Musculoskeletal strain or sprain: This is often the most common cause of lower extremity pain, resulting from overuse, injury, or trauma to the muscles, tendons, or ligaments.

Osteoarthritis: A common condition characterized by wear and tear of the joint cartilage, leading to pain and stiffness, especially in older adults.
Peripheral artery disease (PAD): A condition where narrowed arteries reduce blood flow to the limbs, causing pain, especially during walking.
Deep vein thrombosis (DVT): A blood clot in the deep veins of the legs, which can cause pain, swelling, and warmth.
Nerve compression or neuropathy: Conditions such as sciatica or peripheral neuropathy can cause pain, numbness, and tingling in the lower extremities.

Compartment syndrome: A serious condition where increased pressure within a muscle compartment can lead to nerve and muscle damage, requiring prompt medical attention.
Septic arthritis: A bacterial infection within a joint, which can cause severe pain, swelling, and systemic symptoms, requiring urgent treatment.
Aortic aneurysm or dissection: Although rare, these conditions can cause lower extremity pain due to impaired blood flow or compression of surrounding structures.
Osteomyelitis: A bone infection that can cause severe pain, swelling, and systemic symptoms, requiring prompt antibiotic treatment.

Ehlers-Danlos syndrome: A group of genetic disorders affecting connective tissue, which can cause joint hypermobility, skin hyperextensibility, and tissue fragility.
Complex regional pain syndrome (CRPS): A chronic pain condition characterized by intense burning or aching, usually affecting one limb after injury or trauma.
Pseudogout: A type of arthritis caused by calcium pyrophosphate dihydrate crystal deposition, leading to sudden, severe joint pain and swelling.
Lymphedema: A condition characterized by chronic swelling of the limbs due to impaired lymphatic drainage, which can cause pain and discomfort.