366 THE MUSCLES AND FASCIA 



rudimentary. They are the homologues of large and important muscles in some 

 of the mammalia. 



Dissection. This requires considerable care, and should be performed in the following 

 manner: To expose the Attollens aurem, draw the pinna, or broad part of the ear, downward, 

 when a tense band will be felt beneath the skin, passing from the side of the head to the upper 

 part of the concha; by dividing the skin over this band in a direction from below upward, and 

 then reflecting it on each side, the muscle is exposed. To bring into view the Attrahensaurem, 

 draw the helix backward by means of a hook, when the muscle will be made tense, and may be 

 exposed in a similar manner to the preceding. To expose the Retrahens aurem, draw the pinna 

 forward, when the muscle, being made tense, may be felt beneath the skin at its insertion into 

 the back part of the concha, and may be exposed in the same manner as the other muscles. 



The Attrahens aurem (m. auricularis anterior), the smallest of the three, 

 is thin, fan-shaped, and its fibres pale and indistinct; they arise from the lateral 

 edge of the aponeurosis of the Occipitofrontalis, and converge to be inserted 

 into a projection of the front of the helix. 



The Attollens aurem (m. auricularis superior}, the largest of the three, is 

 thin and fan-shaped; its fibres arise from the aponeurosis of the Occipitofrontalis 

 and converge to be inserted by a thin, flattened tendon into the upper part of the 

 cranial surface of the pinna. 



The Retrahens aurem (m. auricularis posterior) consists of two or three 

 fleshy fasciculi, which arise from the mastoid portion of the temporal bone by 

 short aponeurotic fibres. They are inserted into the lower part of the cranial 

 surface of the concha. 



Nerves. The Attrahens and Attollens aurem are supplied by the temporal branch of the 

 facial ; the Retrahens aurem is supplied by the posterior auricular branch of the same nerve. 



Actions. In man, these muscles possess very little action: the Attrahens aurem draws the 

 pinna forward and upward; the Attolens aurem slightly raises it; and the Retrahens aurem 

 draws it backward. 



3. The Palpebral Region (Fig. 289). 



Orbicularis palpebrarum. Levator palpebrae. 



Corrugator supercilii. Tensor tarsi. 



Dissection (Fig. 287). In order to expose the muscles of the face, continue the longitudinal 

 incision made in the dissection of the Occipitofrontalis down the median line of the face to the 

 tip of the nose, and from this point onward to the upper lip; and carry another incision along the 

 margin of the lip to the angle of the mouth, and transversely across the face to the angle of the 

 mandible. Then make an incision in front of the external ear, from the angle of the mandible 

 upward; to join the transverse incision made in exposing the Occipitofrontalis. These incisions 

 include a square-shaped flap, which should be removed in the direction marked in the figure, 

 with care, as the muscles at some points are intimately adherent to the integument. 



The Orbicularis palpebrarum (m. orbicularis oculi) is a sphincter muscle, which 

 surrounds the circumference of the orbit and eyelids. It arises from the internal 

 angular process of the frontal bone, from the frontal process of the maxilla in 

 front of the lacrimal groove for the nasal duct, and from the anterior surface 

 and borders of a short tendon, the tendo oculi, or internal tarsal ligament, placed 

 at the inner angle of the orbit. From this origin the fibres are directed outward, 

 forming a broad, thin, and flat layer, which covers the eyelids, surrounds the 

 circumference of the orbit, and spreads out over the temple and downward on the 

 cheek. The internal or palpebral portion (pars palpebralis) of the Orbicularis is 

 thin and pale; it arises from the bifurcation of the tendo oculi, and forms a series 

 of concentric curves, which are on the outer side of the eyelids inserted into 

 the external tarsal ligament. The external or orbital portion (pars orbitalis) is 

 thicker and of a reddish color; its fibres are well developed, and form complete 



