The anatomy of the human skeleton / by J. Ernest Frazer.

  • Frazer, John Ernest Sullivan, 1870-1946.
Date:
1920
Catalogue details

Licence: In copyright

Credit: The anatomy of the human skeleton / by J. Ernest Frazer. Source: Wellcome Collection.

    271/396 (page 185)
    Fourth Metatarsal.—Notice the very oblique plane of the base, the heaviness of this end of the bone, with the appearance of a notch and twist in it ; this, with the fact that its basal facet is not triangular but rather four-sided, is enough to distinguish the bone. There is a small marginal facet internally for the outer cuneiform, because this bone projects very slightly beyond the cuboid, and this facet is continuous with that for the third metatarsal. A single facet externally for the fifth metatarsal: just in front of this is the notch or pit that gives the crooked appearance to the proximal part of the bone, for the strong interosseous ligament which connects it with the last bone of the series. Fifth Metatarsal.—The proximal end has a very oblique tarsal facet, a slightly concave metatarsal facet, and a prominent styloid process: to this are fastened the Peroneus brevis at the point and, on the dorsal side of its base, the Peroneus tertius. This latter muscle has usually a fairly extensive aponeurotic insertion spreading along the dorsal border of the bone, where there is a sharp ridge that marks its attachapent and that of the dorsal fascia with wfpfh it is blended. The Abductor metatarsi quinti, deep fibres of the abductor of the little toe, is attached, with much ligamentous tissue, to the outer and under part of the process, and the Flexor brevis has a part of its origin from the plantar surface further in. The strong base and styloid process may support some weight when the outer arch is sufficiently flattened to bring them to the ground; this probably occurs when any pressure is made on the arch beyond that supported in balancing the body, and thus there is no extra strain thrown on the shaft or small head. The whole of the dorsal and outer surface of the bone can be palpated, but its lower aspect is covered by the marginal musculature. The heads of the four metatarsals are comparable with those of the metacarpals (see pp. 105 et seq.), and the same may be said about the structure of the metatarso¬ phalangeal joints, save that the transverse metatarsal ligament extends to the capsule of the great toe and has an Adductor muscle arising from it. The shafts, however, differ from those in the hand in that the markings for inter¬ osseous muscles, being arranged on a slightly different plan, do not render each shaft distinguishable. Fig. 156.—Left fifth metatarsal. Dorsa and plantar aspects. A. is the sub¬ cutaneous surface outside the dorsal ridge for Peroneus tertius ; a tendinous slip from Peroneus brevis passes on to this surface along the groove B., covered by ligamentous fibres attached to the margins of the groove. PHALANGES. Compared with those in the hand, the phalanges of the foot in general are recognised at once (Fig. 85) by their thin and rounded shafts and large extremities : in the big toe they are broad and strong, but short for their size, and the first shows an obliquity of its base (Fig. 138), which enables one to place it at once on its proper side.