Exam #3: Deep Back Flashcards
Which germ layer are the deep back muscles derived from?
Mesoderm
Which germ layer do somites differentiate from?
Mesoderm
What do somites differentiate into?
- Sclerotomes
- Myotomes
- Dermatomes
What does the myotome give rise to?
Myoblast cells
What are myoblast cells?
Embryonic muscle cells
What two layers do myotomes divide into?
Epaxial & Hypaxial
Epaxial
Dorsal division of the myotome
Hypaxial
Ventral division of the myotome
Nerve supply to the epaxial division
Dorsal Primary Ramus
Nerve supply to the hypaxial division
Ventral Primary Ramus
What muscles are derived from the epaxial division?
Deep Extensor Muscles of the Back
What muscles are derived from the hypaxial division?
1) Infrahyoid
2) Flexor muscles of the vertebral column
3) Quadratus Lumborum
What is the functional outcome of the origins and insertions of the deep back muscles over-lapping?
Smooth movement during flexion, extension, and rotation
What is the main function of the muscles of the deep back?
- Support body weight by extending the vertebral column
- Maintaining posture & balance
- Movement of the back
What are the only muscles of the body innervated by the Dorsal Primary Ramus?
Intrinsic muscles of the deep back
Anatomically, what is a back strain?
Microscopic tearing of intrinsic muscle cells or ligaments
How are the muscles of the deep back innervated?
Segmentally by the dorsal primary ramus
What are the five major groups of intrinsic back muscles?
1) Splenius Group
2) Erector Spinae Group
3) Trasversopinalis Group
4) Suboccipital Muscles
5) Segmental Group