Westphal's sign

Westphal's sign is the clinical correlate of the absence or decrease of patellar reflex or knee jerk. Patellar reflex or knee jerk is a kind of deep or stretch reflex where an application of a stimulus to the patellar tendon such as strike by a solid object or hammer caused the leg to extend due to such stimulus causes the quadriceps femoris muscle to contract.^{[citation needed]}

Westphal's sign
Patellar tendon reflex arc
Differential diagnosis	Peripheral nerve disease, Motor cortex lesion

It is named for Karl Friedrich Otto Westphal (1833–1890).^[1][2]

Associated conditions

Westphal's sign has a clinical significance used in determining neurological disorders or diseases such as:^{[citation needed]}

• receptor damage, peripheral nerve disease, involving the dorsal(sensory) columns of the spinal cord and cerebellar lesions
• lesions present within the motor cortex of the brain or the pyramidal tracts which it combined with muscular spasms^{[clarification needed]}
• complete interruption of sensory and/or motor impulse transmission in the femoral nerve