When the upper fibers of the trapezius are paralyzed, how will the affected shoulder appear?

When the upper fibers of the trapezius are paralyzed, the affected shoulder will appear lower than the unaffected shoulder. This is due to the role the trapezius muscle plays in stabilizing and elevating the scapula. The upper fibers of the trapezius are responsible for raising the shoulder girdle. When this muscle is impaired, the support for the shoulder is compromised, leading to a downward drooping appearance of the affected shoulder.

In functional terms, the trapezius aids in maintaining proper alignment and elevation of the scapula, particularly during movements and weight-bearing activities of the upper limb. Paralyzing these fibers means that there is a lack of muscular support, allowing gravity and the weight of the arm to pull the shoulder down. Thus, the shoulder on the affected side will sag in comparison to the unaffected side, creating the appearance of being lower.