Sehne

Sehne is the German word for tendon, the fibrous structure that connects muscle to bone. Tendons transmit the force generated by muscle contractions to the skeleton, enabling movement, and they contribute to joint stability and the storage and release of elastic energy during gait and other activities.

Anatomy and composition: Tendons are dense regular connective tissue, composed mainly of collagen type I organized into parallel fascicles to resist tensile loads. Tenocytes, the resident tendon cells, maintain the extracellular matrix. The tendon proper is enclosed by a fibrous sheath and may have additional layers such as the epitenon and paratenon. At their ends, tendons attach to bone via the enthesis, which can be fibrous or fibrocartilaginous, providing a gradual transition to bone.

Blood supply and innervation: Tendons have relatively limited blood supply, with nourishment arising from surrounding tissue, the paratenon, and the peritenon. They are richly innervated by sensory nerves, which contribute to proprioception and pain perception.

Function and variation: Tendons differ in function; some act as energy storers and shock absorbers (notably the Achilles tendon and other large proximal tendons), while others primarily stabilize joints. Their mechanical properties adapt with training and use, showing changes in stiffness and collagen turnover over time.

Clinical relevance: Tendinopathy describes degenerative or inflammatory changes in a tendon, often linked to overuse. Acute injuries can cause partial or complete ruptures. Diagnosis commonly uses ultrasound or magnetic resonance imaging. Treatments include rest, physical therapy with eccentric loading, and gradual rehabilitation; medications may address pain, and surgery may be considered for ruptures or refractory tendinopathy. Preventive measures include progressive loading, proper technique, and adequate recovery.