Iliacus

ILIACUS

The iliacus muscle is shaped like a triangle, flat and an exact fit of the iliac fossa — the curved surface of the largest pelvic bone. Together with the psoas major muscle, it is also called the iliopsoas muscle.A portion of this muscle is attached to the iliac fossa, two-thirds from its top. Another portion is attached to the inside portion of the iliac crest, the top, outer portion of the pelvic bone.Other fibers of this muscle are attached to the iliolumbar and anterior sacroiliac ligaments (located at the base portion of the sacrum) and up to the anterior iliac spines (bony projections that lie toward the edges of the iliac). These muscle fibers then converge and insert on the tendon at the lateral (outer) side of the psoas major muscle, which stretches from the lumbar spine in the lower back to the lower pelvis. Some of these fibers extend to the femur bone, or thighbone.

ANATOMY

Origin

Upper 2/3 of iliac fossa of ilium, internal lip of iliac crest, lateral aspect of sacrum, ventral sacroiliac ligament, and lower portion of iliolumbar ligament

Insertion

Lesser trochanter of femur. Its fibers are often inserted in front of those of the psoas major and extend distally over the lesser trochanter.

Nerve supply

The iliacus muscle is supplied with nerves by the branches of the second and third nerves of the lumbar area through the femoral nerve.(L2,L3)

Artery

Lumbar branch of iliopsoas branch of internal iliac artery and medial circumflex femoral artery.

Action

• The iliacus muscles flexes and externally rotates the femur.
• It is also one of the key muscles that helps to maintain proper body posture.
• When combined with the psoas muscle the two muscles are considered the strongest hip flexors in the body.
• It is also one of the key muscles that helps to maintain proper body posture.
• The Iliacus muscle can also add to an anterior tilt of the pelvis (down and forward).
• Just like the iliacus, the iliopsoas is responsible for hip flexion. This muscle is also involved in trunk flexion, which is bending the trunk forward such as when you perform a sit-up or bend down to tie your shoes.

ILIACUS DYSFUNCTION

1. Excessive use of the muscle can make it shorter, especially if someone does desk job each day. This muscle can also become shorter through lots of exercising without stretching. As this muscle shortens, it can start to cause dysfunction and injuries in the hip and pelvic regions of the body, such as:

• Trigger points - tight areas or knots in the iliacus muscle that are painful, tender, and stiff.
• Iliacus ischemia - a condition of reduced blood flow to the muscle.
• Hip, knee, and lower back problems - If the iliacus on one side of the hip becomes shorter than the iliacus on the other, this can cause a person to walk with imbalanced hips, affecting the normal gait of a person. (Try walking while keeping one hip lower than the other, you will probably start to feel pain and irritation in your hips, knees, and lower back)

The main symptom of iliacus dysfunction is pain. This pain can be in the hips, groin, lower back, and upper thigh regions of the body. Other symptoms include:

• Stiffness
• Decreased range of motion
• Tenderness

2. Traumatic iliacus muscle injury is rare; it is usually caused by trauma or intense exercise involving the pelvic girdle; it can produce a hematoma with femoral nerve neuropathy. Spontaneous muscle hematomas occur in patients with coagulation disorders.It causes intense pain in the right buttock, groin and iliac fossa, with an inability for hip flexion and ambulation caused by inadequate exercise (supine double leg lifts).

3. ILIACUS COMPARTMENT SYNDROME

Iliacus compartment syndrome is a rare retroperitoneal compartment neuropathy caused by bleeding within the iliacus muscle leading to hematoma formation and compression upon the femoral nerve, causing both sensory and motor deficits.Iliac hematomas are rare and can be caused by traumatic and non-traumatic injury, and can be exacerbated by complications of anticoagulant therapy.Delaying surgical evacuation of the hematoma can lead to prolonged or permanent disability. However, there are other reports describing good recovery with non-operative management. Non-surgical intervention is recommended if radiological studies do not explicitly confirm the presence of a discreet hematoma compressing the femoral nerve, unless progression of symptoms increases.