The lower limb extends from the hip joint to the toe and can be divided into the :
- Thigh – between the hip and knee.
- Leg – between the knee and ankle.
- Foot – beyond (distal) the ankle.
Often the entire lower limb is referred to as the leg.
The lower limb’s main function is to propel the body when moving and stabilize the upper body when standing . Since it has to bear the weight of the entire upper body, the muscles, bones and joints are designed for maximum force and impact. While most of us may experience leg or foot pain at some point in our life, we often do not take it seriously unless it hampers our daily functioning, reaches a point where the pain is unbearable or persistent or there are other signs and symptoms, like leg swelling.
Causes of Leg, Foot Pain
The causes below are common conditions that may contribute to leg and foot pain. However some causes may be specific to certain age groups, like leg pain in children.
Traumatic Foot and Leg pain
Lower limb pain may occur due to various causes, of which trauma or injury to the leg is a common occurrence. Damage to bones, muscles, tendons, or joints due to overuse or strenuous activity or sustained during a fall or car accident injuries are the most common causes of traumatic leg or foot pain.
- Injury of the skin or soft tissue as a result of an accident or other types of trauma. This can lead to an infection like cellulitis, with the typical symptoms of inflammation (pain, redness and swelling), coupled with a fever and swollen lymph nodes.
- Fracture of any bone in the leg may occur as a result of motor vehicle accidents, falls (especially from a height), or due to osteoporosis, such as fracture of the neck of femur (refer to diagram) often seen in the elderly even after a minor fall.
- Stress fractures may occur in the lower leg as a result of overuse or cumulative trauma to the muscles and bones over a period of time. The fatigued muscles transfer the stress to the neighboring bone, resulting in a crack fracture. In sports such as running, gymnastics, and kickboxing, the repetitive stress of the foot striking a hard surface increases the risk of developing a stress fracture of the foot, especially if proper shoes are not worn and there is inadequate rest between workouts.
- March fracture is another type of stress fracture which occurs in the metatarsal bones of the foot, often due to s sudden increase in activity, such as in soldiers marching for long periods. This type of fracture can cause pain with activity, or pain and swelling even at rest, and without proper and timely rest, it may develop into a more severe fracture.
- Sprains are the result of a ligament stretching, or even tearing, and may result from a sudden abnormal movement, like twisting at a joint. Swelling, pain and redness may be evident, with severe pain when moving or placing pressure on the affected area.
- A stretched or torn muscle, often referred to as muscle strain, is another common leg injury, since the leg is a muscular part of the body. The leg muscles are among the most hard working muscles of the body as they have to bear the entire body weight when walking or running, as well as stabilizing the body when standing. Injuries to a tendon, the connective tissue band that connects muscle to bone, is also common – for example Achille’s tendon pain.
- Other cases of traumatic leg or foot pain may be overt, especially in cases of a gunshot, knife stabbing or an impaled object. While this will cause leg or foot pain and requires immediate medical attention, it may cause long term pain, even after the cause has been attended to.
Non-traumatic foot pain
Leg or foot pain without any history of trauma may occur due to one or more of the following causes.
- Peripheral artery disease is a decrease in blood supply to the leg due to narrowing of the arteries in the leg. This type of pain is known as claudication. It gets worse with exercise or walking and improves with rest and is therefore referred to as intermittent claudication. In severe cases there may be pain even at rest. Pain may be present in one leg or if a number of arteries are involved, there may be bilateral pain (in both right and left leg).
- Blood clots may cause acute leg pain if one of the arteries responsible for blood supply to the leg is blocked by a clot. In heart problems such as atrial fibrillation, blood clots may travel from the heart and obstruct blood vessels in the leg. There are two systems of veins in the legs – deep and superficial. A blood clot in the deep vein is known as deep vein thrombosis (DVT) and causes pain and swelling in the affected area of the leg. People who are immobilized for a long time, such as after surgery or during air travel, or women on contraceptive pills or hormone replacement therapy may be more at risk for developing DVT. The main complication of DVT is a pulmonary embolism, which may be life-threatening. A clot in the superficial veins also gives rise to leg pain but the complications are not as severe or life threatening as in DVT. The superficial veins may dilate gradually, resulting in varicose veins, which may also cause pain in the leg.
- Raynaud’s phenomenon occurs due to extreme constriction of the blood vessels in the skin due to cold environment and affects mainly the fingers and toes. Tingling, numbness, and pain may be felt in the toes, which is however reversible on application of warmth.
- Sciatica or sciatic nerve pain is a condition which arises as a result of compression and inflammation of the sciatic nerve due to a herniated intervertebral disc, arthritis, muscle spasm, injury, or other causes. It is typically felt as a shooting pain from the low back to the buttocks, behind the thighs, traveling down the back of the leg to the foot. The pain may be associated with leg numbness, tingling or a burning sensation. Sciatica is often aggravated by walking and bending at the waist, and relieved on lying down.
