What is Quadrilateral Space Syndrome (QSS)?

Quadrilateral Space Syndrome (QSS) is a rare condition that occurs when the axillary nerve and/or the posterior circumflex humeral artery get squeezed or compressed as they pass through a small area in the back of your shoulder called the 'quadrilateral space.' This compression can lead to pain, numbness, tingling, and weakness in your arm.

QSS is often caused by repetitive overhead activities, common in athletes like throwers, swimmers, and tennis players. It can also result from repeated motions that narrow the space (overuse), extra bands of tissue that can form and compress the nerve or artery (fibrous bands), trauma or injury such as a shoulder dislocation or a direct blow to the shoulder which can cause swelling or scar tissue, or muscle enlargement if muscles in the area grow significantly (e.g., in bodybuilders), they can crowd the space.

What are the common symptoms of QSS?

Symptoms typically include vague pain or a dull ache in the back of the shoulder, sometimes radiating down the arm; numbness, tingling, or a 'pins and needles' sensation in the shoulder and upper arm; pain that worsens with overhead movements or when your arm is in a 'throwing' position; tenderness when pressure is applied over the back of the shoulder in the quadrilateral space; weakness or fatigue in the arm, especially when lifting or rotating it; and sometimes, shrinking (atrophy) of certain shoulder muscles like the teres minor or deltoid.

How is QSS diagnosed?

Diagnosing QSS can be challenging because its symptoms can be similar to other shoulder problems. Your doctor will ask about your symptoms, activities, and any past injuries; perform a physical examination to check your shoulder's range of motion, strength, sensation, and tenderness; may order imaging tests like MRI or ultrasound to look at the quadrilateral space, assess muscle size, and check for any abnormalities or scarring. In some cases, nerve conduction studies (NCS) or electromyography (EMG) might be performed to evaluate how well the axillary nerve is working. An injection of local anesthetic into the quadrilateral space that temporarily relieves your symptoms can also help confirm the diagnosis.

What are the non-surgical treatment options?

Most cases of QSS improve with non-surgical treatment. These options focus on reducing pressure on the nerve and artery, managing pain, and restoring function: rest and activity modification (avoiding or modifying activities that worsen your symptoms, especially overhead movements); anti-inflammatory medications (over-the-counter or prescription NSAIDs like ibuprofen can help reduce pain and inflammation); ice or heat packs (applying ice can help reduce pain and inflammation, especially after activity, heat can help relax muscles); physical therapy (a physical therapist will guide you through exercises to maintain or improve shoulder range of motion and flexibility, strengthen the muscles around your shoulder to provide better support, improve posture and body mechanics); and corticosteroid injections (in some cases, your doctor may suggest an injection of corticosteroid medication into the area to reduce inflammation and pain).

When is surgery considered for QSS?

Surgery is usually considered if non-surgical treatments haven't significantly improved your symptoms after about six weeks or more; symptoms are severe or progressively worsening; or there's clear evidence of nerve damage or significant compression.

What does the surgical procedure involve?

The goal of surgery, called decompression, is to relieve pressure on the axillary nerve and posterior circumflex humeral artery. This typically involves making a small incision at the back of your shoulder; identifying the compressed nerve and artery; carefully removing or cutting any fibrous bands, scar tissue, or other abnormal structures that are causing the compression. The procedure is designed to free up the nerve and artery, allowing them to function normally.

What are the potential risks of surgery?

As with any surgery, there are potential risks, though QSS surgery is generally safe. These can include infection, bleeding, damage to surrounding nerves or blood vessels, scarring, persistent pain or incomplete relief of symptoms, and reaction to anesthesia. Your surgeon will discuss these risks with you in detail.

What do I need to do before surgery?

Your healthcare team will provide specific instructions, but generally, you may need to undergo a pre-operative physical examination and blood tests; stop certain medications (e.g., blood thinners, some anti-inflammatory drugs) a week or two before surgery; arrange for someone to drive you home after surgery and help you during the first few days of recovery; and avoid eating or drinking for a certain period before the surgery.

What can I expect immediately after surgery?

You will likely have your arm in a sling to help it rest and heal. You may experience some pain, which will be managed with medication. Your surgical site will be covered with a dressing. Your surgeon will give you instructions on wound care and activity restrictions.

How long is the typical recovery period?

Recovery times vary for each person, depending on the severity of the condition and how long the nerve was compressed. First few weeks (0-2 weeks): Focus on rest, pain management, and protecting the surgical site. Gentle elbow and wrist movements will be encouraged. Weeks 2-6: You will start physical therapy, focusing on gentle range-of-motion exercises for your shoulder. After 6 weeks: As healing progresses, your physical therapist will introduce strengthening exercises to rebuild muscle strength. Overall, it can take several weeks to months to feel significant improvement, as nerve healing is a slow process.

What does rehabilitation/physical therapy involve?

Physical therapy is crucial for a successful recovery. Your therapist will design a personalized program that may include pain and swelling management (using ice, gentle massage, or other techniques); range of motion exercises (to restore full movement in your shoulder); strengthening exercises (targeting the muscles around your shoulder, including the deltoid and teres minor, which may have been weakened); postural correction (to improve overall shoulder mechanics); and activity-specific training (gradually reintroducing movements related to your work, sports, or daily activities).

How will pain be managed?

Your doctor will prescribe pain medication to help manage discomfort after surgery. This may include prescription pain relievers (e.g., opioids for a short period); over-the-counter pain relievers (e.g., acetaminophen, ibuprofen) as recommended by your doctor. You may also use ice packs to reduce localized pain and swelling.

When can I expect to return to daily activities, work, driving, and sports?

