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Lacertus Syndrome


Lacertus Syndrome

Lacertus syndrome is a nerve compression condition caused by the entrapment of the median nerve under a fibrous tissue layer called the lacertus fibrosus at the elbow. Symptoms of lacertus fibrosus syndrome are often mistaken for carpal tunnel syndrome, leading to delayed diagnosis.


In some cases, both carpal tunnel syndrome and lacertus fibrosus syndrome can coexist in the same arm. The median nerve can be compressed both at the wrist (carpal tunnel syndrome) and at the elbow (lacertus fibrosus syndrome). When this happens, it is referred to as double crush syndrome. The primary treatment for lacertus fibrosus syndrome is surgical intervention.


What is Lacertus Fibrosus?

Lacertus fibrosus is a connective tissue located at the front of the elbow. It is also referred to as the bicipital aponeurosis. Lacertus fibrosus originates from the inner part of the biceps tendon and attaches to various structures on the inner side of the elbow. The median nerve passes directly beneath the lacertus fibrosus.


What is Lacertus Syndrome?

Lacertus syndrome, also known as lacertus fibrosus syndrome, is a type of nerve entrapment neuropathy caused by the compression of the median nerve by the lacertus fibrosus at the elbow.


While carpal tunnel syndrome occurs due to the compression of the median nerve at the wrist, lacertus fibrosus syndrome occurs at the elbow. Carpal tunnel syndrome is far more common, while lacertus fibrosus syndrome is rare and often overlooked during diagnosis.


One of the most common reasons for unsuccessful carpal tunnel surgeries is undiagnosed lacertus fibrosus syndrome.


For detailed information on carpal tunnel syndrome, you can click here.


What is Pronator Syndrome?

Pronator teres syndrome is a general term for median nerve compression at the elbow. Lacertus fibrosus syndrome is considered a subtype of pronator syndrome.

There are five anatomical structures around the elbow that can compress the median nerve, and lacertus fibrosus is one of them.


You can also take a look at our article on Ulnar nerve compression, which is another painful disease.



What are the Symptoms of Lacertus Syndrome?

The symptoms of lacertus syndrome worsen with increased hand use, especially when the elbow is bent, and the palm faces downward (forearm pronation position).

1. Weakness:

  • Most common symptom.

  • Reduced flexion strength in the wrist, thumb, and index finger.

  • Patients often report poor hand dexterity and frequently dropping objects.

  • Markedly reduced ability to grasp a key between fingertips.

  • In carpal tunnel syndrome, weakness primarily affects thumb abduction, not flexion.

2. Numbness:

  • Tingling, burning, or numbness in the thumb, index finger, middle finger, and half of the ring finger.

  • In lacertus fibrosus syndrome, numbness is intermittent rather than constant.

  • In carpal tunnel syndrome, numbness is more persistent and can become severe enough to wake patients from sleep at night, a symptom not observed in lacertus fibrosus syndrome.

3. Pain:

  • Pain in the elbow and forearm.

  • In many cases, pain can radiate up to the shoulder.


How is Lacertus Syndrome Diagnosed?

If a physician experienced in nerve entrapment syndromes suspects lacertus fibrosus syndrome during a physical examination, additional diagnostic tools like EMG (Electromyography) and MRI imaging may be used for confirmation. However, lacertus syndrome often cannot be definitively detected via EMG. EMG primarily helps identify other coexisting nerve compressions, such as carpal tunnel syndrome.


Additionally, cervical MRI can rule out cervical disc herniation, which may present with similar symptoms.


Differentiating lacertus syndrome from carpal tunnel syndrome is crucial, as both conditions involve compression of the median nerve. The key difference lies in the compression site:

  • Carpal tunnel syndrome: Compression occurs at the wrist.

  • Lacertus syndrome: Compression occurs at the elbow.


Although the symptoms are similar, an experienced physician can make an accurate differential diagnosis.


One of the most common reasons for failed carpal tunnel surgery is misdiagnosis — the patient may actually have lacertus fibrosus syndrome instead of carpal tunnel syndrome. In some cases, both syndromes can coexist, a condition referred to as double crush syndrome.


How is Lacertus Syndrome Treated?

If the diagnosis of lacertus syndrome is confirmed, the primary treatment is surgery.

  • The procedure is typically performed under local anesthesia.

  • 5-6 cm incision is made in the elbow region to release the lacertus fibrosus.

  • Local anesthesia allows for immediate strength testing of the fingers and wrist once the release is completed.

  • The strength of the fingers and wrist should return immediately after the release.

If the patient also has carpal tunnel syndrome, the carpal tunnel release surgery is performed simultaneously.


What is the Recovery Process After Lacertus Syndrome Surgery?

  • Immediate Relief: Patients typically feel an immediate improvement in symptoms and regain strength right after the surgery.

  • Return to Work: If the patient does not have a physically demanding job, they can return to office work within 2-3 days after surgery.

  • Wound Healing: The surgical wound generally heals within 10-14 days.

  • No Physical Therapy Required: Post-surgical physical therapy is not necessary for recovery.


For more detailed information, feel free to visit our website at utkuerdemozer.com. Thank you for reading!

Kiss. Dr. Utku Erdem Özer Contact

To Get More Information, Please Contact Us

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