title: Evaluation of the neurosensory function of the medial meniscus in humans.
abstract: OBJECTIVE
  Menisci are known to have receptors mainly concentrated at the anterior and posterior horns. Although they are purported to send afferent impulses to the central nervous system, this function has not been thoroughly evaluated. The purpose of the study was to investigate whether stimulation of the menisci initiates a cortical response. The reaction of the end organ to the reflex arc is also evaluated.
  
  
  METHODS
  Prospective case series.
  
  
  METHODS
  Fourteen patients with normal medial menisci were included in the study. Different parts of the knee joint (the posterior horn and the body of the medial meniscus, the medial femoral condyle, the capsule, and the joint space) were electrically stimulated by a probe during arthroscopy. The cortical response was monitored with somatosensory-evoked potentials (SEPs). The compound muscle action potentials (CMAPs) of the semimembranosus, quadriceps, and biceps femoris muscles were also monitored with electroneuromyography (ENMG).
  
  
  RESULTS
  Among the stimulated parts, only the posterior horn of the meniscus produced cortical responses. No response was obtained with stimulation of the medial femoral condyle, the body of the medial meniscus, the capsule, or the joint space. Stimulation of the posterior horn of the medial meniscus produced a measurable amount of CMAP latency for the semimembranosus muscle, but not for the quadriceps and biceps femoris muscles.
  
  
  CONCLUSIONS
  Stimulation of the posterior horn of the medial meniscus produces reproducible cortical SEPs and results in ENMG-verified response of the semimembranosus muscle where no response of the semimembranosus muscle is detected with stimulation of the other parts of the knee.
  
  
  CONCLUSIONS
  The knowledge that only the horns of the medial meniscus have mechanoreceptors in the medial compartment of the knee helps to understand patients' signs and symptoms in medial compartment disease.
authors.affiliation: PTT Hospital, Department of Orthopaedic Surgery, Istanbul, Turkey. baranselsaygi@superonline.com
authors.forename: Baransel
authors.initials: B
authors.lastname: Saygi
authors.forename: Yakup
authors.initials: Y
authors.lastname: Yildirim
authors.forename: Nadire
authors.initials: N
authors.lastname: Berker
authors.forename: Demet
authors.initials: D
authors.lastname: Ofluoglu
authors.forename: Evrim
authors.initials: E
authors.lastname: Karadag-Saygi
authors.forename: Mustafa
authors.initials: M
authors.lastname: Karahan
mesh_terms: D000200:Action Potentials; D000344:Afferent Pathways / Q000502:physiology; D001182:Arthroscopy; D004558:Electric Stimulation; D004576:Electromyography; D005073:Evoked Potentials, Somatosensory; D005269:Femur / Q000294:innervation; D006801:Humans; D017746:Joint Capsule / Q000294:innervation; D008465:Mechanoreceptors / Q000502:physiology* / Q000648:ultrastructure; D008592:Menisci, Tibial / Q000294:innervation* / Q000502:physiology / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology; D011446:Prospective Studies; D011930:Reaction Time; D012018:Reflex; D015203:Reproducibility of Results; D013979:Tibial Nerve / Q000502:physiology*