58 HUMAN ANATOMY. 



above its articulation with semi-lunar. This process gives at- 

 tachment to annular ligament, flexor brevis minimi digiti, flexor 

 ossis metacarpi minimi digiti, and is grooved for passage of other 

 flexor tendons. External surface articulates with os magnum 

 and internal with cuneiform. 



Muscular attachments are those to unciform process. Each 

 carpal bone is developed from a single ossific centre. 



Table of Articulations of Carpal Bones. Scaphoid, five; 

 semi-lunar, five; cuneiform, three; pisiform, one; trapezium, 

 four; trapezoid, four; os magnum, seven; unciform, five. 



THE METACARPUS are five long bones, resembling each other, 

 and presenting a shaft and two extremities. Anterior surface is 

 concave, posterior convex; superior extremity irregular for ar- 

 ticulation with carpal bones and with the adjoining bones; in- 

 ferior extremity presents rounded head for articulation with 

 phalanges. The first metacarpal for thumb is supported on 

 trapezium, articulates with first phalanx, and has three muscles 

 attached first dorsal interosseus, flexor, and extensor ossis meta- 

 carpi pollicis; the second metacarpal by three, trapezium, trape- 

 zoid, and os magnum, articulates also with third metacarpal and 

 second phalanx, and has five muscles attached first and second 

 dorsal interosseus, first palmar interosseus, flexor carpi radialis, 

 and extensor carpi radialis longior; the third metacarpal sup- 

 ported by os magnum, articulates also with second and fourth 

 metacarpal and third phalanx, and has five muscles attached 

 flexor brevis pollicis, extensor carpi radialis brevior, adductor 

 pollicis, and second and third dorsal interosseus. The fourth 

 metacarpal is supported on os magnum and unciform, articulates 

 with third and fifth metacarpal and fourth phalanx, and has 

 three muscles attached second palmar and third and fourth dor- 

 sal interosseus. The fifth metacarpal, supported on unciform, 

 articulates with fourth metacarpal and fifth phalanx, and has five 

 muscles attached flexor ossis metacarpi minimi digiti, flexor 

 and extensor carpi ulnaris, and fourth dorsal and third palmar 

 interosseus. 



Ossific centres are two for each bone, one each for shaft 

 and head, except thumb, which has one each for shaft and 

 base, resembling the phalanges. 



PHAL-ANGES. Each finger has three phalanges, except the 

 thumb, which has but two. Palmar surface concave, dorsal con- 

 vex; the superior extremity articulates with head of metacarpal, 

 and the inferior, concave from side to side, convex from before 

 backward, articulates with second phalanx, which presents an 

 opposite arrangement, except in the thumb, where it articulates 

 with ungu-al or terminal phalanx. 



