Hearing a clicking or popping sound when handling an infant can be unsettling for a parent. Medical professionals call this phenomenon crepitus, which occurs when a joint makes an audible noise during movement. While this sound is often a harmless result of normal infant anatomy, it can occasionally signal an underlying medical issue. Understanding the distinction between a benign joint sound and one that warrants a pediatrician’s evaluation is important.
Understanding Benign Baby Joint Sounds
The majority of joint noises in infants are normal and are a consequence of their developing bodies. One common cause is joint cavitation, which involves the rapid formation of a gas cavity within the synovial fluid that lubricates the joint. When joint surfaces are quickly separated, dissolved gases like nitrogen come out of solution, creating a temporary bubble that rapidly collapses, producing a popping sound. This mechanism is the same process that causes an adult’s knuckles to crack and is not linked to long-term joint damage.
Another source of harmless popping is the movement of soft tissues over bony structures. An infant’s ligaments and tendons are more flexible and lax than an adult’s, allowing them to stretch and “snap” past a bone prominence as the joint moves. This tissue laxity, or hypermobility, is common in babies and toddlers and often decreases naturally as muscles strengthen with age. Benign clicking or popping is typically isolated, meaning it does not happen with every movement, and is not accompanied by signs of pain or discomfort.
When Popping Sounds Signal a Medical Concern
A joint sound becomes a concern when it is accompanied by other symptoms or when the sound changes in character. Signs such as swelling, redness, limited range of motion, or crying when the joint is moved suggest a problem requiring medical evaluation. The presence of crepitus, described as a bubbly or crunching sensation in the collarbone area, especially following a difficult birth, indicates a clavicle fracture. Symptoms of this injury include decreased arm movement and an absent Moro reflex (the startle response) on the affected side.
A different sound is associated with Developmental Dysplasia of the Hip (DDH). While many hip clicks are harmless, a pathological “clunk” is a palpable sensation felt as the hip socket slips out of or back into place. This is distinct from a soft-tissue “click” and signals structural instability in the hip joint. Other signs of DDH include unequal thigh skin creases, one leg appearing shorter than the other, or restricted hip abduction.
A Brachial Plexus Injury (BPI) affects the network of nerves controlling the shoulder, arm, and hand. This nerve injury may occur alongside a clavicle fracture, resulting in a shoulder that appears weak or limp, often held awkwardly against the body. The most telling symptom of BPI is the lack of active movement in the arm or hand, or noticeable weakness compared to the unaffected side.
Safe Lifting and Handling Techniques
Mindful handling can help minimize stress on a baby’s joints, which may reduce the frequency of benign popping sounds. When lifting an infant, always ensure support for the head and neck, especially in newborns who lack the muscle tone to stabilize themselves. The proper technique involves sliding one hand under the baby’s head and neck and the other under their bottom, scooping them up close to the body. This approach prevents sudden strain or pulling on the limbs or shoulder area.
Parents should avoid lifting a baby by pulling on their hands or wrists, which can put stress on the shoulder and elbow joints. Instead, use smooth, deliberate motions, keeping the baby’s body centered and balanced to prevent twisting or yanking. During dressing, avoid forcefully pulling a baby’s arm through a sleeve. A gentler method involves gathering the sleeve material, putting your hand through the opening, grasping the baby’s hand, and guiding the arm through the sleeve without tugging on the joint. These techniques protect the naturally lax ligaments and tendons in the baby’s joints during everyday care.