What physical exam finding is characterized by a hard nodule at the PIP joint, commonly seen in osteoarthritis?

The presence of a hard nodule at the proximal interphalangeal (PIP) joint is characteristic of a Bouchard node, which is often observed in patients with osteoarthritis. These nodes are formed from bone spurs (osteophytes) and are indicative of the degenerative joint changes that occur with this condition.

In osteoarthritis, the cartilage in the joints deteriorates, leading to the development of these bony growths at the joints, particularly in the hands. Bouchard nodes specifically appear on the PIP joints, whereas Heberden nodes would appear on the distal interphalangeal (DIP) joints. This distinction is important in diagnosing the type of arthritis present, as the distribution of these nodules can help differentiate osteoarthritis from other forms of arthritis.

The other listed conditions involve different pathologies and characteristic findings. Gouty tophi are deposits of monosodium urate crystals found in chronic gout, rheumatoid nodules are associated with rheumatoid arthritis and typically appear subcutaneously, and Heberden nodes are related to osteoarthritis but specifically found at the DIP joints. Recognizing these distinctions is crucial for proper diagnosis and management of joint-related disorders.