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Vertebral Column For the Lecture Final Exam The Axial Skeleton • Skull • Sternum • Vertebrae – 7 Cervical – 12 thoracic – 5 lumbar – 5 sacral – 5 fused coccygeal • Ribs Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Intervertebral disc Superior articular process Spinal cord Pedicle Spinous process Body of vertebra Transverse process Intervertebral disc Spinal nerve Inferior articular process Lamina Transverse costal facet (for tubercle of rib) Angle of rib Superior costal facet (for head of rib) Body of vertebra Head of rib Intervertebral disc Neck of rib Tubercle of rib Shaft Crosssection of rib Costal groove Sternum Costal cartilage (b) Vertebral and sternal articulations of a typical true rib Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Articular facet on tubercle of rib Spinous process Shaft Ligaments Neck of rib Head of rib Superior costal facet (for head of rib) Transverse costal facet (for tubercle of rib) Body of thoracic vertebra (c) Superior view of the articulation between a rib and a thoracic vertebra Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Axis (2nd cervical vertebra) Atlas (1st cervical vertebra) Typical cervical vertebra Typical thoracic vertebra Typical lumbar vertebra C1 2 3 4 5 6 7 T1 2 3 4 5 6 7 8 9 10 11 12 L1 2 3 4 5 Anterior view Cervical curvature (concave) 7 vertebrae, C1 – C7 Spinous process Transverse processes Thoracic curvature (convex) 12 vertebrae, T1 – T12 Intervertebral discs Intervertebral foramen Lumbar curvature (concave) 5 vertebrae, L1 – L5 Sacral curvature (convex) 5 fused vertebrae sacrum Coccyx 4 fused vertebrae Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Right lateral view Intervertebral discs The intervertebral discs are composed of an outer layer that is thick and fibrous, called the anulus fibrosus, and a spongy inner layer called the nucleus pulposus. Both layers are composed of water, collagen, and proteoglycans (PGs), which are proteins + sugar. The nucleus pulposis is mostly water and PGs, and acts like a water balloon. When compressed, it stretches in all directions. The anulus fibrosis is mostly water and collagen. It holds the nucleus pulposis in place so it does not pop. Ligaments of the vertebral column Supraspinous ligament Transverse process Intervertebral disc Anterior longitudinal ligament Sectioned spinous process Ligamentum flavum Interspinous ligament Inferior articular process Intervertebral foramen Posterior longitudinal ligament Anulus fibrosus Nucleus pulposus Sectioned body of vertebra (a) Median section of three vertebrae, illustrating the composition of the discs and the ligaments Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Posterior longitudinal ligament Anterior longitudinal ligament Body of a vertebra Intervertebral disc (b) Anterior view of part of the spinal column Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Herniated Intervertebral Discs • The narrow PLL in the lumbar region does not provide much support to the intervertebral discs, which is one of the reasons that posterolateral herniations are more common in the lumbar region. • Increased pain in the flexed position is common in a PLL defect with subsequent herniation. Vertebral spinous process (posterior aspect of vertebra) Spinal cord Spinal nerve root Transverse process Herniated portion of disc Anulus fibrosus of disc Nucleus pulposus of disc (c) Superior view of a herniated intervertebral disc Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Nucleus pulposus of intact disc Herniated nucleus pulposus (d) MRI of lumbar region of vertebral column in sagittal section showing normal and herniated discs Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Dens of axis Transverse ligament of atlas C1 (atlas) C2 (axis) C3 Inferior articular process Bifid spinous process Transverse processes C7 (vertebra prominens) (a) Cervical vertebrae Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. The sacrum and coccyx. Body Sacral promontory Ala Sacral canal Body of first sacral vertebra Facet of superior articular process Auricular surface Transverse ridges (sites of vertebral fusion) Apex Median sacral crest Anterior Posterior sacral sacral foramina foramina Coccyx (a) Anterior view Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Coccyx (b) Posterior view Lateral sacral crest Sacral hiatus Jugular notch Clavicular notch Manubrium Sternal angle Body Xiphisternal joint Xiphoid process True ribs (1–7 False ribs (8–12) Intercostal spaces L1 Vertebra Floating ribs (11, 12) (a) Skeleton of the thoracic cage, anterior view Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Costal cartilage Costal margin