Inflammation of soft tissues is a common source of musculoskeletal discomfort, with tendonitis and bursitis being two frequent causes. Both conditions involve irritation near a joint, leading to similar symptoms that often confuse people seeking relief. This overlap, coupled with the fact that both can arise from overuse, makes distinguishing between them challenging. Understanding the fundamental anatomical differences between the affected structures is the first step toward clarifying these distinct conditions. This article will define the anatomical variations, mechanisms of injury, and unique pain characteristics to differentiate tendonitis from bursitis.
Defining the Affected Structures
The fundamental difference between these two conditions lies in the specific anatomical structure that becomes inflamed. Tendonitis is the inflammation of a tendon, a thick, cord-like structure composed of fibrous connective tissue. Tendons connect muscles to bones, transmitting force generated by muscle contraction to enable skeletal movement.
In contrast, bursitis involves the inflammation of a bursa. A bursa is a small, flattened sac lined with a synovial membrane and filled with lubricating fluid. Bursae act as cushions between bones and moving structures like tendons and muscles. Their primary function is to reduce friction and allow smooth gliding motion, particularly where a tendon passes over a bony prominence. Bursae are located in areas where friction is high, such as the shoulder, elbow, hip, or knee.
How They Originate and Where They Occur
The mechanisms leading to inflammation differ based on the structure’s function, dictating where these conditions arise. Tendonitis originates from strain, involving an acute overload or chronic repetitive micro-trauma that stresses the tendon fibers. This repeated pulling and tension can lead to degeneration or small tears within the tissue, often termed tendinopathy in chronic cases. Common sites of tendonitis include the Achilles tendon, the patellar tendon, and the tendons of the rotator cuff in the shoulder.
Bursitis, however, results from compression or friction, rather than strain. This condition develops when the bursa is subjected to direct pressure, prolonged kneeling, or excessive rubbing. For example, leaning on an elbow for extended periods can irritate the olecranon bursa. Common locations for bursitis are directly over bony areas, such as the trochanteric bursa on the outer hip, the olecranon bursa at the elbow, or the prepatellar bursa in front of the kneecap.
Distinguishing Pain Patterns and Clinical Diagnosis
While both conditions cause joint discomfort, the nature and location of the pain provide significant clues for differentiation. Tendonitis pain is exacerbated by active movement that engages the affected muscle-tendon unit, especially against resistance. Patients report stiffness, particularly upon waking, and the pain is localized along the specific path of the tendon. Reproducing the pain by stretching the muscle is a common finding.
Bursitis pain, conversely, is often sharp and highly localized directly over the inflamed sac, which may feel swollen or warm. The pain is intensified by direct pressure on the area, such as lying on the affected hip or kneeling. Unlike tendonitis, bursitis pain can be constant, even at rest, if the bursa is significantly distended with fluid. Clinicians differentiate the two using specific physical examination techniques, such as palpation for tenderness directly over a known bursa location and testing range of motion against resistance to assess tendon involvement.
Targeted Treatment and Management Strategies
Because the underlying inflamed structures are different, treatment approaches are tailored to each condition. Management of tendonitis centers on controlling the mechanical load placed on the tendon and promoting tissue repair. This involves physical therapy focusing on eccentric exercises, which strengthen the muscle while it lengthens, to remodel the tendon fibers and build load tolerance. Avoiding the specific motion that caused the initial strain is paramount for recovery.
Bursitis management is aimed at eliminating the compression and friction that irritated the sac. Treatment includes using pads or cushions to offload pressure from the affected area, such as avoiding lying on the painful side. In cases of significant swelling or persistent pain, a physician may perform an aspiration to drain excess fluid or administer a corticosteroid injection directly into the bursa. Bursitis resolves more quickly once direct pressure is removed, while chronic tendon issues require a more prolonged rehabilitation period focused on rebuilding strength and endurance.