The Triceps Superior hath its beginning in the top of the Os Pubis, and is terminated in the top of a Line, which is on the inside of the Thigh.
The Triceps Medius proceeding from the middle of the Os Pubis, is inserted in the Thigh-Bone a little lower than the Triceps Superior.
The Triceps Inferior hath its Source in the bottom of the Os Pubis, and is implanted in the Thigh-Bone, a little lower than the Triceps Medius. Some Anatomists make only one Muscle of these three, attributing thereto three Originals and three Insertions. These Muscles serve to draw the Thighs one against another.
The Abductors of the Thigh are the Iliacus Externus, or Pyriformis, the Quadratus, and the Gemelli.
The Pyriformis arising from the upper and lateral part of the Os Sacrum, and the the Os Ilion cleaves to the Neck of the great Trochanter.
The Quadratus or square Muscle of the Thigh takes its Origine from the external Prominence of the Os Ischion, and adheres to the outward part of the great Trochanter.
The Gemelli or Twin Muscles arise from two small Knobs in the hinder-part of the Ischion and insinuate themselves into a small Cavity in the Neck of the great Trochanter.
The Circular Motion of the Thigh is performed by the means of two Muscles, named the Obturatores Externi and Interni.
The Obturator Internus springs from the inner Circumference of the Oval Hole of the Ischion and its Tendons passing between the two Gemelli are inserted in a small Cavity at the Root of the great Trochanter or Rotator.