spinal nerve hemi articulation for head of rib spinous process articulation for tubercle of rib annulus fibrosus nucleus pulposus superior articular facet (b) pedicle posterior primary ramus inferior articular facet Figure 5.2 Typical thoracic vertebra (T5) from side. superior articular facet pedicle body anterior primary ramus lamina Figure 5.4 (a) Lumbar intervertebral disc viewed from below. (b) Prolapse of nucleus pulpos us ( \200\230slipped disc \200\231). spinous process Ligaments The ligaments of the spine are classi \201 ed as long or short. The short ligame nts include: \200 Interspinous ligaments, which attach adjacent spinous processes. Intertransverse ligaments, which attach adjacent trans- verse processes. inferior articular facet Figure 5.3 Typical lumbar vertebra (L4) from above and the side. THE SPINE 120 Ligamenta \202 avum, elastic ligaments, which attach to the laminae of adjacent arches. T he long ligaments include: The anterior longitudinal ligament on the anterior surface of th e vertebral bodies. The posterior longitudinal ligament on the posterior surface of the ver tebral bodies. The supraspinous ligament, which attaches to the tip of the spinous processe s. exits the spinal cord cranial to the C1 vertebra and this dictates the nomenclature of all the nerve roots thereafter. The C8 nerve root exits the spine cranial to the T1 verte- bra and the T1 root, therefore, exits under the pedicle of T1. This pattern is continued in the lumbar spine. For example, the L5 nerve root exits under the L5 pedicle in the L5/S1 exit foramen. This is of particular importance in nomenclature with respect to neural compressio n. Spinal tracts The spinal cord has an ellipsoid cross-section and has a central H-shaped are a referred to as the gray matter, which contains the cell bodies. The surrounding white mat ter contains the ascending and descending columns of nerve \201 bres. The white matter is divided anatomically into the posterior white column, the lateral white column and the ant erior white column. The alar ligaments extend from the top and sides of the odontoid peg to the foramen magnum. The cruciate ligament is the name given to the transverse ligament of the atlas. Muscles Longus colli and longus capitus extend from the base of the skull to the upper thor acic vertebrae with attachments to the cervical vertebrae and result in \202 exion of the cervi- cal spine. In the lumbar spine, \202 exion is primarily achieved by contraction o f the psoas muscles, a powerful paraverte- bral muscle whose origin is the transverse proce sses of the lumbar vertebrae and insertion is the lesser trochanter of the femur. Lateral \202 exion is achieved by contraction of the scalene muscles, the origin of which is the t ransverse pro- cesses of the cervical vertebrae, and insertion is the \201 rst and second ribs. Extension of the spine arises due to the action of short, deep muscles that attach t ransverse pro- cesses to adjacent spinous processes, more super \201 cial me- dium length muscles, and longer, superficial muscles including the erector spinae muscles. Afferent impulses usually enter the spinal cord via the \201 rst order neurons, whose cel l bodies reside in the poste- rior root ganglion of the spinal nerves. These synapse with s econd order neurons, which are usually located in the spinal cord. Subsequent synapses are on to third order neurons whose cell bodies reside in the thalamus, although this is a fair ly simplistic schema, and in reality several varia- tions and complex patterns exist. The efferent pathways are divided in to the direct cortical spinal or pyramidal system and the indirect cortical spinal or extra pyramidal system. The pyramidal system originates wit h cell bodies in the cerebral cortex with \201 bres extending directly onto the anterior horn cells within the spinal cord. In the extra pyramidal system, the cortical \201 bres synapse with intermediate neurons located either in the pons, cerebellum, thalamus, or any other number of nuclei. Cells from these intermediate nuclei then project on to the anterio r horn cells and this accounts for the reference to this system as an indirect cortical spi nal pathway. Anatomy of the spinal cord In the adult human, the spinal cord extends from the foramen mag num to its termination at approximately the L1/2 disc space. In the fetus, the cord extends down to the lower lumbar segments, but the termination of the cord migrates cranially due to the greater velocity of longitudinal growth of the spinal column compared with the spina l cord. At birth, the cord terminates at the L1/2 level. As a conse- quence of this the