Các phân đoạn thấp hơn bụng và vây lưng rễ thần kinh thắt lưng và xương cùng hình thành cauda equina. Các rễ thần kinh thắt lưng chạy chéo xuống và sang hai bên. Các dây thần kinh cột sống xương cùng phân chia thành Rami trong ống cột sống. | 137 Cauda equina Genetic testing NCV EMG Laboratory Imaging Biopsy The conus medullaris terminates at vertebrum L1. The lower segmental ventral Anatomy and dorsal lumbar and sacral nerve roots form the cauda equina. The lumbar nerve roots run obliquely downwards and laterally. The sacral spinal nerves divide into rami within the spinal canal. Each ramus passes through a pelvic sacral foramen to join the sacral plexus each dorsal ramus emerges through a dorsal sacral foramen to supply paraspinal muscles and the skin over the sacral and medial gluteal areas. The cauda equina is loosely enveloped by arachnoid membrane from which a sleeve extends to cover each nerve root. As a nerve passes into the nerve foramen it is invested in a short sleeve of dura. Acute central disc herniation Pain bilaterally in the buttock sacral perineal and posterior leg regions and sphincter dysfunction. Symptoms Chronic Back pain perineal pain paresthesias. Urinary and erectile dysfunction may occur in men. Acute Signs Weakness of S1 and S2 muscles sensory loss from soles to perineal region with saddle anesthesia. Loss of anal wink. Roots positioned most laterally lower lumbar and upper sacral are most often affected while the central roots can be spared S3-S5 . Thus the bladder is often spared. Chronic Similar signs as acute injury. Muscle wasting in chronic conditions may resemble chronic polyneuropathy. Toxic Anesthesia spinal and epidural anesthesia Contrast media Cytotoxic drugs intrathecal methotrexate Radiation TRI transient radicular irritation Spinal arachnoiditis Pathogenesis 138 Vascular AV fistulas spinal dural may mimic spinal stenosis Cauda equina claudication Spinal subarachnoid hemorrhage Infectious AIDS CMV infections Herpes simplex infection Others cryptococcal syphillis tuberculosis Inflammatory Immune Bechterew s disease Neoplastic Ependymoma Neurofibroma Rare dermoid hemangioblastoma lipoma meningioma paragangliomas schwannoma Malignant disease astrocytoma bone tumors .
