Embryology · Skeleton, muscles, limbs and skin
Developmental dysplasia of the hip !
- Malformation
The head of the thigh bone does not sit well in its socket; if it is not caught in the first months, the hip grows wrongly.
Updated 2026-11-01
See it in 3D: Hip bone · Acetabular labrum · Femur · Femoral head cartilage · Acetabular cartilage · Hip capsule · Ligament of the femoral head
What it is
In developmental dysplasia of the hip, the acetabulum and the femoral head do not form or do not stay seated together. The bone changes start in fetal life, although dislocation usually appears after birth. It is a core paediatrics and exam topic in Colombia: every newborn is screened because early treatment almost always works.
Embryological cause
- The joint forms as a cleft in the mesenchyme of the lower limb bud around weeks 6 to 8.
- Acetabulum and femoral head shape each other: the socket only deepens if the head sits centred inside it.
- If the head stays out or unstable, the acetabulum stays shallow and the head deforms.
- Mechanical factors late in pregnancy: breech position, first pregnancy, little amniotic fluid, a tight uterus.
- Capsular laxity: more common in girls, partly from maternal hormones.
- Swaddling a baby with the legs straight and together favours dislocation after birth.
Markers
- Ortolani
- Barlow
- Galeazzi
- Graf
How it presents
- Risk factors: female sex, breech presentation, family history, first-born, oligohydramnios.
- The left hip is the one most often affected.
- Newborn: Ortolani (reduces a dislocated hip) and Barlow (dislocates an unstable hip) manoeuvres.
- Older infant: limited abduction, asymmetric skin folds and one shorter leg (Galeazzi sign).
- Once walking: a limp, or a waddling gait if both sides are affected.
- Linked to other 'tight space' problems in the uterus: clubfoot and torticollis.
Diagnosis
- Hip ultrasound (Graf method) in the first months, while the femoral head is still cartilage.
- Pelvic X-ray once the ossification centre of the femoral head appears, around 4 to 6 months.
- One normal exam does not rule it out: it is repeated at well-child visits.
Test yourself
Think of the answer, then tap the question to see it.
Why does a femoral head out of place leave a shallow acetabulum?
Because the acetabulum deepens only under the pressure of a centred femoral head; without it, it grows shallow.
What are the main risk factors for hip dysplasia?
Female sex, breech presentation, family history, being first-born and oligohydramnios.
Which imaging test is preferred in the first months of life?
Hip ultrasound, because the femoral head is still cartilage and does not show well on X-ray.
How do the Ortolani and Barlow manoeuvres differ?
Ortolani reduces a dislocated hip with abduction; Barlow dislocates an unstable hip with adduction and backward pressure.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
- Hip bone
- Acetabular labrum
- Femur
- Femoral head cartilage
- Acetabular cartilage
- Hip capsule
- Ligament of the femoral head
Related
- Limb development: the apical ectodermal ridge, ZPA and limb rotation
- Clubfoot (talipes equinovarus)
- Amniotic fluid: polyhydramnios and oligohydramnios
- Neural tube defects: anencephaly, spina bifida and encephalocele
- Muscles: somites, epaxial and hypaxial
Related conditions
- Developmental dysplasia of the hip
- Hip Osteoarthritis
- Avascular necrosis of the femoral head
- Clubfoot (talipes equinovarus)
- Torticollis
Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given.
Sources: Developmental dysplasia of the hip: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Langman's Medical Embryology, 13th ed., ch. 12: Limbs (Wolters Kluwer, 2015).
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Representative model, for educational purposes only.