[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Embryology](https://durgical.com/en/embryology/) › [Skeleton, muscles, limbs and skin](https://durgical.com/en/embryology/#a-musculoskeletal) › Poland sequence and prune belly syndrome [Embryology](https://durgical.com/en/embryology/) · [Skeleton, muscles, limbs and skin](https://durgical.com/en/embryology/#a-musculoskeletal) # Poland sequence and prune belly syndrome - Malformation Two rare muscle defects: in Poland part of the chest muscle on one side is missing; in prune belly the belly wall lacks muscle. Updated 2026-11-01 **See it in 3D:** [Pectoralis major](https://durgical.com/en/anatomy/pectoralis-major-muscle/) · [Pectoralis minor](https://durgical.com/en/anatomy/pectoralis-minor-muscle/) · [Nipple](https://durgical.com/en/anatomy/nipple/) · [Rectus abdominis](https://durgical.com/en/anatomy/rectus-abdominis-muscle/) · [External oblique](https://durgical.com/en/anatomy/external-abdominal-oblique-muscle/) · [Transversus abdominis](https://durgical.com/en/anatomy/transversus-abdominis-muscle/) · [Kidneys](https://durgical.com/en/anatomy/kidney/) · [Ureters](https://durgical.com/en/anatomy/ureter/) · [Testes](https://durgical.com/en/anatomy/testis/) ## Key points - Poland: sternal head of pectoralis major missing, with symbrachydactyly on the same side. - Poland hypothesis: reduced subclavian artery flow around week 6. - Prune belly: deficient abdominal wall + bilateral undescended testes + dilated urinary tract. - Prune belly: almost only boys; kidneys and lungs set the outlook. - Oligohydramnios → pulmonary hypoplasia and compression deformities. ## What it is Both are defects of hypaxial muscles. In Poland sequence the sternal head of pectoralis major is missing on one side, often with a small hand and joined fingers on the same side. In prune belly syndrome the abdominal wall muscles are deficient, together with bilateral undescended testes and dilated urinary tract. Both are asked as examples of congenital muscle defects. ## Embryological cause - Poland: an interruption of blood flow in the subclavian artery or its branches around week 6, when the pectoral muscle and the hand form, is proposed. - Poland: the defect reaches the derivatives of the same territory: pectoral muscle, breast, nipple, upper ribs and hand. - Prune belly, obstruction theory: an early urethral obstruction distends the bladder and abdomen and the wall atrophies. - Prune belly, mesoderm theory: a primary mesodermal defect affects the abdominal wall, urinary tract and testicular descent together. - Oligohydramnios from the uropathy causes pulmonary hypoplasia and compression deformities. ## Markers - Subclavian artery - Symbrachydactyly - Megacystis - Oligohydramnios ## How it presents - Poland: one-sided, more often right; more than twice as common in males; about 1 in 20,000. - Poland: asymmetric chest, a higher or absent nipple, a small breast in girls and symbrachydactyly. - Prune belly: triad of a lax, wrinkled abdominal wall, bilateral undescended testes and urinary tract dilation. - Prune belly: almost always boys; severity depends on the kidneys and lungs. - Prune belly: clubfoot, hip dislocation and pectus excavatum from lack of amniotic fluid. ## Diagnosis - Poland: clinical; chest CT or MRI defines muscle and ribs. - Prune belly, prenatal: megacystis, dilated ureters and kidneys and oligohydramnios on ultrasound. - Prune belly, at birth: renal ultrasound, voiding cystourethrogram and kidney function. ## Memory aid Poland loses 'one side of the chest'; prune belly loses 'the belly's girdle' and drags the kidneys and testes with it. ## Test yourself Think of the answer, then tap the question to see it. ## Which muscle is missing in Poland sequence? The sternal head of pectoralis major on one side, sometimes with pectoralis minor. ## What is the triad of prune belly syndrome? Deficient abdominal muscles, bilateral undescended testes and dilated urinary tract. ## Which vascular mechanism is proposed for Poland sequence? Reduced flow in the subclavian artery or its branches around week 6 of development. ## Why can prune belly syndrome cause pulmonary hypoplasia? The uropathy reduces fetal urine, causing oligohydramnios, so the lungs do not expand enough. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/embryology/poland-sequence-and-prune-belly-syndrome/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Pectoralis major](https://durgical.com/en/anatomy/pectoralis-major-muscle/) - [Pectoralis minor](https://durgical.com/en/anatomy/pectoralis-minor-muscle/) - [Nipple](https://durgical.com/en/anatomy/nipple/) - [Rectus abdominis](https://durgical.com/en/anatomy/rectus-abdominis-muscle/) - [External oblique](https://durgical.com/en/anatomy/external-abdominal-oblique-muscle/) - [Transversus abdominis](https://durgical.com/en/anatomy/transversus-abdominis-muscle/) - [Kidneys](https://durgical.com/en/anatomy/kidney/) - [Ureters](https://durgical.com/en/anatomy/ureter/) - [Testes](https://durgical.com/en/anatomy/testis/) ## Related - [Muscles: somites, epaxial and hypaxial](https://durgical.com/en/embryology/muscles-somites-epaxial-and-hypaxial/) - [Skin, hair, nails and the mammary glands](https://durgical.com/en/embryology/skin-hair-nails-and-the-mammary-glands/) - [Limb defects: amelia, meromelia, polydactyly and syndactyly](https://durgical.com/en/embryology/limb-defects-amelia-meromelia-polydactyly-and-syndactyly/) - [Cryptorchidism](https://durgical.com/en/embryology/cryptorchidism/) - [Pulmonary hypoplasia](https://durgical.com/en/embryology/pulmonary-hypoplasia/) - [Amniotic fluid: polyhydramnios and oligohydramnios](https://durgical.com/en/embryology/amniotic-fluid-polyhydramnios-and-oligohydramnios/) - [Duplicated ureter, UPJ obstruction and posterior urethral valves](https://durgical.com/en/embryology/duplicated-ureter-upj-obstruction-and-posterior-urethral-valves/) ## Related conditions - [Cryptorchidism (undescended testis)](https://durgical.com/en/conditions/cryptorchidism/) [← All of embryology](https://durgical.com/en/embryology/) 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: [Poland syndrome: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/poland-syndrome/) (MedlinePlus, US National Library of Medicine, 2026); [Prune belly syndrome: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/001269.htm) (MedlinePlus, US National Library of Medicine, 2026); Langman's Medical Embryology, 13th ed., ch. 11: Muscular System (Wolters Kluwer, 2015). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/embryology/poland-sequence-and-prune-belly-syndrome/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/embryology/poland-sequence-and-prune-belly-syndrome/