Skeletal System Flashcards
Skeletal dysplasias can be caused by
Genetic mutations, or teratogens
Rhizomelic
Shortening of the proximal segment of an extremity such as femur or humerus
Mesomelic
Shortening of distal segment of an extremity
Such as radius, ulna, tib, fib
Micromelia
Shortening of both proximal and distal limb segments
Acromelia
Shortening of distal segments in hands and feet
Amelia
Absence of extremity
Polydactyl and Syndactyly
More than 5 digits
Or webbed hands/feet
Most common lethal dysplasia
Thanatophoric Dysplasia
Lethal Dysplasia is characterized by
- Severe Micromelia, small thoracic circumference with pulmonary hypoplasia
- Associated with polyhydramnios and thickened skin
Types of lethal dysplasias
Thanatophoric Dysplasia
Achondrogenesis
Osteogenesis Imperfecta
Short rib polydactyly
Thanatophoric Dysplasia
Rhizomelia Bowed long bones Cloverleaf head Horseshoe Kidney ASD Holoprosencephaly Large abd Hypertelorism
Achondrogenesis
Short limbs due to abnormal bone formation and hypomineralization
Sono of achondrogenesis
- Large cranium (macrocranium)
- Short limbs (micromelia)
- Short trunk length and thoracic cavity
2 types of achondrogenesis
Type 1: parenti-fraccaro
Type 2: Langer-Saldino
Type 1 of achondrogenesis
Less common BUT more severe
Autosomal Recessive
Partial/complete skull lack of ossification
Type 2 of achondrogenesis
More common BUT less severe
Spontaneous
No ossification of spine
Osteogenesis Imperfecta type 2!
Rare disorder of collagen forming factors causing fragile bones
Sono will show many fx, bowing and short limbs
Hypophospatasia Congenita
Diffuse hypomineralization caused by ALP deficiency
Auto recessive
How do you dx hypophospatasia congenita
Fetal blood sample, CVS, DNA analysis
Camptomelic dysplasia
Hypoplastic or completely absent fibula
Club foot, scoliosis, heart disease, other abnormalities
Bent limb dysplasia
Camptomelic Dysplasia
Short rib polydactyly dysplasia
Auto recessive
Short ribs, limbs and polydactyly
Non lethal dysplasias
Heterozygous achondroplasia
Diastrophic dysplasia
Chondroectodermal dysplasia
Osteogenesis imperfecta 1,3 and 4
What is the most common NON lethal dx
heterozygous achondroplasia
Heterozygous achondroplasia
Spontaneous OR auto dominant
Neuro complications
Sono: rhizomelia, frontal bossing, small nasal bridge
Asphyxiating thoracic dysplasia
Narrow thoracic cavity Pulmonary hypoplasia Micromelia Renal dysplasia Polydactyly
Jeune’s Syndrome
Asphyxiating thoracic dysplasia
Diastrophic dysplasia
Rare!
Talipes, Cleft Pal, micrognathia, scoliosis
Normal life but under 4ft tall
Sono: hitchhiker thumb, club foot, dislocations
Ellis-can creveld syndrome
Chondroectodermal dysplasia
- disorder of bone growth leading to dwarfism
- common with inbred communities
- 50% have heart defects
Miscellaneous limb deformities
Amelia Phocomelia Oligodactyly Polydactyly Sirenomelia Radial Ray Defects Asso. with aneuploidy
Phocomelia
Absence of PART of the limb
Caudel Regression
Partial/total sacral a genesis
Sirenomelia is most severe form
Sirenomelia
Mermaid Syndrome
Bilateral renal agenesis
Oligohydramnios
Single umbilical artery
ABS
-Amniotic band breaks away from amnion and sticks to fetus, entangles and can cause amputations
Radial Ray Defects
- Absence of radius with a weird thumb
- Asso. T18, T13, VACTERL, Faconi’s, pancytopenia
Arthrogyropsis Multiplex Congenita
Joint Contractures
Fetal Akinesia
Limb Ptyergium
Talipes and clinched hands
Possible causes for Arthrogyrposis Multiplex Congenita
Oligo
Twinning (extrinsic)
Uterine masses
Neuromuscular disorder
Skeletal disorder
Connective tissue disorder (intrinsic)
Limb Pterygium
Webbing of skin
Hand and Foot Deformities
Hitch Hiker thumb Ectrodactyly Clinodactyly Camptodactyly Syndactyly
Hitch Hiker thumb
Suggestive diastrophic dwarfism
Asso with aqueducts stenosis
Ectrodactyly
Lobster Claw
Split hand and foot
Clinodactyly
Permanent curvature of 5th digit
Asso with trisomy 13, 15, 18, 21
Camptodactyly
Permanent flexion of digit
Syndactyly
Fusion of digits
Asso with IUGR and triploidy
Talipes equinovirus
Fancy name for club foot
Rocker bottom foot
-Prominent calcaneus and convex plantar surface
Sandal Toe
Large gap between 1st digit and the rest of the toes
Asso. with T21
