with the knee extended, because the gastrocnemius is shortened during flexion of the knee. During walking it not only lifts the heel, but also flexes the knee, assisted by the plantaris.[9]
In the deep layer of posterior muscles, the tibialis posterior arises proximally on the back of the interosseous membrane and adjoining bones, and divides into two parts in the sole of the foot to attach to the tarsus. In the non-weight-bearing leg, it produces plantar flexion and supination, and, in the weight-bearing leg, it proximates the heel to the calf. The flexor hallucis longus arises on the back of the fibula on the lateral side, and its relatively thick muscle belly extends distally down to the flexor retinaculum where it passes over to the medial side to stretch across the sole to the distal phalanx of the first digit. The popliteus is also part of this group, but, with its oblique course across the back of the knee, does not act on the foot.[10]
Intrinsic
On the top of the foot, the tendons of extensor digitorum brevis and extensor hallucis brevis lie deep in the system of long extrinsic extensor tendons. They both arise on the calcaneus and extend into the dorsal aponeurosis of digits one to four, just beyond the penultimate joints. They act to dorsiflex the digits.[11] Similar to the intrinsic muscles of the hand, there are three groups of muscles in the sole of foot, those of the first and last digits, and a central group:
Muscles of the big toe: the abductor hallucis stretches medially along the border of the sole, from the calcaneus to the first digit. Below its tendon, the tendons of the long flexors pass through the tarsal canal. The abductor hallucis is an abductor and a weak flexor, and also helps maintain the arch of the foot. The flexor hallucis brevis arises on the medial cuneiform bone and related ligaments and tendons. An important plantar flexor, it is crucial to ballet dancing. Both these muscles are inserted with two heads proximally and distally to the first metatarsophalangeal joint. The adductor hallucis is part of this group, though it originally formed a separate system (see contrahens). It has two heads, the oblique head originating obliquely across the central part of the midfoot, and the transverse head originating near the metatarsophalangeal joints of digits five to three. Both heads are inserted into the lateral sesamoid bone of the first digit. The adductor hallucis acts as a tensor of the plantar arches and also adducts the big toe and might plantar flex the proximal phalanx.[12]
Muscles of the
Central muscle group: The four lumbricals arise on the medial side of the tendons of flexor digitorum longus and are inserted on the medial margins of the proximal phalanges. The quadratus plantae originates with two slips from the lateral and medial margins of the calcaneus and inserts into the lateral margin of the flexor digitorum tendon. It is also known as the flexor accessorius. The flexor digitorum brevis arises inferiorly on the calcaneus and its three tendons are inserted into the middle phalanges of digits two to four (sometimes also the fifth digit). These tendons divide before their insertions and the tendons of flexor digitorum longus pass through these divisions. Flexor digitorum brevis flexes the middle phalanges. It is occasionally absent. Between the toes, the dorsal and plantar interossei stretch from the metatarsals to the proximal phalanges of digits two to five. The plantar interossei adduct and the dorsal interossei abduct these digits, and are also plantar flexors at the metatarsophalangeal joints.[14]
Clinical significance
Due to their position and function, feet are exposed to a
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,
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.
Fractures of the foot include:
- fifth metatarsal
- March fracture – a fracture of the distal third of one of the metatarsals occurring because of recurrent stress
- Calcaneal fracture
- Broken toe – a fracture of a phalanx
- Cuneiform fracture – Due to the ligamentous support of the midfoot, isolated cuneiform fractures are rare.[16]
Pronation
In anatomy,
- Neutral pronation
An individual who neutrally pronates initially strikes the ground on the
This rolling inward motion as the foot progresses from heel to toe is the way that the body naturally absorbs shock. Neutral pronation is the most ideal, efficient type of gait when using a
- Overpronation
As with a neutral pronator, an individual who overpronates initially strikes the ground on the lateral side of the heel. As the individual transfers weight from the heel to the metatarsus, however, the foot will roll too far in a medial direction, such that the weight is distributed unevenly across the metatarsus, with excessive weight borne on the hallux. In this stage of the gait, the knee will generally, but not always, track inward.
An overpronator does not absorb shock efficiently. Imagine someone jumping onto a diving board, but the board is so flimsy that when it is struck, it bends and allows the person to plunge straight down into the water instead of back into the air. Similarly, an overpronator's arches will collapse, or the ankles will roll inward (or a combination of the two) as they cycle through the gait. An individual whose bone structure involves
When choosing a running or walking shoe, a person with overpronation can choose shoes that have good inside support—usually by strong material at the inside sole and arch of the shoe. It is usually visible. The inside support area is marked by strong greyish material to support the weight when a person lands on the outside foot and then roll onto the inside foot.
