Which statement is true about trapezius?

Which statement is true about trapezius?

• A. It is innervated exclusively by the axillary nerve.
• B. Proprioceptive input to the trapezius comes from C3-C4.
• C. It originates from the iliac crest.
• D. It inserts on the intertubercular groove of the humerus.

Answer: (B)

Proprioception for the trapezius comes from the C3–C4 spinal nerves, not from a motor nerve alone. The trapezius is driven by the spinal accessory nerve (CN XI) for its motor action, but the sensory feedback about position and stretch—the proprioceptive input—travels with the C3–C4 nerves back to the CNS. This helps coordinate scapular movements during elevation, depression, retraction, and rotation. Understanding the other details also clarifies why this point is true: the trapezius does not get its motor supply from the axillary nerve (that nerve serves deltoid and teres minor). It doesn’t originate from the iliac crest (its origin is the skull, the nuchal ligament, and the spinous processes of C7–T12) and it doesn’t insert on the intertubercular groove of the humerus (that groove is where latissimus dorsi attaches). So the statement about proprioceptive input from C3–C4 accurately reflects how this muscle senses its own position.

Proprioception for the trapezius comes from the C3–C4 spinal nerves, not from a motor nerve alone. The trapezius is driven by the spinal accessory nerve (CN XI) for its motor action, but the sensory feedback about position and stretch—the proprioceptive input—travels with the C3–C4 nerves back to the CNS. This helps coordinate scapular movements during elevation, depression, retraction, and rotation.

Understanding the other details also clarifies why this point is true: the trapezius does not get its motor supply from the axillary nerve (that nerve serves deltoid and teres minor). It doesn’t originate from the iliac crest (its origin is the skull, the nuchal ligament, and the spinous processes of C7–T12) and it doesn’t insert on the intertubercular groove of the humerus (that groove is where latissimus dorsi attaches). So the statement about proprioceptive input from C3–C4 accurately reflects how this muscle senses its own position.