The pulling force of which muscle tendon is responsible for the dislocation of the bone fragment in an avulsion fracture of the base of the fifth metatarsal bone?

The muscle tendon responsible for the dislocation of the bone fragment in an avulsion fracture of the base of the fifth metatarsal bone is the peroneus brevis tendon.

Here's the step-by-step explanation:

1. An avulsion fracture occurs when a small chunk of bone attached to a tendon or ligament gets pulled away from the main part of the bone.

2. The fifth metatarsal bone is the long bone on the outside of the foot that connects to the little toe.

3. The peroneus brevis muscle runs down the outside of the lower leg and its tendon attaches to the base of the fifth metatarsal.

4. When the peroneus brevis muscle contracts forcefully, it can pull on the tendon attached to the base of the fifth metatarsal.

5. If the force is too strong, it can cause an avulsion fracture, pulling a piece of the bone away with the tendon.