A physical therapist performs Tinel's sign by gently tapping over the posterior tibial nerve at the medial malleolus, looking for reproduction of paresthesia. In a patient with tarsal tunnel syndrome, the expected tingling symptoms would MOST likely radiate to which of the following locations?

1. The dorsal web space between the first and second toes

2. The plantar surface of the foot

3. The medial ankle and shin

4. The dorsum of the foot

Transcript

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A physical therapist performs Tinel's sign by gently tapping over the posterior tibial nerve at the medial malleolus, looking for reproduction of paresthesia. In a patient with tarsal tunnel syndrome, the expected tingling symptoms would MOST likely radiate to which of the following locations?

1. The dorsal web space between the first and second toes

2. The plantar surface of the foot

3. The medial ankle and shin

4. The dorsum of the foot

Tarsal Tunnel Syndrome

Tarsal tunnel syndrome is a compressive neuropathy that affects the posterior tibial nerve or its branches as it passes through the tarsal tunnel. The tarsal tunnel is a fibro-osseous tunnel located behind the medial malleolus, formed by the flexor retinaculum.

This question is asking about the sensory distribution of the posterior tibial nerve, which is the nerve affected in tarsal tunnel syndrome. When we perform Tinel's sign, we're looking to reproduce the patient's symptoms by tapping over the nerve at the site of compression.

A helpful tip: Try to visualize the course of the posterior tibial nerve. It runs behind the medial malleolus (where we tap for Tinel's sign), then dives under the flexor retinaculum and into the foot, where it branches to supply the plantar surface. Following the anatomical path of the nerve can help you determine where symptoms would be felt. So where would we expect to feel symptoms if this nerve is compressed?

Let's explore each of the options:

Option 1 - The dorsal web space between the first and second toes

The dorsal web space is on the top of the foot between the big toe and second toe. Which nerve supplies that area? That's the deep peroneal nerve territory. The deep peroneal nerve runs along the anterior compartment of the leg and crosses the ankle anteriorly. It's nowhere near the tarsal tunnel, which is on the medial side of the ankle. So this can't be our answer.

Option 2 - The plantar surface of the foot

The plantar surface is the bottom of the foot. The posterior tibial nerve divides into the medial and lateral plantar nerves, which supply sensation to the entire plantar surface of the foot. If you've ever had your foot "fall asleep," you've experienced paresthesia in this distribution. That tingling sensation on the bottom of your foot is similar to what patients with tarsal tunnel syndrome might experience when you perform Tinel's test.

Option 3 - The medial ankle and shin

The medial ankle and shin are supplied primarily by the saphenous nerve, which is a branch of the femoral nerve. The saphenous nerve runs superficially along the medial aspect of the leg and ankle. It's not related to the posterior tibial nerve or the tarsal tunnel.

Option 4 - The dorsum of the foot

The dorsum (top) of the foot receives sensory innervation primarily from the superficial peroneal nerve. Like the deep peroneal nerve, the superficial peroneal nerve is not involved in tarsal tunnel syndrome.

So, if we're tapping over the posterior tibial nerve at the tarsal tunnel and looking for the reproduction of symptoms, where would those symptoms most likely be felt? On the plantar surface of the foot!

The correct answer is Option 2.

Let's explore the all student data:
20% of students selected Option 1 - The dorsal web space between the first and second toes
59% of students selected Option 2 - The plantar surface of the foot - the correct response
10% of students selected Option 3 - The medial ankle and shin
11% of students selected Option 4 - The dorsum of the foot

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 it 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: PTEXAM: The Complete Study Guide.  

Thanks for joining us on the Scorebuilders Q&A podcast! See you next week!