Quadrilateral Space Syndrome - Causes, Symptoms, Diagnosis, and Treatment

Introduction

Quadrilateral space syndrome (QSS) is a rare condition that affects the nerves in the upper arm, leading to pain, weakness, and limited mobility. Although not as well-known as other nerve compression syndromes, such as carpal tunnel syndrome, QSS can significantly impact a person's quality of life. This article will delve into the intricacies of quadrilateral space syndrome, exploring its causes, symptoms, diagnosis, and potential treatment options.

What Is Quadrilateral Space Syndrome?

The quadrilateral space is a small anatomical region located in the shoulder area. It is bounded by four structures - the teres minor muscle, the teres major muscle, the long head of the triceps, and the humerus bone. Within this confined space runs the axillary nerve, a critical nerve that supplies sensation and motor function to the shoulder joint and the skin over the deltoid muscle.

Quadrilateral space syndrome occurs when the axillary nerve gets compressed or entrapped within this quadrilateral space. The compression can be caused by various factors, such as trauma, repetitive motion, inflammation, or anatomical abnormalities. The exact cause of QSS is not always identifiable, making diagnosis and management a challenging task.

What Are the Causes of Quadrilateral Space Syndrome?

• Compression or irritation of the axillary nerve.

• Trauma or injury to the quadrilateral space region.

• Overuse or repetitive motion of the shoulder and arm.

• Anatomical variations or abnormalities in the structures within the quadrilateral space.

• Space-occupying lesions or masses, such as cysts or tumors, in the vicinity of the quadrilateral space.

• Muscular hypertrophy or hypertonicity in the adjacent shoulder muscles.

• Nerve entrapment or impingement due to inflammation or fibrous bands in the region.

What Are the Symptoms of Quadrilateral Space Syndrome?

• Shoulder Pain: The most common symptom of QSS is shoulder pain. The pain is often deep and aching, and it may be localized to the back of the shoulder or upper arm. Patients may have difficulty pinpointing the exact location of the pain.

• Muscle Weakness: Due to nerve compression, weakness in the shoulder muscles can occur. The deltoid muscle and rotator cuff muscles may be affected, leading to difficulty in lifting or moving the arm properly.

• Numbness or Tingling: Nerve compression can cause sensory disturbances like numbness or tingling in the shoulder, upper arm, or back of the arm. In some cases, patients may also experience altered sensations that extend down the arm toward the hand.

• Limited Range of Motion: Compression of the axillary nerve can lead to limited shoulder joint mobility, restricting its full range of motion. Patients may find it challenging to perform activities that involve raising the arm overhead or reaching behind the back.

• Muscle Atrophy: Over time, muscle atrophy, which is the wasting or loss of muscle mass, may develop in the affected shoulder. This can lead to visible changes in muscle appearance and tone.

• Exacerbated Pain with Movements: Certain shoulder movements or activities can worsen the pain in QSS. Actions like lifting heavy objects, repetitive overhead motions, or positions that compress the quadrilateral space may trigger or aggravate the symptoms.

How to Diagnose Quadrilateral Space Syndrome?

• Medical History and Physical Examination: The doctor will begin by taking a detailed medical history, including any symptoms the person is experiencing, how and when they started, and any relevant past medical conditions or injuries. They will then conduct a physical examination, assessing the shoulder's range of motion and strength and looking for any specific signs that may suggest QSS.

• Clinical Tests: There are specific clinical tests that can help in assessing nerve and vascular compression in the shoulder. The "Quadrilateral Space Compression Test" is one such test. During this test, the doctor will exert pressure on the quadrilateral space while maneuvering the arm into specific positions to determine if it elicits the same symptoms that the person has been experiencing.

• Imaging Studies: Imaging studies can be helpful in ruling out other conditions and visualizing any structural abnormalities. MRI (magnetic resonance imaging) may be ordered to assess soft tissues, muscles, and nerves in the shoulder area.

• Electromyography (EMG) and Nerve Conduction Studies: These tests can help evaluate the electrical activity of muscles and the function of nerves. EMG can detect nerve damage or compression and determine if the axillary nerve is affected in QSS.

• Angiography: Angiography may be used to assess the blood flow in the posterior humeral circumflex artery, which could be affected in QSS.

• Differential Diagnosis: It is essential for the doctor to rule out other conditions that may present with similar symptoms, such as rotator cuff injuries, impingement syndrome, or brachial plexus compression.

What Are the Treatment of Quadrilateral Space Syndrome?

1. Conservative Treatment:

• Rest: Avoid activities that worsen the symptoms to allow the affected area to heal.

• Physical Therapy: The recommended approach includes engaging in shoulder muscle strengthening exercises and performing range of motion exercises to enhance mobility, alleviate discomfort, and minimize pain.

• Pain Management: Non-steroidal anti-inflammatory drugs (NSAIDs) or other pain-relieving medications may be prescribed to alleviate pain and inflammation.

• Avoiding Overhead Activities: Minimizing movements that exacerbate the symptoms.

2.Corticosteroid Injections:

• If conservative treatment does not provide sufficient relief, corticosteroid injections may be considered to reduce inflammation and alleviate symptoms temporarily.

3. Surgical Intervention:

• If conservative treatments fail to relieve the symptoms or if there is significant nerve or vessel compression, surgery may be necessary to release the structures in the quadrilateral space.

• During the surgical procedure, the surgeon will alleviate compression of the axillary nerve and the posterior circumflex humeral artery by releasing the structures responsible for the compression.

• Following the surgery, physical therapy might be advised to facilitate the recovery and rehabilitation process.

Conclusion

In conclusion, quadrilateral space syndrome (QSS) is a rare but significant neurological condition affecting the upper extremity. Characterized by compression of the axillary nerve and posterior circumflex humeral artery within the shoulder's quadrilateral space, QSS presents with shoulder pain, weakness, and sensory disturbances. Timely and accurate diagnosis is essential to prevent delays in treatment and mismanagement. While conservative approaches like physical therapy and medications are often attempted, surgical decompression may be necessary in severe cases. Continued research and awareness among healthcare professionals are vital to enhancing early recognition and effective management of QSS, ultimately improving patients' quality of life and functional outcomes.