1. Anatomy The transverse process of the lumbar vertebrae is the attachment of the anterior layer of the lumbar dorsal fascia, and there are intertransverse muscles and intertransverse ligaments between the transverse processes. The transverse process is the starting and ending point of the lumbar square muscle and the transverse spinous muscle, and the internal oblique muscle and transverse abdominis muscle start here through the healthy membrane. The transverse process of the 3rd lumbar vertebra is in the center of the whole lumbar vertebra and is the pivot point for the regulation of balance. 2. 3rd lumbar transverse process lesion is a common soft tissue painful disease with acute and chronic myofascial lumbago caused by accumulative injury. The trauma reaction, hematoma adhesion, scar contracture, and fascial thickening cause the posterior lateral branch of the lumbar nerve to be ‘stuck’ when it crosses the lesion site, and it is believed that the excessive length of the transverse process of the third lumbar vertebra is repeatedly strained and injured to cause a series of syndromes. 3. Etiology 1) The transverse processes of the first and second lumbar vertebrae are covered by the lower ribs laterally, the transverse processes of the fourth and fifth lumbar vertebrae are deep inside the iliac bones, and only the transverse processes of the third lumbar vertebrae lack the protection of the ribs and iliac bones and are therefore vulnerable to damage. 2) The transverse processes of the third lumbar vertebra have greater posterior extension curvature than the other lumbar vertebrae, extend the longest laterally, and are located in the middle of the lumbar vertebrae, and the transverse processes of both lumbar vertebrae join to form a longitudinal rhombus with the tip of the third lumbar vertebra as the apex. The third lumbar vertebra is located at the apex of the lumbar anterior convex curve, and the fibers of the iliopsoas portion of the latissimus dorsi muscle stop at the transverse process of the third lumbar vertebra, some of the muscle fibers of the psoas major muscle also stop here, and part of the muscle fibers of the sacrospinous muscle also stop here, so the third lumbar vertebra is the activity center of the lumbar vertebra, playing a role similar to that of a relay station, and is the hub of lumbar flexion, extension, lateral bending and rotation of the body, and is subject to the greatest leverage. This anatomical feature forms the basis of terminal vulnerability to injury and often causes fibrillitis around the end of the transverse process due to strain. The longer the transverse process, the higher the incidence, and it is more common unilaterally. 3) The posterior end of the transverse process of the third lumbar vertebra is immediately behind the posterior branch of the second lumbar nerve root, and when bending forward and to the opposite side, this posterior branch is provoked by the transverse process or is abraded and causes pain and numbness in the innervation area of this nerve branch, which can also involve the anterior branch of the second lumbar nerve and cause reflex pain, reaching the buttocks and anterior thighs. The lateral femoral cutaneous nerve trunk of the lumbar plexus nerve passes deep in front of the transverse process of the third lumbar vertebra and is distributed to the lateral thigh and knee. When the lesion affects the nearby foraminal nerve or even the musculocutaneous nerve, the pain may also appear in the hip or thigh. 4. Clinical manifestations Patients often feel low back pain or diffuse pain in the lumbar hip area, which radiates to the back of the thigh to above the knee joint, and the pain increases when the lumbar activities such as bending and rotating the lumbar area, and has no effect when increasing abdominal pressure such as coughing and sneezing. In the early stage, the patient’s lumbar hip is slightly plump, while in the late stage, there may be mild muscle atrophy. X-ray examination: hypertrophy of the transverse process of the 3rd lumbar vertebra is visible. 5. Treatment 1) muscle relaxation, obvious relief of pain, release spasm. 2)Physiotherapy to relax the muscles and release the spasm. 3)Block at the tip of the transverse process and peripheral nerves, once a week for 3 times. 4)Generally, non-surgical treatment can mostly relieve and cure the pain. Only a few cases of more persistent pain require surgical stripping or removal of the transverse process.