spina (spi'nah)

Gen. and pi. spinas. See spine, s. helicis. A projection on the lower anterior margin of the helix, s. jugular is. A sharp elevation on the jugular proce of the occipital bone. s. mental is extern a. The mental protuberance, s. muscular is inferior. An elevation on the outer surface of the arytenoid cartilage near its lower third, s. muscular is superior. A blunt, knotlike prominence near the upper part of the external surface of the arytenoid cartilage, s. orbital is inferior. A slight prominence below the s. orbital is superior, s. orbital is superior. A slight prominence on the border of the ala magna of the sphenoid bone, projecting into the sphenoidal fi ure at the point where it is slightly constricted, s. tympanic a anterior. A prominent point on the anterior and upper part of the tympanic ring, at the anterior end of a ridge forming the upper boundary of the sulcus malleolar is. s. ventosa. i. A disease of the bones which causes them to dilate as if distended with air. 2. A bony tumor due to internal caries, generally confined to the wrist or ankle, s. zygomatic a. An offshoot from the zygomatic proce of the superior maxilla which aids in forming the sphenomaxillary fi ure.