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Session 10 Thoracic and Lumbar spine Sacroiliac joint • Anatomy and biomechanics of the thoracic spine • Conditions and management • Lumbar spine anatomy and biomechanics • Intervertebral disc in health and disease • Conditions affecting the lumbar spine and management • Sacroiliac joint anatomy - brief look at what can go wrong Typical thoracic vertebra • The body of the vertebra has equal transverse and antero-posterior diameter • There are demi-facets on the posterolateral aspect of the vertebral body for articulation with the ribs • The transverse processes are thickened for articulation with the tubercle of the rib (Cf later) • The superior zygapophyseal facets face superiorly and laterally, orientated for rotation movement • The spinous processes slope downwards and overlap the adjacent vertebra below Articulation of the rib with the thoracic vertebra • The head of the rib articulates with the demi-facet of the vertebra above and below • It also articulates with the intervertebral disc • The radiate ligament, not shown, fans out from the head of the rib to attach it to the vertebra above and below and to the disc between • The back of the rib articulates with the transverse process • The tip of the rib articulates with costal cartilage which attaches to the sternum Articulation of ribs with sternum • • • • Ist rib articulation is fibrocartilaginous Ribs 2-7 synovial joints with sternum 5 remaining false ribs attach indirectly to the sternum Ribs 11 and 12 have no attachment to the sternum and are termed floating ribs • Tip of the sternum termed the xiphisternum • Joint between the manubrium and sternum • Costal cartilages ossify with age Ligaments of the thoracic region • Ligamentous support structure is the same as for the cervical spine • The anterior longitudinal ligament and ligamentum flavum are thicker than in the cervical region • Extensors of the thoracic region Intercostal muscles • Much controversy about functions of the intercostal muscles • Widely thought that the external intercostal muscles have a role in inspiration and the internal intercostals have an expiratory function Rib movement during respiration • Inhalation - the diaphragm moves down whilst the ribs move upwards and outwards • The action is like a bucket handle lifted away from the side of a bucket Sympathetic chain • Sympathetic trunk runs parallel to the thoracic spine • Part of the nervous system responsible for fight or flight responses • Raising the heart rate and blood pressure • Increasing rate of respiration • Release of blood sugars from the liver • Intercostal nerve supplies the intercostal muscles and skin of the chest wall Thoracic rotation • Arms across chest localises movement to the thoracic region • Generally the range of movement is 30 degrees • Rotation in the upper thoracic spine is more restricted • Complex rib movements also occur with all thoracic movements Thoracic flexion/extension Side bending in the thoracic spine • Again the range of side bending in the upper thoracic region is less than for the mid to lower regions • Side bending also occurs with rotation of the vertebral body • Again there is complex movement of the ribs with spinal movement Thoracic conditions • Usually associated with postural problems such as kyphosis, scoliosis • Although the majority of cases of thoracic pain are mechanical there is a higher incidence of serious pathology • OA of the facet joints, rib articulation can cause pain, stiffness and irritation of the intercostal nerves • Inflammatory disorders such as ankylosing spondylitis diagnosed in teenagers and young adults affects the thoracic spine • Disc prolapses occur less frequently in the thoracic spine but can cause spinal cord compression, as discussed for the cervical spine • Wedge fractures may be due to osteoporosis or can be due to spinal metastases or other bone cancers such as multiple myeloma Internal structure of thoracic vertebral body: Within a thin shell of compact bone, a series of vertical trabeculae (loadbearing beams) are “tied together” by transverse trabeculae (crossties) which resist buckling of the vertical trabeculae under axial load. Section of thoracic vertebral body X-ray of mid thoracic region from cadaver spine Osteoporosis: Predominantly affects postmenopausal women and generally affects men about a decade later. The x-ray shows collapse of the vertebral endplates with marked increase in endplate concavity or loss of vertebral height. The decreased bone density of the internal cancellous bone contrasts with the preservation of the peripheral compact shell. Adequate calcium, hormones & exercise can prevent it Loss of bone density Increased concavity Loss of height Lumbar vertebra • The body of the lumbar vertebra is enlarged with a greater transverse than anterior diameter • The spine is broad and thick for muscle attachment • The facet joints are more vertically orientated • The superior facets are concave and face medially (inwards) • The inferior facets are convex and face laterally L5 vertebra articulating with the sacrum • The L5 vertebra has a wedge shaped body with a greater height anteriorly compared with posteriorly • The spinous process is smaller • The transverse processes are large and directed superiorly and