It's almost there. You did find the land marks and the shapes of the bones are starting to show some tridimensionality. However you're pointing the bones in the wrong direction. You got the position of the medial epicondyle right but the cylinder at the elbow is wrong. The lateral should be higher the cylinder should be more inclined, yours is too horizontal. The angle of the ulna should accompany that. There's also a little space between the ulna and the radius, in your drawing it looks that they are glued together.The angle of the ulna in the wrist should be more horizontal (Try do this pose yourself in front of a mirror and pay attention at the position of your hand and how much your wrist rotates). This is a personal impression, but I think the ulna is too big, Is almost poking through the palm of the hand. This is a very difficult pose. You can't see the lateral epicondyle , the end of the ulna is hidden and on top of that the arm is foreshortened. So don't get discouraged and try again. Best regards