Anat. Pl. -i. [mod.L., a. Gr. ταρσός the flat of the foot between the toes and the heel; also the rim of the eyelid; in F. tarse.]
1. The first or posterior part of the foot: a collective name for the seven small bones of the human ankle, arranged in two transverse series, the proximal or tibial, consisting of the astragalus and os calcis (or calcaneum), and the distal, or metatarsal, consisting of the naviculare (centrale, or scaphoides), the cuboides, and the three ossa cuneiformia; also, the corresponding part in mammalia generally, and in some reptiles and amphibia.
1676. Wiseman, Chirurg. Treat., VII. ii. 479. The Conjunction is called Synarthrosis; as in the joyning … the Tarsus to the Metatarsus.
1693. trans. Blancard’s Phys. Dict. (ed. 2), Tarsus … also eight backward Bones of the Foot, ordered like Grates.
1704. J. Harris, Lex. Techn., I. Tarsus, is the Space between the lower end of the two Focils, and the beginning of the Five long Bones which sustain, and are articulated with the Toes.
1713. Cheselden, Anat., I. vi. (1722), 37. The Bones of the Tarsus have the same kind of elastick Structure with those of the Carpus, and for the same Ends, but in a much greater Degree; because here the whole Body is sustain’d.
1872. Nicholson, Palæont., 305. The small bones of the ankle, known as the tarsus.
1875. Huxley & Martin, Elem. Biol. (1883), 225.
b. In birds, the third segment of the leg, the shank (which is rarely fleshy or feathered), corresponding to the mammalian tarsus and metatarsus conjoined: = TARSO-METATARSUS.
1828. Stark, Elem. Nat. Hist., I. 253. (Birds, Bucco) Tarsus shorter than the exterior toe; the anterior toes united to the second joint.
1874. Coues, Birds N. W., 321. Tarsi nearly naked, the feathers extending but a little way below the heel-joint.
1880. A. R. Wallace in 19th Cent., XXXV. 100.
c. In insects and other Arthropoda, a series of small articulations forming the true foot; in spiders, the last joint, forming, with the preceding joint or metatarsus, the foot.
1826. Kirby & Sp., Entomol., III. xxviii. 48. [In insects] the foot or Tarsus, is almost universally monodactyle.
1828. Stark, Elem. Nat. Hist., II. 155. (Crustacea, Cryptopoda) None of the tarsi are fin-shaped.
1834. H. M’Murtrie, Cuvier’s Anim. Kingd., 311. (Arachnides, Clotho) The tarsi, only, are furnished with spines.
1867. J. Hogg, Microscope, II. iv. 587. The tarsus, or foot of the Fly consists of a deeply bifid, membranous structure.
2. The thin plate of condensed connective tissue found in each eyelid. Now rare or Obs.
1691. Ray, Creation, II. (1692), 119. The side of the Triangle, which is toward the little Corner of the Eye, and is moveable, was reinforced with a Border, which supplies the place of the Tarsus.
1727–41. Chambers, Cycl., Tarsus is also a name given by some anatomists to the cartilages which terminate the palpebræ, or eyelids.
