_Origin._—By a broad tendinous attachment from a small depression above and anterior to the temporal fossa. From here the fibers pass upward and backward and then downward. _Insertion._—A few fibers blend with those of the cleido-trachealis. The fibers are then lost upon the skin in front and opposite the shoulder-joint. Some of the fibers blend with those of the dermo-tensor patagii. _Shape._—Long, flat, and ribbon-shaped. The lower portion consists of delicate fibers. _Relations._—Superior to the temporal muscle and sphenotic process. Superior to the cleido-trachealis and inferiorly to the shoulder-joint. The superior portion touches the skin throughout its entire length. _Action._—A tensor of the lateral cervical integument. It is an auxiliary to the tensor patagii. =Platysma Myoides.= _Location._—The inferior portion of the throat. _Origin._—From the lower margin of the rami of the jaw. Just inferior to the attachment of the masseter. [Illustration: FIG. 18.—Muscles of the upper neck region, 1, Dermo-temporalis. 2, Cornu of the os hyoideum. 3, Carotid artery. 4, Jugular vein. 5, Pneumogastric nerve. 6, Esophagus. 7, Trachea. ] _Insertion._—From the point of origin it spreads out into a thin fan-like layer and meets its fellow in the median raphe. It is attached to the skin in this region. _Shape._—A very thin fan-shaped muscle. _Relations._—Closely adherent to the skin. _Action._—Assists in supporting the lingual apparatus and superior larynx. Compresses and elevates the part. =Dermo-cleido Dorsalis.= _Location._—Anterior shoulder region. _Origin._—From the upper mesial part of the clavicular bone. _Insertion._—Three fasciculi forming a fan-like arrangement attached to the skin in the shoulder-joint and scapular region. The extremities of the fasciculi may meet in the median line of the dorsal region and merge with the dermo-dorsalis. _Shape._—Three fasciculi forming a fan-shaped radiation. _Relations._—Superiorly with the skin. Inferiorly with the shoulder-joint. _Action._—Contracting with the origin as the fixed point, they brace the skin over the forepart of the back. With the integumental attachment as the fixed point, they aid in the act of respiration. =Cleido-trachealis.= _Location._—Extending from the shoulder to the superior laryngeal region. _Origin._—From a small area on the antero-inner part of the middle of the arm of the furcula. _Insertion._—The fibers pass upward and become flattened and attached to the skin and dermo-temporalis muscle. They touch each other on the anterior border of the superior larynx, the trachea, and the skin over these parts. _Shape._—A slender bundle of muscles. _Relations._—Superiorly the skin, and internally the larynx and the trachea. _Action._—Controls the skin region of this part of the neck. =Dermo-spinalis.= _Location._—In the region of the shoulder.