1206 SURFACE AND SURGICAL ANATOMY. 
which separates the forearm from the hand, is the pisiform bone, above which is the 
tendon of the flexor carpi ulnaris, passing to be inserted into it. The hook of the 
unciform is felt deeply beneath the radial side of the hypothenar eminence, and a 
full finger’s breadth below and external to the pisiform. 
The bases of the first, third, and fifth metacarpals, all of which can be readily 
identified on the dorsal aspect, furnish a sufficient guide to the line of the carpo- 
Superficial palmar arch— 
Deep branch of ulnar ~Deep palmar arch 
artery 
Hook of unciform bone — Anterior annular ligament 
Deep branch of ulnar nerve : . : 
“ — Ridge of trapezium 
Ulnar nerve - 
As Radial artery, 
Pisiform bone- 
Palmaris longus— — Median nerve 
Styloid process of ulna- —Styloid process of radius 
Ulnar artery ——— Radial artery 
—— Flexor carpi radialis 
Fic. 813.—PALM OF HAND. 
metacarpal articulations. At the base of the third metacarpal is a tubercle, which 
can be felt projecting from its dorsal aspect at a point 1? in. vertically below the 
tubercle upon the back of the lower end of the radius. This metacarpal tubercle 
marks the insertion of the extensor carpi radialis brevior, the favourite site for 
the development of a “ ganglion,’ which may frequently be ruptured by pressing 
it firmly against the tuberele. Anteriorly, the carpo-metacarpal articulations 
correspond to the lower border of the anterior annular ligament. 
The prominences of the knuckles are formed entirely by the heads of the 
metacarpal bones. Anteriorly, the metacarpo-phalangeal articulations are situated 
} in. above the level of the web of the fingers; posteriorly, the joints may be felt 
as a groove immediately above the projecting ridge at the base of the first 
phalanges. A well-marked crease crosses obliquely over the anterior aspect of the 
metacarpo-phalangeal joint of the thumb. To cut into the first interphalangeal 
