Acquired brachydactyly may arise in several ways. Occasionally it is to be traced to an arrest of development either due to an injury during childhood or adolescence, or without apparent explanation, but more frequently it is a result of disease. In younger subjects the most common cause is the destruction of bone in tuberculous disease, which may practically eliminate a phalanx, leaving the rest healthy. In older people it may be met with in cases of perforating ulcer, the proximal phalanx of the great toe and sometimes other bones undergoing a slow and painless disintegration, which is manifested chiefly by a progressive shortening of the digit with few or none of the more obvious signs of caries. FOOTNOTES [1] “Les doigts, et particulièrement les trois derniers, sont sujets à une flexion permanent involontaire; à laquelle on a donné le nom de ‘contracture,’ et que quelques auteurs out appelée en latin ‘crispatura tendinum.’” This name is usually attributed to Boyer himself. (“Maladies Chirurgicales,” vol. ii. p. 55, first edition, 1826). [2] See “The Hand as a Diagnostic Factor in Diseases of the Nervous System” (Long-Fox: _Med. Annual_, 1891, p. 54). [3] _Transactions of the College of Physicians_, 1895, p. 67. [4] _Therapeutic Gazette_, February 15, 1892. [5] _Ibid._ October 16, 1893. [6] _Brit. Med. Journal_, 1888, vol. i. p. 961. [7] See _Transactions of the Anatomical Society_ (1892), “On the Course and Relations of the Deep Branch of the Ulnar Nerve,” by W. Anderson. [8] “Orteil en Marteau” (Baillière, 1888). [9] “Traité des Maladies Chirurgicales.” [10] “The Human Foot,” 1889. [11] It is unnecessary to enter minutely into the conformation of the inter-phalangeal joints, but it must be understood that the proximal attachment of the plantar fibres of the lateral ligaments lies at a point below the centre of the dorsal half of the condylar curve, and hence these fibres become more and more stretched as their distal attachment is carried upwards in the direction of extension, until at last the motion is checked by their tension. The point at which the arrest occurs necessarily depends upon the relation existing between the length of the fibres and that of the radii of the condylar curve. If the ligaments of a joint be artificially elongated by acrobatic training in early life, they may lose their power of fixing the range of movement, and extension may then go on until it is stopped by contact of bones or by contraction of opposing muscles. The latter factor, of course, is always an important one, but it does not affect the present aspect of the question. [12] It must be recollected that morphologically the metatarso-phalangeal joint of the great toe corresponds to the first inter-phalangeal joint of the smaller digits. [13] _Lancet_, 1885, vol. i. [14] _St. Thomas’s Hospital Reports_, vol. xxii. (1893). [15] _Journal der Chirurg. und Augenheilk._, v. Graefe u. Walther, 1824.