This blog post is an evolution of the October 2019 blog post entitled “Cubital Tunnel Syndrome.” Be sure to scroll down to the video showing the anatomy and acupuncture needle technique for opening the myofascial cubital tunnel.
Ulnar nerve entrapment at the elbow, also known as cubital tunnel syndrome, is a common sports injury in throwing and racket sports that require repetitive elbow flexion and extension combined with ulnar and radial deviation of the wrist. String musicians, such as guitar, bass and violin players, also get this injury, usually on the fret hand, as the fingers and wrist flexor muscles are used to hold the strings. In a position of full forearm supination and elbow and wrist flexion, the contracted wrist flexors subject the medial epicondyle to excessive and prolonged strain (Fig. 1). These repetitive activities create valgus tension on the medial elbow, which contributes to a soft tissue adhesions and eventual entrapment of the ulnar nerve. The ulnar nerve passes posterior to the medial epicondyle and is secured by ligamentous tissue that is located deep to SI 8 (xiaohai).
Continuing along the Small Intestine channel approximately 1 cun distal from SI 8 and the medial epicondyle, the ulnar nerve passes through a tunnel of aponeurotic tissue that connects the humeral and ulnar heads of the flexor carpi ulnaris (FCU). This soft tissue passageway
for the ulnar nerve is called the cubital tunnel and it is a common site for ulnar nerve entrapment (Fig. 2). See the video below for anatomy and needle technique.
Numbness and tingling in the ring finger and little finger are common symptoms of ulnar nerve entrapment. Often, these symptoms are intermittent and can happen more often when the elbow is bent, such as when driving or holding a phone to the ear. This condition can be exacerbated by particular sleeping positions. Many people sleep on their sides with their arm tucked under themselves in a position of elbow flexion, forearm supination and wrist flexion, which can aggravate the symptoms of ulnar nerve compression. The patient will often wake with the last two fingers numb and tingling. The symptoms of ulnar nerve entrapment presents similarly to that of thoracic outlet syndrome, so these two conditions must be differentiated. The common orthopedic examinations are Tinel’s sign at the elbow and also Elbow Flexion Test. Tinel’s sign is not as reliable of examination and a false positive is a common result of this test.
Elbow Flexion Test
This test is used to assess for the presence of ulnar nerve entrapment in the cubital tunnel at the elbow. The position of the elbow flexion test emphasizes stretching of the flexor carpi ulnaris. The tendon of this muscle is often involved in soft tissue entrapments of the ulnar nerve at the elbow.
The patient flexes their elbows and externally rotates the shoulder joints with abduction. The wrists are extended and deviated to the radial side (Fig. 3). This position is common among food and beverage servers when holding a service tray slightly above shoulder level.
- Have the patient hold this position for 3-5 minutes, noting any tingling or paresthesia within the ulnar nerve distribution along the Small Intestine or Heart channels of the forearm or hand.
- A positive test indicates ulnar nerve entrapment in the cubital tunnel.
Target Tissue Needling
Presented here is an acupuncture needle technique developed by the author that can open the cubital tunnel and decompress the ulnar nerve. This needle technique should be combined with other points along the HT and SI sinew channels (for more information, see “Binding Region of the Heart and Small Intestine Channel Sinews” below).
Ulnar Nerve Entrapment at the Elbow: Shallow Needling Technique
Palpate for a tender ropy band of tendinous tissue approximately 1 cun distal from the medial epicondyle, located near the Small Intestine channel. This is the region of nerve entrapment in the cubital tunnel. Once the point has been located, the practitioner should determine the direction that the needle will be inserted by palpating in two different directions:
- On a line following the FCU muscle fibers, push toward the medial epicondyle (Fig. 4A).
- On a line following the FCU muscle fibers, push away from the medial epicondyle toward HT 7 (shenmen) (Fig. 4B).
Whichever direction is the most uncomfortable is the direction toward which the needle will be angled. After inserting the needle perpendicularly just past the skin, the practitioner uses a Shallow Needling technique, or Qian Ci, with an oblique/transverse needle angle in the appropriate direction. The needle should travel beneath the skin and along the superficial tendinous tissue. Once qi is obtained, rotate the needle clockwise and counterclockwise 180˚ to determine which direction provides the most resistance. Once the direction of most resistance is determined, rotate the needle in the same direction until the needle cannot be turned any further due to tissue tightness. The needle sensation should be strong but tolerable for the patient. The practitioner will then gently pull on the needle for 30-60 seconds (Fig. 4C). Leave the needle in place as part of the treatment protocol. After 15-20 minutes, the needle should withdraw easily, if it does not, rotate the needle in the opposite direction until the needle withdraws easily. The goal of this technique is to wrap the fascial and connective tissue affecting the cubital tunnel around the needle and apply a “pulling” technique to open up the dense tissue and re-establish qi and blood flow and proprioception, which help to counteract the pressure on the entrapped nerve. Due to the amount of torsion placed on the acupuncture needle, it is important to use a high quality, uncoated, stainless steel acupuncture needle.
Caution: Too steep of a needle angle or too aggressive of a needle technique can penetrate the ulnar nerve and cause patient discomfort.
An Additional Binding Region of the Heart and Small Intestine Channel Sinews (Jingjin)
The diagnosis of ulnar nerve entrapment at the elbow (i.e., cubital tunnel syndrome) can be made from the patient’s signs and symptoms that match the history and applicable orthopedic examinations. Digital imaging and possible EMG studies are useful to assess the extent of the nerve entrapment and nerve signaling potential.
Because the stress on the medial elbow is frequent, even in the activities of everyday living, this region of the elbow anatomy should be assessed and treated in cases involving the Fire element channels before the signs and symptoms of cubital tunnel syndrome are experienced. Because there are varying levels of nerve entrapment, vertebral spondylosis is a good example, mild ulnar nerve compression can disrupt nerve conduction velocity proximal and distal to the actual impingement site. Nerve compression can alter cellular metabolism and action potentials necessary for efficient muscle contraction. Eventually, soft tissue adaptations can occur with pain and dysfunction often found away from the entrapment site. Mild ulnar nerve compression in the cubital tunnel is an early stage of neuropathy, a silent contributor to injury, before the actual signs and symptoms of cubital tunnel syndrome occurs. The flexor carpi ulnaris belongs to both the Heart and Small Intestine channel sinews (jingjin) and this anatomical location should be considered as a binding region that occurs in the different areas of the channel sinews. Binding regions are particular to the jingjin terminology and are discussed as areas where the qi and blood has a tendency to “bind” or “stagnate”. For example, in the literature, the binding region of the HT jingjin is at the medial elbow and the Small Intestine jingjin the binding region is found slightly proximal to the medial elbow (Fig. 5). The cubital tunnel, where the ulnar nerve can become entrapped is found slightly distal to the elbow and should be included as a region of binding. The acupuncture treatment as described above can soften the tension in these myofascial channels and should be considered as an adjacent or distal treatment for any pain or injury involving the Fire element channels.
Thank you to Brian Lau and Lesley Spencer for their help with this blog post and video production.