Final answer:
Elbow flexion and extension movements occur in the sagittal plane, which is related to anterior and posterior movements of the body.
Step-by-step explanation:
Elbow flexion and extension occur in the sagittal plane. The sagittal plane involves movements that are anterior or posterior to the body, meaning they move back and forth in alignment with the body's left and right sides. When you perform an elbow flexion, you are bringing the forearm closer to the upper arm, and during an extension, you are straightening the arm back out. Other joints that also operate in the sagittal plane include the shoulder, hip, knee, wrist, metacarpophalangeal, metatarsophalangeal, and interphalangeal joints.