Flexion-extension sensitivity of elbow joint afferents in cat

Single units from stretch receptors in the elbow joint of the cat were studied in split-down filaments of the musculocutaneous nerve of the cat. The majority of fibres isolated responded to elbow extension with a phasic and then graded tonic or slowly adapting response. All fibres had a maximum adapted discharge at full extension. Over half the units also gave a phasic or tonic response at full flexion of the elbow, but this was non-graded and only appeared at the extreme position of the arm. These results are discussed briefly in the context of previous joint afferent studies.