Final answer:
The limitation in reaching forward and upward after an arm has been casted is likely due to a restriction in the humeral head rolling and gliding superiorly, which is necessary for full range motion in the shoulder joint.
Step-by-step explanation:
A person experiencing difficulty in reaching forward and upward after having their arm immobilized in a cast is likely facing limitations in specific arthrokinematic movements. The movement in question when lifting the arm forward and upward is typically a combination of flexion, abduction, and external rotation at the shoulder. For the arm to fully reach upwards, there must be an upward (superior) rolling and gliding movement of the humeral head in the glenoid cavity, along with superior rotation of the scapula.
Therefore, the correct statement that best describes the arthrokinematic movements that are likely limited is: D. Humeral head rolling superiorly and gliding inferiorly. This reflects the combination of movements necessary for the humerus to properly articulate in the shoulder joint and allow for the full range of motion required to reach forward and upward.