a. (sb.) [a. F. costal (Paré, 16th c.), ad. med. or mod.L. costāl-is, f. costa rib: see above.]
1. Phys. Pertaining to or connected with the ribs.
Costal respiration: respiration produced chiefly by the movements of the ribs; opposed to abdominal or diaphragmatic respiration.
1634. T. Johnson, trans. Parey’s Chirurg., 571. The sharp splinters pricke the Costall membrane.
1836. Todd, Cycl. Anat., I. 281/1. The costal vertebræ.
1878. Foster, Phys., II. ii. § 1. 259. The movement of the upper chest characteristic of female breathing, which is called costal.
† b. (See quot.) Obs.
1646. Sir T. Browne, Pseud. Ep., IV. x. 203. Whereby are excluded all cetaceous … fishes, many pectinall, whose ribs are rectilineall, many costall, which have their ribs embowed.
2. Nat. Hist., etc. Pertaining to, or of the nature of, a COSTA, q.v. Hence costal-nerved adj.
1839. Todd, Cycl. Anat., II. 927/1. The costal nervure is the first longitudinal nervure of the wing.
1880. Gray, Struct. Bot., iii. § 4. 92. Leaves … Costal-nerved, the nerves springing from a midrib or costa.
B. sb.
† 1. The side. Obs. rare.
1634. Malory’s Arth., VII. xii. (1816), I. 235. Sir Beaumains smote him through the costal [ed. Caxton cost] of the body.
2. Anat. and Zool. Short for costal vein, muscle, plate, etc.
1828. Stark, Elem. Nat. Hist., II. 405. Pelvis of five plates, supporting five costals.
1852. Todd, Cycl. Anat., IV. I. 282. The great lateral costals.
Hence Costally adv., in a costal manner, position or direction; in reference to the costa.
