Muscle architecture for pennate muscles. Pennate muscles can be further divided into uni-, bi- or multipennate. Unipennate muscles are those where the muscle fibers are oriented at one fiber angle to the force-generating axis and are all on the same side of a tendon. The pennation angle in unipennate muscles has been measured at a variety of resting length and typically varies from 0° to 30°. The lateral gastrocnemius of wild turkeys is an example of this muscle architecture. Muscles that have fibers on two sides of a tendon are considered bipennate. The stapedius in the middle ear of humans, as well
Stapedius muscle Stapedius muscle The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes. The stapedius emerges from a pinpoint foramen in the apex of the pyramidal eminence (a hollow, cone-shaped prominence in the posterior wall of the tympanic cavity), and inserts into the neck of the stapes. The stapedius is supplied by the nerve to stapedius, a branch of the facial nerve. The stapedius dampens the vibrations of the stapes by pulling on the neck of that bone. It prevents