Anterolateral femoral numbness and ankylosing sensation is a manifestation of lateral femoral dermatomal neuritis. Lateral femoral cutaneous neuritis, also known as abnormal sensory femoral pain, Bernhardt’s disease, and Roth’s disease, is a disease of abnormal sensation in the lateral femoral skin. The lateral femoral cutaneous nerve extends from the outer edge of the psoas major muscle and enters the subcutaneous tissue 3 to 5 cm below the inguinal ligament. Lateral femoral dermatomal neuritis is a relatively common peripheral neurological disorder. The clinical manifestations are ankylosis, numbness or pain in the lateral skin of one or both thighs, which can be aggravated by standing or walking for a long time, and localized hyperalgesia or hypersensitivity of the skin, but no muscle atrophy or motor impairment. Any injury to any segment of the lateral femoral cutaneous nerve can cause this disease, such as spinal proliferative osteoarthropathy, ankylosing spondylitis, and lumbar intervertebral disc lesions can compress and stimulate the nerve to cause this disease. In addition, systemic diseases such as gout, diabetes, obesity, rheumatic fever, syphilis, ethanol poisoning and even influenza can cause inflammation of the lateral femoral cutaneous nerve and lead to the development of this disease. Some neurological pathologies such as multiple sclerosis, radiculitis, inflammation of the abdominal pelvis, tumors, and stones can also lead to the development of this disease. This shows that the causes of lateral femoral dermatomal neuritis are complex, and the primary cause should be carefully searched for during diagnosis and treatment. Diagnosis of anterolateral femoral numbness and ankylosis: Most often seen in obese men aged 20 to 50 years. The symptoms are numbness, ankylosis, tingling, burning sensation, chill, reduced sweating and heaviness of the anterior lateral femur, etc., with numbness being the most common. The symptoms may increase with physical exertion and prolonged standing, and may be relieved after rest. On physical examination, there may be varying degrees of superficial sensory loss or absence, mainly pain and temperature sensation is reduced while pressure sensation exists. The disease is often unilateral, chronic in course, sometimes mild and sometimes severe, and often does not heal for months to years. The disease can be considered. Patients feel a pins-and-needles pain in the skin of the anterolateral thigh, accompanied by abnormal sensations, such as ankylosis, burning, coldness, and numbness. The pain is intermittent at the onset and gradually becomes continuous, sometimes very severe.