Muscle ID
Actions/Movement
Innervation
Layers
Clinical Cases
100
This broad superficial muscle elevates and retracts the scapula.
Trapezius
100
What movement is produced by bilateral contraction of erector spinae?
Extension of the vertebral column
100
Intrinsic back muscles are innervated by these nerves.
Posterior (dorsal) rami of spinal nerves
100
What fascia is important for lower back stability?
Thoracolumbar fascia
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100
A patient cannot shrug their shoulders after neck surgery. Which muscle is affected?
Trapezius
200
This muscle connects the vertebral column to the humerus.
Latissimus dorsi
200
This muscle assists in pulling the upper limb downward and backward.
Latissimus dorsi
200
This cranial nerve innervates the trapezius muscle.
Accessory nerve (CN XI)
200
Trapezius belongs to this muscle group.
Superficial extrinsic back muscles
Muscles of the Back:
-Extrinsic Muscles = Superficial group and Intermediate group
-Intrinsic Muscles = Deep group and Suboccipital group
Superficial group of back muscles (5):
1) Trapezius, 2) Latissimus dorsi, 3) Levator scapulae, 4) Rhomboid major, 5) Rhomboid minor
200
A patient has pain extending the spine after lifting heavy boxes. Which muscle group is likely strained?
Erector spinae
300
These muscles lie deep to trapezius and retract the scapula.
Rhomboid major and minor
300
What movement occurs when the superior fibers of trapezius contract?
Elevation of the scapula
300
This nerve innervates the latissimus dorsi muscle.
Thoracodorsal nerve
300
Erector spinae belongs to this category.
Intrinsic deep back muscles
Muscles of the Back:
-Extrinsic Muscles = Superficial group and Intermediate group
-Intrinsic Muscles = Deep group and Suboccipital group
Deep groups of muscles (4) (superficial to deep):
1) Spinotransversales muscles, 2) Erector spinae muscles, 3) Transversospinalis muscles, 4) Segmental muscles
300
A patient has difficulty retracting the scapula. Which nerve may be injured?
Rhomboid major and Rhomboid minor innervated by DORSAL SCAPULAR NERVE
400
This deep intrinsic muscle group extends the vertebral column.
Erector spinae
400
These muscles help stabilize the scapula during movement.
Rhomboids and trapezius
400
These nerves generally innervate extrinsic back muscles.
Anterior (ventral) rami
400
What structure separates superficial and deep back muscles?
Thoracolumbar fascia
400
A patient presents with weakness pulling the arm downward while climbing. Which nerve is likely affected?
Latissimus dorsi innervated by the THORACODORSAL NERVE.