The nerve trunks that do not pass through the biceps band, or loop can be divided into a medial (Fig. 69, No. 15) and a lateral (Fig. 69, No. 17) portion. The medial portion (Fig. 69, No. 15) soon divides into numerous branches which supply the muscles of the posterior and the inner portion of the thigh. A rather large, long branch passes downward along the tendon of the plantar muscle, which lies on the posterior median edge of the tibia, and gives off twigs to the median and posterior part of the intertarsal joint, supplying the periosteum and other structures and the adjacent skin. It passes downward along the outer side of the medial metatarsal insertion of the tendon Achillis. The _fifth branch_ is given off from the second trunk and lies laterally. It is covered by the external head of the gastrocnemius, passes along the vena saphena, and gives off a short main branch to the inner side of the intertarsal joint. The main part passes the tibial side of the joint, becomes subcutaneous, and finally innervates the two plantar muscles. A lateral ascending inner branch innervates the flexor perforatus digitorum, and, in company with an outer branch, the external head of the gastrocnemius, and also the flexor pedis perforatus. The _plexus pedundus_ is formed from the spinal nerves coming out of the plexus ischiadicus. These fibers emerge caudalward and are directed horizontally. They frequently anastomose with each other, especially on the pubic rim and on the outside of the plexus ischiadicus. These branches are deeply imbedded in the kidney substance and innervate the pubio-coccygeus, or depressor coccygis lateralis, the ilio-coccygeus, the transversalis, the sphincter, and other muscles of this region, and the skin of the anal region. THE BRAIN