The iliacus is a flat, triangular muscle which fills the iliac fossa. It forms the lateral portion of iliopsoas, providing flexion of the thigh and lower limb at the acetabulofemoral joint.
Structure
The iliacus arises from the
iliac fossa on the interior side of the
hip bone, and also from the region of the anterior inferior iliac spine (AIIS). It joins the psoas major to form the
iliopsoas.
It proceeds across the iliopubic eminence through the
muscular lacuna to its insertion on the lesser trochanter of the
femur.
Its fibers are often inserted in front of those of the psoas major and extend distally over the lesser trochanter.
[Platzer (2004), p 234]
Nerve supply
The iliopsoas is innervated by the
femoral nerve and direct branches from the
lumbar plexus.
[ Thieme Atlas of Anatomy (2006), p 422]
Function
In open-chain exercises, as part of the
iliopsoas, the iliacus is important for lifting (flexing) the femur forward (e.g.
front scale). In closed-chain exercises, the iliopsoas bends the trunk forward and can lift the trunk from a lying posture (e.g.
sit-ups,
back scale) because the psoas major crosses several vertebral joints and the
sacroiliac joint. From its origin in the lesser pelvis the iliacus acts exclusively on the
Hip.
== Additional images==
. Internal surface. Iliac fossa visible at upper left.]]
Notes
External links
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PTCentral
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- "Muscles and nerves of the posterior abdominal wall."
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(, )
