Why is my left leg numb?

When your left leg is numb, you need to pay attention to a full body check-up, especially now that the incidence of cardiovascular and cerebrovascular diseases is high, and this disease often causes patients to experience leg numbness. Diabetes and cervical spondylosis may also be the cause.

1) Cardiovascular and cerebrovascular diseases

Hypertensive patients may experience numbness in the hands and feet due to vasoconstriction, spasm of small arteries throughout the body, narrowing of the arterial lumen, and blood circulation disorders in the limbs. Elderly people suffering from cerebral arteriosclerosis suffer from ischemia of brain tissue, especially the cerebral cortex, and functional disorders of the sensory and motor centers of the brain, resulting in numbness of the limbs in the corresponding parts. This type of numbness is often characterized by numbness of one upper limb or lower limb or half of the body. If elderly people with hypertension find that one side of the thumb feels numb, it is often a precursor to a stroke.

2) Diabetes

Under normal circumstances, the energy required by brain nerve tissue mainly comes from sugar metabolism. Because diabetic patients have impaired sugar metabolism, the nervous tissue suffers from nutritional disorders due to insufficient energy supply. Diabetic patients excrete more vitamin B1. Vitamin B1 deficiency causes the accumulation of pyruvate and lactic acid in the nervous tissue, which also hinders the formation of acetylcholine and causes degeneration of the myelin sheath of peripheral nerves. Therefore, diabetic patients are prone to multiple peripheral neuritis, with symmetrical paresthesias of the extremities, numbness and tingling of the skin of the hands and feet, and an electric shock-like sensation. In the later stages, they may develop glove-type or sock-type sensory loss.

3) Cervical spondylosis

Due to stimulation from factors such as cervical vertebrae degeneration, hyperplasia or dislocation, or due to bone spurs at the posterior edge of the vertebral body and the uncinate joint invading the intervertebral foramen, the cervical nerve roots are compressed, causing immobility and numbness of the fingers in the corresponding nerve-controlled areas, accompanied by symptoms such as pain in the shoulder, neck and upper limbs.

4) Lumbar disc herniation

Injuries to the waist such as twisting, spraining, impact, excessive force when lifting heavy objects, overwork, etc. may cause rupture of the intervertebral disc annulus, and the nucleus pulposus tissue may protrude from the ruptured tissue, stimulating or compressing the spinal cord and nerve roots, causing numbness of the lower limbs, accompanied by symptoms such as pain in the back of the thigh.

5) Lower limb arterial occlusive disease

Due to the loss of elasticity and hardening of the arterial walls of the lower limbs, as well as the narrowing and blockage of the lumen, the lower limbs suffer from insufficient blood supply. Generally, the affected limb will feel numbness and pain within 100 meters of walking, and one must stop and rest for a while before continuing to walk. This symptom is called "intermittent claudication."

6) Thromboangiitis obliterans

The lesion is mainly a chronic inflammation of the small and medium-sized arteries and superficial veins in the limbs, which gradually develops into blood clots, causing poor blood flow to the affected limbs, numbness and coldness of the feet, numbness and pain in the calves when walking, and even lameness.