Membrane that surrounds the bone is known as

The correct answer is periosteum.

To understand why this is the correct answer, let's break down the anatomical terminology and examine the different types of membranes mentioned in the options:

1. Periosteum:
The prefix "peri-" means "around" or "surrounding", and the root word "-osteum" (from Greek osteon) refers to "bone". Therefore, the periosteum is the dense, fibrous membrane that covers and surrounds the outer surface of all bones, except at the joints where articular cartilage is present. It serves as a channel for the blood supply and nutrients to the bone tissue and provides an attachment site for tendons and ligaments.

2. Pericardium:
The prefix "peri-" means "around", and the root word "-cardium" refers to the "heart". The pericardium is the double-walled sac that surrounds and protects the heart, not bones.

3. Perichondrium:
The prefix "peri-" means "around", and the root word "-chondrium" refers to "cartilage". The perichondrium is the layer of dense connective tissue that surrounds cartilage, particularly elastic and hyaline cartilage.

4. Endosteum:
The prefix "endo-" means "within" or "inside", and "-osteum" refers to "bone". The endosteum is the thin vascular membrane that lines the inner surface of the bony tissue, forming the medullary cavity of long bones, rather than surrounding the outside of the bone.

Thus, the membrane that surrounds the bone is specifically known as the periosteum.