Why Does My Baby’s Shoulder Click When Picked Up?

A clicking or popping sound from your baby’s shoulder when you lift them under the arms is almost always harmless. Infant joints are loosely assembled by design: the bones are partly cartilage, the ligaments are stretchy, and the capsule surrounding the shoulder is thinner in some regions than others. When you change your baby’s position, tendons and ligaments can slide across these soft, still-forming structures and produce an audible snap or click. That said, the sound can occasionally signal something worth checking, from a healing clavicle fracture to a nerve injury sustained during birth. Understanding the difference between a benign click and a worrisome one comes down to a handful of observations you can make at home.

Why Infant Shoulders Are Built to Click

An adult shoulder is the most mobile joint in the body, and it achieves that range of motion by sacrificing some stability. A baby’s shoulder takes that trade-off even further. The ball-and-socket arrangement is present, but much of what will eventually be solid bone is still cartilage in the first months of life. The socket (glenoid) is shallow, and the ligaments that will one day hold everything snugly in place are not all fully developed yet. Research on neonatal shoulder anatomy shows that while the inferior glenohumeral ligament is already a prominent, layered structure at birth, the middle and superior glenohumeral ligaments are thinner and harder to identify as distinct bands. The capsule itself is notably thin in the region above the inferior ligament, and a gap in the capsule called the rotator interval defect is often present even by fifteen weeks of gestational age.¹

What this means in practical terms is that the parts holding a newborn’s shoulder together are loose, partially formed, and flexible. When you scoop a baby up, gravity pulls their body weight downward while your hands support them, and the shoulder structures shift slightly under that gentle traction. A tendon riding over the head of the humerus, or a ligament snapping back into its groove, produces the click you hear. It is essentially the same mechanism behind the cracking sound an adult’s knuckle makes, just happening in a joint that has more slack to begin with.

How Human Shoulders Evolved to Stay Small at Birth

There is actually an evolutionary reason why baby shoulders are so underdeveloped compared with the rest of their skeleton. Human infants have to fit through a birth canal that is narrow relative to body size, and broad shoulders can cause dangerous complications during delivery. Research published in the Proceedings of the National Academy of Sciences found that compared with other primates, human shoulder development follows a unique trajectory: the shoulders grow at a reduced rate relative to trunk length before birth and then catch up with enhanced growth after birth.² The shoulders are, in a sense, deliberately kept small and pliable so the baby can be born safely. The trade-off is that for the first several months, those shoulders are loose and mobile enough to produce clicking sounds with routine handling.

Could It Be a Healing Clavicle Fracture?

One of the more common birth injuries that can produce clicking or crepitus around the shoulder is a fractured clavicle. The collarbone sits right at the top of the shoulder, and it can break during delivery, particularly in larger babies or difficult births. Clavicle fractures occur in somewhere between 0.4% and 10% of births, depending on the population studied.³ That is a wide range, but even at the lower end it is common enough that pediatricians screen for it.

Many clavicle fractures go unnoticed at first. The diagnosis is often made a few weeks after birth when a parent or doctor feels a hard lump of callus forming over the bone as it heals.⁴ Before that callus forms, the broken ends of the bone can shift slightly when the baby is moved, producing a gritty clicking sensation (crepitus) that you might feel under your fingers or hear when you pick your baby up. Other early signs include the baby seeming fussy when the affected arm is moved, swelling over the collarbone, or a Moro reflex that looks different on one side compared with the other.⁴

The reassuring part is that neonatal clavicle fractures heal remarkably fast and almost never need surgical treatment. Imaging studies show that the first signs of healing, a periosteal reaction visible on X-ray, appear as early as seven days after the fracture. A visible callus forms around eleven days, bridging of the fracture starts around twenty days, and full remodeling is typically under way within about five weeks.⁵ By the time most parents notice the lump, the bone is already well on its way to healing. If this is the source of the click, you would expect the sound to stop within a few weeks as the callus solidifies.