ner ve roots in the cervical region exit almost transversely from the cord whereas distal to th e L1 level the nerve roots follow an oblique course until they exit through their respectiv e foraminae. The C1 nerve root Dermatomes Main nerve roots supplying the lower limb \200 Hip: \200 Knee: \200 \200 Ankle: \200 \200 Subtalar joint: \200 \200 Toes: \200 \200 \200 \202 exion, adduction L2, 3, 4. extension, abduction L4, 5, S1; extension L3, 4. Main nerve roots supplying muscles of the upper limb \200 Shoulder: \200 \200 Elbow: \200 \200 Forearm: \200 \200 Wrist: \200 Fingers: \200 Hand: \200 abduction, lateral rotation C5; adduction, medial rotation C6, 7, 8. \202 exion L5, S1; plantar \202 exion L4, 5. \202 exion C5, 6; extension C7, 8. dorsi \202 exion L5, S1; inversion L5. supination C6; pronation C7, 8. eversion, plantar \202 exion L5, S1; \202 exion L5, S1, 2; dorsi \202 exion S1, 2, 3. \202 exion and extension C6, 7. \202 exors and extensors C7, 8. intrinsic muscles C8, T1. CHAPTER 5 Regional musculoskeletal anatomy and conditions 121 C2 C3 C2 C3 C4 T4 T2 T4 T7 T2 T2 T7 T10 C5 C5 C5 C5 T12 L1 T1 T1 C6 C6 T10 T1 T1 L3 C6 S5 T12 L2 L2 S4 C6 L1 L1 C8 S3 S3 C8 C8 C8 L2 L2 C7 C7 C7 C7 S2 S2 L3 L3 L3 L3 L5 L5 L5 L5 L4 L4 L4 L4 S1 S1 S1 S1 L5 L5 Figure 5.5 Dematome chart. Ascending tracts The three principle ascending tracts are: \200 \201 bres located more laterally and therefore more super \201 - cially in the cord. Ant erior and posterior spinal cerebellar tracts are responsible for unconscious proprioception and trans- mit information from the periphery to the cerebellum. Posterior gracile and cuneate tracts: the gracile tracts transmit \201 bres from the lowe r limb and trunk, and the cunate tracts from the upper limb and trunk. They convey proprioc eptive impulses and light touch and vibration sensibility. Anterior lateral tract: afferent \201 bres from the periph- ery cross to the contralateral side of the spinal cord and al so usually ascend to a variable extent. They may do so for over up to 5 segments. Ten per c ent of \201 bres within the anterior lateral tract synapse in the thalamus and are usuall y responsible for perception of super \201 cial pain, such as pin prick. Eighty per cent o f the \201 bres in the anterior lateral tract are, in fact spinoreticular thalamic \201 bres and reach the thalamus after synapsing in the reticular nucleus. These are responsibl e for deep pain perception such as muscle squeeze. These \201 bres are laminated with sac ral Descending tracts \200 \200 The three principle descending tracts are: The lateral cortical spinal tracts, which are fo rmed from the motor decussation in the lower medulla are the principle motor tracts. The re ticular spinal tracts, which modulate activity of the anterior horn cells, are divided into a lateral and medial reticular spinal tract. The lateral vestibular spinal tracts transmit information from the vestibular nucleus of the medulla to the ante- rior horn cells, and a re responsible for trunk and limb musculature posture and balance. THE SPINE 122 of the cortical spinal and anterolateral tracts. This may be the basis for sacral sparing following spinal cord injury. Venous drainage occurs primarily via the anterior and poster ior spinal veins, which drain initially into the inter- nal vertebral venous plexus of Bats on. This occupies the spinal canal and is hypothesized to play a role in tumor metastases a lthough this is controversial. The internal venous plexus then drains alongside the nerve r oots to the external vertebral venous plexus and then the seg- mental venous system. In the cervical region this is into the vertebral vein, in the thoracic region into the azygos ve in, in the lumbar region into the lumbar veins and in the sacral region into the lateral sa cral venous system. Nerve roots supplying re \202 exes \200 \200 \200 \200 \200 Biceps C5 \200\2236. Brachioradialis C5 \200\2236. Triceps C7. Knee L3 \200\2234. Ankle S1. Protective layers of the spinal cord The spinal cord and nerve roots are lined by the menin ges, with a tough protective outer layer called the dura mater. The dura mater consists of a delicate lining, the arachnoid mater, within which is the cerebrospinal \202 uid. The e xtradu- ral space lies between the dura mater and the bony skel- eton, and contains the int erval vertebral venous plexus, which drains the bone marrow contained within the verte- bra l bodies and communicates with the external vertebral venous plexus via the intervertebral foramena. Biomechanics of the spine Upper cervical spine \200 The C0/1 articulation, that is the joint between the occipital condyles