- Underpronation (supination)
An individual who underpronates also initially strikes the ground on the lateral side of the heel. As the individual transfers weight from the heel to the metatarsus, the foot will not roll far enough in a medial direction. The weight is distributed unevenly across the metatarsus, with excessive weight borne on the
Like an overpronator, an underpronator does not absorb shock efficiently – but for the opposite reason. The underpronated foot is like a diving board that, instead of failing to spring someone in the air because it is too flimsy, fails to do so because it is too rigid. There is virtually no give. An underpronator's arches or ankles do not experience much motion as they cycle through the gait. An individual whose bone structure involves
Society and culture
Humans usually wear shoes or similar footwear for protection from hazards when walking outside. There are a number of contexts where it is considered inappropriate to wear shoes. Some people consider it rude to wear shoes into a house and a Māori Marae should only be entered with bare feet.
Foot fetishism is the most common sexual fetish.[19][20]
Other animals
A
The metatarsals are the bones that make up the main part of the foot in humans, and part of the leg in large animals or paw in smaller animals. The number of metatarsals are directly related to the mode of locomotion with many larger animals having their digits reduced to two (
Metaphorical and cultural usage
The word "foot" is used to refer to a "...linear measure was in Old English (the exact length has varied over time), this being considered the length of a man's foot; a unit of measure used widely and anciently. In this sense the plural is often foot. The current inch and foot are implied from measurements in 12c."[1] The word "foot" also has a musical meaning; a "...metrical foot (late Old English, translating Latin pes, Greek pous in the same sense) is commonly taken to represent one rise and one fall of a foot: keeping time according to some, dancing according to others."[1]
The word "foot" was used in Middle English to mean "a person" (c. 1200).[1] The expression "...to put one's best foot foremost first recorded 1849 (Shakespeare has the better foot before, 1596)".[1] The expression to "...put one's foot in (one's) mouth "say something stupid" was first used in 1942.[1] The expression "put (one's) foot in something" meaning to "make a mess of it" was used in 1823.[1]
The word "footloose" was first used in the 1690s, meaning "free to move the feet, unshackled"; the more "figurative sense of "free to act as one pleases" was first used in 1873.[1] Like "footloose", "flat-footed" at first had its obvious literal meaning (in 1600, it meant "with flat feet") but by 1912 it meant "unprepared" (U.S. baseball slang).[1]
See also
- Ball (foot)
- Barefoot
- Comparison of orthotics
- Flat feet
- Foot binding
- Foot fetishism
- Foot gymnastics
- Gait analysis
- Heel
- Pedobarography (foot pressure analysis)
- Pes cavus
- Runner's toe, repetitive injury seen in runners
- Sole (foot)
- Squatting position
References
- ^ a b c d e f g h i j "Foot". etymonline.com. Online Etymology Dictionary. Retrieved 20 May 2017.
- ^ a b c d Podiatry Channel, Anatomy of the foot and ankle
- PMID 8050406.
- ^ Platzer 2004, p. 220
- ^ Mareb-Hoehn 2007, pp. 244–45
- ^ Platzer 2004, p. 256
- ^ Platzer 2004, p. 258
- ^ Platzer 2004, p. 260
- ^ Platzer 2004, p. 262
- ^ Platzer 2004, p. 264
- ^ Platzer 2004, p. 268
- ^ Platzer 2004, pp. 270–72
- ^ Platzer 2004, p. 272
- ^ Platzer 2004, p. 274
- ^ TheFreeDictionary > Lisfranc's fracture Citing: Mosby's Medical Dictionary, 8th edition. 2009
- S2CID 225705519.
- ^ "Overpronation, Explained". Runner's World. 21 September 2001. Retrieved 28 December 2012.
- ^ "Supination, Explained". Runner's World. 21 September 2001. Archived from the original on 17 September 2013. Retrieved 28 December 2012.
- ^ "Rex Ryan's Apparent Foot Fetish Not Necessarily Unhealthy". Abcnews.go.com. 23 December 2010. Retrieved 13 August 2012.
- ^ "Top 10 Most Common Fetishes". Archived from the original on 1 January 2012. Retrieved 4 January 2012.
- ^ France 2008, p. 537
Bibliography
- France, Diane L. (2008). Human and Nonhuman Bone Identification: A Color Atlas. CRC Press. ISBN 978-1-4200-6286-1.
- Marieb, Elaine Nicpon; Hoehn, Katja (2007). Human anatomy & physiology. Pearson Education. ISBN 978-0-321-37294-9.
- Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. ISBN 3-13-533305-1.
- "Anatomy of the foot and ankle". Podiatry Channel. Archived from the original on 31 August 2009. Retrieved 21 August 2009.
External links
- Foot at Curlie