Final answer:
The posterior (dorsal) cavity is the body cavity at the back of the body containing the cranial and spinal cavities, which are continuous with each other and protect the brain and spinal cord.
Step-by-step explanation:
The body cavity located near the back of the body and is a continuous internal opening that includes both the cranial and spinal cavities is known as the posterior (dorsal) cavity. The posterior (dorsal) cavity is at the posterior, or back, of the body, encompassing the head and the trunk's back. It is further subdivided into the cranial cavity, housing the brain, and the spinal cavity (or vertebral cavity), enclosing the spinal cord.
These two subdivisions, the cranial and spinal cavities, form a continuous space, reflecting the continuous nature of the brain and spinal cord within. This protective cavity is vital for safeguarding the central nervous system, enabled by the bones of the skull and vertebral column along with cerebrospinal fluid, which provides cushioning for the brain and spinal cord.