and the C1 vertebra , is cup-like in morphology. The occipital condyles articulate with the concave superior ar ticular facets of C1. There are a series of ligaments between this complex. The alar liga- ments are the principle limitation to axial rotation. There is a signi \201 cant degree of \202 exion and extension between the occiput and C1, which averages about 25 . Lateral bend and axial rotation are each 5 to one side. The C1/2 joint is a biconvex articulation . Posteriorly C1 and C2 are joined by the loose atlanto-axial membrane. There is no ligamen tum \202 avum. Flexion and extension of the C1/2 joint averages 20 . Axial rotation is m aximal at this level of the cervical spine and measures about 40 . This is of clinical rel evance in that patients with cervical spondylosis may experience vertebrobasilar insuf \201 ciency because of this significant degree of axial rotation. Patients undergoing C1/C2 fusion, such as those patients with rheumatoid arthritis, also need to be advised that any residual rotation that they have may be lost by fusion surgery. Overall, 60% of axial rota tion of the cervical spine occurs between the C0 \200\223C1 \200\223C2 complex. Blood supply of the spinal cord The spinal cord receives its blood supply from the anterior spinal artery and the paired posterior spinal arteries. \200 The anterior spinal artery lies in the anterior medial \201 ssure of the spinal cord and is formed by the union of the anterior spinal branches of the vertebral arteries. The arter y runs down the anterior part of the spinal cord and at times along its course tapers down to quite a small caliber. It receives contributions from so-called booster or feeder vessel s, which usually provide both ascending and descending branches. It is possible there- fore for there to be watershed areas of perfusion of the spinal cord, where an ascending vess el meets a descend- ing vessel. The anterior spinal artery supplies the ante- rior and late ral gray and white matter. The paired posterior spinal arteries arise from the posterior in ferior cerebellar arteries or the vertebral arteries at the level of the foramen magnum. Th ere are some anastamoses between the posterior spinal arter- ies, and some scanty anastamos es between these and the anterior spinal artery. Radicular arteries are present bilaterally at every level in embryonic life, but most undergo involution during fetal growth. The rem aining radicular vessels enter the spinal canal via the intervertebral foramen and run alon g the spinal roots to eventually penetrate the meninges. They divide into anterior and post erior radicular branches, which subsequently divide into ascending and descending contribut ions to either the anterior spinal artery or posterior spinal arteries, respectively. These booster vessels may originate from the vertebral artery, the thyrocervical trunk, intercos tal vessels, lumbar, or lateral sacral arteries. They vary in number and size and may be as few as two or as many as twelve in number. The arteria radicularis magna of Adamkiewicz us ually is present on the left side at the T10 or T11 segment, and supplies much of the thora cic spinal cord. This is suscep- tible to injury during repair of abdominal aortic aneu- ry sms or corrective surgery of the spine and in most units temporary clamping of the segmenta l vessels is performed prior to manipulation of the spinal column. Anastamotic connections on the surface of the cord exist between the anterior spinal and posterior spinal arteries, as well as the radicular vessels. These anastomoses sup- ply the periphery of the cord and the super \201 cial laminae Lower cervical spine \200 The C4/5 and C5/6 segments demonstrate the highest degree of \202 exion and extension ave raging about 20 compared with the other segments, which average approximately 10 . This may explain the increased incidence of disc degeneration at these two levels. Lateral bendi ng averages 10 at the C2/3 level and decreases to 5 at C7/T1 level. Axial rotation is m aximal at the C4/5 and C5/6 levels and averages 7 . Thoracic spine Flexion-extension is ma ximal at the T10/11, T11/12 and T12/L1 segments. The average is approximately 12 at these lower segments and averages about 4 at the other segments of the thoracic spine. Similar ly lateral bending is maximal in the lower thoracic spine and averages about 9 , where as at the other segments is averages 6 . Lumbar spine Flexion extension in the lumbar spine i s maximal at L4/5 and L5/S1, and averages about 17 . These segments are also subjected to the highest loads and this may explain why they are the most subject to degenerative