Podcast
Questions and Answers
What is the primary function of the intrinsic back muscles?
What is the primary function of the intrinsic back muscles?
Which of the following accurately describes the thoracolumbar fascia?
Which of the following accurately describes the thoracolumbar fascia?
Which layer of intrinsic back muscles is referred to as the superficial layer?
Which layer of intrinsic back muscles is referred to as the superficial layer?
What are the three columns of the erector spinae muscles?
What are the three columns of the erector spinae muscles?
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How are the intrinsic back muscles innervated?
How are the intrinsic back muscles innervated?
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What is the anatomical position of the erector spinae muscles in relation to the vertebral column?
What is the anatomical position of the erector spinae muscles in relation to the vertebral column?
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Which of the following criteria is used to classify the intrinsic back muscles?
Which of the following criteria is used to classify the intrinsic back muscles?
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In addition to maintaining posture, what other role do the intrinsic back muscles serve?
In addition to maintaining posture, what other role do the intrinsic back muscles serve?
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What is the primary function of the intrinsic back muscles?
What is the primary function of the intrinsic back muscles?
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Which nerve primarily innervates the trapezius muscle?
Which nerve primarily innervates the trapezius muscle?
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What is the role of serratus posterior muscles?
What is the role of serratus posterior muscles?
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Which group of muscles includes the latissimus dorsi?
Which group of muscles includes the latissimus dorsi?
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How does body weight distribution affect the back muscles?
How does body weight distribution affect the back muscles?
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Which muscles are categorized as posterior axio-appendicular?
Which muscles are categorized as posterior axio-appendicular?
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What type of nerves innervate the intermediate extrinsic back muscles?
What type of nerves innervate the intermediate extrinsic back muscles?
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Which of the following best describes the function of the extrinsic back muscles?
Which of the following best describes the function of the extrinsic back muscles?
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Study Notes
Overview of Back Muscles
- Body weight distribution is anterior to the vertebral column, necessitating strong back muscles for support and movement.
- Major muscle groups: extrinsic (superficial and intermediate) and intrinsic (deep) back muscles.
Extrinsic Back Muscles
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Superficial Extrinsic Muscles:
- Include trapezius, latissimus dorsi, levator scapulae, and rhomboids.
- Connect axial skeleton to pectoral girdle and humerus, facilitating limb movements.
- Primarily innervated by anterior rami of cervical nerves; trapezius specifically innervated by spinal accessory nerve (CN XI).
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Intermediate Extrinsic Muscles:
- Serratus posterior (superior and inferior) act as slender respiratory muscles, likely more proprioceptive in function.
- Innervated by intercostal nerves; superior part by the first four intercostals, inferior by the last four.
Intrinsic Back Muscles
- Muscles specifically act on the vertebral column, maintaining posture and controlling movements.
- Innervated by posterior rami of spinal nerves.
- Enclosed by deep fascia, attaching medially to nuchal ligament, spinous processes, supraspinous ligament, and sacrum.
Deep Fascia
- Thoracic and lumbar regions have distinct fascial structures:
- Thoracolumbar fascia serves as a thick covering for lumbar muscles and encases thoracic intrinsic back muscles.
Muscle Layers
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Superficial Layer:
- Splenius muscles (splenius capitis and splenius cervicis) cover deep neck muscles, resembling a bandage.
- Arise from midline and extend to cervical vertebrae and cranium.
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Intermediate Layer:
- Erector spinae muscles lie in a groove alongside the vertebral column, crucial for spinal extension.
- Divided into three columns:
- Iliocostalis (lateral column)
- Longissimus (intermediate column)
- Spinalis (medial column)
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Description
Explore the structure and function of back muscles as discussed in pages 117-129. This quiz covers extrinsic and intrinsic muscle groups, their roles in movement and support of the vertebral column, particularly in the context of body weight distribution. Test your knowledge on anatomy and physiology of the back muscles.