Myotomes are associated with which of the following?

Myotomes are regions of muscle that are innervated by specific spinal nerves. Each myotome corresponds to a particular segment of the spinal cord and is associated with the motor supply to the skeletal muscles. Therefore, when spinal nerves exit the vertebral column, they branch out to control the muscles of the body, and this is why the correct association for myotomes is with muscles.

In the context of the other options, while skin is related to dermatomes, which are sensory regions innervated by specific spinal nerves, they do not pertain to myotomal function. Vertebrae are the bony structures that protect the spinal cord and provide support but do not directly associate with muscle innervation. Tendons, on the other hand, are the fibrous connective tissues that attach muscles to bones; while they play a crucial role in muscle function, they do not represent the anatomical segments that are defined by myotomes. Thus, the association of myotomes is specifically with muscles, confirming that option B is accurate.