Final answer:
The enema tip should generally be inserted 7 to 10 cm (about 2.75 to 4 inches) into the rectum of an adult to ensure safe and effective administration.
Step-by-step explanation:
When administering an enema to an adult, the tip should be inserted into the rectum carefully and to the appropriate depth to ensure effective delivery while minimizing discomfort and risks of injury. An older 'rule of thumb' was 5 side-to-side and 7-8 deep, but newer work suggests up to 8 diameters side-to-side and 15 diameters deep for insertion. It's critical to consider that the rectum extends anterior to the sacrum and coccyx for about 20.3 cm (8 inches), and has a curved contour. To perform the procedure safely and effectively, the enema tip should generally be inserted 7 to 10 cm (about 2.75 to 4 inches) for most adults. It's always important to follow guidelines provided by healthcare professionals and use caution when performing such procedures at home.