change s. CHAPTER 5 Regional musculoskeletal anatomy and conditions 123 Further reading Bono C.M, Gar \201 n S.R. (eds). Spine. Orthopedic Surgery Essentials. Sacro-iliac joint The sacro-iliac joint is ankylosed in 76% of patients over 50 years old a nd its movements are very restricted. It is partly synovial and partly syndesmotic. Some bi ome- chanical studies have demonstrated a maximum of 3mm of anterior translation of the sac rum with respect to the ilium with 1.5 of lateral bend and 6 of axial rotation to each side. Lippincott, Williams & Wilkins, 2004. Fardin D, Gar \201 n S (eds).Orthopedic Knowledge Update: Spine 2. American Academy of Orthopedic Surgeons, 2002. McMinn RMH. Last \200\231s Anatomy, Regional & Applied, 9th edn. Churchill Livingstone, 1994. White AA, Panjabi MM. Clinical Biomechanics of the Spine, 2nd edn. Lippincott, Williams & Wilkins, 2004. CERVICAL SPINE: REGIONAL MUSCULOSKELETAL CONDITIONS 124 Cervical spine: regional musculoskeletal conditions the spinous processes and soft tissues should be sought, although pathology is poorly local ized clinically. Examina- tion should exclude both other serious musculoskeletal pathologie s and non-musculoskeletal causes from anterior structures in the neck. Movements include \202 exion, exten- sion, lateral \202 exion, and rotation. Range of movement is poorly es timated in the cervical spine and restricted move- ment may occur both as a result of mecha nical restriction, with little correlation between movements and underlying pathology. Neur ological examination is normal in mechanical causes of cervical pain. Main differential diagnosis of cervical pain \200 Cervical vertebral body: \200 \200 \200 \200 \200 Mechanical: \200 \200 \200 \200 \200 \200 Nerve derived: \200 fracture, e.g. osteoporotic fracture; tumors, e.g. pathological fracture, metastases; osteo id osteoma; metabolic bone disease, e.g. Paget \200\231s disease; osteomalacia. non-speci \201 c neck pain; whiplash; osteoarthritis of the cervical spine; myofascial pai n; scoliosis; diffuse idiopathic skeletal hyperostosis. Investigations Blood tests are unhelpful in the investigations of mechanical cervical pain. Plain radiographs of the cervical spine are dif \201 cult to interpret as a number of str uctures are super- imposed upon each other. However, in those with non- degenerative mechan ical pain, plain radiographs are usually normal. In those patients with degenerative diseas e, the radiological \201 ndings often do not correlate with the sever- ity of clinical sy mptoms. The incidence of degenerative change of plain radiographs rises with age, is common est at the C5 \200\2236 level, and occurs at the intervertebral disc and the facet joints. Degenerative changes are found in 50% of those over 30 and are almost universal in those ov er the age of 50. However, because of the poor correlation of symptoms and radiographic spo ndylosis, plain \201 lms are unhelpful diagnostically, and are indicated only to exclude other pathology. The role of CT and MRI remains to be fully established in the investigatio n of mechanical neck pain as both potentially detect incidental abnormalities, for example, intervertebral disc disease. Their most useful role is in the exclusion of other pathologi es. nerve root compression by herniated disc or osteophyte; \200 thoracic outlet syndrome; \200 spinal cord tumors. In \202 ammatory/infection: \200 \200 \200 Referred: \200 spondylarthropathy, rheumatoid arthritis; disciitis, meningitis; crystal, e.g. crowned dens syndrome. from pharynx, larynx, thyroid, lymph nodes, prae- cordium, pericardium, heart, abdomen, sho ulder, gastrointestinal tract. Mechanical neck pain The term \200\230mechanical pain \200\231 is used here to describe pa in, where no speci \201 c pathological condition can be identi \201 ed and also includes degenerative disease. The exact cause of most cases of mechanical neck pain remains unclear . Neck pain is common in the population. Although the incidence of acute, self-limiting nec k pain is unclear, the lifetime prev- alence of more chronic pain lasting at least 3 months has been estimated as 71% and is commoner in women than men. Risk factors for neck pain, i nclude whiplash, manual occupations, depression, and age. Management Patient education, analgesics, and physiotherapy and exer- cise are central to m anagement. Tricyclic antidepressants may be helpful in chronic pain and work place assessme nts should be undertaken if indicated. Facet joint injections and denervation are an option in patients in whom pain is thought to arise from these joints. Cervical disc herniation Cervical disc herniation