30 Questions
What happens when cell death in the apical ectodermal ridge (AER) occurs?
Fingers and toes form
What is the function of the secreted molecular WNT14 in limb development?
Inductive signal
How do joints in cartilaginous condensations form during limb development?
Induced by chondrogenesis
What happens in Week 7 related to the digital rays in limb development?
Loose mesenchyme between the digital rays breaks down
At what stage does muscle mass divide into extensor and ventral compartments during limb development?
Week 8
What rotates 90 degrees on their longitudinal axis during limb development?
Upper limbs
At what point do primary ossification centers appear in all long bones?
Week 9
When does the epiphyseal cartilage plate get replaced, leading to the end of bone growth?
Around age 25
Where are secondary ossification centers found?
In irregular bones like vertebrae
When do synovial joints form?
During mesenchymal condensations
In what types of bones are primary centers of ossification typically present?
Long bones
What components form within a synovial joint capsule?
Menisci and ligaments
Where are limb musculature cells derived from?
The somites
How does muscle tissue in limb buds initially split?
Into flexor and extensor components
What do upper limb buds lie opposite to?
Cervical and thoracic segments
Which nerves are responsible for extensor musculature in the limbs?
Radial nerve
What role do spinal nerves play in limb musculature?
Provide both sensory and motor innervation
What determines the resulting complex pattern of muscles in limbs?
The lateral plate mesoderm
Which artery in the upper limb arises from the primary axial artery?
Brachial artery
What do radiologists use to determine proper maturation age in children?
Appearance of various ossification centers
At what rate do limb malformations occur in live births?
3.4 per 10,000
Which artery does the primary axial artery form in the lower limb?
Anterior tibial artery
What provides useful information about bone age in children?
Ossification studies in the hands and wrists
In what part of the body does the marginal sinus break up into the dorsal venous arch?
Upper limb
What is the term for the complete absence of one or more extremities?
Amelia
Which term is used to describe the condition where two or more fingers or toes are fused?
Syndactyly
What is the term for an abnormally short limb?
Micromelia
If a person has extra fingers or toes present, what is this condition called?
Polydactyly
What is the term for the bilateral absence of a digit, such as a thumb?
Ectrodactyly
In which condition is there an abnormal cleft between the second and fourth metacarpal bones and soft tissues?
Cleft hand
Test your knowledge on the intricate process of limb development in embryos, from the division of proximal segments to the formation of fingers and toes. Explore how mesenchyme condenses to form chondrocytes and hyaline cartilage models, leading to the development of extremity bones and joints.
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