_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. _Relations._—With the flexor perforatus medius secundis pedis, posteriorly. _Action._—A flexor of the toes. =Flexor Perforans Digitorum Profundus= (Fig. 24, No. 24 and Fig. 25, No. _G_, 3). _Location._—The posterior tibial region. _Origin._—From the posterior part of the external condyle of the femur, from the posterior part of the tibia just below the summit, and from a point near the origin of the soleus.