thumb1 (thum)

[Early mod. E. also thumbe, thoumbe; that of all other animals. This perfection is seen in the free movements of the member, and its ready apposability to any one of the other digits or to them all together. The extent to which it stands away from the rest indicates the great power and accuracy with which the hand may be used in grasping, as a prehensile organ, as in holding a pen or a knife. Such freedom and versatility are accom 6319 plished by the peculiar construction of the joint at the base of that metacarpal which supports the thumb. This articulation with the carpal bone called the trapezium is by means of reciprocally saddle-shaped articular surfaces, having the ease and extent of movement of a ball-and socket or universal joint, though by a different mechanism. It is the only instance of such an articulation in the human body. The metacarpal bone of the thumb also differs from the rest in its mode of o ification, having, like the phalanges, a proximal and not a distal epiphysis - that is, the gristly cap that o ifies separately from the rest of the bone is on the end of the bone next to the wrist. The thumb is also peculiar in having but two joints or phalanges, the other digits having three apiece. The thumb is likewise moved by more muscles than those which actuate any other digit. They are a long deep flexor, and three separate long extensors (one for each phalanx and for the metacarpal bone), these four muscles coming to the thumb from high up in the forearm; and also several short muscles confined to the hand, the short flexor, the abductor, the adductor, and the opponens altogether eight muscles in long and short sets of four each. The short muscles form the thenar eminence, or fleshy ball of the thumb. Speke cloos all thyng, as thombe in fiste. Booke of Precedence (E. E. T. S., extra ser.), i. 110. 2. The inner, radial, or first digit of the fore paw of any animal. When there are five digits, the first of these always corresponds to the human thumb; otherwise not.-3. The movable radial digit of a bird's manus or pinion, which bears the packet of feathers called the alula or bastard wing, and which is usually movable apart from the rest of the bones. By some it is to to the human thumb. It is more probably the homologue of the index or forefinger. See cut under pinion. 4. The thumb of the foot; the hallux; the inner digit of the foot, called the great toe in man. In quadrumanous or four-handed animals, as monkeys, opo ums, and some others, it functions as a thumb, stands apart from the other digits, and so converts the hind foot into a grasping member, or "hand." Its condition in man is quite exceptional in comparison with those animals to which he is nearest allied zoologically. 5. The hind toe of a bird (except a three-toed woodpecker); the hallux; when there are two hind toes, the inner one of these (except in trogons). It is functionally a thumb, opposing other digits, and fitting the foot for grasping or perching. It is often absent or very small and functionle . Its length, low insertion, and entire freedom of movement are highly characteristic of the pa erine series of birds, and varying conditions of its principal flexor tendon give rise to nomo pelmous and correlated terms. Ball of the thumb. See def. 1.- His fingers are all thumbs. See finger. Horn for the thumbt. See horn. - Rule of thumb. See rulel. - To bite the thumb att. See bite. To fash one's thumb. See fash1. - Under one's thumb, under one's power or influence; quite subservient. She... is obliged to be silent! I have her under my Richardson, Sir Charles Grand is on, III. xxxviii. thumb. thumb1 (thum), v. t. [ Shall I thumb Holy Books, conf in'd With Abigails, forsaken? Prior , The Female Phaeton. Horace and Virgil must be thumbed by a boy, as well before he goes to an apprenticeship as to the university. Steele, Tatler, No. 173. 3. To turn (one's gla ) over the thumb: an old custom when persons were drinking together, intending to show that the gla had been emptied so that the small drop remaining would lie on the thumb-nail without running off. Compare supernaculum . - To thumb the hat. See hat1 . thumb2 (thum), n. [Prob. a veterinary corruption of thrum2 .] Palpitation of the heart in domestic animals, as the horse, the result of functional or organic disease. See palpitation . thumb-band (thum'band), n. A twist of any thing as thick as the thumb. thumb-bird (thum'bėrd), n. The miller's thumb, a bird: so called from its tiny size. thumb-blue (thum'blö), n. Indigo in the form of small balls or lumps, used by washerwomen to give a clear or pure tint to linen, etc. thumb-cleat (thum'klēt), n. Naut., a cleat, resembling a thumb, for preventing the topsail reef-earings from slipping, and for other purthumb-cock (thum'kok), n. A small cock with a thumb-piece, or small cro -handle, adapting it to be turned by the thumb and finger. thumbed (thumd), a. [