Where are Golgi tendon organs located?

• A. In the muscle belly
• B. At the musculotendinous junction
• C. In the joint capsule
• D. In the synovial fluid

Answer: (D)

Golgi tendon organs reside in the tendon at the musculotendinous junction, in series with the muscle fibers. This placement lets them detect the amount of force generated during contraction by monitoring tendon tension directly. When tension becomes excessive, Ib afferents from the GTOs activate inhibitory interneurons that reduce muscle activity to protect the tendon. They are not located in the muscle belly, joint capsule, or synovial fluid, which are associated with other kinds of receptors (like muscle spindles for length and joint receptors for proprioception).