of the plantar ligaments compels those afflicted with valgus to seek relief.

Fig. 27.

Valgus is generally occasioned by debility; less frequently it proceeds from inflammation of the structures in the sole of the foot and its consequences; and occasionally it is of spasmodic origin.

Thus, as their names imply, there are certain similarities of appearance between congenital and non-congenital talipes, though the distinctions are so marked that the two can never be confounded. In the spasmodic forms of distortion, however, the difference between congenital and non-congenital distortions is occasionally less well marked than when distortion arises from other causes.

Complex varieties occur, also, as non-congenital affections; they are, however of rare occurrence, with the exception of equino-varus, to which attention has been above directed.

WHEN muscles remain long inactive they waste;ultimately fatty degeneration ensues, and the muscular tissue is in part or wholly lost. Any cause having a tendency to destroy, and destroying mobility, occasions this result. Thus, in utero, the muscles which occasion talipes varus destroy the natural movements of the foot, by their tension, and by the rotation they induce of the tarsal bones on their axes. The contracted muscles become more or less immoveable, and when spasm has ceased to exist, they remain still shortened, in consequence of the changed positions of the bones, and by reason of their own contractility. Their antagonists, also, from want of power to overcome the retracted muscles, remain extended.

But, although the contracted muscles are shortened, their extremities being approximated, they have not at birth undergone structural shortening; nor, indeed, does structural shortening occur, until inaction, or some other abnormal condition, has destroyed the power of the muscle or if

structural shortening is ever found at birth, it is so rare as to prove the rule. That structural shortening has not taken place at birth is proved by the restoration of the shape of the foot through mechanical means alone. And further, it is proved by the unaided restoration of the limb on cessation of spasmodic action, when the bones do not interfere to prevent the antagonistic action of the muscles, as is witnessed in talipes calcaneus, and in club-hand. In these congenital affections, as spasm ceases to affect one set of muscles, their opponents resume their power and restore the normal shape of the limb.

By structural shortening of muscle is understood permanent approximation of its extremities without power of elongation. Atrophy, or structural change induced by inflammation or other cause, always precedes structural shortening.

It is pretended by some that the contracted muscles are, in their development, too short for the normal position of the foot. Others assert that shortening of the muscle is subsequent to the production of distortion, and commences simultaneously with, or immediately after, distortion. But both of these hypotheses are disproved by the restoration of the limb to its normal position by traction, or by the natural antagonistic force of the muscles themselves.

Atrophy soon follows on inaction, and also degeneration. It is found to occur even in the fœtus: but, whether in the fœtus or after birth, the extended muscles are first affected, and later the contracted muscles. In an instance recorded by my colleague, Mr. W. Adams, this fact is well illustrated. The child lived only some few hours after birth. The distortion (talipes varus) was of the most severe form. Fatty degeneration was so far advanced, that—

"The extensor longus digitorum and peroneus tertius might almost be said to be absent, as far as their muscular fibres were concerned; their tendons existed, but were of very small size, and connected above with an extremely attenuated layer of muscular fibres, representing the extensor muscle; the muscular fasciculi were intermixed with fat dipping between them, so that their dissection could only be conducted to a very limited extent, and it was impossible to trace them to any connection with, or origin from, the bones or interosseous ligaments. The space between the outer border of the tibialis anticus and the fibula, which should be occupied by the fleshy belly of the extensor longus digitorum, was entirely filled with fat, in which no muscular fibres were traceable even with the microscope; the existence of the rudimental portion of this muscle, above described, was only demonstrated by the most careful dissection from below upwards, beginning from the tendons on the dorsum of the foot." and microscopical appearances to indicate a state of arrested development of the muscle, and subsequent decay and degeneration." 1

"Dr. Quain considered both the general

But in the case now cited, in which the extended muscles had undergone such extensive degeneration—

"The tibiales (anticus and posticus) muscles were fully developed, if not somewhat hypertrophied, and their tendons extremely tense.' "2

After birth, it is remarkable how rapidly structural change is occasionally effected in muscle. In the course of a few weeks (a fortnight, says Mr. Paget), the colour of the muscle may have undergone considerable change. But, when structural change is occasioned by inaction, years may elapse before it is induced. The muscle, when this change occurs, becomes pale, stained with yellowish or fawn-coloured patches, which coalesce, and the entire muscle perhaps assumes an uniform fawn colour; the transverse striæ disappear, the

1 Transactions of the Pathological Society,' p. 456, vol. iii.

fibres become disintegrated, and are at last totally lost. The muscles are then transformed into yellowish or whitish fat, their forms are no longer traceable, but they coalesce into a mass not bearing a trace, perhaps, of the distinctive characters of muscle. The skin then loses its softness and elasticity, the nerves become atrophied, the ligaments are softened, and the bones even degenerate with the rest of the limb. In some rare instances these changes are met with to a very remarkable extent. A short time since, Mr. Quekett exhibited, at his Lectures at the College of Surgeons, an instance of distortion of the foot, in which no muscular fibre was to be found in the leg, so complete was the fatty change that had been induced.

In a paralysed limb, the nerves passing to the affected muscles are always atrophied after some duration of paralysis; and the spinal cord, corresponding to the paralytic lesion, undergoes atrophy; it may be a lateral portion, or it may be the entire substance of the lower portion of the cord; it shrinks, becomes hard, and acquires a deeper hue. The bones become light, and their walls thin; the cancelli are increased in size, and are filled with oily matter.

When paralysis of the flexors of the foot, for instance, occurs, so that the foot dangles loosely, and the anterior portion of the foot drops, the limb is rendered comparatively useless until retraction of the extensors of the foot takes place; then, the limb is, so to say, braced up, and talipes equinus is produced. By this provision a certain amount of power is restored to the limb, and it again becomes a more useful member. Retraction increases (in proportion to the amount of paralysis), until the heel is uplifted, and the anterior portion of the foot is alone in contact with the ground.