Introduction to Foot
Foot (plural: feet) is the end of limbs in vertebrates that helps in locomotion. It is one of the most complex structures in vertebrate anatomy. The foot is made up of several components or segments, including bones, muscles, tendons and ligaments.
Functions of Foot
The main function of the feet is to enable locomotion. It allows movement and several physical functions.
It also bears the weight of the body. It balances the entire body weight at different angles and positions.
The structure of foot is designed to be able to absorb the shock while walking.
Feet also help an animal stand upright and perform various physical activities.
Along with helping in walking, climbing or jumping, it can also help in grasping or manipulation.
Postures of Foot
Three types of foot postures are generally observed. These include:
Plantigrade
Most commonly seen in humans and animals like bears, this type of posture involves contact between the entire foot and the ground during locomotion.
Digitigrade
The type of feet where only the toes (phalanges) make contact with the ground during locomotion is called digitigrade. The ankle remains elevated, and this type of posture is seen in dogs and cats.
Unguligrade
This type of feet can be seen in running animals like horses with only tips of a few digits touching the ground during locomotion.
Structure of a Human Foot
The human foot comprises 26 bones and 33 joints. It has structures such as the ankle, heel, arch, and digits. The arched part of the foot that is present between the toes and the ankle is called instep. Let us understand the structure and all the parts of foot in detail.
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The foot can be broadly divided into the following parts:
Hindfoot
It consists of the Talus (ankle bone) and Calcaneus (heel bone). The place where the tibia and fibula connect with the talus makes up the ankle. Calcaneus is the largest bone found in the foot and has a layer of fat cushioning it. It joins with the talus at the Subtalar joint.
Midfoot
It is made up of five bones called the cuboid(1), navicular(1) and cuneiform(3). These bones form the foot arches. The main function of these arches is to absorb shock while walking. The muscles and plantar fascia located in the foot join the midfoot with other parts.
Forefoot
The forefoot of a human has five toes and five proximal bones forming the metatarsus. The bones of the toes are referred to as phalanges. One toe has two phalanges, while the other four have three phalanges. The phalanges are joined together with the interphalangeal joint while connecting with the metatarsus at the metatarsophalangeal joint.
Bones
The bones that are found in the foot are:
Tarsus:
talus, calcaneus, cuneiformes (3), cuboid, and navicular
Metatarsus:
Five metatarsal bones are present, known as the first, second, third, fourth, and fifth metatarsal bone
Phalanges:
14 phalanges can be seen in humans
Muscles
The muscles of the feet can be divided into the following categories:
Central muscles (Located in the sole)
Lateral muscles
Medial muscles
Dorsum muscles
The central, lateral and medial muscles are located in the sole of the feet, while the dorsum muscles are located in the part of the feet that face upwards.
Tendon
The movement of feet is only possible when the strong muscles apply a pull on the rigid bones and relocate them. For this, there has to be a connection between the muscles and the bones. This is provided by tendons which are thick and elastic bands of tissue present as a connection between the bones and associated muscles. They are responsible for aiding the movement. The Achilles tendon in the human foot connects the heel to the calf and helps in standing on toes, running, jumping and other activities.
Ligaments
Since there are so many bones present in the foot, they have to be joined together. This is done with the help of strong and flexible tissues known as ligaments. These are extremely strong and connect various bones together.
Conclusion
A structure that aids in locomotion and is located at the terminal end of a limb is termed the foot. In invertebrates, foot refers to the locomotory organs such as arthropods limbs and mollusc burrowing organs.
Muscles, tendons and ligaments run along with the structure of foot and allow movement to occur. The human foot has a dorsum (the area that faces up when a person is standing) and a planum- (The part of the foot that faces downward). Both the mid and forefoot are included in the dorsum and planum. The foot can be further divided into forefoot, midfoot and hindfoot.
FAQs on Foot
1. What is the human foot from a biological standpoint?
From a biological standpoint, the human foot is the complex terminal structure of the leg, specifically designed for bipedal locomotion and supporting the entire body's weight. It consists of 26 bones, 33 joints, and more than 100 muscles, ligaments, and tendons working together to provide stability, propulsion, and shock absorption during activities like standing, walking, and running.
2. What are the three main anatomical sections of the human foot?
The human foot is anatomically divided into three main sections, each with distinct bones and functions:
- The Hindfoot: This section is composed of the talus (ankle bone) and the calcaneus (heel bone). It forms the foundation of the foot and ankle, crucial for initial contact with the ground.
- The Midfoot: This includes the navicular, cuboid, and three cuneiform bones. These bones form the primary arches of the foot and act as a shock absorber.
- The Forefoot: This section consists of the five metatarsals and the fourteen phalanges (toe bones). It is responsible for propulsion and pushing off during movement.
3. What are the arches of the foot and why are they important?
The human foot has three main arches: two longitudinal (medial and lateral) and one transverse. These arches are formed by the tarsal and metatarsal bones and are supported by ligaments and tendons. Their importance is immense, as they allow the foot to distribute body weight evenly, act as a natural shock absorber, and provide a springy, flexible platform for walking and running efficiently. A collapse in these arches can lead to a condition known as flat feet.
4. How did the human foot evolve specifically for upright walking?
The human foot evolved significantly from the grasping, ape-like foot of our ancestors to a stable platform for bipedalism. Key evolutionary changes include the big toe (hallux) becoming larger and aligned with the other toes for powerful push-off, instead of being opposable for grasping. Furthermore, the development of the strong longitudinal and transverse arches provided shock absorption, and the heel bone (calcaneus) became larger and more robust to handle the impact of heel-strike during walking.
5. How does the structure of the human foot differ from that of a primate's foot?
The primary difference lies in function. A primate's foot is prehensile, meaning it is adapted for grasping branches, much like a hand. It features an opposable big toe. In contrast, the human foot is a rigid, propulsive lever adapted for bipedal walking. Key differences include:
- Big Toe: Human big toe is large, non-opposable, and in line with other toes for push-off. Primate big toe is opposable for grasping.
- Arches: Humans have well-developed arches to absorb shock. Primates have flatter, more flexible feet.
- Bones: Human foot bones are more robust and tightly bound by ligaments for stability, whereas primate foot bones are more mobile.
6. Why is the ankle often considered part of the foot's functional complex?
While the ankle joint (tibiotalar joint) is anatomically distinct from the foot, it is considered part of the foot's functional complex because they are mechanically inseparable. The ankle's movements—dorsiflexion (lifting the foot up) and plantarflexion (pointing the foot down)—are essential for the walking cycle and are directly transmitted to the foot's bones. The stability of the foot's hindfoot bones, like the talus and calcaneus, is critical for proper ankle function, making them a single integrated unit for locomotion and balance.
7. What are the primary types of movement the foot can perform?
The foot can perform several specialised movements essential for adapting to different surfaces and propelling the body forward. The primary movements are:
- Dorsiflexion: Decreasing the angle between the top of the foot and the shin (lifting the foot upwards).
- Plantarflexion: Increasing the angle between the top of the foot and the shin (pointing the toes downwards).
- Inversion: Tilting the sole of the foot to face inwards.
- Eversion: Tilting the sole of the foot to face outwards.