Brachial Plexus Injury and Shoulder Instability

A less common but more significant cause of shoulder clicking in a newborn is a brachial plexus injury, sometimes called Erb’s palsy when it affects the upper nerves of the network. The brachial plexus is a bundle of nerves that runs from the neck through the shoulder and into the arm, controlling movement and sensation. During a difficult delivery, especially when the baby’s shoulder gets stuck behind the mother’s pubic bone, these nerves can be stretched or torn. A baby with a brachial plexus injury will typically have weakness or limited movement on the affected side. You might notice that one arm hangs differently, that the baby does not move the arm as freely, or that the grip on one hand seems weaker.

The clicking in these cases comes from the shoulder joint itself becoming unstable. When certain muscles around the shoulder are weakened by nerve damage, the joint can partially slip out of alignment, a condition called posterior shoulder subluxation. A study of children with neonatal brachial plexus palsy found that about 20% met ultrasound criteria for posterior subluxation, and nearly half showed clinical signs of it.⁶ Reduced active range of motion in the shoulder and a history of nerve surgery were both associated with subluxation.⁶ When the humeral head slides partially in and out of the socket, it can produce a palpable clunk rather than a soft click.

This is an important distinction. A brachial plexus injury is usually identified in the hospital or at the first few pediatric visits. If it was not flagged at birth and you notice a clicking shoulder along with any asymmetry in arm movement, that combination warrants a prompt evaluation. Early physical therapy and, in some cases, surgical repair of the nerves can significantly improve long-term outcomes.

Telling a Benign Click From a Worrisome One

The good news is that the clues distinguishing a harmless joint click from something more serious are straightforward to spot at home. A benign click will have all of the following features:

• No pain reaction: Your baby does not cry, wince, or pull away when the click happens. They seem completely unbothered.
• Symmetry: Both arms move equally well. The Moro (startle) reflex looks the same on both sides.
• No swelling or bruising: There is no visible puffiness, discoloration, or hard lump over the collarbone or shoulder.
• Full movement: Your baby reaches with both arms, bats at toys on both sides, and does not favor one arm over the other.

If any of those features are missing, a visit to your pediatrician is a good idea. The scenarios that matter, a clavicle fracture or a brachial plexus injury, both tend to show at least one abnormal sign beyond the click itself. A baby with a broken collarbone may cry when you move the arm on that side or may have a subtle lump you can feel over the bone. A baby with a nerve injury will have noticeably weaker or less frequent movement on the affected side. In other words, a click that is accompanied by absolutely nothing else is overwhelmingly likely to be normal joint noise from a developing shoulder.

Does the Click Go Away on Its Own?

For the vast majority of babies, yes. As the cartilage gradually ossifies into bone over the first year or so, and as the ligaments and joint capsule tighten with growth, the conditions that produce the click resolve naturally. You may notice the clicking is more prominent when your baby is very young, in the first two or three months, and gradually fades as they get bigger and start using their arms more actively. Tummy time, reaching for objects, and eventually crawling all build the muscles around the shoulder that help stabilize the joint.

If the click persists well past six months and seems to be getting more pronounced rather than fading, or if it starts to be accompanied by any new symptoms like fussiness with arm movement, it is worth mentioning at a well-child visit. Persistent or worsening clicking can sometimes indicate that the joint is not tracking properly, and early detection of any structural issue gives you the widest range of options for treatment.

The Hip Click Comparison

If you have been to a newborn checkup, you have probably seen the pediatrician bend and rotate your baby’s hips, listening and feeling for clicks. Hip clicks in infants are so well-known that many parents immediately worry when they hear a similar sound from the shoulder. But the context is quite different. Hip screening looks for developmental dysplasia of the hip, a condition where the hip socket is too shallow to hold the femoral head properly. The clicks that concern doctors in the hip are specific, reproducible clunks that happen when the hip slides in or out of the socket during a specific maneuver.

