748 REGIONS AND MUSCLES OF THE CRANIUM. 



fibres of the last named muscle, as well as of margin of the frontal bone. By its inner extre- 

 the corrugator supercilii. The aponeurotic mity it is attached to the internal angular pro- 

 slip before alluded to, situated in the middle cess of the frontal bone; the fibres pass thence 

 line, forms the internal boundary of each la- outwards, inclining a little upwards, and are 

 teral portion. On the outside the fibres gra- inserted into the integument of the eyebrow, 

 dually shorten and extend a very short distance being mixed with the orbicularis and occipito- 

 into the temporal region, over the temporal frontalis muscle. This muscle evidently can 

 fascia. Each portion presents a convex margin depress the eyebrow, and acting in conjunction 

 above, which is inserted into the thin tendinous with its fellow, throw the integuments - into 

 aponeurosis, which extends over the middle vertical wrinkles, approximating the eyebrows, 

 portion of the occipito-frontal region, correspond- and occasioning the act of frowning. This 

 ing to the posterior margin of the frontal bone, muscle lies on the supra-orbital nerve and 

 the fronto-parietal suture, internal portions of vessels. 



the parietal bones, the sagittal and lambdoidal 4. Nerves. The anterior part of the occi- 

 sutures and part of the occipital bones, but se- pito-frontal region is freely supplied with nerves 

 parated from them by the pericranium and by from those branches of the ophthalmic portion 

 some fine cellular tissue which connected the of the fifth which originate within the orbit. Of 

 aponeurosis to the last-named membrane. This these the supra-orbital is the largest : imme- 

 aponeurosis is called the cranial or epicranial diately after its emergence from the supra-or- 

 aponeurosis : in some instances its fibrous cha- bital foramen this nerve divides into a series of 

 racter is very distinct in all its extent ; but very branches which pass up on the forehead, some 

 frequently it is most manifest in its posterior adhering to the pericranium, others distributed 

 third or half, the anterior part being little more to the muscle, and others becoming subcu- 

 than condensed cellular membrane, excepting taneous. Here, too, we find ramifications of 

 near to the fleshy fibres of the frontal portion of the supra-trochleator or internal frontal nerve, 

 the muscles, where the aponeurotic structure chiefly distributed in the internal portion of the 

 again becomes manifest. On the sides this muscle. At the external part of this frontal 

 aponeurosis gradually degenerates into cellular region we find some filaments of the portio 

 membrane without leaving any defined margin, dura. In the posterior or occipital region the 

 The aponeurosis in its whole extent adheres principal nerves are derived from the cervical 

 closely to the superjacent subcutaneous cellular plexus; the auricular and mastoid branches of 

 tissue and to the subjacent pericranium through this plexus distribute their filaments here; and 

 the intervention of a fine cellular membrane we also find ramifications from the posterior 

 already referred to. Proceeding from before branch of the first cervical nerve, accompany- 

 backwards, we find that this aponeurosis ends ing the subdivisions of the occipital artery, 

 in affording insertion to the fibres which form 5. Arteries. In front we have ramifications 

 the posterior belly of the muscle. of the supra-orbital and superficial temporal 



This portion of the muscle, also called the freely anastomosing with each other; and 



occipital muscle, consists likewise of two lateral deeper-seated, a few branches of the deep 



portions which are attached inferiorly to the ex- temporal, distributed to the pericranium. In 



ternal part of the superior curved line of the the occipital region we have the occipital, 



occipital bone, and to the mastoid portion of often of considerable size, and the posterior 



the temporal. The fibres are parallel and auricular also sends some of its ramifications 



nearly vertical, inclining a little inwards, and to anastomose with the occipital branches, 



are inserted, as already described, into the pos- Both in front and behind, the arteries of oppo 



terior margin ot the epicranial aponeurosis. site sides inosculate with each other on the 



The attachment of the muscle to the occipital middle line. 



bone is immediately above that of the sterno- 6. Veins. Small veins accompany most of 



mastoid and splenius muscles. On the sides the arteries ; but the most remarkable vein is 



the fibres gradually disappear over the mastoid one which is situated in the frontal region 



portion of the temporal bone, and the fleshy nearly on the middle line ; it is the frontal 



belly of the muscle lies immediately over the vein, or vena preparata, sometimes replaced 



pericranium, some cellular membrane only in- by two or three. Velpeau advocates the re- 



tervening; its adhesion to the skin, however, is vival of the ancient practice of bleeding from 



less intimate than that of the frontal portion. this vein in head affections. It carries the 



This muscle is evidently destined to act upon blood, as he observes, from all the anterior part 



the integuments of the cranium : its influence of the head to the root of the nose, whence he 



is most apparent upon the skin of the forehead argues that venesection practised on this vessel 



and eyebrows ; it distinctly raises the latter, would empty the whole of the scalp. How 



and throws the former into transverse wrinkles, often in practice do we see manifest advantage 



Under its influence the whole scalp may be from cupping the temples or some region of 



made to move backwards and forwards, but the the scalp, when little or no benefit had been 



occipital portion of the muscle cannot create, as derived from other modes of practising the 



the frontal does, wrinkles in its corresponding detraction of blood ! 



integument, owing to the less firm adhesion of 7. Lymphatics. The lymphatics are very 



the muscle to it. few, and pass into the parotid ganglions, or 



Subjacent to the anterior portion of the occi- those behind the ear or in the superior part of 



pito-frontal is is the corrugator tuperciln muscle, the neck . 

 It lies on the inner half or third of the orbital 8. Pericranium. This fibrous tissue, pos- 