This timeline varies greatly based on your recovery progress and the demands of your activities. Daily activities: Light daily activities can usually be resumed within a few days to weeks. Driving: You can typically drive once you are no longer taking strong pain medications and have sufficient control and range of motion in your shoulder to safely operate a vehicle (often a few weeks after surgery). Work: Return to work depends on the nature of your job. Light, desk-based work might be possible within a few weeks, while jobs requiring heavy lifting or repetitive overhead movements will take longer, potentially several months. Sports: A gradual return to sports, especially overhead activities, will be guided by your physical therapist and surgeon, often not for several months after surgery. Full return to competitive sports may take 3-6 months or longer.

What is the expected long-term outcome?

For many patients, surgical decompression of QSS provides significant relief from pain, numbness, and weakness, allowing them to return to their normal activities, including sports. Nerve healing can be slow, so improvement may continue for several months. While some mild symptoms may occasionally linger, the goal is to significantly improve your quality of life and shoulder function.

Non-Operative Exercises

Pendulum (Codman’s) Exercises

Passive distraction techniques for early-stage symptom management (Phase 1) home exercise guide.

Active rehabilitation is a cornerstone of recovery. On this page, we outline key home exercises for Pendulum (Codman’s) Exercises designed to help you regain shoulder function. Always consult your care team before beginning.

In the early stages of shoulder recovery, managing pain and stiffness is the top priority. Pendulum exercises, also known as Codman’s exercises, are designed to relieve pain and gently maintain mobility without placing stress on healing tissues. By letting your arm hang freely and using the momentum of your body, you can create a gentle traction (distraction) within the shoulder joint. This helps circulate joint fluid, reduces muscle spasms, and keeps the joint moving safely.

How Pendulum Exercises Work

The key to these exercises is that they are passive. This means the muscles of your injured shoulder should remain completely relaxed and inactive. Instead of using your shoulder muscles to move your arm, you will move your torso (body) to create momentum, letting gravity swing your relaxed arm like a pendulum.

General Guidelines & Safety Rules

Find Sturdy Support: Stand next to a solid table, counter, or sturdy chair. Lean forward from your hips, placing the hand of your uninjured arm on the support surface.
Let the Injured Arm Hang: Let your injured arm hang straight down toward the floor. Keep it completely limp, like a wet noodle or a pendulum.
Use Your Body, Not Your Shoulder: Move your arm by rocking your torso or shifting your body weight. Your arm should swing only because your body is moving. If you feel the muscles in your shoulder tightening or lifting the arm, stop, relax, and start over.
Follow the Pain Rule: These exercises should be gentle and pain-free. If you feel sharp pain, decrease the size of your movements. If pain persists, stop the exercises immediately.

Exercise 1: Forward-and-Backward Pendulum

Purpose: To gently stretch the front and back of the shoulder joint and reduce stiffness.

Equipment Needed: A sturdy table, kitchen counter, or back of a chair.

Starting Position: Stand next to the support. Lean forward at the waist (about 45 degrees) and rest your healthy hand on the support. Let your injured arm hang straight down, completely relaxed.

Step-by-Step Instructions:

Gently rock your body forward and backward, shifting your weight from your front foot to your back foot.
Let the momentum of your body rock your relaxed arm gently forward and backward.
Start with small movements, gradually increasing the swing as comfort allows. Do not use your shoulder muscles to swing or stop the arm.

Dosage: Perform 1 to 2 sets of 10 to 15 repetitions (or swing for 30 seconds), 2 to 3 times per day.

Tips to Avoid Mistakes: Avoid rounding your back excessively. Keep your knees slightly bent to protect your lower back. Ensure the arm remains completely passive.

Exercise 2: Side-to-Side Pendulum

Purpose: To gently stretch the outer and inner parts of the shoulder joint.

Equipment Needed: A sturdy table, kitchen counter, or back of a chair.

Starting Position: Stand next to the support, leaning forward at the waist. Rest your uninjured hand on the support and let your injured arm hang down, relaxed.

Step-by-Step Instructions:

Gently shift your weight and rock your body side to side, from left to right.
Let the motion of your torso swing your relaxed arm side to side across your body.
Ensure your shoulder muscles are not helping to lift or guide the arm. The movement should come purely from the rocking of your body.

Dosage: Perform 1 to 2 sets of 10 to 15 repetitions (or swing for 30 seconds), 2 to 3 times per day.

Tips to Avoid Mistakes: Do not twist your torso. Keep the side-to-side rocking motion smooth and controlled.

Exercise 3: Circular Pendulum

Purpose: To promote gentle, multi-directional motion and joint lubrication throughout the shoulder socket.

Equipment Needed: A sturdy table, kitchen counter, or back of a chair.

Starting Position: Stand next to the support, leaning forward at the waist. Rest your uninjured hand on the support and let your injured arm hang down, relaxed.

Step-by-Step Instructions:

Move your hips and torso in a small circular motion.
Let your body's movement swing your relaxed arm in a gentle circle on the floor.
Perform the circles clockwise for the designated repetitions, then reverse direction and perform them counter-clockwise.
Keep the circles small (about the size of a dinner plate) to prevent overstretching the joint.

Dosage: Perform 1 to 2 sets of 10 circles in each direction (clockwise and counter-clockwise), 2 to 3 times per day.

Tips to Avoid Mistakes: Keep the motion slow. If the circles feel jerky, it means your shoulder muscles are contracting. Relax the arm and initiate the movement again solely using your hips.

Always consult with your physical therapist or doctor before starting a new exercise routine. If any exercise causes persistent pain or swelling, discontinue it and contact your healthcare provider.

Disclaimer: This guide provides general exercise instructions and is not a substitute for professional medical advice. Always consult your doctor or qualified healthcare provider with any questions you may have regarding your specific medical condition and treatment plan.

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