Chapter B3 Ligament and Tendon

Abstract

Ligaments and tendons (T/L) are a hierarchical structure of dense, parallel connective tissue bands that are hypovascular and hypocellular and span a joint connecting bone to bone and bone to muscle, respectively. T/Ls are initially assembled from cross-linked tropocollagen molecules aggregated progressively into microfibrils, subfibrils, fibrils, and fibers (Fig. B3.1). Collagen fibers, which display a waviness or crimp pattern in an unloaded state, are contained in fiber bundles, called fascicles. The entire T/L is then organized into a collection of fascicles and surrounded by a more vascular connective tissue called the epiligament/epitenon. The paratenon surrounds the epiligament/epitenon and facilitates gliding along contiguous structures. Altogether, this hierarchical structure provides the T/L with high tensile force and resilience while preventing damage and separation of the fibers under mechanical stress.