| jaw skeleton | That part of the skull derived from the embryonic pharyngeal arches; it comprises the facial bones of the facial skeleton (under bone) and is distinct from that part of the skull which forms the neurocranium or braincase. Synonym: cranium viscerale, visceral cranium, jaw skeleton, splanchnocranium. Origin: viscero-+ cranium Cartilaginous viscerocranium, those elements of the foetal skull derived from the second and succeeding pharyngeal arch cartilages. Membranous viscerocranium, membranous bones, developed in the foetal skull, that overlie maxillary and mandibular components of the first pharyngeal arch cartilage. (05 Mar 2000) |
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| fibrous skeleton of heart | A complex framework of dense collagen forming four fibrous rings (annuli fibrosi), which surround the ostia of the valves, a right and left fibrous trigone, formed by connecting the rings, and the membranous portions of the interatrial and interventricular septa; it is found in association with the base of the ventricles, i.e., at the level of the coronary sulcus; its functions include: 1) contributing reinforcement of the valvular ostia while providing attachment for the leaflets and cusps of the valves; 2) providing origin and insertion for the myocardium; and 3) serving as a sort of electrical "insulator," separating the electrically conducted impulses of the atria and ventricles and providing passage for the common atrioventricular bundle of conductive tissue through the right fibrous trigone and membranous interventricular septum. Synonym: cardiac fibrous skeleton, cardiac skeleton, skeleton of heart. (05 Mar 2000) |