Constriction ring

OR = 4.2 Cl = 1.5,12), terminal transverse limb reduction (OR = 12 Cl = 3.5, 41), and limb constriction ring or skin scars (OR = 40 Cl = 11, 153). There were 13 different defects not previously described in the misoprostol-exposed cases, but only holoprosencephaly and bladder exstrophy significantly exceeded the expected number. 

A mass movement is characterized by the following sequence of events. First, a constrictive ring occurs at a distended or irritated point in the colon, usually in the transverse colon, and then rapidly thereafter the 20 cm or more of colon distal to the constriction contract almost as a unit, forcing the fecal material in this segment en masse down the colon. During this process, the haustrations disappear completely. The initiation of contraction is complete in about 30 sec, and relaxation then occurs during the next 2 to 3 min before another mass movement occurs. But the whole series of mass movements will usually persist for only 10 min to half an hour, and they will then return perhaps a half day or even a day later. 

To prolong the erection, the patient can also use constriction bands or tension rings, which are placed at the base of the penis to retain arteriolar blood and reduce venous outflow from the penis. 

Put the bottom of the loaded M.P. tube just above the place where the thermometer constricts (Fig. 40), and carefully roll the rubber ring onto the M.P. tube. 

It is apparent from Table 1 that the cyclohexadiene ring in 1,2-dihydrocorannule-nes is significantly flatter than either 1,3-cyclohexadiene itself or 9,10-dihy-drophenanthrene due to the constriction imposed by the remainder of the bowl-shaped ring system. Nonetheless, the lack of planarity means that substituents at may adopt either pseudoaxial (pa) or pseudoequatorial (pe) positions. However, the surface of the corannulene system is curved, and, unlike 1,3-cyclohexadiene and 9,10-dihydrophenanthrene, neither the two pa positions nor the two pe positions are equivalent. Thus, substituents in 1 -/ -1,2-dihydrocorannulenes may be (1) endo-pseudoaxial (endo-pa), (2) e do-pseudoequatorial (e/ido-pe), (3) exo-pseudoaxial (exo-pa), and (4) exo-pseudoequatorial (exo-pe), where endo and exo are related to concave and convex orientations, respectively. 

Sphincter. A ring-like band of muscle fibers that constricts a passage or closes a natural orifice. 

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