The leg refers to the lower limb which includes the thigh, lower leg and foot with the knee and ankle joints being the major joints of the lower limb. Pain can affect the entire lower limb (leg) or be isolated to just one part of the leg, such as the lower leg. It is important to make this differentiation because there are different structures in each part of the leg. Therfore pain in one part of the leg may not necessarily be due to the same reasons as pain in another part.
Parts of the Lower Leg
Pain is usually due to tissue damage. It is important to understand the different tissues, organs and structures that make up the lower leg in order to identify the cause of the pain. Around the leg lies the skin with fat and connective tissue underneath it. Sheets and bands of connective tissue forms fascia and ligaments respectively. Underneath the skin and between this connective tissue lies bone, muscles, nerves and blood vessels.
There are two main bones of the lower leg – the tibia and the fibula. It makes contact with the bones that form the thigh and knee joint at the top and the bones that form the ankle joint and foot at the bottom. Although the tibia and fibula are relatively thin bones, both are extemely strong.
Wrapped around these bones are many different muscles which are separated into compartments. At the back of the leg lies the larger of these leg muscles, known as the gastrocnemius and soleus muscles. It is the reason the back of the leg, which is referred to the calf, is fleshy. The front part is known as the shin and in contrast to the calf, it tends to be bony. The muscles attach to the bones by means of tendons.
Blood is carried to the lower leg by the popliteal artery which divides into the anterior and posterior tibial arteries. It carries nutrients and oxygen to the tissues of the lower leg. Blood is carried away from the lower leg by veins to the torso. These veins can be divided into the superficial and deep veins of the lower leg.
The nerves of the lower legs arise from the lower back, specifically the lumbar and sacral regions of the vertebral column. Themain nerves of the lower leg arise from the sciatic nerve which in turn arises from the lower back. This sciatic nerve divides into the common peroneal (fibular) and the tibial nerves.
Causes of Pain in the Lower Leg
Pain is a symptom of some underlying condition. It may arise with may different forms of tissue damage, disease and disorders. Some of the more common causes of lower leg pain are discussed below. The pain may be accompanied y other signs and symptoms like swelling, redness, rashes or wounds.
Any part of the lower leg may undergo strain but it is the muscles and tendons that are most likely to be affected. The muscles and tendons of the leg often experience strain with prolonged standing, walking or running. The strain may also lead to cramping of the muscles, particularly the calf muscles.
Muscle strain and inflammation can also be felt at the front of the lower leg (shin). This is commonly referred to as shin splints and contrary to popular belief it is not due to tiny fractures of the shinbone. Tendonitis is where the tendons of the muscles becomes inflamed usuallyd due to overuse and strain of the lower leg muscles.
Read more on shin pain.
Injury to the lower leg can occur for a host of different conditions. It may be mechanical, chemical or electromagnetic in nature. Mechanical injury may include a blow, fall, insect bite, scratching or even wearing tight clothing among other causes. Chemical injury may arise with exposure to harsh chemicals like chlorine or depilatory creams for hair removal. Electromagnetic injury is usually leads to conditions like sunburn. Severe injuries can cause fractured bones or open wounds.
Bone fractures of either the tibia or fibula tend to occur with major force. The bigger of the lower leg bones, the tiba (shinbone), is the most commonly fractured long bone in the bone. The fracture bone can break through the skin (open or compound fracture) or it may not penetrate the skin (closed or simple fracture). It may arise with a motor vehicle accident, fall, assault or contact sports among a host of other events.
Infections of the leg can occur for various reasons and affect the lower leg at different levels. Impetigo is a superficial skin infection. Cellulitis is a deeper infection which is more common in the lower leg. It is a very serious type of bacterial infection. Patients with open sores (ulcers) due to conditions like diabetes or vein problems are also prone to infections. Sometimes the veins can become inflamed due to a blockage with a clot (thrombophlebitis) and then infected.
Problems with blood circulation in the lower leg may also cause pain. Peripheral artery disease is where the artery supplying blood to the lower leg is narrowed or even blocked. This restricts blood flow to the lower leg. It may not always cause pain on a constant basis but only during physical activity when more blood is required by the leg muscles. This pain is known as intermittent claudication.
Pain in the lower leg may also arise with vein problems. In deep vein thrombosis (DVT) the sluggish circulation in the deep leg veins gives rise to a blood clot. It can be a very serious problem if the clot breaks away and lodges in the lung artery and may even lead to death. The superficial veins may become swollen and tortuous (varicose veins) and the impaired blood flow through it can also lead to pain.
Read more on deep vein thrombosis.
Another common cause of lower leg pain is nerve compression. This often arises at the nerve roots – where the nerve exits the spinal cord. Sciatica is one example of a pinched nerve and probably among the most common to cause lower leg pain. This occurs with bony outgrowths from the vertebrae, narrowing of the hole where the nerves exit the spinal cord, a herniated disc, arthritis of the spine or other conditions.
Diabetes has become a common condition in developed countries, often associated with obesity. The raised blood glucose levels can cause widespread damage to different organs and structures in the body. It can damage nerves and this is known as diabetic neuropathy. The nerves of the lower leg are often affected. It causes symptoms like pain, tingling and burning which eventually progresses to numbness.