is much less common than hernia- tion of lumbar disks. Most commonly the C5 \200\2236 or C6 \200\2237 intervertebral disks are impli cated. As in the lumbar spine, an annular tear in the annulous \201 brosis initiates the hernia- tion of the nucleus pulposus. Central disks herniation may result in spinal cord co mpression, and posterolateral protrusion arises hours or days after a twisting injury with associated dermatome symptoms. History Pain may be related to a new or different activity, or there may be a history of tr auma. Where there is no history of trauma, osteoarthritis, or degenerative disc disease is often found. The commonest site of pain is the posterior surface of the neck, with anterior neck pain rarely arising as a re- sult of musculoskeletal causes. The patient describes a deep, aching pain, with superimposed exacerbations of acute pain described as sharp or shoo ting in nature. In those patients with upper cervical pathology, pain may be experienced ov er the back of the head and in lower cervi- cal pathology, shoulder pain may be reported. I n general, pain is exacerbated by cervical movements, and is better at rest. Pain that diff ers from this, for example, with unremit- ting night pain, should raise suspicion and warra nts further investigation. History Pain and stiffness are common, but radicular pain may be severe and disabling. Rare ly, symptoms and signs of spinal cord compression may occur. Coughing and sneezing typicall y exacerbate the pain. Examination Although neurological symptoms are common, hard neurological signs are less com monly found. Weakness may result from fear of exacerbating pain, but dermatomal sensory los s, myotomal weakness and loss of a re \202 ex war- rant further investigation. Determining the level of the neurological defect is vital when interpreting the radio- logical investi gations. Examination When pain arises due to mechanical causes, examination of the cervical spine is often unrewarding. Tenderness in CHAPTER 5 Regional musculoskeletal anatomy and conditions 125 spinal disease. Lateral and posterior subluxation can also occur. Basilar invagination (cra nial settling): as a conse- quence of destruction of the occipitocervical and atlanto-axial articulations the base of the skull can \200\230settle \200\231 onto the cervical spine w ith consequent invagina- tion of the odontoid peg into the foramen magnum. This can lead to direct compression of the brain stem with consequent myelopathic features or sudden death. Subaxial disease: subaxial subluxation is the least com- mon pattern and is found approxim ately 10% of rheuma- toid spinal disease. The typical radiographic appearance is of a step- type deformity with multiple levels of ante- rior subluxation of the cervical spine. Natural history Healing occurs by shrinkage and \201 brosis of the extruded material, rat her than reabsorption of this material into the disc. Resolution of symptoms may take sever al months. Herniation of an intervertebral disc predisposes to future osteoarthritis. Investigations Although plain radiographs may reveal narrowing of the intervertebral disc s pace, MRI is the investigation of choice as nerve root compression can be readily visualize d. However, radiologically it is dif \201 cult to differentiate extruded material from ost eophytic bars in the cervical spine. Treatment Conservative treatment is usually suf \201 cient, although spinal cord compressi on requires urgent surgical intervention. History \200 Patients may present with neck pain and/or myelopathic features. A common mode of presentat ion is with occip- ital headache and facial pain as a consequence of compression of the gre ater occipital nerve in patients with atlanto-axial instability. Patients may report an aud ible or even a palpable clunk on attempted movement of the neck. Atlanto-axial instability or cervical spine involvement in rheumatoid arthritis is frequently an incidental \201 nd ing on preoperative cervical spine radiographs undertaken prior to anesthesia for unrelated procedures. Typically, patients undergoing major lower limb joint replacement surgery are noted at anesthetic assessment to have atlanto-axial instability. Whiplash Whiplash is a complex topic, and the term refers to a variable set of clinical sig ns and symptoms. The onset of symptoms usually follows a minor or moderate rear end collisi on, and a history of a typical shunt type mechanism is usual. Patients usually present with neck pain, but the underlying pathology is as yet undetermined and probably represents a s pectrum of soft tissue injury. Pathology Both primate and cadaveric models have been