Deep Back Flashcards
Which germ layer does the muscular system of the deep back develop from?
Mesoderm
What does each somite differentiate into?
a sclerotomes and a myo - dermatome
What does the myotome region of myo - dermatome region give rise to in the deep back?
myoblast cells (embryonic muscle cells)
What do the myoblast cells (embryonic muscle cells) in the deep back form?
muscles of the trunk
What are the two divisions that the myotomes divide into?
epaxial (dorsal) division
hypaxial (ventral) division
WHICH nerves supply the epaxial division muscles?
DORSAL primary rami of spinal nerves
WHICH nerves supply the hypaxial division muscles?
VENTRAL primary rami of spinal nerves
Even though most of the myoblasts migrate away from their specific myotome level of origin, what do they always maintain from that segment?
their original nerve supply
What muscles are derived from the epaxial division?
deep extensor muscles of the back
What muscles are derived from the hypaxial division?
Infrahyoid
Flexor muscles of vertebral column
Quadratus lumborum
Originally, these muscles have a segmental arrangement and only extend from one vertebra (segment) to the next
Muscles of the deep back
As a group, these muscles extend from the skull (cranium) to the pelvis covered by the deep fascia
Muscles of the deep back
During development, fusion between adjacent segments takes place to form larger muscle masses covering more than one segment (in this muscle group)
Muscles of the deep back
Sequential splitting of muscles takes place later to form different superimposed layers in this muscle group.
Muscles of the deep back
In this muscle group, because the origins and insertions of different muscles overlap, the entire vertebral column moves smoothly during flexion, extension, and rotation.
Muscles of the deep back
In the muscles of the deep back, the entire vertebral column moves smoothly during flexion, extension, and rotation because the origins and insertions of different muscles do what?
overlap
The deep back muscles produce various movements (extension, flexion, rotation) of the back and act to maintain what two qualities of the erectly standing or sitting human?
posture and balance
What various movements do the muscles of the deep back produce?
flexion, extension, and rotation
Since most of the body weight is anterior to the vertebral column, many deep back muscles function to support the body weight be doing what?
extending the vertebral column
The transvers and spinous processes of the vertebrae proved places for what?
attachment of the muscles
THE INTRINSIC back muscles are the only muscles of the body innervated by this.
DORSAL primary rami of spinal nerves
Why do deep back muscles cross more than one segment of the vertebral column and are innervated by more than one spinal cord level?
Because many of the deep back muscles are very long
What do the majority of deep back muscles have multiple of?
origins and insertions
What are back strains the result of?
microscopic tearing of muscle cells or ligaments from extensive extension and rotation.