io68 A MANUAL OF ANATOMY 



the diploe of the bone, and, after emerging from the foramen, it sends 

 downwards palpebral branches to the integument of the upper eyelid. 



The supra-orbital vein passes downwards and inwards to a point 

 just above the inner canthus, where it joins the frontal vein. In 

 this manner the angular vein is formed, which is the commence- 

 ment of the facial vein. The supra-orbital vein receives tributaries 

 from the frontal region and the upper eyelid, and in the region 

 of the inner canthus it communicates with the superior ophthalmic 

 vein. It also communicates with the superior ophthalmic vein 

 through the supra-orbital notch, and this communication receives 

 the frontal diploic vein, which returns the blood from the diploe 

 of the frontal bone and mucous membrane of the frontal air-sinus. 



The frontal artery, like the supra-orbital, is a branch of the 

 ophthalmic, and emerges from the orbit with the supratrochlear 

 nerve. It is distributed to the structures over the frontal bone 

 internal to the supra-orbital artery, with which it anastomoses, as 

 well as with its fellow of the opposite side. 



The frontal vein, of large size, passes downwards near the median 

 line, and at a point just above the inner canthus is joined by the 

 supra-orbital vein, the resultant vessel being the angular vein. At 

 the root of the nose it communicates with its fellow of the opposite 

 side by a transverse vessel, called the transverse nasal vein. 



The supra-orbital and frontal veins communicate with each 

 other, and with the tributaries of the anterior branch of the super- 

 ficial temporal vein. 



The anterior branch of the superficial temporal artery will be 

 described in connection with the temporal region. 



Occipito-frontalis. — ^This muscle consists of the following parts : (i) 

 the occipitalis, (2) the frontalis, and (3) the epicranial aponeurosis. 



Occipitalis. — ^This consists of two thin fleshy bellies, right and 

 left. Origin.— (i) The outer parts of the highest and superior 

 curved lines of the occipital bone ; and (2) the outer surface of the 

 mastoid process of the temporal bone, immediately above the 

 insertion of the sterno-cleido- mastoid muscle. 



Insertion. — ^The epicranial aponeurosis. 



Each belly forms a thin, broad sheet, the length of the fasciculi 

 being about i| inches. The two bellies, right and left, are sepa- 

 rated towards the median line by a portion of the epicranial aponeu- 

 rosis, which here dips down between them. 



Frontalis.— This consists of two parts, right and left, which are 

 separated superiorly by a narrow angular portion of the epicranial 

 aponeurosis, but interiorly, and for the most part, they are in con- 

 tact. Origin. — (i) The subcutaneous tissue of the eyebrow and 

 root of the nose, where the fibres blend with the upper part of 

 the orbicularis palpebrarum and the corrugator supercilii ; and 

 (2) slightly from the external angular process of the frontal bone, 

 and from the nasal bone. 



Insertion. — The epicranial aponeurosis, a little below the level of 

 the fronto-parietal suture. 



