76 ANATOMY OF THE DOMESTIC FOWL 



Relations. — Superiorly with the skin. 



Action. — If the posterior end is fixed, it will cause the feathers 

 to lie close to the skin. Its action would then be opposite to the 

 dermo-dorsalis. 



Dermo-ulnaris. Location. — Outer surface of the anterior upper 

 costal and the posterior humeral region. 



Origin. — By a thin fascia from the outer part of the third and the 

 fourth true ribs at the base of their epineiural appendages. Also 

 from the fascia between them. 



Insertion. — ^The fibers pass forward and upward as a thick 

 muscular bimdle and is loosely attached to the skin at a point just 

 back of the humerus. The tendon later becomes spread out and 

 attached to the fascia as far as the elbow-joint. It covers the 

 olecranon of the ulna. 



Shape. — ^At first rather thick, fascicular-like; later becomes 

 tendinous; and at its attachment it becomes spread out over the 

 olecranon. 



Relation. — Inferiorly with the ribs and humerus, and externally 

 with the skin. " 



Action. — ^A depressor of the humeral region. 



THE Skeletal Muscles 



THE MUSCLES OF THE HEAD 



Temporal Masseter 



Biventer maxiUae Entotympanicus 



Pterygoideus internus Pterygoideus externus 



Digastricus 



Temporal (Fig. 19, No. 4). Location. — Occupies the temporal 

 fossa. 



Origin. — From the mesian line of the sphenotic process, and the 

 adjacent waU of the orbit. 



Insertion. — The fibers passing downward and forward blend with 

 the fibers of the masseter. Inferiorly it inserts by a tendon to the 

 coranoid process upon the superior ramal margin of the mandible. 



Shape. — Fan-shaped with broad portion uppermost. 



Relations. — It occupies the temporal fossa. It is related superiorly 

 with the dermo-temporalis and skin. Inferiorly, with the biventer 

 maxillae and the masseter. 



