FAT. 



231 



name fascia superjicialis interna. It is in 

 contact with the serous membranes of the prin- 

 cipal cavities in the body, with those of the 

 abdomen, thorax, and pelvis in particular; in 

 the former of which it has attracted most atten- 

 tion under the denomination of ihejascia pro- 

 pria. This cellular layer lies between the 

 serous membrane and the fibrous layer which 

 lines the parietes of the cavities, as for instance 

 the fascia transversalis in the abdomen; and 

 consequently in this last cavity, when any 

 viscus is protruded, carrying a peritoneal sac 

 before it, this cellular layer uniformly forms the 

 immediate investment of the sac, and is there- 

 fore called fascia propria, a hernial covering 

 which every practical surgeon well knows is 

 often of considerable density and thickness, 

 and to which indeed is attributable the so-called 

 thickening of the sac itself. 



2. Aponeuroses or aponeurotic fascia. This 

 appellation should be confined to those textures 

 which are purely fibrous, and belong to either 

 the white fibrous tissue or the yellow. In man, 

 they belong entirely to the former class, but we 

 see some interesting examples among the lower 

 animals, where, while the same characters as to 

 intimate texture are preserved, they assume a 

 yellow colour, and exhibit most manifestly the 

 property of elasticity. 



The greatest number of the fibrous aponeu- 

 roses are connected with muscular fibres, and 

 in fact serve as tendons to them, and are de- 

 scribed as such. Of these we have the best 

 examples in the fibrous aponeuroses of the ab- 

 dominal muscles, by which a considerable por- 

 tion of the paries of this cavity is constructed 

 of a resisting inelastic material, which is at the 

 same time under the control and regulation of 

 muscular fibre. These expansions are com- 

 posed of silvery white parallel fibres, in many 

 places strengthened by bundles which cross 

 and interlace with the fibres last named, e. g. 

 the intercolumnar bands at the apex of the ex- 

 ternal abdominal ring. It is interesting to 

 notice that in the larger quadrupeds, when the 

 weight of the viscera is imposed on these 

 aponeuroses, they are composed of the yellow 

 elastic fibrous tissue. I have also seen the 

 fascia lata thus converted. 



A second class of these aponeuroses consists 

 of those which cover the soft parts in particular 

 regions. In general we find that where there 

 are many muscles covered, the aponeurosis 

 sends in processes by which each muscle is 

 separately invested, these processes being ulti- 

 mately inserted into the periosteum of the bone. 

 Thus the fascia lata of the thigh separates by 

 means of processes prolonged from its deep 

 surface, the various muscles to which it forms 

 an external envelope, in such a manner that, if 

 the muscles be carefully dissected away from a 

 thigh, without opening the fascia more than is 

 sufficient for their removal, it will appear to 

 form a series of channels in which the muscles 

 are lodged. A similar arrangement is found in 

 the leg and foot, and in each of the segments 

 of the upper extremity. The fascia lata has the 

 peculiarity of being in a great degree influenced 

 in its tension by a muscle, called from that 



office, tensor vagina femoris, and the fascia 

 which covers the palm of the hand is likewise 

 governed by the palmaris longus, the connec- 

 tion of which, however, with the fascia seems 

 to have reference, not to the functions of the 

 fascia, but to the power of the muscle, in aid 

 of the other flexors of the wrist ; the fasciae of 

 the leg and arm too receive the terminal expan- 

 sion of the tendons of muscles. The strength 

 of these aponeurotic sheaths is proportionate to 

 the strength of the muscles they cover ; this is 

 apparent, by comparing the fasciae of the arm 

 and of the thigh ; the strength of the latter 

 greatly exceeds that of the former, and in the 

 thigh itself the vastus externus muscle is covered 

 by a portion of the fascia lata, much stronger 

 than those which cover the muscles on its 

 posterior and inner aspects. 



In a third class of aponeuroses are enume- 

 rated simple lamellae of fibrous membrane, 

 which are found for the most part in connexion 

 with the walls of cavities : such are the fascia 

 transversalis, connected with the abdomen; the 

 fascia iliaca and pelvica, connected with the 

 pelvis; and the fibrous expansion lining the 

 thorax, which has not received a name. 



The aponeurotic fasciae are most valuable in 

 their power of resistance, and thus efficacious 

 in maintaining organs in their proper situa- 

 tions ; that they exert a considerable degree of 

 compression upon the muscles is rendered 

 evident by the hernia of the muscular fibres 

 which takes place when an incision is made 

 into the fascia lata of the thigh ; they thus re- 

 gulate the combined action of muscles and 

 render more complete their isolated action. It 

 is incumbent on the surgeon to remember how 

 they confine purulent collections and oppose 

 their progress to the surface, a property which 

 is likewise observable in the cellular fasciae, 

 whose power of resistance is, however, much 

 less, but their elasticity much greater. 



Such is a brief notice of the generalities con- 

 nected with the fasciae of the body : the situa- 

 tion, connections, and structure of many of 

 them are of great interest to the surgical anato- 

 mist, and will be found fully detailed in the 

 articles devoted to the surgical anatomy of 

 the regions. The subject is also very com- 

 prehensively treated in the following works, 

 God/nan, Anatomical Investigations, Phila- 

 delph. 1824 ; Velpeau, Anat. Chirurgicale, t. i. 

 ed. 2de ; Paillard, Description complete des 

 Membranes fibreuses, Par. 1827; Cruveilhier, 

 Anat. Descript. t. ii. Aponeurologie, Par. 

 1834 ; Bourgery, Anatomic de 1'homme, t. ii. 

 (R. B. Todd.) 



FAT. (<7Ta, 9rt/xXj, adeps, pinguedo; 

 Fr. graisse ; Germ.Fett; Itzl.grasso.) Under 

 this term we include a variety of animal pro- 

 ducts which bear a general resemblance to 

 each other, and to a series of corresponding 

 substances in the vegetable kingdom ; the fats 

 of animals being, like the vegetable oils, ternary 

 compounds of carbon, hydrogen, and oxygen, 

 and not, apparently in any instance, containing 

 nitrogen, except as an adventitious or acciden" 

 tal ingredient. 



