582 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION, 
Deep Palmar Fascia.—Beneath the long flexor tendons of the palm a broad expanse 
of strong ligamentous fascia exists, which affords a powerful support to and renders 
tense the otherwise loosely connected and mobile carpal and metacarpal bones. This 
remarkably firm aponeurosis, though more or less interlaced into a single broad sheet, 
may nevertheless, for convenience’ sake and mode of action, be described as two planes 
of fibro-ligamentous tissue. 1. The longest and thickest band (D.p.f’, fig. 51) appears 
as a continuation of the flexor carpi radialis, and arises as a semilune from the lower 
end of the ulna. Widening the breadth of the first and second metacarpal bones, it 
runs onwards and lengthwise to their distal extremities, where, inserted into the two 
sesamoid bones of the respective digits, it merges into the palmar and lateral ligaments 
which brace together the distal articular end of the metacarpal and proximal end of 
the first phalangeal bone. 2. The shorter and thinner aponeurotic ligament (D.p.f’) 
is partly continuous with the first, but placed rather underneath. Besides attachment 
and continuity with the wrist-joint, it likewise arises by a firm attachment from the 
carpal bones, and, spreading more transversely than the first band, is fixed to the surface 
of the ligaments of the carpus—processes, however, diverging to the second, third, 
fourth, and particularly and strongly to the proximal end of the fifth metacarpal bone. 
Use. As mentioned, the entire ligament is a steadier and bracer of the carpus. It 
likewise furnishes origin to the interossei, thus in some respects acting as a flexing 
agent. The longer pollicial moiety may be considered a powerful agent in flexion 
through the direct continuity and long leverage of the flexor carpi radialis &e. 
Wristjoint and Carpo-metacarpal Ligaments.—Of the former of these articulations, 
on the dorsal surface of the wrist the ligamentous substance is considerably interwoven 
together, and constitutes a wide sheet of glistening fibre of fair thickness, rather than 
separate well-defined bundles. What properly represents the posterior ligament (po, 
fig. 29) is a broad oblique plane fixed to the end of the radius and scaphoid, and from 
this stretches across the carpus towards the metacarpal bone of the fifth digit. Another, 
deeper carpo-metacarpal plane of fibres strikes more directly forwards than the last from 
the carpal to the metacarpal bones. With a trifid division, but imtimately connected 
the one with the other, it passes to the three middle carpo-metacarpal joints. There 
is, besides, an oblique segment of this carpo-metacarpal sheet (c.m), which runs out- 
wards to the root of the pollicial metacarpal bone. ‘The internal lateral ligament of the 
wrist (7./*) is almost entirely dorsal, bridges the joint betwixt the ulna and posterior 
ligament, sending fibres to the cuneiform, but hardly any to the pisiform bone. The 
external lateral ligament (¢./*) lies partly upon the outer edge of the inferior end of the 
radius, but is chiefly palmar in situation; it is broader and stronger than its fellow 
internal ligament. The anterior ligament of the wrist (an, fig. 30) is stout and 
triangular-shaped. The narrow end springs firmly from the radius, above its epiphysis, 
and with a somewhat oblique direction; the fibres spread fan-shape, sending semide- 
tached portions to the roots of the four inner metacarpals. A similarly shaped deeper 
