Noun explanation of dentate line?

There are two dentate lines in the body, which are the dividing line between rectum and anal canal; The serrated annular line connecting the lower end of each anal column and the edge of each anal valve is called the dentate line.

The anal canal above the dentate line evolved from endoderm cloaca, and its inner surface is mucosa, and the mucosa epithelium is single-layer columnar epithelium, which is adenocarcinoma when it becomes cancerous. The anal canal below the dentate line evolved from ectodermal procanal, and its inner surface is skin.

Epithelial capsule is stratified epithelium, and it is squamous cell carcinoma when it becomes cancerous. In addition, there are differences in arterial origin, venous return, lymphatic drainage and nerve distribution between the intestine above and below the dentate line.

Extended data:

First, the experimental principle

Narrow-band imaging technology (NBI) belongs to electronic staining endoscope technology. Narrow-band light wave imaging technology can highlight the fine structure of blood vessels and mucosal surfaces, which is helpful to determine the scope of lesions and the distribution of blood vessels. Two kinds of filters, 4 15nm and 540nm, are used to replace the broadband filter of traditional endoscope. The penetration depth of light in mucosa depends on the length of wavelength. The shorter the wavelength, the shallower the penetration depth.

NBI observation can clearly show the morphology of tissues and blood vessels, and the principle of combining the function of magnifying endoscope (ME) is similar to that of microscope. By magnifying, the shape of crypt, glandular duct opening or submucosal blood vessels was observed emphatically. NBI+ME was obviously superior to ordinary endoscopy in displaying mucosal subtle lesions.

Second, indicators.

Microvascular manifestations of NBI: According to Miwako standard, IPCL of esophageal microvessels under NBI can be divided into four types: type I capillaries are arranged in regular rings; Type ⅱ capillaries are still arranged regularly, but their diameters are larger or longer than those of type ⅰ. Type ⅲ capillaries are irregularly arranged, with unequal diameters, broken and serpentine bends.

Type Ⅳ capillaries were all destroyed, broken and irregularly arranged, and the blood vessels were staggered or layered, which showed that the new blood vessels were spiral and irregularly arranged. Tooth line shape: A is a sharp ring; B is a wide sawtooth type; C is fine sawtooth type; D is broken, not an integer; E is a triangle; F is tongue-shaped. The positive rate of NBI microvascular abnormality =(IPCLII+IPCLIII+IPCLIV)/ number of cases ×100%; The positive rate of abnormal dentate line =(C+D+E+F)/ number of cases × 100%.

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