iio Anatomy of Skeleton 



Unciform. Recognised at once by the prominent hook on its palmar aspect, from 

 which its name is derived. This process forms part of the inner wall of the flexor 

 sheath, so is concave externally. The concavity is in relation with the synovial cover- 

 ing of the flexor tendons of the little finger : the tip gives attachment to the annular 

 ligament : the convexity outside the tip affords origin to the Opponens distally and 

 Flexor brevis minimi digiti proximally : the upper border has the piso-unciform 

 ligament attached to it, and the lower border has fibres of Opponens arising from 

 it. The inner and lower part of the process is grooved by the deep ulnar nerve turn- 

 ing round it : the artery takes a wider sweep, and so changes its relation to the nerve 

 (see Fig. 87). 



Above the hook the front surface is for ligamentous attachments, and further in 

 is covered by the fibres that connect the pisiform and inner metacarpal bases. 



Outer surface with facet behind for os magnum and roughened in front of this for 

 interosseous ligament. Lower aspect has a continuous articular surface showing two 

 facets separated by a low crest, for the fourth and fifth metacarpals. Upper or supero- 

 internal surface carries a concavo-convex facet for cuneiform, and, external to this, is 

 prolonged proximally to an angle which articulates with semilunar. Dorsal surface 

 large and roughened for ligaments. Inner surface, nearly reduced to a point, gives 

 attachment to ligaments. 



Observe that the unciform process marks by its lower edge the line of the carpo- 

 metacarpal articulation. 



Much of the position of the carpus can be appreciated during life, and many of its 

 bones examined. On the front aspect, the tuberosity of the scaphoid is felt at the 

 proximal end of the thenar eminence, deep and external to the radial flexor tendon 

 where this disappears. The trapezium is covered by the thenar muscles, but can be 

 indistinctly felt through these just distal to the scaphoid : metacarpal movement to 

 and fro does not affect the mass thus felt. The line which curves round and limits the 

 upper end of the thenar eminence passes over the scaphoid-trapezium joint, so that 

 the scaphoid tuberosity is found between this line and the distal one of the two deep 

 creases which cross in front of the wrist. The pisiform is easily felt a little below this 

 last line, at its inner end and in the base of the hypothenar eminence. Between the 

 pisiform and scaphoid, the proximal convexity of the curved upper margin of the 

 carpus reaches the middle third of the upper of the two transverse deep lines, sc that 

 this line can be taken as giving that of the wrist- joint : this part of the carpus cannot 

 be felt, of course, being covered by flexor tendons, but it may be noted that the semi- 

 lunar lies in the middle, between the two transverse creases. The hook of the unci- 

 form can be felt on pressing below and external to the pisiform, and a line drawn out 

 from its lower edge marks the lower level of the carpus. 



The presence of tendons interferes with recognition of the separate bones on the 

 dorsum, though they may sometimes be made out in thin hands. The carpus, as a 

 whole, lies between the bases of the metacarpus and the lower end of the radius, both 

 of which lines can be found. The joint between os magnum and semilunar lies about 

 halfway between the base of the third metacarpal and the end of the radius (see Fig. 93). 

 Trapezium and part of scaphoid lie in the floor of the area between the long and short 

 extensor tendons of the thumb. 



SEPARATE BONES OF METACARPUS. 



With the exception of the first, the metacarpals articulate with each other at their 

 bases, so bear facets on their sides here, and also impressions for interosseous ligaments : 



