Obturator sign

A clinical sign used in the diagnosis of appendicitis

Obturator sign

The obturator sign is a clinical indicator used in the diagnosis of appendicitis. It is elicited during a physical examination by a healthcare provider. The sign is considered positive when the patient experiences pain upon the internal rotation of the hip with the knee bent, which suggests irritation of the obturator internus muscle.

Anatomy involved

Diagram of the posterior hip muscles, including the obturator internus.

The obturator sign is associated with the obturator internus muscle, which is located in the pelvic region. This muscle is responsible for the lateral rotation of the thigh and is innervated by the obturator nerve. The obturator internus muscle passes through the lesser sciatic foramen and is closely related to the appendix, especially when the appendix is located in the pelvic region.

Clinical significance

The obturator sign is particularly useful in diagnosing appendicitis when the appendix is located in the pelvis. In such cases, the inflamed appendix may come into contact with the obturator internus muscle, causing pain during its contraction. This sign is one of several physical examination techniques used to assess for appendicitis, alongside others such as the Rovsing's sign and the psoas sign.

Examination technique

To elicit the obturator sign, the patient is typically positioned supine. The examiner flexes the patient's hip and knee to 90 degrees, then internally rotates the hip by moving the ankle laterally while keeping the knee stationary. A positive obturator sign is indicated by pain in the hypogastric region, suggesting irritation of the obturator internus muscle due to an inflamed appendix.

Limitations

While the obturator sign can be indicative of appendicitis, it is not definitive on its own. It should be considered in conjunction with other clinical findings and diagnostic tests, such as ultrasound or CT scan, to confirm the diagnosis of appendicitis.

Related pages

• Appendicitis
• Rovsing's sign
• Psoas sign
• Physical examination