Advanced Trapezius Quiz

Q1. What anatomical feature explains the diamond-shaped appearance created by the paired trapezius muscles?

• The two triangular muscles meet along the midline to form a broad diamond-shaped sheet
• Both muscles insert into the lumbar vertebral bodies
• Each muscle forms a circular cuff around the shoulder
• The muscles cross each other at the scapula

Q2. Why can injury to the spinal accessory nerve produce difficulty abducting the arm above the horizontal?

• The injury fixes the humerus in medial rotation
• The injury prevents elbow extension
• Loss of scapular upward rotation limits overhead elevation
• The injury directly paralyzes the deltoid

Q3. What visible shoulder change can occur after significant trapezius paralysis?

• Fixed elbow flexion
• Drooping of the affected shoulder
• Anterior dislocation of the humerus in every case
• Permanent elevation of the shoulder

Q4. How does the trapezius-serratus anterior force couple produce upward rotation?

• Complementary pulls on different parts of the scapula rotate the glenoid cavity superiorly
• Serratus anterior downwardly rotates while trapezius protracts
• The muscles act only on the humerus
• All muscles pull the inferior angle medially

Q5. Why does trapezius receive motor innervation that differs from most other superficial extrinsic back muscles?

• It has no spinal nerve association
• It receives motor fibers only from the phrenic nerve
• Its motor supply is primarily from cranial nerve XI rather than a typical anterior ramus-derived peripheral nerve
• It is supplied exclusively by posterior rami

Q6. What is the relationship of trapezius to the posterior triangle of the neck?

• It forms the floor of the oral cavity
• It forms the posterior boundary of the posterior triangle
• It lies entirely inside the carotid sheath
• It forms the anterior boundary of the carotid triangle

Q7. Why can lymph node biopsy in the posterior triangle threaten shoulder function?

• The axillary artery is always divided
• The spinal accessory nerve can be injured, weakening trapezius
• The thoracodorsal nerve supplies trapezius here
• The brachial artery lies superficial to trapezius

Q8. How does the lower trapezius contribute to stable overhead movement beyond simply depressing the scapula?

• It combines depression with a rotational contribution that supports scapular upward rotation
• It immobilizes the clavicle completely
• It directly abducts the humerus
• It downwardly rotates the scapula during all elevation

Q9. Why is trapezius considered extrinsic to the deep intrinsic musculature of the back?

• It is a superficial pectoral girdle muscle with nonsegmental accessory nerve motor supply
• It acts only between adjacent vertebrae
• It belongs to the transversospinalis group
• It is a deep epaxial muscle supplied by posterior rami

Q10. Which statement best integrates trapezius anatomy and function?

• It links the posterior skull and vertebral midline to the pectoral girdle and coordinates scapular elevation, retraction, depression, and upward rotation
• It is a rotator cuff muscle supplied by the suprascapular nerve
• It is a deep intrinsic muscle whose only action is vertebral extension
• It arises from the ribs and inserts on the humerus to adduct the arm