posteriorly • The inferior facets are adapted for articulation with the sacrum and are widely spaced The intervertebral disc • Vertebral endplate – thin layer of cartilage, fibres organised horizontally to resist pressure from the nucleus • The endplate has multiple perforations for nutrition of the disc from the blood supply within the vertebral body • The intervertebral discs make up 20-30% of the length of the spinal column • They increase in size being smallest in the cervical spine and largest in the lumbar spine • The L5/S1 disc is the largest • The ratio of disc to vertebral body is greatest in the cervical and lumbar spines, making these two regions relatively more mobile • The disc has two portions - the central nucleus pulposus and the peripheral annulus fibrosus • The nucleus and annulus are composed of water, collagen and proteoglycans. The relative proportions and the type of collagen varies • Fluid and proteoglycans concentrations are greatest in the nucleus and reduced in the annulus • Collagen concentrations are greatest in the annulus Structure of the nucleus and annulus • Nucleus contains glycosaminoglycans linked to proteins forming large molecules of proteoglycans • The molecule has a number of sidechains one of which is chondroitin 4–sulphate which attracts and retains water • Fluid content of the nucleus decreases with age • Diurnal pattern water lost from the disc when loaded continuously for several hours • Collagen is present in high concentration as resistant to compressive forces • Forms 6-25% dry weight of nucleus rising to 70% dry weight of outer annulus • Nucleus primary collagen II • Annulus subject to tensile and compressive forces, contains more type I than II collagen Ligaments of the lumbar spine • The upper and lower vertebral bodies and interposed disc form the intervertebral cartilaginous joint • The zygapophyseal or facet joints are synovial joints • The ligaments associated with the facet joints resist flexion of the lumbar spine and protect the disc from shearing forces • The anterior longitudinal ligament has deep fibres which reinforce the disc anteriorly • The posterior longitudinal, ligamentum flavum, interspinous and supraspinous ligaments are as for the other regions of the spine Sacroiliac joint • 5 sacral vertebrae are fused to form the sacrum • The 1st segment has a facet for articulation with L5 • The 5th segment has a facet for articulation with the coccyx • The sacroiliac joint is formed by an L shaped articular surface on the sacrum and corresponding surface on the ilium • The articular cartilage on the iliac side is fibrocartilage whilst on the sacrum it is hyaline cartilage • The joint is part fibrous and part synovial • The surfaces of the cartilage are smooth in children but become a series of peaks and troughs in adulthood • The iliolumbar ligament originates from the transverse processes of L5 and L4 and attaches to the iliac crest • The ligament is strong and plays an important role in preventing the L5 vertebra from sliding anteriorly • The sacroiliac ligament extends from the iliac crest to the tubercles of the first 4 sacral vertebra • The sacrospinous ligament connects the ischial spines to the lateral border of the sacrum and coccyx • The sacrotuberous ligament connects the ischial tuberosity to the posterior spines of the ilia and the lateral border of the sacrum and coccyx • Fibres from the hamstring muscles also blends with the sacrotuberous ligament Symphysis Pubis • The symphysis pubis is a cartilaginous joint between the ends of the pubis bones • The end of the pubic bone is covered by articular cartilage • Interposed between the bone ends is a fibrocartilaginous disc • 3 ligaments support the joint, superior, inferior and posterior • Muscle fibres from the abdominals and adductors cross from each side of the pubic rami to add support to the joint The cauda equina • The spinal cord terminates between T12 and L1 • The terminal point is termed the conus medullaris • The spinal nerves from L2-S5 are given off in this region becoming the cauda equina or horses tail • There are sensory, motor nerves and parasympathetic nerves • The latter supply the bladder (Cf later) The lumbar and sacral nerve plexuses • The lumbar plexus is formed from the ventral rami of the L1-L4 nerves • It provides motor supply and sensation to the anterior and medial aspects of the leg • It also innervates the abdominal wall and pelvic region • The sacral plexus is formed from a branch of L4 and the L5-S3 ventral rami • Provides motor and sensory supply to the posterior thigh, most of the lower leg, the entire foot and part of the pelvis • Note the inguinal ligament – the femoral artery and femoral nerve pass under the ligament close to the hip joint Range of movement lumbar spine A – Side bending 20 degrees B – Flexion 50 degrees Extension 15 degrees C – Rotation 5 degrees Movement of the sacrum and ilia • Stability of the sacroiliac joints is very important as these joints support a large proportion of the weight of the head, arms and trunk in standing • Weight is transmitted through the 5th lumbar vertebra and disc to the first sacral segment • The sacroiliac ligaments form the main bond which keeps the sacrum and ilia together • The sacroiliac joints permit a small amount of movement. The degree is