Transrectal ultrasound is usually painless and uncomfortable. Rectal ultrasound is also called endoluminal ultrasound. The probe of endoluminal ultrasound is relatively thin, with a diameter of about 2cm, the surface of the probe is very smooth, and the end of the probe is rounded and blunt. The examination is performed with a sterilized latex condom, usually a condom, which has a lubricant on the surface that allows smooth access to the rectum. Transrectal ultrasound examination, mainly for more obese patients, trans-abdominal ultrasound exploration image display is not ideal or for urinary incontinence of male patients, can not hold urine, the bladder can not be filled, the pelvic organs show unclear, especially to check the prostate and seminal vesicle adenopathy of male patients, can be examined through the rectal ultrasound, transrectal ultrasound can also clearly show the anorectal canal rectal lesions, such as perianal abscesses, anal fistulas, and rectal cancer. Transrectal ultrasound can also be used as an alternative for female patients who cannot undergo transvaginal examination. Rectal ultrasound is not recommended for patients with purulent anal infections and those with hemorrhoids that bleed heavily.