INTERMETACARPAL JOINTS 223 
A number of special short ligaments connect two or more adjacent bones; only the most 
distinct of these will be described here. F 
The accessory carpal bone is connected with adjacent bones by three ligaments ( Fig. 234). 
The proximal one is a short band which extends from the accessory carpal in front of the groove on 
its lateral face and is inserted into the distal end of the radius behind the groove for the lateral 
extensor tendon. A middle band connects the accessory with the ulnar carpal. The distal liga- 
ment consists of two strong bands which pass from the distal margin of the accessory to the fourth 
carpal and the proximal end of the fourth 
metacarpal bone; these bands transmit the 
action of the muscles which are inserted into 
the accessory carpal bone. The other bones 
of the proximal row are connected by two 
dorsal ligaments, which are transverse in direc- 
tion, and two interosseous ligaments. An 
oblique ligament passes from an eminence on 
the volar surface of the radial carpal bone to 
a small depression on the radius medial to the 
facet for the accessory carpal bone. 
Two ligaments connect the proximal and 
distal rows posteriorly. The medial one joins 
the radial to the second and third carpal, and 
the lateral one attaches the ulnar to the third 
and fourth carpals. 
The bones of the distal row are con- 
nected by two strong transverse dorsal 
ligaments and two interosseous ligaments. 
There are four carpo-metacarpal liga- 
ments. Two oblique dorsal ligaments (Ligg. 
carpometacarpea dorsalia) connect the third 
carpal with the large metacarpal bone. Two 
interosseous ligaments pass downward from 
the interosseous ligaments of the distal row 
to end in depressions of the opposed surfaces 
of the proximal ends of the metacarpal bones. 
Volar ligaments (Ligg. carpometacarpea vo- 
laria) connect the second and third carpal 
bones with the metacarpus. Other short 
special ligaments have been described, but 
some of them at least are artefacts. 
Movements.—Taking the joint as 
a whole, the chief movements are flex- 
ion and extension. In the standing Fic. 239.—Lerr Carpat Jornts oF Horse; Vorar View. 
AccessoRY CARPAL AND CAPSULE HAVE BEEN RE- 
position the joint is extended. When Woven, 
the joint is flexed, slight transverse R, Distal end of radius; M, medial ligament; L, 
movement and rotation can be pro- lateral ligament; 1, 2, ligaments connecting radial carpal 
= = bone and radius; 3, ligament connecting intermediate 
duced by manipulation. The dorsal carpal with radius; 4, stump of ligament connecting inter- 
part of the capsule is, of course, tense mediate and accessory carpal; 5, ligament connecting radial 
during flexion, the volar part in exten- and second carpal; 6, 6’, ligaments connecting second 
2 carpal and metacarpal bones; 7, 7’, ligaments connecting 
sion. third carpal and metacarpal bone; 8, ligament connecting 
ulnar and third and fourth carpal bones; 9, deep short part 
of medial collateral hgament; 10, 11, 12, radial, inter- 
mediate, and ulnar carpal bones; 13, 14, 15, second, third, 
and fourth carpal bones; 16, 16’, 17, metacarpal bones. 
(Of the preceding volar ligaments, 1, 3, and 8 are distinct 
from the capsule.) 
The movement practically all occurs at 
the radio-carpal and intercarpal joints, the 
articular surfaces of which are widely separ- 
ated in front during flexion, but remain in 
contact behind. The distal row remains in 
contact with the metacarpus. The inter- 
mediate and ulnar carpals move together as 
one piece, but the radial does not move so far as the intermediate, so that the dorsal and inter- 
osseous ligaments connecting these bones become tense and oblique in direction. 
INTERMETACARPAL JOINTS 
The small joints formed between the proximal ends of the metacarpal bones 
(Articulationes intermetacarpex) are enclosed by the carpal joint capsule, as des- 
eribed above. The opposed surfaces of the shafts of the bones are closely united by 
an interosseous metacarpal ligament (Lig. interosseum metacarpi), which often 
undergoes more or less extensive ossification. 
