TRIANGLE

n. Tri'a2n2-g'l. Gr., rpiyiavov. Lat., trigonum, triangulum, triangulus (from tres, three, and anguhis, an angle). Fr., t. Ger., Dreieck. A three-cornered and three-sided figure, an area or space of three-cornered shape, [a, 48.] Anterior t. of the neck. The space bounded by the middle line of the neck, the anterior border of the sterno-cleido-mastoid. and a line running along the lower border of the inferior maxilla and continued to the mastoid proce of the occipital bone. [L.] A ezat's t. A t. bounded by lines uniting the projection of the nasion on the alveolocondylar plane and the alveolar and nasal points and one uniting the two latter, [a, 34.] Cephalic t. A t. on the antero-posterior plane of the skull formed by lines joining the occiput and forehead and chin, and one uniting the two latter, f" Ann. de gyne'e.," Mar., 1892, p. 165 (a, 34).] Cervical t. Ger., Halsdreieck. See TRIGONUM cervicale. Facial t. A t. bounded by lines uniting the basion and the alveolar and nasal points and one uniting the two latter, [a, 34.] Frontal t. A t. bounded by the maximum frontal diameter and lines joining its extremities and the glabella. [a, 34.] He elbach's t. The space on the posterior surface of the anterior wall of the abdomen bounded by Poupart's ligament, the epigastric artery, and the margin of the rectus abdominis. [L.] Inferior carotid t. Lat., trigonum caroticum inferiua. The space bounded by the middle line of the neck, the anterior border of the sternocieido-mastpid, and the anterior belly of the omohyoid. [L.] Inferior occipital t. Of Welcker, a t. having the bimastoid diameter for its base and the inion for its apex, [a, 34.] Inguinal t. See Scarpa's t. Lurnbo-eos to-abdominal t. The space bounded in front by the obliquus abdominis extern us, above by the lower O, no; Oa, not; O3, whole; Th, thin; Th2. the; U, like oo in [s. 643]