Nerve

Ulnar nerve

Right upper limb, arm abducted, seen from in front

Before you touch the pencil

The one nerve every student has already met, because everyone has banged their funny bone. That is the point behind the medial epicondyle, where the nerve is subcutaneous against bone. Mark that first and the rest of the line follows: down the medial side of the arm, behind the epicondyle, then along the medial forearm to the lateral edge of the pisiform.

Position: Abduct the arm to a right angle with the palm facing forwards.

0 of 4 points placed

Point 1 of 4

Middle of the medial border of the arm

Feel for it: The groove you can press into on the inner side of the upper arm, between biceps in front and triceps behind.

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The points, in order

1. Middle of the medial border of the arm
The groove you can press into on the inner side of the upper arm, between biceps in front and triceps behind.
2. Behind the medial epicondyle
The bony point on the inner side of the elbow; slide just behind it and you are in the groove where a knock tingles down to the little finger.
3. Middle of the medial border of the forearm
The inner edge of the forearm, roughly midway between elbow and wrist.
4. Lateral edge of the pisiform
The pea-sized bone at the base of the heel of the hand on the little-finger side; the point is at its thumb-side edge.

Do not confuse it with

The ulnar artery
At the wrist the artery lies lateral to the nerve; both pass in front of the flexor retinaculum rather than through the carpal tunnel.

Examiner trap

Taking the line in front of the medial epicondyle. The nerve passes behind it, and that is the whole reason it is vulnerable there.

Memory hook

Behind the funny bone, in front of the flexor retinaculum.

Senior’s 30-second takeaway

Ulnar nerve — the whole bench in four lines. Read this on the way in.

If you see this: A line asked for on the medial side of the limb · A dip behind the medial epicondyle · An endpoint at the pea-shaped bone at the wrist
If asked to identify it: From the middle of the medial border of the arm, behind the medial epicondyle, to the lateral edge of the pisiform.
If asked one more: It supplies flexor carpi ulnaris and the medial half of flexor digitorum profundus in the forearm.
If asked why it matters: It is subcutaneous behind the medial epicondyle, which is why a knock there tingles into the little finger.

Then stop. Let the examiner ask the next question.

🩺 Before you touch the pencil

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Senior’s 30-second takeaway

Before you touch the pencil