Hearing a clicking or popping sound when moving your baby’s shoulder can be alarming. This sensation is a common concern that often leads parents to wonder if their child has a joint issue or an injury. While these sounds are usually harmless and related to normal infant development, they can sometimes signal a condition requiring medical attention. Understanding this distinction is important for knowing when to observe and when to seek a professional evaluation.
Common Reasons for Transient Clicking
The majority of joint noises in infants are benign and do not cause discomfort or long-term problems. This harmless clicking often results from soft tissues temporarily catching on bone during movement. Tendons and ligaments, which are pliable and rapidly growing, can snap over the bony ridges of the shoulder joint as the arm is moved.
Another common source of the sound is joint cavitation, the release of small gas bubbles within the synovial fluid that lubricates the joint. This process is similar to the sound produced when an adult cracks their knuckles and is a painless, temporary event. Infant joints also possess natural hyper-flexibility, or laxity, because their ligaments are looser than an adult’s. This flexibility allows for increased movement and contributes to the temporary noisiness of the shoulder.
Structural or Injury-Related Causes
While most clicking is normal, a different type of sound or sensation, especially one accompanied by limited movement, may point to a specific medical issue. One common injury-related cause is a clavicle fracture, or broken collarbone, which can occur during a difficult delivery. This injury is often subtle, but parents may hear a distinct grating or crunching sound, known as crepitus, when the shoulder is moved. The fracture usually heals quickly, but the sound may be noticeable as the bone forms a protective callus.
A less common but more significant cause is a Brachial Plexus Injury (BPI), such as Erb’s Palsy. This nerve injury occurs when the baby’s neck is stretched to the side during birth. BPI involves nerve damage, typically to the C5 and C6 nerve roots, leading to arm weakness and loss of motion. The resulting weakness causes the baby to hold the arm limply or avoid moving it, a symptom known as pseudo-paralysis.
Acquired shoulder instability or subluxation, a partial dislocation of the joint, is a rare cause of clicking usually linked to significant trauma, such as a fall. In these instances, the sound is often a distinct pop that occurs upon initial injury. This trauma can damage the joint capsule or surrounding soft tissues, allowing the ball of the joint to momentarily shift out of the socket.
When a Doctor Visit is Necessary
Parents should observe their baby for specific accompanying symptoms, or “red flags,” that suggest the clicking is pathological and warrants a medical evaluation. The primary indicator is any clear sign of pain, such as the baby crying out or fussing when the arm is moved or lifted. A reluctance to move the arm, where the baby holds the limb still against the body, is another symptom requiring immediate attention.
Other signs include visible changes around the shoulder joint, such as swelling, bruising, or redness. The development of a hard lump over the collarbone area several weeks after birth may indicate a healing clavicle fracture that was previously undiagnosed. If the joint noise is accompanied by a fever or other signs of systemic illness, consult a pediatrician promptly. When any doubt exists about the cause, seeking consultation with a healthcare provider is the safest course of action.