Sternum Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. T2 Jugular notch T3 T4 Sternal angle Heart T9 Xiphisternal joint (b) Midsagittal section through the thorax, showing the relationship of surface anatomical landmarks of the thorax to the vertebral column Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Subclavius Biceps brachii (short head) Biceps brachii (long head) Sternocleidomastoid Coracobrachialis Trapezius Deltoid Triceps brachii Latissimus dorsi Teres major Pectoralis major Pectoralis minor Serratus anterior Biceps brachii Internal intercostals External intercostals External obilque Rectus abdominis Internal obilque Tensor fasciae latae Sartorius Iliopsoas Pectineus Rectus femoris Adductor longus Splenius capitis Levator scapulae Supraspinatus Infraspinatus Teres minor Triceps brachii (lateral head) Triceps brachii (long head) Epicranius (occipital belly) Rhomboid minor Trapezius Rhomboid major Deltoid Teres major Serratus anterior Latissimus dorsi Trapezius Spinalis Iliocostalis Longissimus Serratus anterior Latissimus dorsi External intercostals Internal oblique External oblique Orbicularis oculi Sternohyoid Sternocleidomastoid Pectoralis minor Rectus abdominis Teres major Latissimus dorsi Cervical Plexus Nerves innervate skin of neck, back of head and upper shoulder. Phrenic nerve (important for breathing!) from C3, C4, C5. Carries afferent and efferent fibers to the respiratory diaphragm. Copyright © 2011 Pearson Education, Inc., publishing as Pearson Benjamin Cummings. Patient Case • Mary complained of not being able to breathe easily when playing tennis. She does not have asthma. • Orthopedic consultation showed that Mary has a midthoracic scoliotic curve of 40 degrees. • It is likely that the scoliosis is accompanied by rotation of those vertebrae, which might decrease her pulmonary reserve. • This might be a contributing factor in her shortness of breath when she tries to play tennis. Boston Scoliosis Brace This is a firmly fitting pelvic girdle that extends upward to apply forces to the ribs in a way that limits the exacerbation of the scoliotic curvature. While worn, this device decreases ability to breathe by 15-20%, so it cannot be worn during sport activities. Surgery may be necessary if the brace does not limit the progression sufficiently. Patient Case • Joe is a 33 year old construction worker who, for several months, has been experiencing moderate to severe low back pain which radiates into his right buttock. • He has pain with carrying, and all lifting activities. He can relieve the pain somewhat when sitting or laying down, but has only been able to work for 4 hours at a time. • His history includes several episodes of low back pain that were severe but resolved in a few days. Sciatica • Joe might have sciatica, except that his pain is better when sitting. • Sciatica refers to pain, weakness, numbness, or tingling in the leg. It is caused by injury to or pressure on the sciatic nerve. Sciatica is a symptom of another medical problem, not a medical condition on its own. • Common causes of sciatica include: • Herniated intervertebral disc – Treatment is oral or injected anti-inflammatory meds or surgery • Piriformis syndrome – sciatic pain due to contracture of the piriformis muscle in the buttocks – Treatment is stretching exercises (lay supine and pull one knee to the opposite shoulder) Herniated Intervertebral Discs • These discs may move out of place (herniate) or break open (rupture) from injury or strain. When this happens, there may be pressure on the spinal nerves. This can lead to pain, numbness, or weakness. • The lower back (lumbar area) of the spine is the most common area for a slipped disc. The neck (cervical) discs are affected a small percentage of the time. The upper-to-midback (thoracic) discs are rarely involved. • Radiculopathy is any disease that affects the spinal nerve roots. A herniated disc is one cause of radiculopathy. Sciatica • The pain often starts slowly. • It may get worse: – After standing or sitting – At night – When sneezing, coughing, or laughing – When bending backwards or walking more than a few yards DIAGNOSTIC TESTS for Sciatica • Electomyelogram (EMG) may be done to determine the exact nerve root that is involved. • Nerve conduction velocity test may also be done. • Spine MRI or spine CT will show that the herniated disc is pressing on the spinal canal. • Spine x-ray may be done to rule out other causes of back or neck pain. However, it is not possible to diagnose a herniated disc by a spine x-ray alone. Spondylolisthesis • This is a possible source of Joe’s pain. In this disorder, pain is not usually present in the sitting position. • Flexion activities