Shoulder pain when bringing the arm across the body is a common complaint. This movement, known as horizontal adduction or transverse flexion, involves moving the humerus (upper arm bone) toward and across the chest. Discomfort during this motion can range from a dull ache to sharp pain. Understanding the underlying causes is the first step toward finding relief.
Understanding Shoulder Anatomy and Across-Body Movement
The shoulder is a complex ball-and-socket joint, formed by the humerus, scapula (shoulder blade), and clavicle (collarbone), allowing for extensive mobility. This high degree of motion, however, comes at the expense of stability, making the shoulder susceptible to various injuries. The glenohumeral joint, where the humerus connects to the scapula, is the primary articulation responsible for arm movement.
Horizontal adduction involves the humerus moving in a horizontal plane toward the chest. This motion can narrow the space between structures like the acromioclavicular (AC) joint and the subacromial space. The AC joint connects the clavicle to the acromion, a part of the scapula. The subacromial space, located beneath the AC joint, houses the rotator cuff tendons and the subacromial bursa, a fluid-filled sac that reduces friction. When the arm moves across the body, these structures can be compressed or stretched, potentially leading to pain.
Common Causes of Pain When Bringing Arm Across Body
Pain when bringing the arm across the body often points to specific shoulder conditions. Acromioclavicular (AC) joint issues are a common cause, as the cross-body movement directly compresses this joint. Conditions like AC joint arthritis or a ligament sprain can cause localized pain over the top of the shoulder, aggravated by this motion.
Subacromial impingement, also known as shoulder impingement syndrome, can cause pain during this movement. This occurs when the rotator cuff tendons or the subacromial bursa become compressed or “pinched” in the subacromial space. The narrowing of this space during horizontal adduction can irritate these soft tissues, leading to inflammation and pain.
Rotator cuff tendinopathy or tears, particularly affecting the supraspinatus tendon, can also manifest as pain with across-body movement. The rotator cuff is a group of four muscles and their tendons that stabilize the shoulder and enable its wide range of motion. When the arm is brought across the body, these tendons can be stretched or compressed, leading to a dull ache deep in the shoulder, which may worsen at night or with arm elevation.
Biceps tendinopathy, an inflammation or irritation of the long head of the biceps tendon, can also contribute to pain felt in the front of the shoulder, sometimes radiating down the arm. This tendon travels within a groove in the upper arm bone and can become irritated by repetitive overhead activities or associated shoulder pathologies, such as rotator cuff issues or impingement. The pain may be sharp when reaching overhead or a dull ache after activity.
Finally, referred pain can cause shoulder discomfort that originates from a different area of the body. While shoulder movement might not directly worsen referred pain, it is important to consider if the pain doesn’t change with shoulder motion or if other symptoms are present, such as chest tightness or abdominal pain. Issues in the neck, for instance, can cause pain that radiates into the shoulder due to shared nerve pathways.
Initial Relief and When to Seek Medical Help
Initial self-care strategies can help relieve shoulder pain when bringing your arm across your body. Rest is important, involving avoiding activities that aggravate the pain to allow inflamed tissues to recover. Applying ice packs for 15 to 20 minutes several times a day can help reduce swelling and discomfort. After a few days, if swelling has subsided, applying heat can help relax muscles and promote blood flow.
Over-the-counter pain relievers such as nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, or topical creams containing menthol, can help manage pain and inflammation. Gentle range of motion exercises, carefully avoiding movements that worsen the pain, can help maintain flexibility. For instance, a gentle across-the-chest stretch can improve flexibility, but should be stopped if pain occurs.
It is advisable to consult a healthcare professional if shoulder pain persists beyond a few weeks despite self-care efforts. A doctor’s visit is also warranted if the pain worsens, occurs suddenly after an injury, or is accompanied by significant weakness, numbness, or tingling in the arm or hand. Additional indicators for seeking medical attention include an inability to move the arm, visible deformity of the shoulder, or signs of infection such as redness, warmth, or fever around the joint.