Our feet are constantly under stress. It's no wonder that 80 percent of us will have some sort of problem with our feet at some time or another. Many things affect the condition of our feet: activity level, occupation, other health conditions, and perhaps most importantly, shoes. Many of the problems that arise in the foot are directly related to shoes, so it is very important to choose shoes that are good for your feet.
The foot is an incredibly complex mechanism. This introduction to anatomy (what parts make up the foot) and physiology (how the foot works) will aid nail technicians in performing professional pedicure services, as well as understanding conditions affecting the feet.
The important structures of the foot can be divided into several categories. These include: bones and joints, ligaments and tendons, muscles, nerves, circulatory system, and skin. Physiology of the foot will be discussed as each category of anatomical structure is addressed.
Bones and Joints
The skeleton of the foot begins with the talus, or ankle bone, that forms part of the ankle joint. The two bones of the lower leg, the large tibia and the smaller fibula, come together at the ankle joint to form a very stable structure known as a mortise and tenon joint.
The mortise and tenon structure is well known to carpenters and craftsmen who use this joint in the construction of everything from furniture to large buildings. The arrangement is very stable.
The two bones that make up the back part of the foot (sometimes referred to as the hindfoot) are the talus and the calcaneus, or heelbone. The talus is connected to the calcaneus at the subtalar joint. The ankle joint allows the foot to bend up and down. The subtalar joint allows the foot to rock from side to side.
Just down the foot from the ankle is a set of five bones called tarsal bones that work together as a group. These bones are unique in the way they fit together. There are multiple joints between the tarsal bones. When the foot is twisted in one direction by the muscles of the foot and leg, these bones lock together and form a very rigid structure. When they are twisted in the opposite direction, they become unlocked and allow the foot to conform to whatever surface the foot is contacting.
The tarsal bones are connected to the five long bones of the foot called the metatarsals. The two groups of bones are fairly rigidly connected, without much movement at the joints.
Finally, there are the bones of the toes, the phalanges. The joints between the metatarsals and the first phalanx is called the metatarsophalangeal joint (MTP). These joints form the ball of the foot, and movement in these joints is very important for a normal walking pattern.
Not much motion occurs at the joints between the bones of the toes. The big toe, or hallux, is the most important toe for walking, and the first MTP joint is a common area for problems in the foot.
Anatomy of the Foot: Bones of the Feet
The foot contains 26 bones. These 26 bones are divided into 3 groups; tarsal, meta-tarsal, and the phalangeal Bones. Following is a more in-depth discussion of these bones and their functions.
The tarsal area of the foot contains a total of 7 bones. Tarsal bones are also the largest bones found in the foot.
- Talus: AKA the ankle bone, it is the second largest bone in the foot. It connects the foot to the leg.
- Calcaneous: The heel bone is the largest of the tarsal bones.
- Navicular or Scaphoid bone: Located in the middle of the foot. It can be found between the talus bone and first, second and third cuneiforms.
- Cuboid: This bone can be found on the outer side of the foot (the side with the pinkie toe).
- Medial Cuneiform or Internal Cuneiform: Rests between the navicular, first and second metatarsal.
- Intermediate Cuneiform: Is found between the medial and lateral cuneiform bones.
- Lateral Cuneiform: Located between the intermediate cuneiform and the cuboid, and the second and third metatarsal.
The Metatarsal bones connect the tarsal bones to the toes. The metatarsal are identified as number 1-5.
- The first metatarsal extends from the big toe to the heel and is the shortest and thickest of the metatarsal bones. Two additional small bones can be found underneath the first metatarsal they have small muscles attached to them that aid in stabilization.
- The second metatarsal is the longest of the metatarsal bones.
- Third metatarsal, connects to the middle toe; it is usually slightly shorter than the second metatarsal.
- The fourth metatarsal is slightly shorter than the third.
- Fifth metatarsal attaches to the pinkie toe and is the shortest. It also differs because it has a bump that can be seen on the outer side of the foot.
There are 14 phalangeal bones which make up the toes. They are identified by number just like the metatarsal bones. The first phalangeal is the big toe and the fifth is the little toe. The big toe has only 2 bones, which are much larger than those in the other toes. The second through fifth toes have 3 bones each.
33 joints can be found in the foot and each joint is surrounded with fluid. This fluid is contained in a sack which keeps the joint lubricated. Some customers experience pain from arthritis, which is directly linked to lubrication (lack of) and inflammation of the joints.
