What does "fusiform" refer to?

Fusiform refers to a shape that is tapered at both ends and resembles a spindle. This term is often used in anatomy and biology to describe certain types of structures, such as muscles or cells, that have this elongated, tapered form. For example, fusiform muscles, such as the biceps brachii, are designed for a greater range of motion.

In the context of the other options, while there are various types of cells that can be discussed, as well as diverse medical treatments and legal documents, none of these specifically define the fusiform shape. The clarity and specificity of the definition provided in the correct option emphasize its unique shape, distinguishing it from other concepts in various fields.