Discharge characteristics of the elbow joint nerve of the cat.

Direct recordings were made from intact elbow joint nerves (EJN) in decerebrate cats. These multiunit recordings indicate that the EJN is a relatively pure articular nerve and does not contain significant numbers of muscle afferent fibres. In every cat the EJN exhibited a tonic discharge throughout a full range of elbow joint positions. The discharge was most intense when the elbow was extended to 165 degrees and least intense when the joint was held in midrange positions between 90 degrees and 120 degrees. There was a modest increase in discharge as the elbow was held in more flexed positions and activity at 30 degrees was about half of that at 165 degrees. Alterations in the tone of muscles around the joint did not affect the adapted EJN discharge at any angle.