ANATOMY

Detailed explanation-1: -A bipennate muscle has two sets of fibers that lie obliquely on both sides of a common tendon (e.g., gastrocnemius and rectus femoris muscles).

Detailed explanation-2: -Muscles that have fibers on two sides of a tendon are considered bipennate. The stapedius in the middle ear of humans, as well as the rectus femoris of the quadriceps are examples of bipennate muscles.

Detailed explanation-3: -In a unipennate muscle, the fascicles are located on one side of the tendon. The extensor digitorum of the forearm is an example of a unipennate muscle. A bipennate muscle such as the rectus femurs has fascicles on both sides of the tendon as in the arrangement of a single feather.

Detailed explanation-4: -bi·pen·nate (ˈ)bī-ˈpen-ˌāt. : having the fibers arranged obliquely and inserting on both sides into a central tendon. The biceps brachii is a bipennate muscle with two heads of origin.

Detailed explanation-5: -In bipinnate muscles, such parallel muscle fibers attach to a tendon in two different directions, such as with the rectus femoris (fe-more’-is) in the thigh. These pinnate (or pennate or pinnation) structures resemble the structure of feathers and of some leaves on branches.