Podcast
Questions and Answers
Which of the following best describes the primary function of the deep back muscles?
Which of the following best describes the primary function of the deep back muscles?
A patient is unable to shrug their shoulders. Which muscle is MOST likely affected?
A patient is unable to shrug their shoulders. Which muscle is MOST likely affected?
Which action is NOT performed by the trapezius muscle?
Which action is NOT performed by the trapezius muscle?
What is the common action of both the rhomboid major and minor muscles?
What is the common action of both the rhomboid major and minor muscles?
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The latissimus dorsi muscle is responsible for which of these actions on the humerus?
The latissimus dorsi muscle is responsible for which of these actions on the humerus?
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Which nerve is associated with the action of the latissimus dorsi muscle?
Which nerve is associated with the action of the latissimus dorsi muscle?
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Which nerve is responsible for the movement of the levator scapulae muscle?
Which nerve is responsible for the movement of the levator scapulae muscle?
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Which group of nerves is vital for the innervation of the muscles of the upper limb?
Which group of nerves is vital for the innervation of the muscles of the upper limb?
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Flashcards
Superficial back muscles
Superficial back muscles
Muscles attached to the trunk and upper limb, responsible for supporting and moving the shoulder and arm.
Deep back muscles
Deep back muscles
Muscles located along the spinous processes (back of the spine), their function is to support and move the vertebral column.
Trapezius Muscle
Trapezius Muscle
A large triangular muscle that spans the upper back, responsible for movements like shrugging, scapula adduction, depression, and rotation.
Levator Scapula Muscle
Levator Scapula Muscle
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Rhomboid Minor and Major Muscles
Rhomboid Minor and Major Muscles
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Latissimus Dorsi Muscle
Latissimus Dorsi Muscle
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Brachial Plexus
Brachial Plexus
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Spinal Accessory Nerve, Thoracodorsal Nerve
Spinal Accessory Nerve, Thoracodorsal Nerve
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Study Notes
Superficial Back Muscles vs. Deep Back Muscles
- Superficial back muscles attach to the trunk and upper limb, specifically the scapula and humerus. Their primary function is to support and move the upper limb.
- Deep back muscles, also known as paraspinal muscles, are located along the spinous processes. Their function is to support and move the vertebral column.
Trapezius Muscle
- Origin: External occipital protuberance, nuchal ligament, spinous processes of C7 to T12
- Insertion: Spine of the scapula, acromion, lateral third of the clavicle
- Actions:
- Elevation: Shrugging the shoulders, contraction of the upper fibers pulls the scapula upwards.
- Adduction: Pulling the scapula towards the midline, contraction of the middle fibers pulls the scapula towards the midline.
- Depression: Pulling the scapula downwards, contraction of the lower fibers pulls the scapula downwards.
- Rotation: Combined contraction of all fibers results in rotation of the scapula, crucial for movements like reaching above the head.
- Innervation: Spinal accessory nerve (cranial nerve XI)
Levator Scapula Muscle
- Origin: Transverse processes of C1 to C4 vertebrae
- Insertion: Superior angle of the scapula
- Action: Elevation of the scapula
- Innervation: Dorsal scapular nerve (C5)
Rhomboid Minor and Major Muscles
- Rhomboid Minor:
- Origin: Spinous processes of C7 and T1 vertebrae
- Insertion: Medial margin of the scapula, at the level of the spine
- Rhomboid Major:
- Origin: Spinous processes of T2 to T5 vertebrae
- Insertion: Medial margin of the scapula
- Action: Adduction of the scapula
- Innervation: Dorsal scapular nerve (C5)
Latissimus Dorsi Muscle
- Origin: T7 to sacral region of the vertebral column, thoracolumbar fascia
- Insertion: Intertubercular groove of the humerus
- Actions:
- Adduction: Drawing the humerus towards the midline, or pulling the arm towards the body.
- Extension: Moving the humerus from a flexed to an extended position, extending the arm backwards.
- Innervation: Thoracodorsal nerve (C6, C7, C8)
Brachial Plexus
- A network of nerves that provides innervation to the upper limb.
- The dorsal scapular nerve and the thoracodorsal nerve travel through the brachial plexus to reach their respective muscles.
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Description
This quiz explores the differences between superficial and deep back muscles, including their origins, insertions, and functions. Focus is placed on the trapezius muscle and its various actions in relation to shoulder movement. Test your understanding of muscle anatomy and function.
