Congenital Malformations of  Fingers and Toes

You, reader, exhibit all the symptoms of pentadactyly. Nor can you evade this condition, short of cutting off a toe or a finger, for it is merely the medical word for the possession of five fingers or toes per limb. Far better the genetically ordained five digits a limb than to fumble through life as a glum monodactyl, letting fall the condom just when you ought not to! Had your existence been delayed, you might, with leathern flap, have flitted o’er antique skies as a wing-finger or pterodactyl. You were spared the sorrow of this entry in a 1998 number of The Journal of Hand Surgery: “Another case of the monodactyly type in which we tried to lengthen three transplanted proximal toe phalanges ended in failure.”

The chief and relevant etymon is δάκτυλος daktylos, the Greek word for finger or toe. In poetic meter, dactyl is the name of one metrical foot (long-short-short or ¯ ˘ ˘. It was named after the finger because, beginning at the knuckle, a dactyl is one long bone or syllable followed by two shorter ones. For example, the first line of Henry Wadsworth Longfellow's Acadian poem “Evangeline” is a dactylic hexameter, with stressed syllables in boldface:

This is the / forest prim- / eval. The / murmuring / pines and the / hemlocks . . .

The first five feet of the line are dactyls; the sixth a trochee.
The English word poetry is metrically a dactyl.

Anatomical Anomalies
The medical terms naming congenital malformations of the fingers and toes merely add familiar Greek roots to the –dactyly base.

Polydactyly (Greek polys = ‘many’) is a congenital excess of fingers and/or toes.

Syndactyly (Greek syn ‘with, together') names webbed toes and/or fingers.

Brachydactyly (Greek brachys ‘short’) is abnormal shortness of the digits, as when the fingers have only two joints.

Arachnodactyly (Greek arachnis ‘spider’) names a condition of abnormally long, thin digits.

Macrodactyly (Greek makros ‘big, wide’) is abnormal enlargement of one or more digits.

Clinodactyly describes a bend or pronounced curvature of the little fingers toward the adjacent fourth fingers. It is a fairly common isolated anomaly which often goes unnoticed, but also occurs in combination with other abnormalities in many genetic syndromes, and in approximately 80% of individuals with Down syndrome.

Oligodactyly (Greek oligos ‘few’) is the presence of fewer than five fingers or toes on a hand or foot. It is a rare congenital malformation.
 
In Teratology
The words also appear as part of larger compound names in the annals of teratology (study of fetal anomalies) such as the serious deformity of acrocephalosyndactyly. This is a congenital syndrome characterized by a peaked head due to premature closure of the skull sutures and associated with fusion or webbing of the fingers or toes. In cruel street speech, victims are called pinhead or conehead. Akros is Greek for ‘pointed, sharp’ and kephalos means ‘head, skull.’ Almost all cases are sporadic, signifying fresh mutations or environmental insult to the genome. The offspring of a parent with the syndrome has a 50% chance of inheriting the condition.

A similar but not exactly similar cephalic malformation is oxycephaly (Greek oxys ‘sharp, pointed’), also known as turricephaly or high-head syndrome.

Teratology is the scientific study of congenital abnormalies, from Greek τέρας, τέρατος teras teratos ‘monster, marvel, thing to be stared at.’

Ectrodactyly is total congenital absence of digits. The word began as a modern Latin coinage, ectrodactylia based on Greek ek ‘out, out of, away from normal’ + troma or trosis ‘damage’ + δάκτυλος dactylos ‘finger, toe.’

 If now I offer to tiptoe away, it is not, Gott sei Dank, due to brachydactyly.




Bill Casselman, May 13, 2017

Text Copyright 2017 by William Gordon Casselman

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At the Wording Desk

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