This type of muscle arrangement is called pennate. Pennate muscles maximize the number of muscle fibers in a given space, allowing for greater force production. Examples of pennate muscles include the deltoid and gastrocnemius.
Multipennate.
The rectus femoris muscle has a parallel fascicle arrangement, meaning its muscle fibers run parallel to the long axis of the muscle. This arrangement allows for strong contraction forces and efficient movement.
The extensor digitorum longus muscle has a parallel fascicle arrangement where muscle fibers run parallel to the long axis of the muscle. This arrangement allows the muscle to generate a strong pulling force to extend the toes.
The Pennate arrangement. The fascicles attach obliquely to the tendon.
short fibers, arranged obliquely to their tendons
myofibril
Pennate MusclesIn a pennate muscle, the fascicles form a common angle with the tendon. Because the muscle cells pull at an angle, contracting pennate muscles do not move their tendons as far as parallel muscles do. But a pennate muscle contains more muscle fibers--and, as a result, produces more tension--than does a parallel muscle of the same size. (Tension production is proportional to the number of contracting sarcomeres; the more muscle fibers, the more myofibrils and sarcomeres.)
fascicle
The Fascicle
myofilament myofibril myofiber fascicle muscle
A fascicle is wrapped in perimysium, which is a connective tissue sheath that surrounds bundles of muscle fibers. It provides structural support and helps protect the muscle fibers within the fascicle.