When the tibial nerve or its various branch nerves become compressed within the tarsal tunnel—a space located behind the bony protrusion on the inside of the ankle—it can cause pain and numbness in the foot, which may travel all the way to the big toe and the first three toes. This is known as tarsal tunnel syndrome or posterior tibial neuralgia. Within the tarsal tunnel, the tibial nerve branches into three sections; one travels to the heel, while the other two go to the bottom of the foot. If the compression is severe, the entire foot can be affected, producing pain, burning, and tingling throughout the foot and ankle region. Other symptoms include inflammation, swelling, fluid retention, feelings of electric shock, feelings of heat and coolness, and a cramping sensation. Tarsal tunnel syndrome may be caused by any obstruction within the tarsal tunnel that puts pressure on the local nerves, including tumors, cysts, bone spurs, tendon sheath inflammation, ankle swelling, varicose veins, or nerve ganglions. This condition also has been observed in people with low back issues. Treatment of tarsal tunnel syndrome may include rest, manual therapy or manipulation, strengthening exercises prescribed by a physical therapist, immobilization by a boot, corticosteroid injections, heat therapy, compression, and orthotics. In extreme cases, surgery may be required.