15. Subclavius muscle
This small muscle, stretching under the shoulder from the first rib to the collarbone, would be useful if humans were still walking on all fours. Some people have one, some have none, a few have two.
This small muscle, stretching under the shoulder from the first rib to the collarbone, would be useful if humans were still walking on all fours. Some people have one, some have none, a few have two.