Human anatomy, including structure and development and practical considerations . tirely wanting. The absence of both has been observed. The averagelength f)f the ileo-ca-cal oj^ening on 30 similar specimens was 31 mm., the extremesbeing 46 mm. and 21 mm. It is probable that, owing to the shrinking of the tissues,these dimensions of the opening are Although the lower fold is thelarger, the upper overlaps it almost invariably, so that when the valve is closed thetwo edges do not come in contact, the orifice being closed by the application of thelower fold to the under surface of the
Human anatomy, including structure and development and practical considerations . tirely wanting. The absence of both has been observed. The averagelength f)f the ileo-ca-cal oj^ening on 30 similar specimens was 31 mm., the extremesbeing 46 mm. and 21 mm. It is probable that, owing to the shrinking of the tissues,these dimensions of the opening are Although the lower fold is thelarger, the upper overlaps it almost invariably, so that when the valve is closed thetwo edges do not come in contact, the orifice being closed by the application of thelower fold to the under surface of the upper one. Inflated specimens show thatthe upper fold is tense, while the lower remains flaccid. Much difference ofopinion exists as to the completeness of the closure of the ileo-ca-cal valve, andexperiments do not agree. If the experiment of injecting water or air from thecolon be performed in situ, the closure is more likely to be perfect than if the partshave been removed. These experiments, however, do not represent the true con- FiG. 1414. Ascending colni .Anterior band. Ileo-caecal artery Superior ileo-caecal fossa Mesenter>- Caecum^—^ Meso-appendix\ermiform appendixCaecum and related structures seen from the left. ^ Ileum Apuetitlicular arter>- ditions during life, since the tonicity of the muscular fibres of the gut is lost, and,in the opened abdomen, the pressure of the viscera on the end of the ileum is lessthan normal. In life the valve probablv is efficient. • The orifice of the vermiform appendix is very variable. In some casesthe caecum narrows to it so gradually that it is hard to say where it begins ; inothers it begins suddenlv with an ovaf or round opening measuring from 5 mm. orless to I cm. or more. The vahe which often is found at the orifice is not usuallya true valve, but the projection made by the wall at the union of cjecum and appen-dix in the entering angle when it arisesobliquely. According to .Struthers, there isno valve when it arises a
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Keywords: ., bookauthormc, bookcentury1900, bookdecade1910, booksubjectanatomy
