Fig. 163. Gluteal Region. 



A large ivindoiv lias been cut out of tlie Gluteus Maxhntis Muscle; from the 

 Gluteus Medius and the Pyriformis Muscles, smaller pieces have been removed. 



Under an extremely thick layer of superficial fascia, lies the Gluteus 

 Maximus Muscle, which covers nearly the whole of the Gluteal Region. The 

 following bony prominences can be felt: the Crest of the Ilium, the Great Tro- 

 chanter and with less ease, because covered by the Gluteus Maximus, the Tubero- 

 sity of the Ischium. The upper and outer part of this muscle passes over the 

 posterior and outer aspect of the Great Trochanter and is inserted into the Fascia 

 Lata. A Superficial Trochanteric Bursa placed within the superficial fascia is 

 rare. The Gluteus Maximus covers important vessels and nerves; at the upper 

 border of the Pyriformis Muscle, emerging with it through the Great Sacro- 

 Sciatic Foramen, is the Gluteal Artery, a branch of the Internal Iliac. Outside 

 the Pelvis, the trunk of this vessel is short, and soon divides into 5 — 7 branches 

 to the Glutei Muscles. A large branch (Superficial Branch) becomes more super- 

 ficial by emerging between the Gluteus Medius and Pyriformis Muscle, to run 

 under cover of the Gluteus Maximus. Another large branch (Deep Branch), runs 

 between the Gluteus Medius and the Gluteus Minimus, this divides into a Superior 

 and an Inferior Branch, the former of which follows the middle curved line. Deep 

 to these vessels lies the Superior Gluteal Nerve. At this point a variety of Sciatic 

 Hernia may occur. 



At the lower border of the Pyriformis Muscle, the Great Sciatic Nerve 

 emerges at a point corresponding to the junction of the inner and middle thirds 

 of a line drawn from the Great Trochanter of the Femur to the Tuberosity of 

 the Ischium. At the lower border of the Gluteus Maximus Muscle, the Great 

 Sciatic Nerve is easily exposed, because at this point, it is only covered by skin 

 and superficial fascia; at a lower level it is covered by the long head of the 

 Biceps Muscle. 



Internal to the Great Sciatic Nerve, lies the Sciatic Artery, a slightly 

 smaller vessel than the Gluteal Artery. This vessel gives off the Companion 

 Arterj' to the Sciatic Nerve. Between the Sciatic Artery and the Great Sciatic 

 Nerve lies the Nerve to the Gluteus Maximus Muscle, — the Inferior Gluteal 

 Nerve — . 



Most internally, the Internal Pubic Artery emerges at the lower border 

 of the Pyriformis Muscle, and after crossing the Spine of the Ischium or the 

 smaller Sacro-Sciatic Ligament re-enters the Pelvis through the Sacro-Sciatic 

 Foramen, but does not enter the Pelvic Cavity (cf. Fig. 150). 



A second variety of Sciatic Hernia may protrude below the Pyriformis 

 Muscle, where the structures mentioned leave the Pelvis; a third variety may 

 occur at the Lesser Sacro-Sciatic Foramen. 



The Hip-Joint lies under cover of the Pyriformis Muscle in front of the 

 Obturator Internus and Externus Muscles, and in consequence is scarcely acces- 

 sible from behind. An important Bursa lies between the Tuberosity of the Ischium 

 and the soft parts over it, e. g. the Sciatic Bursa. 



