The phalanges of the foot are the bones of the toes, and number in all fourteen. Except the great toe, each consists of three phalanges, distinguished as first (proximal), second and third (distal) ; in the great toe the second phalanx is absent.

There is thus a similarity as regards number and general arrangement with the phalanges of the fingers. With the exception of the phalanges of the great toe, which are larger than those of the thumb, the bones of the toes are smaller and more rudimentary than the corresponding bones of the fingers. In all the pha- langes, the nutrient foramen is directed toward the distal extremity.

The phalanges of the first row are constricted in the middle and expanded at either ex- tremity. The shafts are narrow and laterally compressed, rounded on the dorsal and concave on the plantar aspects. The base of each presents a single oval concave facet for the convex head of the corresponding metatarsal, whilst the head forms a pulley-like surface [trochlea phalangis], grooved in the center and elevated on each side for the second phalanx.

The phalanges of the second row are stunted, insignificant bones. Their shafts, besides being much shorter, are flatter than those of the first row. The bases have two depressions, separated by a vertical ridge, and the heads present trochlear surfaces for the ungual phalanges.

The third, or ungual phalanges are easily recognised. The bases articulate with the second phalanges; the shafts are expanded, forming the ungual tuberosities which support the nails, and their plantar surfaces are rough where they come into relation with the pulp of the digits.

The muscles attached to the various phalanges of the foot

The first phalanx of the hallux gives insertion to the flexor haUucis brevis; abductor halluois; adductor hallucis transversus and obliquus; extensor digitorum brevis.

The first phalanx of second toe : The first and second dorsal interosseous.

The first phalanx of third toe : Thii'd dorsal interosseous; first plantar interosseous.

The first phalanx of fourth toe : Second plantar interosseous; fourth dorsal interosseous.

The first phalanx of fifth toe: Third plantar interosseous; flexor digiti quinti brevis; and abductor digiti quinti.

The terminal phalanx of hallux: Flexor hallucis longus; extensor hallucis longus.

 

Ossification

Like the corresponding bones of the fingers, the phalanges of the toes ossify from a primary and a secondary nucleus. In each, the center for the shaft appears during the eighth or ninth week of embryonic life. The secondary center forms a scale-like epiphysis for the proximal end between the fourth and eighth years, and union takes place in the eighteenth or nineteenth year - i. e., earlier than the corresponding epiphj'ses in the fingers. The primary centers for the third phalanges appear at the distal extremities of the bones.

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