Numbness on the outside of the palm may be related to physiological factors, or it may be caused by cervical spondylosis, diabetes-induced peripheral neuropathy, elbow-tube syndrome and other reasons. 1. Physiological factors: in the work and life, the outer side of the palm suffered a long time pressure, local blood flow is blocked, it will cause numbness on the outer side of the palm. Accidental trauma to the outer side of the palm, resulting in local nerve damage, may cause numbness of the outer side of the palm, may also be accompanied by swelling, bruising and other symptoms. 2. Cervical spondylosis: usually due to cervical spondylotic hyperplasia or cervical disc herniation and other factors, resulting in localized nerve root compression, may cause numbness on the lateral side of the palm, and may be accompanied by numbness of the upper limbs, weakness and other symptoms. 3. Peripheral neuropathy caused by diabetes mellitus: because the patient’s peripheral nerves are damaged, resulting in poor blood flow to the peripheral nerves, resulting in the peripheral nerves do not get enough energy supply, which may cause numbness on the outside of the palm, and may also be accompanied by pain, weakness and other manifestations. 4. Elbow tube syndrome: may be related to trauma, local lesions and other factors, can lead to damage to the nerves innervating the palm of the hand, will cause numbness of the lateral palm, may also be accompanied by tingling, burning sensation and other symptoms. Lateral numbness of the palm may also be related to other factors, if the symptoms persist, it is recommended to consult a doctor as soon as possible to find the cause of the disease and standardize the treatment.