Development of MSK System Flashcards
During what weeks is the embryo most susceptible for major abnormalities in the upper limb?
Weeks 4-6
What germ layer makes up the notochord?
Mesoderm
_________ Mesoderm is directly lateral to the Notochord, and gives rise to Somites.
Paraxial
Paraxial Mesoderm gives rise to Somites. What do Somites further divide into?
Myotome (muscle)
Sclerotome (axial skeleton)
Dermatome (dermis)
The Myotome gives rise to all muscles except…
Muscles of the eye
When Somites are dividing, they split into what two parts? What do these parts give rise to?
Ventromedial part — makes Sclerotome
Dorsolateral part — makes Dermatome and Myotome
The cells of the _________ migrate around the Notochord to form the Vertebral Column.
Sclerotome
What are the key components of the Vertebral Column?
Notochord
Paraxial Mesoderm
In the Vertebral Column development, each Sclerotome has what two parts?
Cephalic Loose
Caudal Dense
What lies in between each Sclerotome segment?
Intersegmental Arteries
In the process of Vertebral Column development, the (CEPHALIC/CAUDAL) half of the Sclerotome above will fuse with the (CEPHALIC/CAUDAL) half of the Sclerotome below.
Caudal
Cephalic
As the Vertebral Column developments, these insert through the Sclerotome to attach to the Myotome (muscles).
Nerves
***Motor nerves are in muscle by week 5
What germ layer are Somatic Motor Neurons from?
Neuroectoderm
What germ layer are Preganglionic fibers (Sympathetic or Parasympathetic) from?
Neuroectoderm
Does the Cephalic Loose or Caudal Dense part of the Sclerotome signify what number the vertebra will be?
Caudal Dense
***For example if the Caudal Dense part of C3 pairs with the Cephalic Loose part of C4, then the vertebra number being made is C3.
T/F. Cervical nerves alway exit below their respective vertebra number, while Thoracic and Lumbar will exit above.
False. Cervical nerves exit ABOVE their respective vertebra, while Thoracic and Lumbar exit BELOW.
What parts of the Vertebra does the Caudal Dense part of the Sclerotome give rise to?
Superior Articular Process Transverse Process Pedicle Part of Vertebral Body Part of Spinous Process
What parts of the Vertebra does the Cephalic Loose part of the Sclerotome give rise to?
Inferior Articular Process
Part of Vertebral Body
Part of Spinous Process