354 THE ARTICULATIONS, OR JOINTS 



The plantar ligaments (ligamenta accessories plantaria) are thick, dense, fibrous 

 structures. Each is placed on the plantar surface of the joint in the interval 

 between the lateral ligaments, to which it is connected. The plantar ligaments 

 are loosely united to the metatarsal bones, but very firmly to the bases of the 

 first phalanges. The plantar surface of each is intimately blended with the 

 transverse metatarsal ligament, and, except in the great toe, presents a groove 

 for the passage of the Flexor tendons, the sheath surrounding which is connected 

 to each side of the groove. The plantar ligament of the great toe contains two 

 large sesamoid bones. By their deep surface they form part of the articular sur- 

 face for the head of the metatarsal bone, and are lined with synovial membrane. 



The lateral ligaments (ligamenta collateralia) are strong, rounded cords, placed 

 one on each side of the joint, each being attached, by one extremity, to the posterior 

 tubercle on the side of the head of the metatarsal bone; and, by the other, to 

 the contiguous extremity of the phalanx. 



The place of a dorsal ligament is supplied by the Extensor tendon over the 

 back of the joint. 



Movements. The movements permitted in the metatarsophalangeal articulations are flexion, 

 extension, abduction, and adduction. 



IX. The Articulations of the Phalanges (Articulationes Digitorum Pedis). 



The articulations of the phalanges are ginglymoid joints. Besides the cap- 

 sular the ligaments are : 



Plantar. Two Lateral (ligamenta collateralia). 



The arrangement of these ligaments is similar to those in the metatarsophalan- 

 geal articulations; the Extensor tendon supplies the place of a dorsal ligament. 



Movements. The only movements permitted in the phalangeal joints are flexion and exten- 

 sion; these movements are more extensive between the first and second phalanges than between 

 the second and third. The movement of flexion is very considerable, but extension is limited 

 by the plantar and lateral ligaments. 



Surface Form. The principal joints which it is necessary to distinguish, with regard to the 

 surgery of the foot, are the mediotarsal and the tarsometatarsal. The joint between the astragalus 

 and the scaphoid is best found by means of the tubercle of the scaphoid, for the line of the joint 

 is immediately behind this process. If the foot is grasped and forcibly extended, a rounded 

 prominence, the head of the astragalus, will appear on the inner side of the dorsum in front 

 of the ankle-joint, and if a knife is carried downward, just in front of this prominence and behind 

 the line of the scaphoid tubercle, it will enter the astragaloscaphoid joint. The calcaneocuboid 

 joint is situated midway between the external malleolus and the prominent end of the fifth 

 metatarsal bone. The plane of the joint is in the same line as that of the astragaloscaphoid. 

 The position of the joint between the fifth metatarsal bone and the cuboid is easily found by 

 the projection of the fifth metatarsal bone, which is the guide to it. The direction of the line 

 of the joint is very oblique, so that, if continued onward, it would pass through the head of the 

 first metatarsal bone. The joint between the fourth metatarsal bone and the cuboid and external 

 cuneiform is the direct continuation inward of the previous joint, but its plane is less oblique; it 

 would be represented by a line drawn from the outer side of the articulation to the middle of the 

 first metatarsal bone. The plane of the joint between the third metatarsal bone and the external 

 cuneiform is almost transverse. It would be represented by a line drawn from the outer side 

 of the joint to the base of the first metatarsal bone. The tarsometatarsal articulation of the great 

 toe corresponds to a groove which can be felt by making firm pressure on the inner side of the 

 foot one inch in front of the tubercle on the scaphoid bone; and the joint between the second 

 metatarsal bone and the middle cuneiform is to be found on the dorsum of the foot, half 

 an inch behind the level of the tarsometatarsal joint of the great toe. The line of the joints 

 between the metatarsal bones and the first phalanges is about an inch behind the webs of the 

 corresponding toes. 



Applied Anatomy. This is considered on p. 256. 



