Anatomy and Physiology: Mink and Human Muscle Shapes

The biceps brachii is an example of a fusiform muscle.  It is wider in the middle and tapers at the ends.  (This picture was from: http://athleticconditioning.blogspot.com/2010/05/building-bigger-biceps.html.)

Fusiform:
Fusiform muscles are spindle-shaped.  Examples include many of the arm muscles, such as the biceps brachii, flexor carpi radialis, extensor radialis longus, and brachioradialis.

Location of the quadratus femoris, a quadrate -shaped muscle.  (This picture was from: http://medicina.ronnie.cz/c-1451-svaly-kycelniho-kloubu.html.)

Quadrate:
Quadrate muscles are quadrilateral-shaped.  Examples include the pronator quadratus on the distal forearm and the quadratus femoris on the thigh.

Location of the external oblique muscle, a flat muscle with aponeurosis.  (This picture was from: http://www.weight4me.com/fitness/muscles/external_oblique.htm.)

Flat with Aponeurosis:
These muscles have layers of flat, broad tendons.  Examples include abdominal muscles, such as the external oblique muscle and the internal oblique muscle.

Location of the extensor digitorum longus, a unipennate muscle, in relation to the muscle around it.  (This picture was from: http://www.getbodysmart.com/ap/muscularsystem/footmuscles/menu/menu.html.)

Unipennate:
Unipennate muscles have muscle fibers that stretch in the same direction.  Examples include the extensor digitorum longus and the brachialis.

Location of the rectus femoris in relation to the other muscles on the femur.  (This picture was from: http://www.t-nation.com/free_online_article/sports_body_training_performance_repair/18_tips_for_bulletproof_knees.)

Bipennate:
Bipennate muscles have two rows of muscle fibers that stretch in opposite directions and have a central tendon.  Examples include the rectus femoris and the gastrocnemius.

Location of the deltoid muscles.  (This picture was from: http://www.sciencelearn.org.nz/Contexts/Sporting-Edge/Sci-Media/Images/Deltoid-muscles.)

Multipennate:
Multipennate muscles have more than two rows of muscle fibers that stretch in different directions and have a central tendon that branch off into two or more tendons.  Examples include the deltoid muscle and the pectoralis major muscle.


Source:
The list of muscle shapes was taken from this site: http://www.netterimages.com/image/7453.htm.)