individual and less in men than women • When the lumbar spine extends the base of the sacrum nods forwards termed nutation • When the lumbar spine flexes the sacrum leans backwards termed counternutation • If the hip is flexed up towards the chest the ilia posteriorly rotate • As the hip extends the ilia rotate forwards Movement at the symphysis pubis • When standing on one leg there is a small amount of upwards glide on the standing leg side • As the sacrum is driven down between the ilia in standing the pubic bones are subjected to a distraction or separation force • The stability of the pelvic ring depends on the shape of the articular surfaces – ridges and hollows fitting together • The wedge shape of the sacrum • The ligaments associated with the sacroiliac joints are some of the strongest in the body and become tight during sacral nutation • The abdominals, pelvic floor, lumbar multifidus and the diaphragm also provide stability • Also gluteus maximus, latissimus dorsi; there are other combinations of muscles which provide support • The erector spinae form the largest group of back extensors • The most lateral group, iliocostalis, attaches to the ribs • Longissimus attaches to the transverse processes of the lumbar spine • Semispinalis, multifidus, rotatores, interspinales and intertransversarii lie deep to erector spinae • The extensor muscles extend the lumbar spine • They also act eccentrically – paying out to control lumbar flexion • Multifidus - a deep intersegmental muscle is important in controlling intersegmental flexion The abdominal muscles • Rectus – most superficial – from pubic crest + symphysis to costal cartilages 5, 6, 7 ribs and xiphoid of sternum • Flexes the lumbar spine moving the thorax towards the pelvis • External oblique 5th to 12th ribs • To aponeurosis connecting with the linea alba, iliac crest and pubic tubercle • Fibres run down and medially • Acting bilaterally flexes spine, R ext oblique acting with L internal oblique rotates the thorax left • Internal oblique – several sets of fibres, from inguinal ligament, iliac crest, pubis, linea alba, 10 11 and 12th ribs • The lower fibres compress and support the abdominal viscera, upper fibres flex the spine, the lateral fibres laterally flex the spine Transverse abdominis • Transverse abdominis is the deepest of the abdominal muscles • It arises from the cartilages of the lower 6 ribs interdigitating with the diaphragm • It also arises from the iliac crest and inguinal ligament • It inserts in to the linea alba • The fibres run in a transverse or horizontal direction • The muscle acts like a girdle to compress the abdominal contents • The diaphragm, transverse abdominals and pelvic floor muscles acting together raise intra-abdominal pressure (Cf later) Quadratus lumborum and Psoas major • Quadratus lumborum – from iliolumbar ligament, iliac crest and sometimes transverse processes of L5-3 • 12th rib, transverse processes of upper 4 lumbar vertebra • Assists extension, laterally flexes the spine • Bilaterally, acting with the diaphragm, it fixes the last 2 ribs in deep inspiration • Psoas major – ventral surfaces, transverse processes, sides of vertebral bodies and discs T12 to L5 to lesser trochanter of the femur • With the lumbar spine fixed iliopsoas flexes the hip • With the hip fixed, acting bilaterally, the psoas major increases the lumbar lordosis • Acting unilaterally it side flexes the trunk to the same side Response of the nucleus pulposus to different spinal positions • With the spine in a neutral position the disc is subjected to compressive forces • In extension the nucleus migrates anteriorly, forces pass through the posterior disc and the intervertebral joints • In flexion the nucleus migrates posteriorly, the posterior fibres of the annulus and posterior longitudinal ligament become taut • The space in the intervertebral foramen is increased • Compressive forces in the facet joint are reduced • A flat back posture encourages posterior migration of the nucleus pulposus (Cf later) The role of abdominal muscles in reducing intradiscal pressure • Contraction of transverse abdominals with the diaphragm and pelvic floor increases intra-abdominal pressure • This reduces the lumbar lordosis and dissipates downward forces from the weight of the body passing through the vertebral column • This mechanism is important when lifting to reduce the forces on the disc and facet joints Fast twitch and slow twitch muscle fibres • Red slow twitch type I muscle fibres – endurance fibres, low level contraction, requires oxygen therefore a good blood supply to produce energy for contraction. Powered by fat, carbohydrate • Found in greater concentration in postural muscles such as the transverse abdominis • White fast twitch type IIa and IIb muscle fibres – sprinting, short action time, uses anaerobic energy system. Powered by glycogen Conditions affecting the lumbar spine • Nonspecific back pain • Disc degeneration – disc prolapse • OA facet joint • Radiculopathy • Spinal stenosis • Spondylolysis and spondylolisthesis Some facts and figures • Up to 84% of us will experience back pain at some time in our lives. 