The inner flesh of the upper arm has stripes when touched, which is mostly considered to be caused by lymphangitis and phlebitis. 1. Lymphangitis: clinically, lymphangitis is divided into acute lymphangitis and chronic lymphangitis, if it is chronic lymphangitis will be manifested in the skin, subcutaneous tissue or fascia, which may present permanent hypertrophic fibrotic changes or appear as long, thin, cord-like lumps. 2. Phlebitis: when phlebitis reaches grade 3 or 4, it will show that there are cords of material inside the flesh of the inner side of the upper arm. grade 3 patients will show redness and swelling of the venous blood vessels, and there will be cords of sclerosis in the region of the blood vessel; grade 4 patients’ cords of sclerosis can be proliferated to 2-3 cm, and there will be obvious redness and swelling, infection, oozing and other symptoms in the local area. In addition to the above 2 reasons, it is not excluded that cervical spondylosis, frozen shoulder and other diseases are caused by the feeling of the inner flesh of the upper arm. This symptom, should go to the local hospital in time, clear cause, early treatment.