266 



OSTEOLOGY. 



GROOVES FOR SESAMOID BONES 



SHAFT 



The first metatarsal, or metatarsal bone of the great toe, the shortest of the 

 series, is remarkable for its stoutness. Its proximal end or base, where the bone 



is provided with a reniform facet for articula- 

 tion with the first cuneiform, is wider from the 

 dorsal to the plantar aspect than from side to 

 side. The concavity of the kidney -shaped arti- 

 cular area is directed to the fibular side. As a 

 rule the lateral aspects of the base are non-arti- 

 cular, though occasionally on its lateral side there 

 is a "pressure" facet for the base of the second 

 metatarsal bone. The plantar basal angle pro- 

 jects proximally and laterally, and forms a pro- 

 minent tubercle which is pitted for the insertion 

 of the tendon of the peronseus longus muscle, 

 whilst its tibial margin is lipped by a surface 

 for the attachment of part of the tendon of the 

 tibialis anterior. The body, short, thick, and pris- 

 matic on section, tapers rapidly towards the head, 

 the distal and plantar surfaces of which are articular. 

 The former is convex in both directions, and 

 supports the proximal or first phalanx. It is con- 

 fluent with the plantar articular surface, which is 

 divided by a median ridge into two shallow grooves, 



FIG. 273. THE FIRST METATARSAL O f which the tibial is the wider. In these grooves 



are lod g ed the two sesamoid bones of the metatarso- 

 phalangeal joint. On either side of the head, the 

 bone is pitted for the strong collateral ligaments of the joint. 



The second metatarsal, the longest of the series, has a base of wedge-shaped 



TUBEROSITY Tibialis anterior 



Aspe E ct) P 



HEAD 



SHAFT 



BASE 



II. METATARSAL 



.FIRST 

 CUNEIFORM 



I. METATARSAL 

 (pressure facet) 



III. METATARSAL 



III. METATARSAL 



II. METATARSAL' 



IV. METATARSAL 

 IV. METATARSAL 



THIRD CUNEIFORM 



III. METATARSAL 



A. Medial sides. 



V. METATARSAL 



B. Lateral sides. 



FIG. 274. VIEW OF THE BASES AND SHAFTS OF THE SECOND, THIRD, AND FOURTH METATARSAL BONES 



OF THE RIGHT FOOT. 



form, the proximal aspect of which articulates with the second cuneiform. On 

 its tibial aspect, near its dorsal edge there is a small circular facet for the first 