An isolated click in the hip, without other signs like limited hip abduction, is actually not considered a risk factor for dysplasia. Research has shown that isolated hip clicks are usually due to joint hypermobility and can be associated with similar clicks in the shoulders and knees that are not pathological.⁷ In other words, a clicky baby tends to be clicky all over, and the clicks themselves are a sign of general joint looseness, not a specific structural problem. The shoulder click your baby makes when picked up may well be part of that same pattern of generalized laxity, which is normal and self-limiting.

How You Pick Up Your Baby Matters

The way you lift a baby can influence whether the shoulder clicks. When you reach into a crib and pick a baby up by hooking your hands under their armpits, their full body weight pulls downward on the shoulder joints before you bring them to your chest. That traction force is exactly the kind of movement that stretches the loose joint capsule and causes tendons to pop over bony prominences. It does not injure the shoulder, but it is the most common position that triggers the sound.

If the clicking bothers you, or if your pediatrician has asked you to be gentle with a shoulder because of a suspected clavicle fracture, adjusting your technique can help. Sliding one hand behind the baby’s head and neck and the other under their bottom before lifting distributes the load away from the shoulder joints. Scooping the baby toward you in a rolling motion rather than lifting straight up also reduces the traction on the shoulders. These adjustments are not medically necessary for a healthy baby with benign clicking, but they tend to reduce the frequency of the sound and can put a worried parent’s mind at ease.

When Older Babies and Toddlers Still Click

Joint clicking does not always end in infancy. Some toddlers and young children continue to have audible pops and clicks in the shoulders, knees, and ankles, and this is still usually a normal feature of growth rather than a sign of a problem. Children’s joints are more flexible than adults’ joints, and the tendons and ligaments are still catching up to the bones they surround. Active toddlers who are constantly reaching, climbing, and pulling themselves up put their shoulders through a wide range of motion many times a day, and the occasional click is expected.

The time to take a toddler’s clicking shoulder more seriously is when it is accompanied by pain, when the child avoids using that arm, or when you can see or feel the shoulder moving in and out of the socket. True shoulder instability in a young child is rare but can occur after a fall or a pull on the arm. It can also develop in children who had an undiagnosed brachial plexus injury at birth that led to muscular imbalance around the joint. In these cases, the click tends to feel more like a clunk, something you can feel through your hand when you hold the child, rather than a faint snap.

Asymmetries That Show Up Alongside Clicking

Newborns are not always symmetrical. Research suggests that up to about 73% of infants have at least one musculoskeletal or positional asymmetry stemming from the birth process, with head shape asymmetries being the most common, followed by facial asymmetries and torticollis.³ A baby who had a tight fit in the uterus or a long labor may have a head that tilts to one side, a preference for turning one direction, or muscle tightness in the neck. These are common, usually temporary, and treatable with positioning or gentle stretching.

If your baby’s shoulder clicks and you also notice a head tilt, a preference for one arm, or tightness on one side of the neck, these findings together paint a picture of birth-related musculoskeletal stress rather than a single isolated problem. Mentioning all of the observations at your next pediatric visit gives the doctor a fuller picture. Torticollis in particular can cause a baby to favor one side of the body, which might make you think the shoulder on the other side is the problem when the real issue is a tight neck muscle pulling things off balance.

What the Pediatrician Actually Checks

When you report a clicking shoulder, your pediatrician’s evaluation is usually quick and non-invasive. They will watch your baby move both arms, check the Moro reflex for symmetry, run their fingers along both collarbones feeling for swelling or a callus bump, and gently move the shoulder through its range of motion. They are listening for the quality of the click: a soft, high-pitched snap from a tendon is very different from the gritty crepitus of a fracture or the deep clunk of a subluxing joint.

If everything looks and feels normal, no imaging is needed. X-rays are reserved for cases where there is a palpable abnormality over the clavicle, a clear difference in arm movement between sides, or a history suggesting a difficult delivery. Ultrasound can be used to evaluate the shoulder joint directly if subluxation is suspected, particularly in a baby with known brachial plexus involvement. For the vast majority of clicky shoulders, though, the physical exam is all that is required, and the reassurance that follows is the whole point of the visit.