The meaning of the upper and lower limbs.

In humans, the upper limbs (arms) are needed to perform various types of work. The lower limbs are needed for movement. Most primates use the upper limbs as an aid to locomotion, but they also use them for various tasks. Many animals are unable to use the upper limbs to grab objects, and they are only needed for movement. Some rodents are capable of using their forelimbs as hands, while most reptiles and amphibians cannot.