divaricator

1. (zoology) One of the muscles that open the shell of a brachiopod; a cardinal muscle.Examples: "The relative position of the adductor and divaricator impressions varies somewhat in different species of the genus, as we have already described; thus, in P. giganteus, P. longispinus, &c., the divaricators are situated immediately under and outside of the adductor, while in P. pustulosus, P. humerosus, &c., the adductor is located between the two divaricator impressions, as in the case of P. comoides."; "The interior of the ventral valve differs from the dorsal one by having its divaricator scars much narrower, and its occlusor impressions closer at the anterior extremity, and leaving only a very small space between them for the two little scars which Mr. Hancock thinks might belong to the anterior extremity of the dorsal adjustor."; "Relaxation of the divaricator fibers and maximal contraction of the radial myofilaments, which put the medial basement membranes in tension, may cause medial bending in the hook supports and closing of the hook apparatus."

2. (medicine) A surgical device for spreading the surroundings and holding open the area in which one is operating.Examples: "An operation case containing: 1. A tongue forceps. 2. Heister's gag. 3. Author's ringed gag. 4. Three Krishaber's tracheotomoy tubes for children and adults. 5. One divaricator of the commissure. 6. One divaricator of the molars. […]"; "In 1987, Griffith12 proposed an endonasal sphenoidotomy through a sphenoethmoidal recess. Here it is also necessary to use a divaricator."; "The automatic divaricator is placed between the ribs and the operative field is expanded by rotating the lever of the automatic divaricator (see Figure 7.1)."