SCALP 159 



Dissection. The dissector, after studying the attachments of the galea 

 aponeurotica, and after he has made himself thoroughly conversant with 

 the nerve and vascular supply of the scalp, and has appreciated the fact 

 that every part of its area is supplied by more than one nerve and that the 

 blood vessels anastomose very freely together, should next convince himself 

 of the greater looseness of the areolar layer beneath the galea in the medial 

 area and its greater denseness and closer attachment to the various parts 

 of the superjacent epicranius, and the subjacent pericranium at the margins 

 of the scalp area. He may do this by introducing the handle of a scalpel 

 through a median incision in the galea, and passing it anteriorly and 

 posteriorly and from side to side. 



The Layer of Loose Areolar Tissue. This is the fourth 

 layer of the scalp. It is but slightly vascular and is of loose 

 texture, but is not equally loose over the whole area of the 

 scalp ; on the contrary in the regions of the temporal and 

 supra-orbital ridges it becomes much denser, and, at the same 

 time, much more closely connected with the galea aponeurotica 

 and the frontalis muscles, whilst posteriorly it disappears 

 where the occipitalis muscles and the galea become attached 

 to the superior nuchal lines. It is on account of these 

 peculiarities that effusions of blood or inflammatory exudations 

 in the areolar layer easily raise the greater part of the scalp 

 from the bone, but such effusions do not readily pass from 

 beneath the scalp into either the facial, temporal, or occipital 

 regions. 



On the fifth day after the body has been placed upon its 

 back, the eighth after it was brought into the room, the 

 dissector of the head and neck must assist the dissector of 

 the upper extremity to display the whole extent of the brachial 

 plexus and the origins of the branches which spring from it ; 

 and he should take the opportunity to revise his own know- 

 ledge of the plexus. Detach the clavicular head of the 

 sterno-mastoid from the clavicle, and displace the sternal 

 head towards the median plane. When this has been done 

 the anterior and upper parts of the sterno-clavicular joint 

 capsule will be fully exposed, for the pectoralis major, which 

 covered the lower part of the anterior surface, has already 

 been reflected by the dissector of the upper extremity. 



Dissection. The sterno-clavicular joint is described on p. 28 of Vol. I. 

 After the dissectors have noted that the fibres of the capsule run medially 

 and downwards from the clavicle to the sternum, the anterior, superior, 

 and posterior portions must be divided close to the sternum, care being 

 taken to avoid injury to the anterior jugular vein, which passes laterally 

 close to the upper and back part of the joint. When the division is 

 completed, elevate the sternal end of the clavicle by depressing the 



