Found both in the hands and feet. There are three in the upper part oi the hand, and as many on the inferior. Their name describes their origin, and they are blended with the lum bricales, performing the same office, of moving the fingers sideways. The first of the interossei intend is called by Albinus posterior indicis; the second and third are the prior annuluris, and interosseus auricu/aris. These three muscles draw the fingers, into which they are inserted, towards the thumb. There are four interossei externi, for a small muscle, which supports the fore finger, the semi interosseus indicis of Winslow, the prior indicis of Albinis, is included. This muscle then may be styled the first; the second is the prior; and the third the posterior medii. The fourth is the posterior annularis. It is useless to be more minute in these unimportant muscles. They may be cut through with little danger, and will unite with as little trouble.

In the feet several small muscles fill up the four interstices between the metatarsal bones, after the same manner as in the hand. Like the interossei of the hand, there are three internal and four external. Their use is also similar.