1. [TA] [I–XII]. SYN: rib [I–XII]. 2. A rodlike internal supporting organelle that runs along the base of the undulating membrane of certain flagellate parasites such as Trichomonas. SYN: basal rod. [L.]
- c. cervicalis [TA] SYN: cervical rib.
- costae fluctuantes [XI–XII] SYN: floating ribs [XI–XII], under rib [I–XII].
- costae fluitantes SYN: floating ribs [XI–XII], under rib [I–XII].
- c. lumbalis [TA]
- c. prima [I] [TA] SYN: first rib [I].
- costae spuriae [VII–XII] [TA] SYN: false ribs, under rib [I–XII].
- costae verae [I–VII] [TA] SYN: true ribs [I–VII], under rib [I–XII].
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cos·ta (kosґtə) gen. and pl. cosґtae [L. “ribâ€] 1. [TA] rib: one of the elastic arches of bone, found in pairs with twelve on either side (costa I – costa XII), extending from the thoracic vertebrae toward the median line on the anterior aspect of the trunk; they form the major part of the thoracic skeleton. The upper seven (I–VII) are called costae verae (true ribs) and are connected anteriorly with the sternum; the lower five (VIII–XII) are called costae spuriae (false ribs) and are not connected directly with the sternum. 2. the bony part of a rib. 3. a rodlike structure extending along the base of the undulating membrane in certain flagellate protozoa, such as trichomonads.
Costae (ribs), subdivided into the true (costae verae) and false ribs (costae spuriae); of the latter, the bottom two are also known as floating ribs (costae fluctuantes).
Medical dictionary. 2011.