Fat Bottoms Found to Hinder Shots

Standard-sized needles failed to reach the buttock muscle in 23 out of 25 women whose rears were examined after what was supposed to be an intramuscular injection of a drug.

Two-thirds of the 50 patients in the study did not receive the full dosage of the drug, which instead lodged in the fat tissue of their buttocks, researchers from The Adelaide and Meath Hospital in Dublin, Ireland, said in a presentation to the annual meeting of the Radiological Society of North America.

Besides patients receiving less than the correct drug dosage, medications that remain lodged in fat can cause infection or irritation, researcher Victoria Chan said.

"There is no question that obesity is the underlying cause. We have identified a new problem related, in part, to the increasing amount of fat in patients' buttocks," Chan said.

"The amount of fat tissue overlying the muscles exceeds the length of the needles commonly used for these injections," she said.

The buttocks are a good place for intramuscular injections because there are relatively few major blood vessels and nerves.