Hi, my name is Jon Jacobson, and I will be demonstrating Ultrasound of the Cubital Tunnel. So to begin, I have the elbow extended. I’m using two palpable landmarks for orientation the medial epicondyle of the humerus, and the olecranon process. If you connect these two lines with the transducer, this will give you an axial plane of the cubital tunnel region and the ulnar nerve. If you look on the ultrasound image, you can identify the medial epicondyle bone contour and its apex. Directly behind that, you will see the hypo echoic ulnar nerve.
More posterior, you can identify the bone landmark of the olecranon process. Now, this area is not the cubital tunnel itself, but just proximal to it. If you move the transducer distally, you will find you will lose the bone landmarks and then we will see the ulnar nerve between the two heads of the flexor carpi ulnaris and under the arcuate ligament. Therefore, this is the true cubital tunnel. Backing up to the medial epicondyle, this is an ideal starting point given the bone landmarks. Its important not to scan with.
The elbow flexed at this point because what will happen is the triceps will be moved into view and therefore diagnosis of an Anconeus epitrochlearis will not be possible. However, with the elbow completely extended there should be nothing in the space between the medial epicondyle and the olecranon process other than the ulnar nerve. So we will look at the nerve proximally and distally in short axis, or enlargement, as it goes into the cubital tunnel. We can also look at the ulnar nerve in long axis, as shown here. Often this is.
Hot Tip Ultrasound Demonstration of Ulnar Nerve Dislocation Snapping Triceps Syndrome
Difficult as the nerve is not always in one single imaging plane. Lastly, we will look dynamically at the cubital tunnel region. We will again identify the medial epicondyle apex for bone landmark as shown here. I will then passively flex the patient, his elbow, and the key is to keep this bone landmark in view. If I lose the bone landmark, I stop moving my patient and I change my position of the transducer to get the bone landmark back in place, then I will continue movement. And I will do this passively back and forth.