Part 47

=Flexor Longus Hallucis= (Fig. 17, No. 7; Fig. 25, No. 2). Location.—The posterior tibial region.

Origin.—By two tendinous heads: one from the posterior part of the femur, just below the two condyles; the other from the outer part of the external condyle of the femur. The deep flexor passes between these two heads.

Insertion.—Becoming tendinous at the lower third of the leg, passes beneath the superficial flexors in a special canal on the outer side of the tibial cartilage, and extends through the large canal of the hypotarsus (Fig. 12, No. F, 5) next to the shaft, then down to the apex of the accessory metacarpal bone. It is inserted to the tubercle on the inferior proximal end of the ungual phalanx.

Shape.—Large, fusiform.

Relations.—With the exterior of the deep flexors.

Action.—Flexes the hallux as its long flexor.

=Flexor Perforatus Annularis Primus Pedis= (Fig. 17, Nos. D, 8 and C, 6). Location.—The posterior tibial region.

Origin.—From the inner side of the belly of the flexor longus hallucis.

Insertion.—Becoming tendinous at the lower third of the tibia, passes a little to the outer side and through the tibial cartilage, then over the ankle-joint and through the hypotarsal canal (Fig. 12, No. 5) to the under side of the outer toe, where it forms a sheath through which the deep flexors extend. It gives off on either side a tendinous slip which attaches to the basal phalanx.

Shape.—Long, slender, compressed laterally.

Relations.—Internally, with the flexor perforatus indicis secundus pedis, and externally, with the flexor longus hallucis.

Action.—Flexes the toes as their long flexor. A second flexor of the outer toe.

=Flexor Perforatus Medius Secundus Pedis= (Fig. 17, No. 9). Location.—The posterior tibial region.

Origin.—From a strong fascia that merges with the knee-joint, and by a tendon from the external condyle of the femur in common with the tendon of the flexor perforatus indicis secundus pedis.

Insertion.—Continued as a flattened tendon extending from the lower third of the leg, passing obliquely through the tibial cartilage and then through the interno-posterior canal of the hypotarsus, (Fig. 12, No. F, 5) inserted to the second joint of the middle toe.

Shape.—Long, fusiform.

Relations.—With the shaft of the fibula, which it covers.

Action.—Flexes the middle toe.

=Flexor Perforatus Medius Primus Pedis= (Fig. 17, No. 2). Location.—Posterior tibial region.

Origin.—From the inner side of the muscular portion of the flexor perforatus annularis primus pedis.

Insertion.—Terminating in a flattened tendon, passes through the tibial cartilage and hypotarsus, and then extends along the shaft of the basal joint of the third toe, and, dividing into two slips, inserts to either side of its shaft.

Shape.—Long, rather small.

Relations.—With the flexor perforatus annularis primus pedis on the inner side.

Action.—Flexes the third toe.

=Flexor Perforatus Indicis Primus Pedis= (Fig. 17, No. 4). Location.—The posterior tibial region.

Origin.—From a thin, broad tendon, on the external condyle of the femur, in common with the flexor perforatus medius secundus pedis.

Insertion.—Becoming tendinous, passes through the tibial cartilage and the hypotarsus of the metatarsus (Fig. 16, A) and inserts to the sides of the basal joint of the second toe.

Shape.—Long, slender, fusiform; somewhat flattened laterally.