Final answer:
Sesamoid bones are special types of bones enclosed in tendons and fascial tissue, such as the patella. They are surrounded by tendon sheaths and are essential for increasing the leverage and efficiency of muscle contractions that move the skeleton.
Step-by-step explanation:
Sesamoid bones are enclosed in a tendon and fascial tissue. These types of bones, such as the patella (kneecap), develop inside tendons and are held farther away from joints, which increases the leverage of muscles, thereby enhancing the muscle's ability to move the skeleton. Tendons, which are dense connective tissues, connect muscles to bones and are often surrounded by a tendon sheath to facilitate smooth motion across joints without friction.
The connective tissue layers that cover muscle fibers and muscle fiber bundles include the endomysium and the perimysium, respectively. These protective layers are integral in transferring the tension created by muscle contractions through to the tendons and then onto the bones, enabling movement. At times, these connective tissues can fuse to an aponeurosis or to fascia, further demonstrating the intricate nature of musculoskeletal connections.