Arthropods are segmented invertebrates which have articulated exoskeletons. Let us start first with the exoskeleton. Insects do not have a backbone as we do but use a hard outer covering to support and protect their internal organs. The exoskeleton also acts as the attachment site for muscles, much as our bones do. The exoskeleton provides the characteristic appearance of insects.
Insects are bilaterally symmetrical.
They are horizontally oriented and progress in a forward direction. The upper surface is called dorsal and the lower ventral.