The external surface of the capsule is rough, covered by numerous muscles, and separated in front from the psoas major and iliacus by the iliopectineal bursa, which not infrequently communicates by a circular aperture with the cavity of the joint.
22.
In the pelvis area, at the level of the last lumbar vertebra, the abdominal aorta, a continuation the descending aorta, splits into a pair of psoas major to exits the pelvis area through the vascular lacuna under the inguinal ligament.
23.
The obturator nerve ( L2-L4 ) passes medially behind psoas major to exit the pelvis through the obturator canal, after which it gives off branches to quadriceps; and sensory branches to the anterior thigh, medial lower leg, and posterior foot.
24.
Its smaller motor branches are distributed directly to psoas major, while the larger branches leave the muscle at various sites to run obliquely down through the pelvis to leave under the inguinal ligament, with the exception of the obturator nerve which exits the pelvis through the obturator foramen.
25.
Each passes obliquely downward and lateralward behind the peritoneum, resting on the Psoas major, the right lying in front of the inferior vena cava and behind the middle colic and ileocolic arteries and the terminal part of the ileum, the left behind the left colic and sigmoid arteries and the iliac colon.
26.
It descends through the fibers of the psoas major muscle, emerging from the muscle at the lower part of its lateral border, and passes down between it and the iliacus muscle, behind the iliac fascia; it then runs beneath the inguinal ligament, into the thigh, and splits into an anterior and a posterior division.
27.
Below the subcutaneous inguinal ring, they unite to form three or four veins, which pass along the inguinal canal, and, entering the abdomen through the abdominal inguinal ring, coalesce to form two veins, which ascend on the Psoas major, behind the peritoneum, lying one on either side of the internal spermatic artery.
28.
It passes to the right behind the peritoneum, and in front of the right internal spermatic or ovarian vessels, the right ureter and the Psoas major, toward the middle of the ascending colon; sometimes the vessel lies at a higher level, and crosses the descending part of the duodenum and the lower end of the right kidney.
29.
The following are relations of the artery at various points : it is posterior to the ureter, anterior to the internal iliac vein, the lumbosacral trunk, and the piriformis muscle; near its origin, it is medial to the external iliac vein, which lies between it and the psoas major muscle; it is above the obturator nerve.
