| disease | The Third Lumbar Transverse Process Syndrome |
Excessive length of the transverse process of the third lumbar vertebra, subjected to repeated traction injury, leads to localized tenderness and a series of syndromes.
bubble_chart Etiology
The transverse process of the third lumbar vertebra has a greater posterior extension curvature compared to other lumbar vertebrae, extends the farthest laterally, and is located in the middle of the lumbar spine. The connection lines of the bilateral lumbar transverse processes form a longitudinal water caltrop base peel shape with the tip of the third lumbar transverse process as the apex. The lateral sides of the first and second lumbar transverse processes are covered by the lower ribs, while the fourth and fifth lumbar transverse processes are deeply situated medial to the ilium. Only the third lumbar transverse process lacks the protection of ribs and the ilium, making it more susceptible to injury.
The end of the lumbar transverse process attaches to many muscles and fasciae closely related to trunk movement, mainly including the transversus abdominis, quadratus lumborum, psoas major, sacrospinalis, and lumbodorsal fascia. The robust deep layer of the lumbodorsal fascia attaches to the end of the lumbar transverse process, hypochondrium, and iliac crest. The transversus abdominis transitions into the lumbodorsal fascia and attaches to the transverse process. Changes in intra-abdominal pressure can affect the tissues at the end of the transverse process through the transversus abdominis.
The third lumbar vertebra is located at the apex of the lumbar lordotic curve. The iliolumbar fibers of the latissimus dorsi muscle insert into the transverse process of the third lumbar vertebra, as do some fibers of the psoas major and part of the sacrospinalis muscle fibers. Therefore, the third lumbar vertebra serves as the activity center of the lumbar spine, functioning like a relay station and acting as the pivot for lumbar flexion, extension, lateral bending, and rotation, bearing the greatest leverage effect. The transverse process of the third lumbar vertebra is the primary stress point. Due to its longer length, the muscles, fasciae, and ligaments attached here can effectively maintain spinal stability and normal movement. The longer transverse process also enhances the leverage effect of the muscles, increasing the frequency and magnitude of contraction and tension. When these tissues contract abnormally, the end of the transverse process bears the brunt. This anatomical feature forms the basis for susceptibility to injury at the end, often leading to fibrositis around the transverse process due to strain. The longer the transverse process, the higher the incidence, with unilateral cases being more common.
The posterior aspect of the third lumbar transverse process is closely adjacent to the posterior branch of the second lumbar nerve root. When bending forward or leaning to the opposite side, this posterior branch is lifted or rubbed by the transverse process, causing pain and numbness in the area innervated by this nerve branch. It can also refer pain to the anterior branch of the second lumbar nerve, resulting in referred pain to the buttocks and anterior thigh. Deep to the anterior aspect of the third lumbar transverse process, the lateral femoral cutaneous nerve trunk of the lumbar plexus passes through and distributes to the lateral thigh and knee. If the transverse process is excessively long or large, or accompanied by fibrositis, this nerve may be affected, leading to lateral femoral cutaneous neuralgia. If the lesion involves nearby obturator or femoral nerves, pain may also occur in the hip or thigh.Additionally, patients with pre-existing Bi disease-related lumbago may also experience lumbago due to the weakened resistance caused by Bi disease.
bubble_chart Clinical Manifestations
When ill, there may be soreness in the lower back or severe pain, limited movement, and in severe cases, it affects daily life and work. The pain may extend to the buttocks and the front of the thigh. There is no pain when bending backward, but bending sideways is restricted.
An important sign is the outer edge of the transverse process of the third lumbar vertebra, approximately 4 cm beside the spinous process of the third lumbar vertebra. Especially in slender patients, the tip of the transverse process can be palpated with obvious tenderness and localized muscle tension or spasm. Pressing may cause radiating pain to the thigh and knee due to stimulation of the branches of the second lumbar nerve.
After injecting 10–20 mL of 1% or 0.5% procaine at the tender point, the pain and tenderness disappear.
Based on the tender point and the effectiveness of procaine injection, combined with the history, symptoms, and other signs, it can be differentiated from lumbago caused by other diseases.
bubble_chart Treatment Measures
For mild cases, acupuncture, tuina, physiotherapy, topical medications, and oral anti-inflammatory analgesics are all effective.
For acupuncture, a single needle can be used with strong stimulation at the pain point (Ashi point). The needle is inserted deeply into the affected area, and the handle is twisted to enhance the needle sensation. Once the "deqi" response—such as soreness, numbness, distension, or radiating sensations—is achieved, the needle can be retained for 10–15 minutes. A course consists of 10 sessions, typically requiring 1–2 courses.
Block therapy is also a common method, involving the injection of 25mg of prednisolone acetate mixed with 3–10mL of 1% or 0.5% procaine into the tender point, administered once a week for four weeks as one course. Accurate injection is crucial. The doctor first locates the transverse process tip with the left thumb as a guide, then inserts the needle 2–3cm along the thumb tip. A bony sensation confirms contact with the transverse process tip, after which the medication is injected. If the injection is precise, bending and tenderness at the injection site may become completely painless.
If conservative treatments fail, or in cases of recurrent or prolonged symptoms, surgical removal of the elongated transverse process tip and surrounding inflammatory tissue may be considered. During the procedure, decompression of the compressed lateral femoral cutaneous nerve can also be performed to achieve a complete cure.
