344 THE MUSCULAR SYSTEM. | ) 
from the contiguous margins of these vertebree. It forms a slender fleshy belly, 
its margins blending with the fascia covering the psoas magnus, and is inserted by 
a narrow tendon into the middle of the ilio-pectineal line and the ilio-pectineal 
eminence. 
The iliacus muscle arises mainly from a horseshoe-shaped origin around the 
Central tendon (middle part) 
Vena caval opening Césophageal opening 
R : 
_/ DIAPHRAGM, RIGHT CRUS 
ye 
Middle arcuate ligament 
7 Aortic opening 
«\) Central tendon 
“(left part) 
DIAPHRAGM, LEFT 
CRUS | 
Central tendon (right part) 
DIAPHRAGM, COSTAL FIBRES 
Internal arcuate ligament 
External arcuate ligament Ue 
aa 
Last thoracic nerve 
-End of last rib | 
-Lumbar nerve I. | 
_Ilio-hypogastric 
—Lumbar nerve II. 
End of last rib 
Last thoracic nerve 
Ant. layer of lumbar fascia 
Lumbar fascia 
Ilio-hypogastrie— 
Lumbar vessels and sympa- 
thetic communicating nerves — 
Tlio-inguinal 
_Tiio-inguinal 
QUADRATUS 
~~ LUMBORUM 
Lumbar nerve III. 
QUADRATUS LUMBORUM 
Genito-crural 
External cutaneous nerve Lumbar nerve IV. 
PsSOAS MAGNUS 
ILIACU 
Lumbo-sacral cord Lumbo-sacral cord 
Genito-crural nerve An ai tae 
ine external cutaneous nerve 
Anterior crural nerve } SG per 
’ ray thi Ley, = Anterior crural nerve 
Obturator nerve r j Sg 
| - Obturator nerve 
Great sciatic nerve ae 
i Great sciatic nerve 
| Obturator nerve 
ADDUCTOR LONGUS (origin) 
ADDUCTOR BREVIS (origin) 
GRACILIS (origin) 
ADDUCTOR MAGNUS (origin) 
PECTINEUS (cut) 
| Superficial branch of obturator nerve 
| Deep branch of obturator nerve 
OBTURATOR EXTERNUS) 
Fig. 253.—Vrew or THE PosTERIOR ABDOMINAL WALL, TO SHOW THE MUSCLES AND THE NERVES OF 
THE LUMBO-SACRAL PLEXUS. 
margin of the iliac fossa; it has an additional origin also from the anterior sacro- 
iliac and ilio-lumbar ligaments. It is a fan-shaped muscle, its fibres passing down- 
wards over the hip-joint towards the small trochanter of the femur. It is inserted 
(1) into the outer side of the tendon of the psoas; (2) into the concave anterlor 
surface of the small trochanter; and (3), by its most external fibres, into the cap- 
sule of the hip-joint. These fibres are often separate, forming the iliacus minor, or 
ilio-capsularis. The muscle occupies the false pelvis and Scarpa’s triangle. It 
forms the back wall of the false pelvis, covered anteriorly by the iliac fascia, and 1s 
ee | 
