What type of movement occurs in the transverse plane?

Movement in the transverse plane primarily involves rotational movements around the vertical axis of the body. External rotation, specifically, refers to the outward rotation of a bone away from the midline of the body. This type of movement is essential for activities that require turning or twisting, such as swinging a bat or throwing a ball.

In contrast, other movements listed such as flexion, adduction, and extension occur in different planes. Flexion and extension take place in the sagittal plane and involve movements that decrease or increase the angle between body parts (like bending and straightening a joint), while adduction, which is a movement toward the midline of the body, occurs in the frontal plane. Therefore, external rotation is the only movement that fits the criteria for the transverse plane.