Tinel's Sign at the Knee: Checking the Common Peroneal Nerve

Tinel's Sign is a general neurological test used to assess nerve irritation. At the knee, it is specifically used to detect entrapment or regeneration of the Common Peroneal Nerve (Common Fibular Nerve) at the fibular head.

[Image of Tinel's sign at the knee]

1. Purpose

The primary purpose of Tinel's Sign at the knee is to **test for** irritation or entrapment of the Common Peroneal Nerve (Common Fibular Nerve). This nerve wraps around the neck of the fibula and is susceptible to compression from tight casts, crossing legs, or direct trauma.

2. How to Perform

1. The patient is positioned in sitting or supine with the knee flexed to 90 degrees.
2. The examiner locates the head of the fibula on the lateral (outer) aspect of the knee.
3. The examiner locates the common peroneal nerve just inferior (below) and posterior to the fibular head.
4. The examiner gently but firmly taps over the nerve using a finger or reflex hammer.

3. Positive & Negative Sign

Positive Sign (Test is POSITIVE):
A positive test (indicating nerve irritation) is:

• Reproduction of tingling, paresthesia ("pins and needles"), or an electric shock sensation.
• The sensation radiates down the lateral leg and onto the dorsum (top) of the foot.

Negative Sign (Test is NEGATIVE):
A negative test is the absence of neurological symptoms upon tapping.