Tibial nerve Nerve roots: L4-S3 Sensory: Innervates the skin of the posterolateral leg, lateral foot and the sole of the foot. Motor: Innervates the posterior compartment of the leg and the majority of the intrinsic foot muscles. Clinical Relevance Injury to the tibial nerve can cause motor loss and altered sensation and pain to any of the areas it supplies, depending on site of involvement. Popliteal Fossa region. Injury may occur due to: Space occupying lesion Laceration injury Posterior dislocation of knee. Fractures of the tibia and fibula Local trauma to the posterior lower leg. Medial malleolus level: Compression of the tibial nerve in the osseofibrous tunnel below the flexor retinaculum of the ankle causes tarsal tunnel syndrome. On examination it presents as pain and paresthesia in the sole of the foot. Tarsal Tunnel Syndrome Tarsal tunnel syndrome (TTS) is a compressive neuropathy of the posterior tibial nerve. The tunnel lies posterior to the medial malleolus of the ankle, beneath the flexor retinaculum. Symptoms include pain radiating into the foot, usually, this pain is worsened by walking (or weight-bearing activities). Etiology Tarsal tunnel syndrome is divided into intrinsic and extrinsic etiologies. Extrinsic causes include poorly fitting shoes, trauma, anatomic-biomechanical abnormalities (tarsal coalition, valgus or varus hindfoot), post-surgical scarring, systemic diseases, generalized lower extremity edema, diabetes, and post-surgical scarring. Intrinsic causes include tendinopathy, tenosynovitis,osteophytes, hypertrophic retinaculum, and space-occupying or mass effect lesions (enlarged or varicose veins, ganglion cyst, lipoma, neoplasm, and neuroma). Pathophysiology Up to 43% of patients have a history of trauma including events such as ankle sprains. Abnormal biomechanics can contribute to disease progression. Risk factors include systemic diseases such as diabetes mellitus, hypothyroidism, gout, mucopolysaccharidosis, and hyperlipidemia History and Physical There is no specific test for the diagnosis of tarsal tunnel syndrome, and diagnosis is made with a detailed history and clinical examination. Sharp shooting pain in the foot, numbness on the plantar surface, radiation of pain and paresthesias along the distribution of the posterior tibial nerve, pain with extremes of dorsiflexion and eversion, and a tingling or burning sensation. The symptoms may worsen at night, with walking or standing, or after physical activity, and typically get better with rest. On exam, the provider may observe pes planus, pronated foot, or talipes equinovarus. In chronic cases, atrophy, weakness of the intrinsic foot muscles, and contractures of the toes may be appreciated. They are typically tender on deep palpation of the tarsal tunnel. The gait should be analyzed for abnormalities including excessive pronation or supination, toe eversion, excessive foot inversion or eversion, and antalgic gait. Light touch and two-point discrimination