. Cunningham's Text-book of anatomy. Anatomy. 254 OSTEOLOGY. not complete until a period somewhat later than that for the distal epiphysis. The mode of ossification of the distal extremity is an All4,voars>Ut ^KjZt 20-24^3 exception to the general rule that epiphyses which are the first to ossify are the last to unite with the shaft. This may possibly be accounted for by the fact that the distal end is functionally more important than the rudimentary proximal end, since in man alone, of all vertebrates, does the lateral malleolus reach beyond the level of the medial malleolus. Its early uni
. Cunningham's Text-book of anatomy. Anatomy. 254 OSTEOLOGY. not complete until a period somewhat later than that for the distal epiphysis. The mode of ossification of the distal extremity is an All4,voars>Ut ^KjZt 20-24^3 exception to the general rule that epiphyses which are the first to ossify are the last to unite with the shaft. This may possibly be accounted for by the fact that the distal end is functionally more important than the rudimentary proximal end, since in man alone, of all vertebrates, does the lateral malleolus reach beyond the level of the medial malleolus. Its early union with the shaft is doubtless required to ensure the stability of the ankle-joint necessitated by the assumption of the erect position. In its earlier stages of development it has been stated, on the authority of Leboucq, Gegenbaur, and others, that the fibula as well as the tibia is in contact with the femur. This is, however, denied by Grunbaum (" Proc. Anat. Soc," Joum. Anat. and Physiol, vol. xxvi. p. 22), who states that after the sixth week the fibula is not in contact with the femur, and that prior to that date it is impossible to differentiate the tissue which is to form femur from that which forms Appears about 2nd year Fuses with shaft about 19 years At birth. About About 12 years. 16 years. Fig. 253.—Ossification of Fibula. BONES OF THE FOOT. The bones of the foot, twenty-six in number, are arranged in three groups : the tarsal, seven in number; the meta- tarsal, five in number; the phalanges, fourteen in number. Comparing the foot with the hand, the student will be struck with the great proportionate size of the tarsus as compared with the carpus, and the reduction in size of the bones of the toes as compared with the fingers. The size of the metatarsal segment more nearly equals that of the metacarpus. The Tarsus. The tarsus consists of seven bones (ossa tarsi)—the talus or astragalus-, calcaneus, navicular or scaphoid, three cuneiforms, and
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