Limb Embryology X

Question 1

Derivatives of Scleratome

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Answer 1

Chondroblasts - cartiligounous precursors of axial skeleton = vertebral bodies + interveterbral discs (notochord)

Question 2

Derivatives of Dermatome

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Answer 2

Skin

Question 3

Derivatives of Myotome

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Answer 3

Muscles

Question 4

Inducing of limb buds

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Answer 4

Mesenchyme capped by ectoderm, appearing week 4

Divided in ventral flexors and dorsal extensors

Question 5

Anatomical organization of limb bud v adult limbs

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Answer 5

.Myotomes have segmental distribution in the embryo.

most muscles are innervated by more than one spinal segment

Question 6

To bone and skeletal muscle - origin

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Answer 6

Mesoderm - Somites - Dermamyotomes - Myotomes & Dermotome

Medoderm - Somites - Mesencyme - Chondroblasts - Cartilaginous precursors - bone (endochondral ossification)

Question 7

Extremity rotation during development

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Answer 7

Upper limb rotates 90 laterally and Lower limb roates 90 medially

Question 8

Anterior v posterior Brachial plexus UE

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Answer 8

Nerve branches of anterior division go to flexors while posterior division go to extensors
Also in leg (but turned)

Question 9

Adult dermatome

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Answer 9

Significant

Question 10

dermatomal v peripheral nerve innervation + clinical significance
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Answer 10

Sensory loss overlapping dermatomes can indicate lesions closer to spine
Problems can be related to peripheral nerves (Which have own pattern of cutaneous innvervation) or dermatomes

Question 11

Dysplasia

Answer 11

malformation of parts of limb - Syndactyly