such as sitting decreases the anterior shear forces on the lumbar spine. • Extension activities are the most painful with this disorder. Patient Case • Joe’s pain could also be caused by damage to the posterior aspect of the anulus fibrosus in the lumbar discs. The overloading of forces there can also cause fluid loss in the disc, resulting in loss in disc height. • The lumbar discs might even be herniated. • There are no posterolateral anular ligaments in the lumbar region, so flexion with rotation can damage the discs there. • Damage in the cervical discs is unlikely because flexion and rotation in the cervical region will not damage the anulus fibrosus there. Patient Case • The shape of an individual’s lumbar joints may be a factor that predisposes some people to have injury, but not others. • If the superior and inferior articular facets in the lumbar region are oriented entirely in the sagittal plane, they offer little bony resistance to anterior sheer forces. Patient Case • Joe’s daily activities at work causes large anterior sheer forces. • That puts stress on the iliolumbar ligaments, the posterior anulus fibrosus, the PLL, and the joint capsules. • It is even more likely to be the problem if his superior and inferior articular facets are oriented in the sagittal plane. • Some or all of these structures might have failed. They are all innervated and may be the source of pain. Superior articular process Spinal cord Pedicle Spinous process Body of vertebra Transverse process Intervertebral disc Spinal nerve Inferior articular process Lamina Patient Case • Joe needs exercises to maximize the ability of the deep erector spinae muscles to control the excessive anterior shear forces. • Right now, he needs to minimize activities that cause the anterior shear forces to decrease his symptoms. • If he cannot change his activities, he could use a lumbosacral brace to provide proprioceptive input for positioning and possible protect him from further injury. Is the base of your sitting spine being asked to flex or extend? • If you are too tall for your seat, sitting in the standard office chair has you flexing your discs(L4-L5 and L5-S1) to excess (see middle diagram next slide). • If you are a short person (possibly with a large abdomen), sitting in the standard office chair has you extending your discs (L4-L5 and L5-S1) to excess (see right hand diagram next slide). • Add to this the possibility that you are constantly twisting in your chair to open a file cabinet to your side or to pick up a phone on the table behind you, and you have a recipe for back pain disaster! easyvigour.net.nz easyvigour.net.nz • The three directions of force that can injure a "pre-flexed" intervertebral joint: • Over flexing of the Lower Spine • Anterior Shear of the Lower Spine • Twisting/Side Bend of the Lower Spine easyvigour.net.nz Over flexing of the Lower Spine • The forward bending subject in the diagram to the right - typically a middle aged man who spends a lot of time in slumped chair sitting - has his spine bent at the lower lumbar region (L4-L5, and L5-S1) (and also at the lower thoracic region). The torso of this man has adopted the same shape as that of a chair sitting man slumped down into his chair. The lowest two discs are being taken to their flexed extremes. Now ask this man to pick up a heavy carton... Lumbar herniation and pinched sciatic nerve (or sciatic nerve root to be precise) is a certainty! easyvigour.net.nz Anterior Shear Force on the Lower Spine • Anterior shear is when a vertebra slips forward on the vertebra (or the sacrum) immediately below it (diagram of anterior shear, see below). Like disc herniation, most anterior shear happens at L4-L5 and L5-S1. There is minimal anterior shear force while sitting, but sitting does train the low lumbar spine to go easily into flexion. And here is the connection: it takes as little as one fifth of the anterior shear force to damage the flexed intervertebral joint as compared with the same joint in neutral. The habitual chair sitter who carries his "chair sitter" lumbar flexion tendency with him during a "fall onto the buttock" (see diagram) may thus be up to five times more likely to sustain damage. Diagrams illustrating Anterior Shear Force on the flexed lumbar spine of a person sustaining a backward fall onto the buttock. Note: While anterior shear force can do painful damage to the flexed lumbar spine, actual visible anterior slippage on plain x-ray images is not likely to be seen. You need fractures or developmental defects in the vertebra close to the facet joints (spondylolysis) for anterior slippage (sponylolisthesis) to occur. easyvigour.net.nz Dangerous rotation/side-bending • Moving your lower back into extremes of rotation or twisting is especially damaging in terms of disc damage and pinched sciatic nerve pain. For example: you sit directly in front of your computer, but you have to reach behind you to answer your phone; you constantly open a file cabinet to the left of your desk; people are constantly opening a door to your right to interrupt you. You are under pressure, and you are forgetting to maintain a neutral curve in your spine (similar to your standing curve).... In short you are suffering a prolonged and damaging onslaught to your spinal health. You will definitely damage your lumbar discs, with a high likelihood of disc herniation and sciatic nerve pinching. easyvigour.net.nz Note • Lumbar flexion is not the same as hip flexion. • You can flex your hips while keeping the spine straight. This is especially important when squatting. • Lumbar flexion causes anterior shear forces, which are dangerous to the lumbar intervertebral discs. Deep Erector Spinae muscles • Like the levator scapulae in the cervical region, the deep erector spinae will become overworked and painful when subjected to anterior shear forces. • However, therapy should focus on strengthening instead of stretching them because they are the only restraint to the excessive anterior shear forces, and stretching may worsen the symptoms. • Wear a lumbar brace until these muscles are strengthened. Levator Scapula • Anterior shear forces (flexion) of the neck, increases loading on the levator scapula. • Stretching as therapy for this muscle can be beneficial, since the anterior shear forces are restrained by other structures. • Exercises that involve strengthening the upper extremity will help to stabilize the trunk as well, since they produce tension on the fascia (connective tissue) that connects those muscle groups. • The upper extremity muscles can be strengthened without producing trunk movement, so this us good therapy for early stages of rehabilitation. Exercises for Low Back Pain • Exercises to increase the strength of the back extensors are often performed in the prone position. • The lowest compression forces in the low back are single-leg extension while on the hands and knees. Raising an arm and leg simultaneously increases compression, and might worsen the condition. • Sit ups of any kind are also not good for someone with a low back injury. GOOD BAD The rest of this PPT is not on any exam DISC PRESSURE IS MEASURED IN POUNDS PER SQUARE INCH Lying down: 25 psi Laying on your side: 75 psi Standing: 100 psi Sitting: 140 psi Bending forward: 150 psi Leg lifts: 180 psi Looking at computers all day Putting phones between the ear and shoulder Lifting incorrectly Weightlifters Your body will respond and adapt to these positions. Proper back support in bed How do you lift properly? The knees are bent, the back is straight, the buttocks are tucked in, and the shoulders are back, with the weight on the legs and the buttocks The “Ready” Position PROPERLY LIFTING BOX OFF FLOOR Keep the knees bent, back straight, keep the box close to the body, and lift with the legs. This keeps a neutral lumbar spine position, which removes some strain from the deep erector spinae and allow them to control the anterior shear forces. IMPROPERLY LIFTING BOX OFF FLOOR = 30 lbs Bending over at the waist, without bending the knees Holding box away from body: = 150 lbs 30 + 150 = 180 lbs 100 + 150 = 250 lbs PROPER SITTING Don’t slouch Sit up straight Put a pillow behind your low back Nothing in back pockets IMPROPER SITTING Sitting on your foot Phone between ear and shoulder Sitting with the computer too low Looking down all day compresses the discs in the neck PROPER WRIST POSITION Using the computer with your wrists bent causes problems: Backaches Headaches Neck Aches Carpel Tunnel Syndrome Special devices keep your wrists straight while you type. PROPER DESK WORK STATION Phone headset for hands-free use Computer at eye level and 18-25” away from your face Chair with good lumbar support or $10 lumbar pillow Keyboard pad under your wrists The front of the chair should drop off Adjustable seat: Feet flat to the floor Or a foot rest under the feet EXERCISES TO DO DURING THE DAY AT WORK Turn your head to the left and right Tilt head to both sides Roll head in circle Reach your spine to the ceiling Pull your shoulders back and forth a few times Pull shoulders up and down Retract the neck Stretch your arms and hands out in front of you with fingers interlocked Turn hands up and down Wrist stretches Use a step stool while standing Arch your back a little Look around and away Stretch the legs and feet out Twirl feet in circle Don’t reach too far