A physical therapist performs Tinel's sign by tapping over the cubital tunnel. The patient reports tingling sensations consistent with a positive finding. Which region of the hand would MOST likely be affected?

1. Dorsal-lateral aspect of the hand and first web space
2. Palmar aspect of all five digits
3. Hypothenar eminence and fifth digit
4. Thenar eminence and lateral three digits

Transcript

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A physical therapist performs Tinel's sign by tapping over the cubital tunnel. The patient reports tingling sensations consistent with a positive finding. Which region of the hand would MOST likely be affected?

1. Dorsal-lateral aspect of the hand and first web space
2. Palmar aspect of all five digits
3. Hypothenar eminence and fifth digit
4. Thenar eminence and lateral three digits

Tinel's Sign and the Cubital Tunnel

Tinel’s sign is a clinical test used to assess for nerve irritation or entrapment by gently tapping over a suspected compression site. When positive, it reproduces tingling or “electric shock” sensations in the sensory distribution of the affected nerve.

This question is really testing two things at once - first, do you know which nerve runs through the cubital tunnel, and second, do you know the sensory distribution of that nerve in the hand? The cubital tunnel is located on the medial side of the elbow. Think about what happens when you hit your "funny bone" - that tingling sensation you feel shooting down into your hand? That's the ulnar nerve, and that's exactly what we're talking about here.

Let's explore each of the options:

Option 1 - Dorsal-lateral aspect of the hand and first web space

The dorsal-lateral aspect of the hand and the first web space - that's the area on the back of the hand near the thumb. Which nerve supplies that region? The radial nerve. The radial nerve travels down the posterior aspect of the arm and forearm and provides sensory innervation to the dorsal-lateral hand and first web space. It has nothing to do with the cubital tunnel. Since cubital tunnel syndrome involves the ulnar nerve, this region would not be affected. Eliminate this option.

Option 2 - Palmar aspect of all five digits

All five digits? That would require involvement of both the median AND ulnar nerves working together. The median nerve supplies the palmar aspect of the thumb, index, middle, and lateral half of the ring finger. The ulnar nerve supplies the palmar aspect of the little finger and the medial half of the ring finger. Since cubital tunnel syndrome involves only the ulnar nerve, we would expect symptoms in some digits - but certainly not all five. This option casts too wide a net and can be eliminated.

Option 3 - Hypothenar eminence and fifth digit

The hypothenar eminence is the fleshy muscle group on the medial side of the palm - the side of the little finger. The ulnar nerve supplies the hypothenar eminence, the fifth digit, and the medial half of the fourth digit.
When we tap over the cubital tunnel and provoke the ulnar nerve, the tingling sensation would radiate into exactly this distribution - the medial hand and little finger. 

Option 4 - Thenar eminence and lateral three digits

The thenar eminence is the fleshy muscle group at the base of the thumb, and the lateral three digits are the thumb, index, and middle fingers. This is the sensory distribution of the median nerve, not the ulnar nerve. The median nerve passes through the carpal tunnel at the wrist, not the cubital tunnel at the elbow. If we were tapping over the carpal tunnel and got a positive Tinel's sign, this would be the correct answer. But we're at the cubital tunnel, so this option doesn't fit.

When we follow the ulnar nerve from the cubital tunnel all the way down to the hand, it leads us directly to the hypothenar eminence and fifth digit.

The correct answer is Option 3.

Let's explore the all student data:
6% of students selected Option 1 - Dorsal-lateral aspect of the hand and first web space
4% of students selected Option 2 - Palmar aspect of all five digits
65% of students selected Option 3 - Hypothenar eminence and fifth digit - the correct response
25% of students selected Option 4 - Thenar eminence and lateral three digits

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 pages 108 in PTEXAM: The Complete Study Guide.

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