When it comes to treating ulnar nerve irritation, I often prefer to focus just distal to the cubital tunnel, rather than at or proximal to it. If you look closely, you’ll typically see the nerve spanning the gap between the lateral epicondyle and the olecranon. In many patients, the fascial layers around the nerve can appear slightly swollen here, which is fairly common. But the question is whether that’s where the real issue is.
By following the nerve distally, you may notice a distinctly swollen fascial segment, often just below Osborne’s ligament or fascia. In my experience, this distal spot is frequently where the injury actually occurred or where repeated pressure was applied, leading to localized swelling and nerve irritation. That’s the area I like to target for hydrodissection.
Setting Up the Injection
Before injecting, it’s important to position the probe carefully to keep your view stable and avoid unnecessary movement. For this technique, I like to have the needle come in from the right side. Watch out for the small artery that runs nearby. If you track it distally, you’ll see it leaves the plane of the flexor carpi ulnaris, which helps you avoid it during the injection.
The goal is to enter the plane just above this artery, ideally through the flexor carpi ulnaris. This approach lets you dissect the nerve away from the surrounding fascial tissue both above and below. It’s not unusual to encounter some resistance, especially when trying to pop through the last fascial plane, but keep adjusting your needle angle until you see the fluid track spread around the nerve.
Final Check and Why It Matters
Once you’ve completed the hydrodissection, scan along the nerve to ensure fluid extends distally into the mid-forearm and proximally toward the cubital tunnel. You should see the fluid wrap around the nerve, which confirms the nerve is well separated from the surrounding fascia. Even if the fluid doesn’t extend all the way up to the medial epicondyle, you’ll usually see good coverage up to where the flexor carpi ulnaris attaches.
Taking this approach can make a big difference for patients whose symptoms stem from distal compression or injury rather than from the classic cubital tunnel site.
Give it A Try
Hydrodissection can be a very effective, targeted technique when guided by careful scanning and attention to anatomical detail. It can help relieve nerve irritation and improve patient outcomes, especially when you identify the true problem area rather than assuming it’s always at the same spot.
Ready to refine your skills and gain confidence in ultrasound-guided injections and procedures like this? Call the Gulfcoast Ultrasound Institute at 727-363-4500 for all of your ultrasound training needs! We’re conveniently located at 111 2nd Ave NE, #800, St. Petersburg, FL 33701.
Whether you’re looking to sharpen your technique or learn new applications, we’re here to help.