35-55 most common age group • Less than 15% of back pain can be related to a specific problem with the back • Research shows that 77% - 90% of back pain gets better within 6 weeks • 23% of non-specific back pain lasts longer than 12 weeks • 11-12% of the population are disabled by back pain • Human beings have always had back pain, it is no more common and no more severe, it is the experience which has changed Assessment • Distribution of symptoms • Aggravating and easing factors • History of the condition, previous history • Medical history – screening for ‘red flags’ – infection, primary or secondary cancers, bone disorders such as osteoporosis, inflammatory diseases such as ankylosing spondylitis, infection – TB, diseases outside the spine – dissecting abdominal aortic aneurysm, kidney stones • Bladder +/- bowel dysfunction, retention, incontinence, numbness over the perineum Examination • Posture – spine, pelvis • Lumbar spine movements and the effect on pain • Neurological examination for leg pain +/- pins and needles +/numbness – sensation, muscle strength, reflexes • Straight leg raise to examine the response to movement of the sciatic nerve • Prone knee bend to examine the response of the femoral nerve • Palpation to identify level of dysfunction • Core stability – function of abdominal muscles, multifidus, gluteal muscles • The ankle jerk tests the conductivity of the S1 nerve root • If the nerve is compressed the reflex will be depressed or reduced • Straight leg raising tests the mobility of the sciatic nerve • If the nerve is compressed or irritated the degree of SLR will be reduced • Dorsiflexion of the foot increases tension along the nerve and is a refinement to the test • The knee jerk reflex tests the function of the L3 nerve • If the nerve is compressed the reflex will be depressed • Prone knee bending with the patient in prone the knee is gently flexed • The range of movement and pain provocation tests the mobility of the femoral nerve What causes back pain? • Usually there is not a specific condition underlying back pain • Nothing shows up on tests or is permanently damaged • It is termed simple or non-specific back pain Reasons for getting back pain • Sitting or bending for long periods of time • Poor posture • Lifting, carrying or pushing loads which are too heavy, doing it the wrong way, not having strong enough muscles • Tripping or falling • Pregnancy • Being overweight • Stress or anxiety How can I get rid of back pain? • For back pain only: • Rest for 1or 2 days only, longer makes no difference, it only weakens the supporting muscles of the spine • NSAIDs if there is no reason why you shouldn’t. Paracetamol has been found to have no effect on back pain • If you need analgesia low dose opioids such as codeine for a short time only • Use ice packs or heat, whichever helps most • Start to move your back as soon as possible Mobility and core stability exercises • Arching and hollowing on all fours • Rocking backwards towards heels, forwards towards hands • Transverse abdominal activation – suck lower tummy in. Keep breathing normally. Hold for 10 seconds, repeat 10 times • Knee rolling side to side. As far as is comfortable • Hip hitching – lie on back, legs straight, stretch one leg down, hitch the other leg up to tilt the pelvis upwards on that side • Progress abdominal exercises lying on back, hollowing tummy and holding • Slide heel towards bottom of bed without pelvic movement • Let bent knee move out to the side without pelvic movement • Lie on tummy – hollow tummy and squeeze buttocks together at the same time • Hold at 30% effort for 10 times 10 seconds • If unable to perform try lying over a pillow • Progress to contracting tummy and bottom muscles and flexing knee without back hollowing • A Pilates class can be very helpful once the basic exercises can be completed without loss of spinal and pelvic stability How can I prevent it happening again? • Improve your posture • Lift correctly • Lose weight to reduce the stresses on your spine • Do regular exercises to keep your spine flexible • Do specific tummy muscle exercises to support your spine – NOT SIT UPS • Keep yourself generally fit Correct lifting • • • • • • • • Assess environment Correct clothing and foot wear Test the load Bend knees and get as close to load as possible Hold the load as close in to body as you can Pull in tummy muscles Push using legs to stand If you think it is too heavy for you ask someone else to lift the load if possible • You need to be fit to lift – good tummy muscles, strong quadriceps Age changes affecting the disc • The nucleus pulposus has reduced water content due to changes in proteoglycans • Annulus fibrosis made of concentric rings called lamellae, adjacent rings fibres orientated in opposite direction • Annulus surrounds and contains the nucleus • With loss of water content tears appear in the annulus allowing the nucleus to migrate, usually posteriorly • There is also loss of disc height Nerve supply to the outer layers of the disc • The outer layers of the annulus of the disc are supplied by the sinuvertebral nerve • It also supplies the posterior longitudinal ligament, blood vessels in the spinal canal, the anterior covering of the spinal cord, the outer sleeves of the spinal nerves, the posterior periosteum of the vertebra • Pain can therefore be felt from all of these structures – hence the intense pain from sciatica The consequences of reduced disc height • Reduced disc height