Signs
 

Patellar Tap

Bookmark

Overview

  • The patellar tap test assesses for an effusion of the knee joint; in a patient with a significant effusion there will be fluid behind the patella, and tapping the knee will result in a satisfying clunk as the patella makes contact with the femur posteriorly.
    • How to Perform

    • Using 2-3 fingers, sharply tap onto the patient's patella.
    • Abnormal If

    • A palpable ‘clunk' occurs, when the patella makes contact with the trochlea.
    • Causes of Knee Effusion

    • Trauma - ligament tear, menisceal tear, fracture, patellar dislocation
    • Arthritis - osteoarthritis, psoriatic arthritis, reactive arthritis, IBD-related arthritis, gout, pseudogout
    • Infection - septic arthritis, tuberculosis, Lyme disease, syphilis
    • Blood - haemarthrosis
    • Malignancy - osteosarcoma
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Want more info like this?
  • Your electronic clinical medicine handbook
  • Guides to help pass your exams
  • Tools every medical student needs
  • Quick diagrams to have the answers, fast
  • Quizzes to test your knowledge
Explore
   
 
Feedback