GLUTEAL MUSCLES. 



229 



placed two or three synovial bursas, or a single multilocular bursa of large size, 

 A bursa is also situated between the muscle and the tendon of the vastus externus, 

 and another separates it from the tuber ischii. 



The great size of the gluteus maximus and the consequent prominence of 

 the buttock, is a characteristic of man as compared 'with those animals which 

 most nearly approach him in general structure. 



Varieties. — Tliis muscle varies chiefly in the extent of its origin ; it may 

 obtain a high fascial slip from the lumbar aponeiu-osis, or it may be attached 

 only to the last two sacral vertebras. It may also be considerably subdivided. 

 Thus it has been seen wholly or partly bilaminar (Tiedemann, Macalister) ; or 

 with a separate muscle, constituting in animals the agitator caudas attached to 

 the coccyx and lowest jjart of the sacrum (Macalister). 



The gluteus medius muscle, covered partly by the gluteus maximus, 

 partly by the fascia lata, arises from the surface of the dorsum ilii 

 above the superior curved line, and in front of the gluteus maximus, 

 from the strong fibres of the fascia lata, covering its outer surface. 

 The muscular fibres converge as they descend, the anterior fibres 

 passing obliquely backwards, the posterior fibres obliquely forwards, and 

 terminate in a fan-shaped tendon, which is inserted into an oblique 

 line directed downwards and forwards on the outer surface of the 

 great trochanter. The tendon is separated by a smal' bursa from the 

 upper part of the trochanter. 



Iif'Jationx. — Between this muscle and the gluteus minimus are the gluteal nerve 

 and deep branches of the gluteal artery. At its anterior and inferior border its 

 fibres are parallel to and united with those of the gluteus minimus. This border 

 also is in contact with the tensor vaginas femoris. The posterior border is in 

 contact vv'ith the pyriformis, being separated by the gluteal vessels and nerves. 



VtiTicttcs. — The gluteus medius has been found bilaminar by Henle. It may be 

 united posteriorly by a tendinous slip to the tendon of the pjTiformis. or the two 

 tendons may be separated by a bursa (the bursa of Loder). This last condition 

 occurs once m every fifteen subjects (Macalister). 



Fig. 185. — Deep Muscles of the Hip on Fig. 185. 



THE Left side, from beuind. \ 



The gluteus maximns, and the muscles of 

 the thigh have been removed. 1, gluteus 

 medius ; 2, pyriformis ; 3, gemellus su- 

 perior ; 4, gemellus inferior ; 5, obturator 

 internus, seen partially within the pelvis, 

 and, after' issuing by the lesser sciatic notch, 

 between the gemelli muscles ; (i, quadratus 

 femoris ; 7, tendon of the obturator ex- 

 ternus between the gemellus inferior and 

 quadratus. 



The gluteus ininiinus, covered 

 by the preceding muscle, arises from 

 the whole space on the dorsum ilii 

 between the superior and inferior 

 curved lines. The fibres, converg- 

 ing as they descend, terminate in 

 an aponeurotic tendon on the outer 

 surface of the muscle, which be- 

 coming narrowed is inserted into 

 an impression on the anterior 

 border of the great trochanter. The tendon is bound down to the 

 promuience of the trochanter by a strong fibrous band which joins 



