A physical therapist is performing Tinel's sign to assess for tarsal tunnel syndrome. Where should the therapist tap to provoke symptoms when performing this test?

Option 1- Over the anterior ankle joint line between the tibia and talus
Option 2- Posterior to the medial malleolus
Option 3- Over the dorsum of the foot near the base of the first metatarsal
Option 4- Posterior to the lateral malleolus

Transcript

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A physical therapist is performing Tinel's sign to assess for tarsal tunnel syndrome. Where should the therapist tap to provoke symptoms when performing this test?
Option 1- Over the anterior ankle joint line between the tibia and talus
Option 2- Posterior to the medial malleolus
Option 3- Over the dorsum of the foot near the base of the first metatarsal
Option 4- Posterior to the lateral malleolus

Tarsal Tunnel Syndrome and Tinel's Sign
Tarsal tunnel syndrome is a condition caused by compression of the tibial nerve as it passes through a narrow space at the ankle. It can lead to pain, tingling, or numbness in the foot, often reproduced by certain clinical tests. A physical therapist may use Tinel's sign over the tibial nerve to assist in the diagnosis of tarsal tunnel syndrome.
Recall that Tinel's sign works by tapping directly over a compressed or irritated nerve at its entrapment site. When performed correctly, the tapping provokes tingling or electric shock-like sensations in the sensory distribution of that nerve - what we call a positive Tinel's sign. So the question really comes down to one thing - where does the tibial nerve travel as it passes through the tarsal tunnel?

Let's explore each of the options:

Option 1 - Over the anterior ankle joint line between the tibia and talus

The anterior ankle joint line is not the location of the tibial nerve. Therefore, tapping in this region would not reproduce the symptoms of tarsal tunnel syndrome.
The anterior ankle is the territory of the deep peroneal nerve and the dorsalis pedis artery - structures that run along the front of the ankle. The tibial nerve travels along the posterior and medial side of the ankle, not the front. Tapping over the anterior joint line would be tapping in entirely the wrong neighborhood for tarsal tunnel syndrome.

Option 2 - Posterior to the medial malleolus

The tibial nerve passes through the tarsal tunnel posterior to the medial malleolus. Tapping here may reproduce tingling or burning in the plantar aspect of the foot.
The tarsal tunnel is formed by the flexor retinaculum, which spans from the medial malleolus to the calcaneus, creating a fibro-osseous tunnel on the medial side of the ankle. The tibial nerve, along with the posterior tibial artery and several tendons, passes through this tunnel just behind the medial malleolus. 

Option 3 - Over the dorsum of the foot near the base of the first metatarsal

The dorsum of the foot near the base of the first metatarsal is innervated by branches of the deep peroneal nerve, not the tibial nerve. Therefore, tapping in this region would not reproduce the symptoms of tarsal tunnel syndrome.
The deep peroneal nerve travels along the dorsal surface of the foot and provides sensation to the first web space. It is a completely different nerve from the tibial nerve, and tapping over its distribution would not provoke tarsal tunnel symptoms. Wrong nerve, wrong location.

Option 4 - Posterior to the lateral malleolus

The lateral malleolus region is associated with the sural nerve, not the tibial nerve. Therefore, tapping in this region would not reproduce the symptoms of tarsal tunnel syndrome.
The sural nerve travels posterior to the lateral malleolus and provides sensation to the lateral aspect of the foot and the little toe. It is a sensory branch derived from both the tibial and common peroneal nerves, but it has nothing to do with the tarsal tunnel. 
When we follow the tibial nerve to its entrapment site in the tarsal tunnel, it leads us directly to the posterior aspect of the medial malleolus - and that is precisely where Tinel's sign must be performed.

The correct answer is Option 2.

Let's explore the all student data:
9% of students selected Option 1 - Over the anterior ankle joint line between the tibia and talus
74% of students selected Option 2 - Posterior to the medial malleolus - the correct response
5% of students selected Option 3 - Over the dorsum of the foot near the base of the first metatarsal
12% of students selected Option 4 - Posterior to the lateral malleolus

System Classification
This question is a Neuromuscular and Nervous Systems question which represents approximately 24% of all exam items.

Content Outline Classification
This question is a Physical Therapy Examination question which represents approximately 24% of all exam items.

Level Classification
This question is a Level 1 question since the question requires students to possess basic foundational academic knowledge. Remediation of Level 1 questions occurs through academic review of entry-level content using textbooks, review books, Basecamp, and flash cards.

Academic Focus Area
Looking to review related academic content? Check out page 226 in PTEXAM: The Complete Study Guide.