Cubital tunnel syndrome, also called ulnar nerve entrapment is a condition caused by compression of the ulnar nerve in an area of the elbow called the cubital tunnel. The ulnar nerve travels down the back of the elbow behind the bony bump called the medial epicondyle and through a passageway called the cubital tunnel. The cubital tunnel is a narrow passageway on the inside of the elbow formed by bone, muscle, and ligaments with the ulnar nerve passing through its center. The roof of the cubital tunnel is covered with soft tissue called fascia. When the elbow is bent, the ulnar nerve can stretch and catch on the bony bump. When the ulnar nerve is compressed or entrapped, the nerve can tear and become inflamed leading to various symptoms.