[Choosing an intramuscular injection needle according to body type].

The sample of this study consisted of 360 patients with asthenic, sthenic or ortho-sthenic type. The thickness of hypodermic fat at dorsogluteal site was measured and the effect was compared. The result suggested that needle should be selected according to different habitus before intramuscular injection. The commonly used No. 6. 5 and No. 7 needle are not suitable for elderly females patients with ortho-sthenic type or male and female patients with sthenic type. For these kind of patients, a needle with a length of 35 mm, 40 mm or 45 mm should be used respectively in order to reach muscular tissues, have good effect, and reduce local pain and tissue hardening.