leads to new bone formation around the edges of the vertebral body • The posterior annulus can bulge like a flat tyre which can reduce the space for the nerve in the intervertebral foramen • Reduced disc height also causes the anterior, posterior and ligamentum flavum to slacken allowing more translator movement to occur • The facet joints are subjected to more compression forces which can lead to osteoarthritis Facet joint degeneration • OA of the facet joint leads to formation of bony spurs which can irritate or compress the spinal nerve • If the S1 nerve is affected this causes pain down the back of the leg, weakness of the calf muscle, reduced ankle jerk • In the early stages there may be low back pain, +/leg pain with stiffness of the lumbar spine • At this stage, manual therapy, manipulation to increase spinal movement may help • This is combined with mobility exercises, postural correction • Core stability exercises to off load the spine • If pain and disability is considerable further investigations such as an MRI scan may be indicated MRI scan showing facet joint degeneration • If the facet joint is thought to be the main source of pain and surgery is not indicated • Facet joint denervation of the medial nerve branches to the joint may be offered • This can be very effective in treating the pain for a year or more Radiofrequency denervation of the facet joint Pathologies: Disc Protrusion • As described earlier the annulus of the disc can bulge due to reduced water content • The annulus can also tear allowing the nucleus to migrate backwards towards the central canal or laterally towards the intervertebral canal • A central prolapse can compress the cauda equina giving symptoms of bladder retention, incontinence of bladder or bowel • Numbness over the perineum is also a symptom of compression • It is important to seek urgent medical attention as prolonged compression of these nerves can cause permanent damage to the nerves with permanent bladder and or bowel dysfunction • A more lateral disc bulge causes spinal nerve root compression • Occasionally a disc fragment can become extruded causing variable symptoms as it is free to move within the spinal canal Management of an annular disc bulge • In younger patients where facet joint OA is not significant back extension exercises can be helpful to encourage the nucleus to migrate anteriorly away from the spinal canal • In the early stages lying on the tummy and gently pushing up as far as is comfortable and repeating this 10 times every hour can dramatically reduce the pain • Avoiding sitting which increases intradiscal pressure is important • Core stability exercises should be started early again to offload the disc • If there are significant neurological changes early referral for further investigations and possible surgical intervention is indicated • Microdiscectomy • If there is significant neurological involvement surgery should be considered early in the episode • In some patients conservative management may resolve the problem but where significant pain and disability remains referral for an MRI should be considered • Where the MRI findings match the clinical presentation an epidural may be considered or surgery such as microdiscectomy can be very effective • Surgical intervention is the option of choice for about 2% of all cases of back and leg pain • Post operative rehabilitation is required to increase spinal mobility, ensure good nerve mobility, retrain core stability muscles, encourage return to normal fitness Spinal stenosis • Narrowing of the central canal due to enlargement of the facet joints, bulging disc and thickening of the ligamentum flavum • Age 50s onwards, pain usually in both legs made worse with standing or walking, reduced by bending forwards • Leg pain on walking can be due to reduced circulation therefore it is important to examine the peripheral circulation to the legs. Doppler can be a useful test for this • In the early stages techniques to open the spinal canal can be helpful, flexion exercises, joint mobilisation into flexion, sitting in a more flexed position, lying on side with knees bent at night • If symptoms persist and are sufficiently disabling to consider surgery referral for MRI scan • Possible decompression and fusion Spinal fusion • Discussion with surgeon re possible risks and benefits of surgery • Can be a good treatment option if only 1 or 2 spinal levels affected • Stenosis found at multiple levels or significant surgical risk may be better to consider using a motorised scooter to increase mobility Spinal instability • Can be in young people with a genetic fault in the bone - swimmers, gymnasts, cricketers • Repeated episodes of severe back and leg pain associated with trivial incidents • In older people worn discs can cause small movements of the bony structures which are painful • Treatment – strengthen tummy muscles to support the back, correct over hollowed back posture • MRI scan • Possible spinal fusion Pathologies: Spondylolisthesis Finally • Thank you for staying the course • Thank you for your participation and very helpful comments • Helpful website www.patient.info. The professional tab gives in depth information. There are also links to helpful patient leaflets • Happy Christmas and here's to 2017 with fewer aches and pains!!