The latter mode of attachment occurs in all the penniform and bipenniform muscles, and in those muscles the tendons of which commence in a membranous form, as the Gastrocnemius and Soleus.    From Wordnik.com.  [IV. Myology. 3. Tendons, Aponeuroses, and Fasciæ] Reference

They are bipenniform muscles, each arising by two heads from the adjacent sides of the metacarpal bones, but more extensively from the metacarpal bone of the finger into which the muscle is inserted.    From Wordnik.com.  [IV. Myology. 1F. The Muscles and Fasciæ of the Hand] Reference

The Rectus femoris is situated in the middle of the front of the thigh; it is fusiform in shape, and its superficial fibers are arranged in a bipenniform manner, the deep fibers running straight down to the deep aponeurosis.    From Wordnik.com.  [IV. Myology. 8b. The Muscles and Fasciæ of the Thigh] Reference

They are bipenniform muscles, each arising by two heads from the adjacent sides of the metatarsal bones between which it is placed; their tendons are inserted into the bases of the first phalanges, and into the aponeurosis of the tendons of the Extensor digitorum longus.    From Wordnik.com.  [IV. Myology. 8e. The Muscles and Fasciæ of the Foot] Reference

This muscle is remarkably coarse in texture, and the arrangement of its fibers is somewhat peculiar; the central portion of the muscle—that is to say, the part arising from the acromion—consists of oblique fibers; these arise in a bipenniform manner from the sides of the tendinous intersections, generally four in number, which are attached above to the acromion and pass downward parallel to one another in the substance of the muscle.    From Wordnik.com.  [IV. Myology. 7c. The Muscles and Fasciæ of the Shoulder] Reference