WOUND CLOSURE 



671 



layers and played no part in exerting a contractile force, as could be shown by 

 the use of radiopaque markers (Billingham and Russell, 1956). Furthermore, no 

 thickening of the panniculus was found. Circular wounds contract slower than 

 triangular or rectangular ones. In the latter the corners remain stationary and 

 the sides respond to increased tension by moving inward. Although tension 

 is essentially equal throughout the wound a relatively greater amount is exerted 

 at the sides because their length exceeds that of the corners. Circular wovmds, on 

 the other hand, collapse only slightly since the perimeter is under equal tension 

 at all points. 



{b) Intussusceptive growth 



Intussusceptive growth, e.g. growth within the framework of pre-existing skin, 

 has been demonstrated by Billingham and Medawar (1955). Islands of rabbit 

 skin when surrounded by a wound surface ultimately expand. This expansion is 

 due to the response of the fibrous corium to chronic tension. The hair follicles 

 become further separated and histological sections reveal new collagen formation 

 indicating true growth. Re-excision of the skin adjacent to the initial island 

 resulted in immediate contraction followed by growth whose rate exceeds that of 

 the first experiment. 



(<:) Growth from the wound edge 



Many problems arise in accurately assessing dermal growth into a wounded area. 

 An excellent review of the subject has been present by Van den Brenk (1956), 

 and a large number of articles in the literature describe the growth of granulation 

 tissue in vivo in transparent chamber preparations (Sandison, 1928, 1931; Clark 

 et al., 1931; Clark and Clark, 1936; Ebert et al., 1939; Williams, 1954). Van den 



Fig. I. Third-degree burn of the left upper chest and arm at the time of initial debridement 



of the eschar. 



Literature p. yo3 



