Page:Laboratory Manual of the Anatomy of the Rat (Hunt 1924).djvu/59

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Biceps Femoris Muscle. This muscle has three portions, or heads—the anterior, posterior, and accessory. The origin of the anterior head is the last sacral and the first caudal vertebra. The posterior and accessory heads originate at the sciatic tuber of the ischium. All three are inserted by an extensive fascia into the distal end of the femur and the proximal two-thirds of the tibia.

Glutaeus Maximus Muscle. This triangular muscle originates by fascia from the dorsal border of the ilium, from the last three sacral vertebrae, and the first caudal vertebra. It is inseparably united anteriorly with the tensor fasciae latae muscle. Its origin is covered posteriorly by the anterior head of the biceps femoris. Insertion, the third trochanter of the femur.

Tensor Fasciae Latae Muscle. Origin, iliac crest. Insertion, fascia lata of the thigh. This muscle is exposed antero-ventrad to the glutaeus maximus.

Semitendinosus Muscle. Origin, the posterior part of the sciatic tuber. Insertion, by a tendon on the tuberosity of the tibia. It joins the tibia from the medial side. It passes from its dorsal origin down around the posterior side of the thigh on to the medial surface of the shank. Action, flexes and rotates the shank.

Exercise XI. Outline the whole body of the rat as seen in the lateral view, and in this outline draw and label the muscles visible after the removal of the cutaneous maximus and platysma muscles.

Place the skinned animal on its back, then dissect and identify the following muscles.

Digastricus Muscle. This muscle lies between the mas-