Anatomy of the Foot: Ligaments and Tendons
Ligaments are the soft tissues that attach bones to bones. Ligaments are very similar to tendons. The difference is that tendons attach muscles to bones. Both of these structures are made up of small fibers of a material called collagen. The collagen fibers are bundled together to form a rope-like structure. Ligaments and tendons come in many different sizes, and like rope, are made up of many smaller fibers. The thicker the ligament (or tendon) the stronger the ligament (or tendon) is.
The large is the most important tendon for walking, running, and jumping. It attaches the calf muscles to the heel bone to allow us to raise up on our toes. The posterior tibial tendon attaches one of the smaller muscles of the calf to the underside of the foot. This tendon helps support the arch and allows us to turn the foot inward. The toes have tendons attached that bend the toes down (on the bottom of the toes) and straighten the toes (on the top of the toes). The anterior tibial tendon allows us to raise the foot. Two tendons run behind the outer bump of the ankle (called the lateral malleolus) and help turn the foot outward.
Many small ligaments hold the bones of the foot together. Most of these ligaments form part of the joint capsule around each of the joints of the foot. A joint capsule is a watertight sac that forms around all joints. It is made up of the ligaments around the joint and the soft tissues between the ligaments that fill in the gaps and form the sac.
There are 107 Ligaments holding your bones in place in a foot. Ligaments are like rubber bands, meaning that they can stretch and return. When you sprain your ankle it is the ligaments that have been stretched too far or have torn, thus causing pain and injury.
Most people refer to the longitudinal arch as “the arch” of the foot. It extends from the big toe to the heel.
Muscles in the feet help stabilize the toes, which effect the way we walk. Of the 20 muscles located in a foot, 19 of them can be found on the bottom. Weak or damaged muscles can cause many disorders.
Most of the motion of the foot is caused by the stronger muscles in the lower leg whose tendons connect in the foot. Contraction of the muscles in the leg is the main way that we move our feet to stand, walk, run, and jump.Joints of the feet
There are numerous small muscles in the foot. While these muscles are not nearly as important as the small muscles in the hand, they do affect the way that the toes work. Damage to some of these muscles can cause problems.
Most of the muscles of the foot are arranged in layers on the sole of the foot (the plantar surface). There they connect to and move the toes as well as provide padding underneath the sole of the foot.
The main nerve to the foot, the tibial nerve, enters the sole of the foot by running behind the inside bump on the ankle, the medial malleolus. This nerve supplies sensation to the toes and sole of the foot and controls the muscles of the sole of the foot. Several other nerves run into the foot on the outside of the foot and down the top of the foot. These nerves primarily provide sensation to different areas on the top and outside edge of the foot.
Anatomy of the Foot: Circulatory System
Blood flow and circulation play a big part in foot health and performing pedicures. Blood that will reach your foot starts at your heart and travels through the largest artery in your body: the aorta. This artery splits and travels down each thigh where it continues by branching out until it reaches the toes. Blood then begins its return trip as it travels through veins and capillaries to the heart.
The main blood supply to the foot, the posterior tibial artery, runs right beside the nerve of the same name. Other less important arteries enter the foot from other directions. One of these arteries is the dorsalis pedis that runs down the top of the foot. You can feel your pulse where this artery runs in the middle of the top of the foot.
As blood travel through veins and capillaries, the fluid portion of the blood travels into the surrounding tissue, which is known as the lymph system. As simple as this may sound, the lymph system is a complex system of vessels, ducts, and nodes that control the entire fluid portion of the body. When performing a massage you are moving the flow of fluid through the lymph system, promoting a feeling wellness.
The largest organ in our body, our skin is an incredible organism that serves and performs many functions. It can protect itself from damage caused by friction by developing a callus as protection. It insulates us from hot and cold weather and it can protect itself from the sun by producing pigment and vitamin D. Our skin can give the brain warnings with sensory receptors for touch, such as hot, cold, sharp, smooth.
The skin is made up of 3 basic parts: Epidermis, dermis and hypodermis. The epidermis covers most of our body and is about as thick as a sheet of paper. The dermis is the next layer and is the layer that the epidermis is attached too. This layer makes up 15-20% of our body weight and is primarily made of collagen (a type of keratin protein). The hypodermis is a continuation the dermis with less collagen than the dermis layer. This layer is where you will find larger blood vessels, nerve endings, and lymph tissue.
The net result of a pedicure should not only be to beautify the foot (skin and nails), but also physically improve the health of the foot: through proper procedure and educating the clients. Your own education of the basic anatomy and physiology of the foot will help you achieve both. With these two goals accomplished, you will see happy clients and a booming pedicure business!