The inability to urinate, where the bladder is filled with urine and cannot be expelled properly, is also called urinary retention. The main manifestation is bulging of the bladder area in the lower abdomen with obvious pressure pain, and the patient shows painful irritability. According to their medical history and characteristics, they are divided into two categories: acute urinary retention and chronic urinary retention. The main causes of its appearance are mechanical urethral obstruction, such as urethral inflammation, stricture, fracture, stone, foreign body and other causes blocking the urethra and causing it; in addition, obstructive lesions of the bladder neck such as bladder neck contracture, fibrosis, tumor, acute prostatitis or abscess, prostate hyperplasia, prostate tumor, etc. can also cause urinary retention; secondly, power obstruction due to voiding power disorder can also cause urinary retention, commonly The causes are central and peripheral nervous system lesions, such as spinal cord or cauda equina injuries, tumors, pelvic surgery that damages the nerves innervating the bladder, and diabetes mellitus, causing neurogenic bladder dysfunction. There are also certain medications such as atropine, probenecid, scopolamine and other drugs that relax smooth muscle that can occasionally cause urinary retention. The presence of urinary retention requires emergency catheterization and cystostomy to drain the urine. In summary, the main causes of inability to urinate are classified as mechanical obstruction of the lower urinary tract, dynamic obstruction, and the application of certain drugs that relax the smooth muscle of the bladder.