Foot Anatomy

 Foot Anatomy

The function and structure of human foot is extremely complex. By understanding this foot structure and its physiology some commonly occurring sports injuries like sprains in the ankles, fractures etc can be treated in a better and convenient way.

 

Foot Structure

The forefoot is made up from five significant bones and the toes (medically called phalanges). The smallest significant bone is the thickest and mainly provides for connection in various tendons during forward movement. These significant bones are also called as metatarsal bones. The next three metatarsal bones count for the stability.

Sesamoid bones

Small bones that grow inside the tendon are called as sesamoid bones. Two such bones exist near smallest metatarsal bone at the foot planter surface. Ligaments and tendons hold them onto their place.

Bones in midfoot

Out of the seven, five tarsal bones lie in the midfoot (the three cuneiforms, cuboid and navicula ) Proximally, navicular bone and the  cuneiform bones  are coherently and lucidly connected.

 Anatomy

The human ankle and foot in all consist of 26 bones having 33 joints. These bones along with a hundred tendons, ligaments and muscles act as a mechanical structure that is strong and accurate.

 For better understanding foot has been divided into the forefoot, the midfoot, and the hind foot:

 The hind footmainly possesses an ankle bone or talus and the heel bone or calcaneus. Fibula and tibia are the two bones stretching in lower leg altogether with talus form an ankle. Calcenous the principal foot bone connects to talus through subtalar joint and is inferiorly protected by a layer of fat.

 Foot structure

The five asymmetrical midfoot bones, the cuneiform bones, navicular and the cuboid compose the arch structure of foot thereby resisting and absorbing the shocks. Plantar fascia and the muscles are responsible for connecting all the three parts of the foot together.

 Forefoot

The five toes along with their corresponding long bones form the forefoot. Toe bones are also called as phalanges. Except the big toe which has two phalanges the rest four toes have three phalanges each.  Interphalangeal joints are those joining phalanges to each other whereas metatarsophalangeal (MTP) joints are the one joining phalanges and metatarsus.

The arched segment is the jointer between the toes and the ankle part.

Out of the total 28 bones consisted in the foot:

• 7 are  tarsal bones (medial cuneiform, lateral cuneiform, intermediate cuneiform ,talus, calcaneus, navicular and cuboid).
• 5 are metatarsal bones (five from little toe to great toe respectively).
• 5 are proximal phalanges (five from little toe to great toe respectively).
• 4 are middle phalanges (total four  as it is not present in great toe).
• 5 are distal phalanges (five from little toe to great toe respectively).
• 2 are sesamoid bones present below the smallest metacarpal head.

Skeleton

A number of the sesamoid bones can be present in the metatarsophalangeal joint structure, although regularly they are present in the section of the first and small metatarsal bone only.

Arches

Out of the three arches maintained in human foot two are longitudinally arranged whereas one is in slanting position. These are supported by interlocking bone structure, pulling muscles and powerful ligaments during activities. Energy spent during mobility is a lot more economical with the support of these arches. Excessive strain falling on ligaments and tendons alters the arch arrangement causing flat feet. The first longitudinal arch stretches between the heel bone and the ankle bone and finally ends at three metatarsals. With disparity, the second longitudinal arch existing is very short or low. Slanting arch which runs diagonally into tarsometatarsal joints is supported by these longitudinal arches.

Muscles

The muscle structure of the foot is divided into intrinsic and extrinsic muscles depending upon their origination. Those originating from posterior or anterior of lower leg fall under extrinsic ones and those from planter or dorsal of the plantar branch form an intrinsic muscle structure.

Evolutionary variations

The hard foot in mammals is called as hoof and the soft one as paw. Paw is quadruped and has nails or claws.

The metatarsal bone structure is present in all the beings and is responsible for forming the foot arrangement. Depending upon manner  of locomotion the number of metatarsals is variable like it is five in human beings, two in cow, sheep etc and got reduced to  one in horses .But unlike the hands, having  diverged thumb from rest metacarpus arrangement, the feet and paw have bones   grouped tight together.

It’s important to study foot anatomy in order to take good care of it.