Corpus: Iliopsoas muscle

The iliopsoas muscle is part of the internal hip musculature and is located in the retroperitoneal space. It consists of the psoas major muscle, the iliacus muscle and, in some cases, the psoas minor muscle.

Origin[Bearbeiten]

The two components of the iliopsoas muscle have a different origin, whereby the psoas major muscle can be further subdivided into a superficial and a deep layer.

The superficial layer of the psoas major muscle originates from the twelfth thoracic vertebral body, the first four lumbar vertebral bodies and the associated intervertebral discs (Disci intervertebrales). The deep layer of the psoas major originates from the transverse processes (processus costales) of the first to fifth lumbar vertebrae. The psoas major muscle has a close local relationship to the lumbar plexus.

The iliacus muscle originates from the iliac fossa and the anterior inferior iliac spine.

Approach[Bearbeiten]

The psoas major muscle and iliacus muscle pass through the lateral lacuna musculorum and insert together as the iliopsoas muscle on the small trochanter of the femur.

Other[Bearbeiten]

There is a bursa iliopectinea in the area of the hip joint. The psoas minor muscle, which lies on the psoas major muscle, is very variable and is often replaced by a fascia.

The common fascia of the psoas major and iliacus muscles is known as the iliac fascia. Abscesses of the spinal column can descend into this fascia to below the inguinal ligament (sink abscess).

The iliopsoas muscle is innervated by branches from the lumbar plexus (segments L1-L4) and the femoral nerve.

The iliopsoas muscle is the strongest flexor of the hip joint. It is also involved in straightening the trunk from the supine position, as this is achieved by flexion in the hip joint. If it is paralysed on both sides, straightening is no longer possible. It can also rotate the thigh outwards.

The iliopsoas muscle and its neighbouring structures can be affected by various conditions. These include, among others:

• Psoas abscess: a bacterial infection that spreads to the psoas ligament. Symptoms include pain in the flank or lower abdominal area and fever.
• Iliopsoas syndrome: Also known as iliopsoas tendinopathy. A symptom of overuse with pain in the groin area. It can be caused by repetitive activities that strain the muscle.
• Iliopsoas bursitis: An inflammation of the bursa located between the iliopsoas muscle and the hip bone. Typically causes pain and swelling in the hip region.

Clinical examination and imaging procedures (MRI, CT, ultrasound) play a role in the diagnosis of these diseases.