What is a common effect of left torticollis combined with plagiocephaly?

Left torticollis is characterized by a shortening or tightening of the left sternocleidomastoid (SCM) muscle, which results in the head tilting to the left side. Consequently, due to the nature of the muscle's restriction, the head also rotates to the right. This is a direct result of the muscle imbalance—the tight left SCM influences the head's position, leading to the specific tilt and rotation observed.

When this condition is present alongside plagiocephaly, which typically involves an asymmetrical head shape often related to positioning issues, the tightness of the SCM on the left side may exacerbate the head's asymmetry. The combination of these conditions can create further complications regarding head shape and muscle function. The description of a tight left SCM leading to a left head tilt and right rotation is consistent with typical presentation in torticollis, making it the correct interpretation of these conditions.

Other choices reflect incorrect configurations of muscle tightness and head tilt/rotation characteristics, thus failing to accurately describe the common effects of left torticollis in relation to plagiocephaly.