A jerk or kick produced by a blow or sudden strain upon the patellar tendon of the knee, which causes a sudden contraction of the quadriceps muscle.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). knee jerk. Retrieved September 26, 2026, from http://smartdefine.org/knee_jerk/definitions/2025667 |
| Chicago | Webster's. 2011. "knee jerk" http://smartdefine.org/knee_jerk/definitions/2025667 (accessed September 26, 2026). |
| Harvard | Webster's 2011, knee jerk, Smart Define, viewed 26 September, 2026, <http://smartdefine.org/knee_jerk/definitions/2025667>. |
| MLA | Webster's. "knee jerk" 27 May 2011. Web. 26 September 2026. <http://smartdefine.org/knee_jerk/definitions/2025667> |