THE MUSCLES OF THE EYELIDS AND EYEBROW. 281 



The auricularis anterior or attrahens auriculam, scarcely separate from 

 the preceding muscle, is pale and indistinct, and is attached to the thin lateral 

 prolongation of the epicranial aponeurosis, from which it passes backwards to be 

 inserted into the fore part of the helix. % 



The auricularis posterior or retrahens auriculam muscle consists of two or 

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

 tendinous fibres, and are inserted into a vertical ridge of the cartilage of the pinna 

 at the back part of the concha. The fibres are deeper in colour and more distinctly 

 marked than in either of the other auricular muscles. 



Varieties. Of the auricular muscles the posterior and the anterior are subject to greater 

 varieties than the superior, but all vary somewhat in the extent of their development, the 

 posterior more frequently by an increase in the number of its slips, the anterior by a 

 diminution of the volume and distinctness of its fibres. The origin of part of the retrahens 

 is sometimes carried backwards to a variable extent along- the superior curved line of the 

 occipital bone. Cruveilhier describes as normal a deep anterior auricular muscle, passing from 

 the zygomatic process to the outer surface of the tragus. (See also Schwalbe, Arch. f. Anat., 

 Supplt, Bd., 1889, 264.) 



Actions. The three auricular muscles respectively draw the pinna of the ear upwards, 

 backwards, and forwards. In the majority of persons their action is not directly under 

 voluntary control. 



THE MUSCLES OP THE EYELIDS AND EYEBROW. 



These are four in number, namely, the orbicularis palpebrarum and tensor tarsi, 

 the levator palpebrse superioris, and the corrugator supercilii. 



The orbicularis palpebrarum is a thin elliptical muscle surrounding the 

 fissure between the eyelids and covering their surface, and spreading for some 

 distance outwards on the temple, upwards on the forehead, and downwards on the 

 cheek. It consists of two parts which differ in their arrangement and action. The 

 central or palpebral portion is that part of the muscle which is contained in the 

 eyelids. It is composed of thin pale fibres which arise from the upper and lower 

 margins of the internal tarsal ligament, and pass outwards, describing a slight 

 curve, to be inserted into the much less developed external tarsal ligament. A 

 somewhat thicker fasciculus, which lies along the free margin of each lid, is 

 distinguished as the ciliary bundle. The peripheral or orbital portion is larger, 

 stronger, and of a deeper colour. Internally its fibres are attached to the inner 

 part of the tarsal ligament, to the whole length of the nasal process of the superior 

 maxilla, and to the inner part of the orbital arch of the frontal bone, while 

 externally the fibres pass uninterruptedly from the eyebrow to the cheek, thus 

 forming a series of concentric loops or, in the case of the more central fibres, nearly 

 complete rings. 



Relations. The palpebral portion of the muscle is separated anteriorly from the skin by 

 a layer of loose areolar tissue devoid of fat ; posteriorly it rests upon the fibrous groundwork 

 of the lids (tarsi) with the palpebral fascia. The orbital portion is more closely united to the 

 skin ; it lies in its upper part over the frontal bone and the corrugator supercilii, and is 

 intimately connected with the insertion of the frontalis muscle : in its lower part it rests upon 

 the superior maxillary and malar bones, and the origins of the elevator muscles of the upper 

 lip and ala of the nose, and from both its inner and outer ends fibres are sent downwards to 

 those muscles and to the skin of the cheek. These slips are described separately by Henle 

 under the name of malaris muscle. 



The internal tarsal or palpebral ligament (tendon of the orbicularis, tendo palpe- 

 brarum) is a small white band which is often obscured by the fibres of the orbi- 

 cularis muscle, but is rendered prominent by drawing the lids outwards. This 

 ligament is about two lines in length and half a line in breadth, and is attached to 

 the nasal process of the superior maxilla, in front of the lachrymal groove ; thence 



