A fibula is one of the bones in the lower leg. When anatomists refer to bones, they use special location references to describe where a bone is. Proximal is one of these terms, and refers to the end of the bone that is closest to the center of the body. Proximal fibula refers to a specific point on a particular bone.
Two long bones are present in the lower leg of humans, running from the ankle up to the knee. These are the tibia and the fibula. On the inside of the leg is the tibia bone. This is a thick and strong bone that holds the weight of the leg and the body above the leg.
Farther out to the side of each leg is the fibula. This bone is thinner and more delicate than the tibia. It does not carry any weight, but instead acts as an attachment point for muscles. Both tibia and fibula are attached to each other.
Anatomists have a system of reference so that one anatomist can identify a point on a body to another anatomist, and be entirely understood. This system uses complex terms such as proximal fibula, or distal tibia. Anatomical language like this does not generally find uses in areas outside of science and medicine.
"Proximal," in the field of anatomy, refers to the end of a part of the body that is closest to the center of the body. The proximal fibula is the end of the fibula bone that is closest to the body's center. As the fibula runs roughly from the ankle to the knee, then the proximal fibula is the end nearest the knee. "Distal" on the other hand, means the end furthest away from the center, which in this case is the end of the bone nearest the ankle.
In Latin, "fibula" means brooch. The two lower leg bones together form a clip or brooch shape, which may be what the name was first meant to describe. The fibula actually attaches to the tibia, and not directly to the knee at the proximal end. It is also attached to the ankle at the distal end. Because of this, at the proximal fibula, ligaments hold the bone to the proximal end of the tibia. The fibula ends here rather than directly making up a part of the knee joint.