Images in endocrinology: Archibald's metacarpal sign.

Sir,

A young girl, of age 19 years, presented with a constellation of physical features of primary amenorrhea, short stature, short neck, with dimpling of the knuckles of the fists of both hands, along with short fourth and fifth metacarpals on an X ray of the hands, and a positive Archibald's sign [Figures 1]. She was diagnosed as XO Turners syndrome.

Figure 1

(a) Classical short fourth metacarpal sign (Archibald's sign) in a girl with Turner's syndrome. (b) Absence of the fourth knuckle on the dorsum of the hand. (c) Fourth metacarpal falls short of the line joining the third and fifth metacarpal head. Tangential line drawn from the distal end of head of the fourth and fifth metacarpals passes through the distal end of third metacarpal

In 1959, Archibald, Finlay, and De Vito were the first to describe a sign that depended on the relative lengths of the lateral three metacarpals (the metacarpal finding). When a line is drawn tangentially to the circumference of the heads (distal ends) of the fourth and fifth metacarpals, the extension of this line normally passes distally to the head of the third metacarpal and does not intersect the third metacarpal (negative metacarpal finding). In some hands such a line is tangential also to the circumference of the head of the third metacarpal (borderline metacarpal finding). In others the line runs through the distal end of the third metacarpal (positive metacarpal finding).[1]

Archibald et al., (1959) labeled a borderline or positive metacarpal finding as, ′the metacarpal sign,’ characterized by shortening of the fourth and fifth digits, presenting as dimpling over the knuckles of a clenched fist, which was described as a diagnostic marker of gonadal dysgenesis.[12]

Patients having the metacarpal sign usually have delayed skeletal development with mean height less than the average expected for skeletal age. The metacarpal sign, when found in more than one generation of the same family, is without significance as far as gonadal development in any generation is concerned. In fact, it is reported to be positive in four to two percent of the normal subjects.[1] However, when it is found in a single generation, it is frequently associated with gonadal aberration and the converse is also true. The incidence of positive metacarpal sign is reported to be 33.8% in patients with Turners syndrome, with no significant difference between XO and non-XO Turners.[3] Apart from gonadal dysgenesis, the Archibald's sign is also seen in pseudohypoparathyroidism of Albert's hereditary osteodystrophy, brachydactyly, acrodysostosis, and occasionally with homocystinuria.[4]