My Baby's Ribs Stick Out
The short answer
Mild rib flaring (lower ribs that protrude slightly) is common in babies and toddlers, especially when lying down or with their arms up. It is often a normal anatomical variation, particularly in lean babies. However, significant rib flaring can sometimes indicate rickets (vitamin D deficiency) or core muscle weakness.
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By Age
What to expect by age
Baby ribcages are naturally flexible and soft. Some prominence of the lower ribs is common, especially in lean babies. Mention it at your next well visit for reassurance.
If rib flaring is accompanied by delayed motor milestones, it may indicate core weakness. If it is present alongside bowed legs or other bone changes, rickets should be evaluated with a blood test.
Rib flaring that worsens or is accompanied by bowing of the legs, swollen wrists, or delayed walking may indicate nutritional rickets. A vitamin D level and X-rays can diagnose this treatable condition.
Mild rib flaring in an otherwise healthy, active child is usually a cosmetic concern only. Severe or worsening flaring should be evaluated.
What Should You Do?
When to take action
- Mild rib prominence in a lean, healthy baby.
- Ribs are symmetric.
- Your baby is meeting motor milestones.
- No other bone or growth concerns.
- Rib flaring is pronounced or worsening.
- Rib flaring with bowed legs or swollen wrists.
- Rib flaring with motor delays.
- Rib flaring with breathing difficulty.
- Rapid worsening of ribcage shape.
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
Worrying about your baby means you care. That is a good thing.
Related Physical Concerns
My Baby Looks Bowlegged
Almost all babies are born with bowlegs because of how they were curled up in the womb. This is completely normal and usually corrects itself by age 2-3 as your child grows and starts walking. True bowleggedness that needs treatment is rare and usually only a concern if it's severe, gets worse over time, or affects just one leg.
Poor Trunk Control
Trunk control - the ability to hold the torso upright and stable - develops progressively throughout the first year. It is essential for sitting, crawling, standing, and walking. Babies build trunk control through tummy time, supported sitting, and active play. If your baby seems unusually floppy in the trunk or slumps significantly when sitting, your pediatrician can assess whether their core strength is developing as expected.
My Baby Seems to Use One Side More Than the Other
Babies should use both sides of their body fairly equally during the first 18 months of life. While slight preferences can be normal, a consistent pattern of favoring one side - using one arm much more than the other, crawling with one leg dragging, or turning the head predominantly one way - should always be discussed with your pediatrician. Early identification of asymmetry leads to the best outcomes.
My Baby Only Army Crawls
Army crawling (also called commando crawling) is a completely valid and normal way for babies to move. Many babies army crawl for weeks or even months before transitioning to hands-and-knees crawling, and some skip hands-and-knees crawling entirely. What matters is that your baby is independently mobile and exploring their environment.
One Side of My Baby's Body Moves Differently
Babies should generally use both sides of their body equally. If one side consistently moves differently, is weaker, stiffer, or less coordinated, this warrants evaluation. Asymmetric movement can indicate hemiplegia (cerebral palsy affecting one side), brachial plexus injury, or other neurological conditions that benefit from early therapy.
My Baby Crawls Unevenly
While some variation in crawling patterns is normal, consistently favoring one side or dragging one limb while crawling warrants attention. Babies should use both arms and both legs relatively equally when crawling. Persistent asymmetry could indicate muscle tone differences, hip issues, or neurological concerns that benefit from early evaluation.