Common Foot Conditions

Introduction:

The foot is the part of the lower limb in the body used for locomotion. The foot is the structure extending beyond the ankle joint, and it is the weight-bearing portion of the leg. The area of the foot facing upward while standing is called the dorsum. The front portion of the dorsum has five digits called the toes with toenails, and the back dorsum is known as the instep.

The area of the foot facing downward while standing is called the planum. The front portion of the planum also has the backend of the toes; next to it is the padded portion called the ball of the foot. The other end of the planum has a broad flat surface just below the ankle region called the heel. In between the ball and the heel, there exists a concave curvature called the arch of the foot.

What Is the Anatomy of the Foot?

The foot is a complex structure that contains 26 bones, 33 joints, and more than hundreds of muscles, ligaments, and tendons.

Bones and Joints of the Foot: The foot has three divisions, namely the forefoot, the midfoot, and the hindfoot. Each division can be described separately:

1. The Forefoot: The forefoot has five toes, which correspond to the bones called phalanges. Each phalange has three sections, the distal (towards the nail), the middle (between the distal and the proximal), and the proximal (that joins with the body of the foot). There are about 15 phalanges, three in each toe except the big toe, which has only two phalanges. The phalanges join with five proximal long bones called the metatarsals. The articulation between the phalanges forms the interphalangeal joints, and those between the phalanges and metatarsal are the metatarsophalangeal joints.

2. The Midfoot: The midfoot is composed of five irregular bones that are named cuboid, navicular, medial cuneiform, intermediate cuneiform, and lateral cuneiform. These bones form the arch of the foot and act as a shock absorber.

3. The Hindfoot: The hindfoot contains two large bones of the foot called the talus (the ankle bone) and the calcaneus (the heel bone). The top of the talus articulates with the tibia and the fibula (two long bones of the lower leg) to form the talocrural joint (the ankle joint). The talus articulates with the calcaneus to form the subtalar joint.

The bones of the midfoot and the hindfoot are together known as the tarsals. The articulation of the tarsal and metatarsal forms the tarsometatarsal joints. Overall there are seven tarsals, five metatarsals, and 14 phalanges, constituting 26 bones of the foot.

Muscles of the Foot:

The muscles of the foot are classified as extrinsic and intrinsic muscle groups. The extrinsic muscles originate from the bones of the lower leg and get attached to the foot bone. On the other hand, the intrinsic muscles originate from one aspect of the foot and attach to the other aspect of the same foot.

Ligaments and Tendons:

Ligaments and tendons are the bands of connective tissues essential for body mechanics. The ligaments attach one bone to the other bone while the tendons attach a muscle to the bone. As there are a lot of bones and muscles in the foot, there also exist numerous ligaments and tendons. The ligaments of the foot form a thick web and bound the bones together to keep them strong and stable.

One of the most important tendons associated with the foot is the Achilles tendon, which is also called the heel cord or calcaneal tendon. This is the thickest tendon in the body present at the back of the lower leg that attaches the calf muscles to the heel bone.

What Is the Physiology of the Foot?

The action of extrinsic muscles brings out the movements of the feet like dorsiflexion or plantarflexion (bending the foot upward or downward), eversion or inversion (turning the feet sideways), abduction or adduction (moving the feet towards or away from the midline). The movements of the toes are controlled by the intrinsic muscles. All these movements are controlled by the joints, ligaments, and tendons of the foot.

What Are the Conditions Associated With the Foot?

1. Hallux Rigidus: This condition is characterized by a painful bony prominence on the top of the big toe caused by arthritic degeneration of the first metatarsophalangeal joint. The foot seems to be deformed, and the joint has a limited range of mobility.

2. Hallux Valgus: Commonly called a bunion, that is characterized by deviation of the big toe towards the lesser toes. This results in the development of a bony prominence on the inner aspect of the foot at the base of the big toe.

3. Claw Toe: The middle and the distal interphalangeal joints bend downward in a claw-like fashion resulting in severe pressure and pain. Claw toes can occur in any toe except the big toe.

4. Hammertoe: The middle interphalangeal joint is bent, causing curling of the toe. Commonly found in the second toe. The base of the toe points upward, and the end of the toe points down.

5. Mallet Toe: The distal interphalangeal joint is only bent, giving a mallet-like appearance at the end of the toe.

6. Turf Toe: The turf toe is caused by excessive upward bending of the metatarsophalangeal joint, often from repetitive motions such as running and jumping.

7. Jones Fracture: The injury was first described by Sir Robert Jones, resulting in the fracture of the first metatarsal bone at the proximal end. The patients will have severe pain, swelling, and walking difficulties.

8. Plantar Fasciitis: Plantar fasciitis is the inflammation of the band of tissues that support the arch of the foot along the bottom.

9. Heel Spurs: The abnormal bony growth on the calcaneus (heel bone) is often related to chronic plantar fasciitis. Also called the calcaneus spur.

10. Lateral Ankle Sprain: It is one of the common injuries of the ankle joint that affects the lateral ankle ligament. 90% of ankle sprains are inversion injuries (sudden stretching of the connective tissues when the ankle is rolled inward).

11. Eversion Ankle Sprain: Eversion injuries are less common where the foot is forcefully rolled outward.

12. Calcaneal Bursitis: This condition is most common in young individuals and is characterized by the inflammation of the bursa between the Achilles tendon and the calcaneus (heel bone).

13. Achilles Tendonitis: Inflammation of the Achilles tendon with a gradual onset and worsened over time. It is a common injury seen in runners. The term is also spelled as Achilles tendinitis.

14. Achilles Tendon Rupture: This is a degenerative condition caused by repetitive microtrauma resulting in Achilles tendon rupture. The theory behind it is the violent muscle contraction that exceeds the limit of the tendon.

15. Athlete’s Feet: Athelete's foot is medically termed tinea pedis, referring to a fungal infection on the sole, skin, and between the toes resulting in open cuts and peeling of the skin.

16. Corns and Calluses: These are the most common foot lesions characterized by thickening of the skin due to pressure and friction. Corns are smaller and involve focal areas, while the calluses are larger and diffuse.

17. Diabetic Feet: The foot of the diabetic patient has a potential risk of acquiring infections, ulcerations, and deep-tissue destruction that result from long-term diabetic complications. Proper foot care in diabetes patients is necessary.

18. Flat Feet: Also known as the pes planus, where the curvature in the arch of the foot is lost, and the sole entirely comes in contact with the floor while weight-bearing.

19. Morgan’s Neuroma: It is a neuralgic pain caused by the pinching of the plantar nerve (the nerve that innervates the sole of the foot), resulting in the growth of nerve tissue between the third and fourth toes.

Conclusion:

The foot forms the base of the leg and is one of the important structures that help in locomotion. The science of anatomy and physiology of the foot gives a better understanding of the diseases associated with the foot and is useful in formulating the treatment plan. Most foot diseases can be prevented. Patients with diabetes and vascular disease should be educated about foot care and must be well aware of the foot problems.