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Questions and Answers
Which intrinsic back muscle originates from the occipital bone and inserts into the spine of the scapula?
Which intrinsic back muscle originates from the occipital bone and inserts into the spine of the scapula?
What is the primary innervation of the intrinsic back muscles?
What is the primary innervation of the intrinsic back muscles?
Which of the following intrinsic back muscles inserts into the medial border of the scapula?
Which of the following intrinsic back muscles inserts into the medial border of the scapula?
What is the origin of the erector spinae muscle?
What is the origin of the erector spinae muscle?
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Which nerve innervates the levator scapulae muscle?
Which nerve innervates the levator scapulae muscle?
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What is the function of the intrinsic back muscles?
What is the function of the intrinsic back muscles?
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Which intrinsic back muscle originates from the transverse processes of the vertebrae?
Which intrinsic back muscle originates from the transverse processes of the vertebrae?
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What is the insertion point of the trapezius muscle?
What is the insertion point of the trapezius muscle?
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Which nerve innervates the rhomboids muscle?
Which nerve innervates the rhomboids muscle?
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Which intrinsic back muscle group is divided into superficial and deep layers?
Which intrinsic back muscle group is divided into superficial and deep layers?
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Study Notes
Intrinsic Back Muscles
Intrinsic back muscles are a group of muscles that originate and insert within the back, playing a crucial role in maintaining posture, stabilizing the spine, and facilitating movement.
Superficial Intrinsic Back Muscles
- Trapezius: originates from the occipital bone, ligamentum nuchae, and spinous processes of C7-T12; inserts into the spine of the scapula, acromion, and lateral third of the clavicle; innervated by the spinal accessory nerve (CN XI)
- Rhomboids: originates from the spinous processes of T2-T5; inserts into the medial border of the scapula; innervated by the dorsal scapular nerve (C4-C5)
- Levator scapulae: originates from the transverse processes of C1-C4; inserts into the superior angle of the scapula; innervated by the dorsal scapular nerve (C4-C5) and the cervical nerve (C3-C4)
Deep Intrinsic Back Muscles
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Erector spinae: originates from the iliac crest, sacrum, and spinous processes of L1-L5; inserts into the ribs, thoracic vertebrae, and cervical vertebrae; innervated by the posterior rami of the spinal nerves (T1-L5)
- Iliocostalis: originates from the iliac crest and sacrum; inserts into the ribs and thoracic vertebrae
- Longissimus: originates from the iliac crest and sacrum; inserts into the ribs and thoracic vertebrae
- Spinalis: originates from the spinous processes of L1-L5; inserts into the cervical vertebrae
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Transversospinalis: originates from the transverse processes of the vertebrae; inserts into the spinous processes of the vertebrae; innervated by the posterior rami of the spinal nerves (T1-L5)
- Semispinalis: originates from the transverse processes of the vertebrae; inserts into the spinous processes of the vertebrae
- Multifidus: originates from the transverse processes of the vertebrae; inserts into the spinous processes of the vertebrae
- Rotatores: originates from the transverse processes of the vertebrae; inserts into the spinous processes of the vertebrae
Innervation of Intrinsic Back Muscles
- The intrinsic back muscles are primarily innervated by the posterior rami of the spinal nerves (T1-L5) and the dorsal scapular nerve (C4-C5).
- The spinal accessory nerve (CN XI) also innervates the trapezius muscle.
Intrinsic Back Muscles
- Intrinsic back muscles originate and insert within the back, playing a crucial role in maintaining posture, stabilizing the spine, and facilitating movement.
Superficial Intrinsic Back Muscles
- Trapezius: originates from the occipital bone, ligamentum nuchae, and spinous processes of C7-T12; inserts into the spine of the scapula, acromion, and lateral third of the clavicle; innervated by the spinal accessory nerve (CN XI)
- Rhomboids: originates from the spinous processes of T2-T5; inserts into the medial border of the scapula; innervated by the dorsal scapular nerve (C4-C5)
- Levator scapulae: originates from the transverse processes of C1-C4; inserts into the superior angle of the scapula; innervated by the dorsal scapular nerve (C4-C5) and the cervical nerve (C3-C4)
Deep Intrinsic Back Muscles
- Erector spinae: originates from the iliac crest, sacrum, and spinous processes of L1-L5; inserts into the ribs, thoracic vertebrae, and cervical vertebrae; innervated by the posterior rami of the spinal nerves (T1-L5)
- Iliocostalis: originates from the iliac crest and sacrum; inserts into the ribs and thoracic vertebrae
- Longissimus: originates from the iliac crest and sacrum; inserts into the ribs and thoracic vertebrae
- Spinalis: originates from the spinous processes of L1-L5; inserts into the cervical vertebrae
- Transversospinalis: originates from the transverse processes of the vertebrae; inserts into the spinous processes of the vertebrae; innervated by the posterior rami of the spinal nerves (T1-L5)
- Semispinalis: originates from the transverse processes of the vertebrae; inserts into the spinous processes of the vertebrae
- Multifidus: originates from the transverse processes of the vertebrae; inserts into the spinous processes of the vertebrae
- Rotatores: originates from the transverse processes of the vertebrae; inserts into the spinous processes of the vertebrae
Innervation of Intrinsic Back Muscles
- Intrinsic back muscles are primarily innervated by the posterior rami of the spinal nerves (T1-L5) and the dorsal scapular nerve (C4-C5).
- The spinal accessory nerve (CN XI) also innervates the trapezius muscle.
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Description
Test your knowledge of the intrinsic back muscles, including their origins, insertions, and functions in maintaining posture and facilitating movement.
