anatomical study of the ligamentum flavum

The functional importance of the ligamentum flavum to the integrity of the vertebral column and the frequency with which they are encountered surgically justify consideration of its anatomy in adults. The aim of this study was to make a detailed investigation of the gross and microscopic anatomy of the ligamentum flavum. The information reported in this study is of clinical value in the practice of lumbar epidural anaesthesia. The material used were 14 normal male cadaveric lumbar vertebral columns in the middle and old age. Length, width and thickness of the ligamentum flavum were measured in the lumbar region in millimeters. Computed tomography was done on 30 patients [18 males and 12 female] complaining of problems far away from the lumbar region that was studied. Width and thickness of the ligamentum flavum were measured by CT. Various portions of the 14 gross specimens were chosen for microscopic study. Sections were prepared and stained by Masson trichrome and Orcein and examined by light microscopy. The ligamentum flavum was found to be attached inferiorly to the superior edge and the posterosuperior surface of the lamina below. Some deep fibres were attached to the antero superior surface of the lamina below. Thus the ligamentum flavum was considered to be formed of superficial and deep parts. The ligamentum flavum was attached superiorly to the inferior edge and the anteroinferior surface of the lamina above. The medial border of the ligamentum flavum corresponded to the base of the spinous process. The lateral border extended as far as the intervertebral foramen. The direct-ion of fibres of the superficial part of the ligament was upwards and medially towards the spine and was more oblique in its lateral portion close to the intervertebral foramen. The direction of the deep fibres was craniocaudal. The length, width and thickness of the ligamentum flavum of the normal male cadavers had a mean of 16.4 +/- 5.2mm, 18.7 +/- 3.4mm and 4.5 +/- 0.8mm respectively. By CT of thirty patients, the width and thickness had a mean of 16.7 +/- 2.6mm and 43 +/- 0.6mm respectively. Histological results showed that the ligamentum flavum was chiefly made up of elastic connective tissue which in older age specimens decreased due to its fragmentation with increase in the amount of the collagenous tissue. The information reported in this study is of clinical value in the practice of lumbar epidural anaesthesia. It is suggested that the epidural puncture can be best performed through the lower and medial portion of the ligamentum flavum [slightly lateral to the midline] to be away from the intervertebral foramen

anatomical study of the lumbosacral ligament

The structure of the human lumbosacral region should be studied extensively in attempts to diagnose possible anatomical sources of low back pain. Only few studies have examined the correlation between the disposition of the ligaments at the level of the fifth lumbar intervertebral foramen and nerve root entrapment. This work was carried out to investigate the anatomical attachment, length and width of the lumbosacral ligament and to determine if the ligament could cause compression of the 5[th] lumbar nerve. In this study, fifteen cadavers [thirty specimens] were dissected and the position and relations of the lumbosacral ligament were examined bilaterally. The ligament was found to be present in all the specimens. It extends from the transverse process of the 5[th] lumbar vertebra to the ala of sacrum. The ligament was found to pass anterior to the 5[th] lumbar nerve in thirteen specimens out of thirty [43.3%]. This may cause compression of the nerve at that site. The measurements of the ligament were done with a digital sliding caliper. The 5[th] lumbar nerves passing deep to the ligament were examined histologically to see signs of compression of the nerve. The compressed nerves showed increased thickness of endoneurial perineurial and epineurial connective tissue. These results are of interest to the clinician whose patient presents with L5 root signs and with a myelogram or computed tomographic scan which do not show any abnormality. The possibility of extra-foraminal compression must be considered as a possible source of the clinical signs