Answer
A fascicle is a bundle of skeletal muscle fibers surrounded by perimysium (connective tissue). These bundles or fascicles have various geometric patterns of attachment to tendons. These forms include the parallel. circular, triangular and pennate forms
a. Parallel arrangement : The fascicles run parallel to the longitudinal axis of the muscle
An example is the sternohyoid muscle
b. Circular arrangement: In this arrangement fascles run concentrically, and form a sphincter that
encloses an orifice. For example, obicularis oris.
c. Triangular arrangement: In this pattern, fascicles spread over a broad area and converge on the central
tendon, giving the muscle a triangular shape. An example of this type is the deltoid muscle.
Work Step by Step
d. Pennate arrangement. In this pattern, fascicles are short relative to muscle length and the tendon
extends nearly the full length of the muscle. There are three variations in this plan ; unipennate
arrangement; the bipennate arrangement, and the multipennate arrangement.
In the unipennate arrangement , the fascicles are arranged on one side of the tendon. An example of a
muscle with this arrangement is extensor digitorum longus. In a bipennate arrangement, fascicles are
arranged on both sides of the muscle tendon; an example of such a muscle is rectus femoris.
Multipennate muscles are the strongest; the fascicles are attached obliquely to the tendon and
approach from many directions. The deltoid muscle has a multipennate arrangement of fascicles.
