Bilateral: Affecting both sides. For example, bilateral arthritis affects joints on both the left and right sides of the body. From Healthy Resources 10 Rheumatoid Arthritis SymptomsHigh-Risk Myelofibrosis: Treatment Options10 Ways to Take Control of Your Migraine Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew