Final answer:
Lateral rotation of the upper limbs results in the thumbs pointing outward. It occurs at the shoulder joint where the humerus rotates around its long axis away from the body's midline.
Step-by-step explanation:
The type of angular rotation that results in the thumbs pointing outward is lateral rotation of the upper limbs. During human embryonic development, the upper limb rotates laterally by 90 degrees allowing the palm of the hand to face anteriorly, with the thumb pointing laterally. This lateral rotation is distinct from medial rotation, where anterior surfaces move toward the midline of the body. Lateral rotation can occur at the ball-and-socket joints, such as the shoulder joint, where the humerus rotates around its long axis moving the thumb outwards, away from the midline of the body.