Podcast
Questions and Answers
Which nerve innervates the latissimus dorsi muscle?
Which nerve innervates the latissimus dorsi muscle?
- Thoracodorsal nerve (correct)
- Long thoracic nerve
- Dorsal scapular nerve
- Accessory nerve (CN XI)
Which of the following is NOT a function of the trapezius muscle?
Which of the following is NOT a function of the trapezius muscle?
- Depression of the scapula
- Adduction of the scapula
- Abduction of the scapula (correct)
- Elevation of the scapula
What action is performed by the middle fibers of the trapezius muscle?
What action is performed by the middle fibers of the trapezius muscle?
- Medial rotation of the humerus
- Adduction of the scapula (correct)
- Elevation of the scapula
- Depression of the scapula
Which muscle is primarily responsible for extending, adducting, and medially rotating the humerus?
Which muscle is primarily responsible for extending, adducting, and medially rotating the humerus?
The rhomboid major and minor muscles are innervated by which nerve?
The rhomboid major and minor muscles are innervated by which nerve?
Which muscle attaches to the posterior tubercles of the transverse processes of vertebrae C1-C4?
Which muscle attaches to the posterior tubercles of the transverse processes of vertebrae C1-C4?
What is the relative size difference between the rhomboid major and minor muscles?
What is the relative size difference between the rhomboid major and minor muscles?
Which of the following muscles directly acts on the shoulder joint?
Which of the following muscles directly acts on the shoulder joint?
If a patient has damage to the dorsal scapular nerve, which of the following movements would be MOST affected?
If a patient has damage to the dorsal scapular nerve, which of the following movements would be MOST affected?
A weightlifter strains a muscle while performing a pull-up. The injury results in an inability to effectively depress and adduct the scapula. Which specific portion of which muscle is MOST likely affected?
A weightlifter strains a muscle while performing a pull-up. The injury results in an inability to effectively depress and adduct the scapula. Which specific portion of which muscle is MOST likely affected?
What is the primary function of the superficial muscle group of the back?
What is the primary function of the superficial muscle group of the back?
Which muscle in the superficial extrinsic group attaches the pectoral girdle to the skull and vertebral column?
Which muscle in the superficial extrinsic group attaches the pectoral girdle to the skull and vertebral column?
The superficial and intermediate muscle groups of the back are considered what?
The superficial and intermediate muscle groups of the back are considered what?
How many layers are in the superficial muscle group of the back?
How many layers are in the superficial muscle group of the back?
What is the primary function of the trapezius muscle?
What is the primary function of the trapezius muscle?
Which of the following actions is NOT typically associated with superficial back muscles?
Which of the following actions is NOT typically associated with superficial back muscles?
If a patient is experiencing difficulty in elevating and rotating their scapula, which muscle is MOST likely affected?
If a patient is experiencing difficulty in elevating and rotating their scapula, which muscle is MOST likely affected?
Damage to which nerve would MOST directly impact the function of the trapezius muscle?
Damage to which nerve would MOST directly impact the function of the trapezius muscle?
Which of the following is a key distinction between the intermediate and superficial muscle groups of the back?
Which of the following is a key distinction between the intermediate and superficial muscle groups of the back?
A patient presents with an inability to shrug their shoulders and difficulty abducting their arm beyond 90 degrees. Assuming a single point of failure, which anatomical structure is MOST likely compromised?
A patient presents with an inability to shrug their shoulders and difficulty abducting their arm beyond 90 degrees. Assuming a single point of failure, which anatomical structure is MOST likely compromised?
Flashcards
Back Muscles Grouping
Back Muscles Grouping
Muscles divided into superficial, intermediate, and deep groups, based on location.
Extrinsic Back Muscles Function
Extrinsic Back Muscles Function
Superficial and intermediate back muscles primarily control limb movement and respiration.
Superficial Back Muscles
Superficial Back Muscles
Superficial back muscles are extrinsic muscles that connect the upper limb to the trunk and deal with the upper limb movement..
Trapezius Function
Trapezius Function
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Superficial Extrinsic Function
Superficial Extrinsic Function
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Trapezius Muscle
Trapezius Muscle
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Latissimus Dorsi
Latissimus Dorsi
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Levator Scapulae
Levator Scapulae
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Rhomboid Major and Minor
Rhomboid Major and Minor
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Superior fibers of Trapezius
Superior fibers of Trapezius
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Middle fibers of Trapezius
Middle fibers of Trapezius
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Inferior fibers of Trapezius
Inferior fibers of Trapezius
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Latissimus Dorsi action
Latissimus Dorsi action
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Levator Scapulae action
Levator Scapulae action
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Rhomboids action
Rhomboids action
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Study Notes
- There are 3 groups of muscles in the back: superficial, intermediate, and deep.
- Superficial and intermediate muscle groups are extrinsic muscles dealing primarily with limb movement and respiration.
The Superficial Group
- These muscles are extrinsics dealing with upper limb rotation.
- There are two layers in the superficial muscle group that function in connecting the upper limb to the trunk.
Superficial Extrinsics
- Trapezius attaches the pectoral girdle to the skull and vertebral column and assists in suspending the upper limb.
- The trapezius is innervated by CN XI (accessory nerve) and exhibits three groups of fibers.
- Superior fibers elevate the scapula.
- Middle fibers adduct the scapula.
- Inferior fibers depress and adduct the scapula.
- Latissimus dorsi is another large fan-shaped muscle that covers the inferior part of the back from roughly T6 to the iliac crest.
- The latissimus dorsi passes between the trunk and attaches to the floor of the intertubercular groove on the humerus.
- The latissimus dorsi acts directly on the shoulder joint and indirectly on the pectoral girdle.
- It is innervated by the thoracodorsal n.
- The latissimus dorsi extends, adducts, and medially rotates the humerus.
Deep Extrinsics
- Levator scapulae attaches to the posterior tubercles of the transverse processes of C1-4 and the vertebral (medial) border of the scapulae.
- The levator scapulae assists the trapezius in elevating the scapulae as well as maintaining.
- It is innervated by the dorsal scapular n.
- Rhomboid major and minor lie deep to the trapezius forming parallel bands that pass inferolaterally from the vertebrae to the medial border of the scapula.
- The major is generally twice as wide as the minor.
- Both rhomboids brace back the shoulders by retracting the scapula as well as elevate and maintain its level and fix it to the thoracic wall.
- Both rhomboids are innervated by the dorsal scapular n. and the 3rd and 4th cervical nn.
- The remainder of the muscles of the back: the intermediate layer (extrinsics) and deep layer (intrinsics) will be covered in the section on the trunk.
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Description
Overview of the superficial muscle group in the back, including the trapezius and latissimus dorsi. The trapezius attaches the pectoral girdle to the skull and vertebral column, while the latissimus dorsi covers the inferior part of the back.
