Fascicle Patterns and Muscle Shapes

parallel muscle

evenly spaced fascicles attaching to a tendon that is about the same width as the muscle

ex: strap like muscle (sartorius muscle in the thigh)

convergent muscle

broad at one end and uniformly tapers to a single tendon

ex: pectoralis major muscle in the chest

pennate muscle

has fibers and fascicles that attach to the tendon at an angle in such a way that the muscle resembles a feather

unipennate​​ muscle

has a single tendon, and its fascicles feather out at an angle from only one side of it ex: flexor pollicis longus muscle of the forearm

bipennate​ muscle

has a single tendon, but its fascicles angle out from both sides of its tendon

ex: rectus femoris muscle of the thigh).

multipennate ​muscle

composed of several tendons, and the way the fascicles are attached makes the muscle look like several feathers joined together

ex: deltoid muscle of the shoulder

circular (sphincter) muscle

encircles a structure, such as the opening of the eye, to close or constrict it when it contracts

ex: orbicularis oculi muscle

spiral muscle

wraps around a bone or have the twisted appearance of a towel wrung out to dry

ex: supinator muscle in the forearm).

fusiform muscle

muscle is thicker in its belly, or middle region, and tapered at its ends

ex: biceps brachii muscle