- Peripheral neuropathy may cause foot pain due to inflammation of the peripheral nerves. Tingling, numbness, weakness, or a burning sensation are the most common symptoms of peripheral neuropathy. Diabetes mellitus and post herpetic neuralgia (shingles) are some of the most common causes of peripheral neuropathy, but often no cause can be detected (idiopathic peripheral neuralgia). Other causes may include vitamin deficiencies, rheumatoid arthritis, cancer therapy drugs, the uterus pressing on the nerves when pregnant, or a pinched peripheral nerve. Pain, in most cases, is in one leg.
- Muscle pain or myalgia may occur due to overuse or aches and pain associated with viral fever. Muscle cramps are very common in the calf and foot muscles and may result in severe pain, often occurring at night (nocturnal leg cramps). Muscle cramps may occur due to overuse of the leg muscles, water-electrolyte imbalance (particularly sodium, potassium, or calcium) as seen in dehydration, or inadequate muscle stretching prior to strenuous exercise.
- Nerve compression or a pinched nerve within the leg may occur in a case of tarsal tunnel syndrome. This condition is caused by compression of the tibial nerve at the ankle as it passes under the flexor retinaculum of the foot. It may be caused by trauma due to a crush injury, stress injury, fracture, or ankle sprain. There may be a “pins and needles” sensation and sharp pain radiating out to the foot from the medial (inner) side of the ankle.
- Phantom pain in the leg is a peculiar phenomenon which occurs after amputation of a part of the lower limb. The exact cause of phantom pain is not known but it seems to originate in the brain and spinal cord. After removal of the foot or leg, pain is usually felt in the farthest (distal) point of the foot. It may be felt as a shooting, stabbing, throbbing, or any other type of pain which starts within a few days of amputation of the leg or foot, whether traumatic or surgical. The pain seems to come and go and is often aggravated by weather changes (due to changing air pressure), emotional stress, or physical pressure on the remaining stump.
- Paget’s disease of the bone is a chronic disorder of the skeleton where areas of the bone enlarge and soften. It can affect any bone but most commonly affects the pelvis, thigh (femur), shin (tibia), vertebrae and upper arm. The disease may be symptomless or it may cause a deep, aching type of bone pain, which is often severe at night.
- Malignancy, either metastasis (spread of cancer cells from other organs to the bone) or bone cancer can cause severe pain in the leg. Osteosarcoma or osteogenic sarcoma is the most common type of cancer that develops in the bone, usually around the end of long bones such as the femur, most often around the knee.
- Joint disorders like osteoarthritis, rheumatoid arthritis and gout may cause leg or foot pain, although the symptoms are usually isolated to the affected joint and surrounding area.
- Infections of the leg or foot, like septic arthritis, osteomyelitis or cellulitis will also cause pain. Apart from redness, swelling and pain, there is also a fever and lymphadenopathy.
Other Causes of Foot Pain
Apart from the causes above, certain factors may affect the foot specifically and result in foot pain. These include :
- Ingrown toe nail
- Corns and calluses
- Flat feet
- Hammer toe and mallet toe
- Morton’s neuroma
Some Causes of Heel Pain
The heel of the foot is prone to many conditions that may result in heel or sole pain, often due to excessive or repetitive pressure on the heel. Possible causes of heel pain include :
- Plantar fasciitis.The plantar fascia is the thick connective tissue on the sole of the foot which is attached to the heel. Inflammation of this fascia, called plantar fasciitis, gives rise to pain at the bottom of the heel, which may be worse on getting up from bed in the morning. Repetitive stress on the heel caused by long distance running on hard or uneven surfaces without correct footwear often gives rise to this condition.
- Heel bursitis is heel pain due to inflammation at the back of the heel. Possibly causes may be pressure from ill-fitting shoes or by landing awkwardly on the heel.
- Bone spurs – refer to Calcaneal Heel Spur.
- Achilles tendon inflammation or tear – refer to Achilles Tendon Pain.
Causes of Unilateral (One Side) Foot Pain – Right or Left
The dominant foot, the right foot in most people, is more likely to be involved in fractures, muscle strain, and sprain, especially those occurring due to overuse or as a result of strenuous physical activity. Another reason for pain occurring more often in the dominant foot is that weight distribution of the body tends to be more on that side.
The following are the most common causes of unilateral leg pain, but could also account for pain in both legs.
- Trauma or injury
- Muscle strain
- Deep vein thrombosis (DVT)
- Nerve compression
- Peripheral neuropathy
- Raynaud’s phenomenon
- Phantom pain
- Intermittent claudication