The interrelation of neural discharge, intra‐articular pressure, and joint angle in the knee of the dog.

Abstract

SUMMARY1. Single-and multi-unit recordings were obtained from the medial articular nerve (m.a.n.) of knee joints in the anaesthetized dog. The single-unit recordings were confined to low threshold (group I and II) articular mechanoreceptors.2. Multi-unit recordings revealed that the m.a.n. discharge was maximal in extension, submaximal in flexion, and minimal at intermediate angles, i.e. a U-shaped profile.3. Subatmospheric intra-articular pressures do not appear to influence the m.a.n. discharge.4. Intra-articular infusion of even small quantities of fluid, although not affecting the U-shaped profile, reversed the m.a.n. discharge pattern with maximum neural activity occurring in flexion and being submaximal in extension.5. Recordings from single units indicated that the enhanced discharge after fluid infusion was a result of increased discharge frequency and ' recruitment ' of individual afferents.

The role of joint receptors in human kinaesthesia when intramuscular receptors cannot contribute.

“…It is therefore likely that human joint afferents would respond to capsular distortion and to intra-articular injection of local anaesthetic in a similar fashion to those in the cat or dog (Clark et al 1979;Ferrell, 1980;Wood & Ferrell, 1985;Ferrell, Nade & Newbold, 1986). Thus, the improved kinaesthetic performance with injection of dextran would result from capsular stretching and enhanced joint afferent discharge while the reduced acuity on injection of local anaesthetic would result from abolition of articular afferent discharge.…”

Deficits in Detection of Inversion and Eversion Movements Among Subjects With Recurrent Ankle Sprains

“…Indeed, these units also become more sensitive during experimentally induced swelling in the cat and dog. 7,9,34 Furthermore, during experimentally induced swelling, proprioceptive acuity is enhanced in the human finger. 8 These findings provide some evidence that neither damage to the joint structures nor presence of swelling in the joint that sometimes accompanies ankle sprain result in a proprioceptive deficit, but may actually improve proprioception in the acute phase.…”

Responses to passive movement of receptors in joint, skin and muscle of the human hand.

“…Previously, mechanoreceptors associated with the ligaments and capsular tissues of the joints were considered responsible for kinaesthesia, in part because of the alleged capacity of slowly adapting afferents of the cat knee joint to signal both the position and velocity of angular displacements across the range of joint rotation (Boyd & Roberts, 1953;Skoglund, 1956). However, subsequent studies of the behaviour of afferents from various joints of the cat, dog and monkey have reported a limited capacity to encode joint position and movement (Burgess & Clark, 1969;Clark, 1975;Clark & Burgess, 1975;Millar, 1975;Grigg, 1975Grigg, , 1976Grigg & Greenspan, 1977;Tracey, 1979;Rossi & Grigg, 1982;Ferrell, Nade & Newbold, 1986), the consensus being that articular afferents respond primarily at, or towards, the limits of passive joint rotation. Articular afferents often respond at both ends of a range of movement and in more than one axis of rotation (e.g.…”