Muscles are attached to the bones by tendons, not ligaments. Tendons are tough, fibrous connective tissues that connect muscles to bones, allowing for movement and stability.

Tendons play a crucial role in the musculoskeletal system as they transmit the force generated by the muscles to the bones, enabling movement and providing support to the joints. They are composed of dense regular connective tissue and are strong and flexible.

Here is a detailed explanation of why tendons are responsible for attaching muscles to bones:

1. Structure and Composition of Tendons:
- Tendons are composed mainly of collagen fibers, which are arranged in parallel bundles.
- Collagen fibers provide strength and flexibility to the tendons, allowing them to withstand the forces exerted by muscles during movement.
- The collagen fibers are embedded in a gel-like substance called the extracellular matrix, which provides additional support and nourishment to the tendon cells.

2. Muscle Contraction and Tendon Function:
- When a muscle contracts, it generates force that is transmitted through the tendon to the bone.
- The force generated by the muscle pulls on the tendon, causing it to stretch and transmit the force to the bone.
- This pulling action of the tendon on the bone creates movement at the joint.
- Tendons also help in stabilizing the joints by holding the bones together and preventing excessive movement.

3. Types of Tendons:
- Tendons can be classified into two types: primary and accessory tendons.
- Primary tendons attach directly to the bone and are responsible for transmitting the majority of the muscle's force.
- Accessory tendons, also known as aponeuroses, are broad, flat tendons that spread the force of a muscle over a larger area, reducing stress on the underlying bone.

4. Examples of Tendon Attachments:
- The Achilles tendon is one of the most well-known tendons in the body. It attaches the calf muscles (gastrocnemius and soleus) to the heel bone (calcaneus).
- The quadriceps tendon attaches the quadriceps muscles to the patella (kneecap) and then continues as the patellar tendon, which attaches the patella to the tibia bone.
- The biceps tendon attaches the biceps muscle to the radius bone in the forearm.

In summary, tendons are responsible for attaching muscles to bones. They transmit the force generated by the muscles to the bones, allowing for movement and stability. Understanding the role of tendons is essential in comprehending the functioning of the musculoskeletal system.

Muscles are attached to the bones by Tendons and Bone attached to the other bone by Ligaments.