AURICLE 



43 



stituent parts are arranged in five layers : (i) skin; (2) super- 

 ficial fascia ; (3) the epicranius, consisting of four muscular 

 bellies, the two occipitales and the two frontales muscles, and 

 the aponeurosis called the galea aponeurotica, which connects 

 them together ; (4) a layer of loose areolar tissue ; (5) the 

 periosteum, which in the region of cranium is called the 

 pericranium. In the temporal region the wall of the cranium 

 is much more thickly covered than in the scalp area, and it 

 is possible to distinguish seven layers of soft tissues between 

 the surface and the bone: (i) skin; (2) superficial fascia; 

 (3) extrinsic muscles of the ear ; (4) the thin lateral extensions 



Integument 



L Superficial fascia 



Galea aponeurotica 

 Loose connective tissue 

 Pericranium 



Cranial wall 



-- Dura mater 



FIG. 13. Section through the Scalp and Cranial Wall. 



of the galea aponeurotica; (5) the strong temporal fascia; 

 (6) the temporal muscle; (7) periosteum. 



The Scalp. The scalp and the superficial temporal region 

 are richly supplied with blood vessels and nerves, which all 

 enter from the periphery, passing into the superficial fascia 

 after piercing the deep fascia of adjacent regions. As a 

 consequence of that arrangement large flaps of the scalp may 

 be torn from the centre towards the margin, but, so long as 

 they remain attached at the periphery, their sources of 

 vitality are not seriously interfered with, and, if they are cleaned 

 and replaced, healing occurs rapidly and satisfactorily. 



Dissection. The skin has already been removed from the 

 anterior parts of the scalp and the temporal region. A median 

 longitudinal incision must now be made through the skin of the 

 posterior part of the scalp as far as the external occipital pro- 

 tuberance, and the flap on each side of the incision must be 



