8 HEAD AND NECK 



ligament, the adjoining part of the frontal bone, and the 

 frontal process of the maxilla, and they sweep laterally round 

 the margin of the orbit in the form of a series of con- 

 centric loops. The upper fibres blend with the frontal belly 

 of the epicranius, and the lower fibres overlap the upper 

 parts of the muscles of the upper lip. Some of the fibres 

 spring from the nasal part of the frontal bone and terminate 

 in the skin of the eyebrow. 



The palpebral part consists of fibres which sweep in 

 gentle curves from the medial palpebral ligament to the 

 lateral palpebral raphe, to both of which they are attached. 

 Peripherally they blend with the orbital part, and they form 

 a continuous layer of uniform thickness, except near the free 

 margins, where, close to the bases of the eyelashes, there is 

 a more pronounced fasciculus, termed the ciliary bundle. 

 Some of the fibres of the palpebral portion pass from the 

 deep surface of the medial palpebral ligament to the lacrimal 

 bone ; they constitute the pars lacrimalis^ which will be 

 described when the eyelids are dissected (see p. 29). 



The orbicularis oculi is supplied by the facial nerve. 

 It closes the eyelids and compresses them against the eye- 

 ball. The pars lacrimalis helps to force the lacrimal secretion 

 from the lacrimal sac into the naso-lacrimal duct. Those 

 fibres of the orbital part of the muscle which spring from 

 the nasal process of the frontal bone and terminate in the 

 skin of the eyebrow pull the eyebrow towards the median 

 plane, and throw the skin of the central part of the fore- 

 head into vertical folds ; they were at one time described as 

 a separate muscle which was called the corrugator supercilii. 



Musculus Epicranius (O.T. Occipito - Frontalis). The 

 epicranius is a quadricipital muscle possessing two occipital 

 heads, the occipitales muscles, and two frontal heads, the 

 frontales muscles ; they are all inserted into an intermediate 

 aponeurosis, the galea aponeurotica (O.T. epicranial aponeur- 

 osis), which extends from the frontal to the occipital region 

 (p. 50). The lower part of each frontal head blends with the 

 orbicularis oculi, and from its medial border a small muscular 

 bundle, known as the musculus procerus (O.T. pyramidalis 

 nasi\ descends to the dorsum of the nose. At present only 

 the frontalis and the procerus have been displayed (Fig. 2). 



The Frontalis becomes apparent immediately above the 

 upper border of the orbicularis oculi. As it is cleaned care 



