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 epineural appendages. Also 

 from the fascia between them. 



Insertion. The fibers pass forward and upward as a thick 

 muscular bundle 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 maxillae 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 wall 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. 



