81

61
Tibalis anticus (Pl. XI. XIV. 8). - This muscle is overlapped and concealed by the
peroneus; it rises partly in common with that muscle, and partly by separate short
tendinous threads from the outer part of the head of the tibia; it gradually becomes
narrower, and finally tendinous two-thirds of the way down the leg; its strong tendon
glides through the oblique pulley* in front of the distal end of the tibia, expands as it
passes over the ankle-joint, and is inserted into the anterior part of the proximal end of
the tarso-metatarsal bone, sending off a small tendinous slip to the aponeurosis covering
the extensor tendons of the toes, and a strong tendon (8') which joins the fibular side of
the tendon of the following muscle.

Extensor longus digitorum (Pl. XIV. 9). - This lies between the tibialis anticus and the
front and outer facet of the tibi, from which it derives an extensive origin; its tendon
commences half-way down the leg, runs along the anterior part of the bone, first under
the broad ligamentous band representing the anterior part of the annualar ligament, then
through a ligamentous pulley, and inclines to the inner or tibial side of the anterior sur-
face of the metatarsal bone, where it expands and divides into three tendons. Of these
the innermost is given off first, and subdivides into two tendons, one of which goes to
be inserted into the base of the last phalanx of the second toe; the other portion is prin-
cipally inserted into the middle toe. The second tendon is inserted by distinct
portions into the second, third and last phalanges of the middle toe. The third tendon
supplies the outer toe.

Extensor brevis digitorum (Pl. XIV. 10). - A small extensor muscles arises from the
insertion of the tibialis anticus, and sends its tendon to the outer side of that of the great
extensor digitorum.

Extensor pollicis brevis (Pl. XIV. 11). - An extensor of the small innermost toe arises
from the upper and inner side of the tarso-metatarsal bone.

Peroneus medius, Cuv., Accessorius flexoris digitorum, Vicq. D'Azyr (Pl. XI. XIV. 12).
-This strong penniform muscle arises fleshy from nearly the whole of the outer surface
of the fibula, also from the posterior part of the tibia and the interosseous space; the
tendon of the biceps perforates its upper part in passing to its insertion. It ends in a
strong flat tendon at the lower third of the leg, which tendon runs through a particular
sheath at the back part of the tarsal pulley, becomes thickened and expanded as it ad-
vances forwards beneath the tarsus, joins the tendon of the flexor perforatus (1), and
forms with it the expansion which finally divides into three strong perforating tendons,
which bend the last joints of the three long toes.

In the outer, or fourth toe, both the perforans and perforatus tendons are cont[a]ined by
a double annular ligament; the exterior one being continued from the adjoining toe, the
inner and stronger one from the sides of the proximal phalanx of the outer toe.

* This is ossified in the Bustard and most true Grallæ.