Which structure supports the eyeball and contains extraocular muscles, fat, vessels, and nerves?

The periorbital cone is the correct answer because it is the anatomical structure that surrounds and supports the eyeball within the orbit. This fibroelastic structure not only provides support to the eyeball but also contains vital components such as extraocular muscles, which are responsible for eye movement. Additionally, it encompasses adipose tissue that cushions the eye, as well as the blood vessels and nerves that supply the eye and surrounding tissues.

The orbital ligament primarily serves to provide structural support but does not contain these key components associated with the eyeball. The retinal layer is found within the eye itself and is responsible for light detection, while the ciliary body is involved in accommodation and fluid production but does not provide the structural support necessary for the positioning of the eyeball within the orbit. Thus, the periorbital cone is the comprehensive structure that encompasses all the necessary elements to support the eyeball and facilitate its functions.