used to investigate the injuries sust ained in whiplash, and both demonstrate a signi \201 cant incidence of tears of the anteri or longitudinal ligament. High energy trauma has also been demonstrated to cause failure of the disc. Examination Physical assessment of these patients is extremely dif \201 cult. As a consequ ence of their usually long-standing rheuma- toid arthritis, they frequently have involvemen t of all the joints of the appendicular skeleton. Clinical assessment of muscle power is th erefore dif \201 cult in the context of pain, joint destruction, and muscle atrophy. It is important, therefore, that any assessment of neurological status is made in the context of the patient \200\231s normal motor function, which is likely to be compromised as a conseq uence of their disease. Nevertheless, a careful assessment must be made for any myelopathic signs including: \200 \200 \200 \200 The classi \201 cation system of mobility de veloped by Ranawat is the most widely used amongst spinal surgeons. The subdivisions of the Ranawat classi \201 cation system are listed in Table 5.1. Mechanism of injury A biphasic mechanism of injury initially involving \202 exion of the upper cervical spine with hyperextension of the lower spine occurs within the \201 rst 11 0 ms, and is followed by extension of the entire cervical spine. The response to this traum a is modulated by many factors. Patients who have had a history of prior injury demonstrate greater pain behavior and the presence of pre-existing degenerative change also predicts a poorer outcome. The position of the head at the time of the collision modulates the clinic al presentation, so if the head is rotated at the time of colli- sion there is an increased incidence of pain in the long term. Females seem to have a higher symptoms prevalence comp ared with males. Up-going plantar re \202 exes Clonus Hyperre \202 exia Gait abnormalities Prognosis At least 45% of patients had persistent symptoms at 2 years after resolution of a ny claims for compensation. In a prospective study involving 93 patients, 58% of patients h ad continued symptoms in the long-term with 44% of the overall population having substantia l neck pain and stiffness. Table 5.1 Ranawat classi \201 cation of cervical rheumatoid involvement The rheumatoid spine Pathology Spinal involvement in rheumatoid arthritis is a consequence of the formation of pannus: granulation tissue, which is formed by in \202 ammatory cells leading to the destruction of articular cartilage and to synovial proliferation. As a conse - quence of articular and ligamentous destruction, the spinal elements may become unstable. The most common site of spinal involvement in the rheumatoid patient is the cervical spine . Three distinct patterns of involvement have been reported: \200 Grade 1 No neurological de \201 cit Grade 2 Subjective weakness and hyperre \202 exia Grade 3a Objective weakness with de \201 nite physical signs of myelopathy but in an ambul ant patient Grade 3b Objective weakness with de \201 nitive signs of myelopathy but in a non-ambulator y patient Investigations Plain cervical spine radiography and MRI are essential in assessing the rheu matoid patient presenting with cervical spine pain or instability. Atlanto-axial instability: this is the commonest pat- tern of involvement, reported in up t o 50% of rheumatoid CERVICAL SPINE: REGIONAL MUSCULOSKELETAL CONDITIONS 126 Frontal, lateral, open mouth and \202 exion-extension views of the cervical spine should be requested. The most useful of these is the lateral radiograph which will often demonstra te destruction of the odontoid peg by pannus. There may also be widening of the anterior at lantodental interval on the neutral lateral radiograph (the normal value is 3 mm). Flexion- extension views allow a dynamic assessment of the stability of the occipitocervical spine s ee Figure 5.6. The posterior atlantodental interval (PADI) should be greater than 14 mm. A PADI of less than 14 mm has been shown to be a good predictor of subsequent neurological co mpromise. The plain lateral radiograph historically was also very useful in determining the presence or absence of cranial settling. The most widely used radiographic parameter is Ma cGregor \200\231s line. This is a line drawn from the base of the occiput to the tip of the hard palate. Any migration of the tip of the peg more proximal to this line than 4.5 mm su ggests a diagnosis of cranial settling. MRI has superseded plain radiography in the determi nation of cranial settling. MRI shows with greater clarity if the odontoid peg has migrated into the cranium. It also images the spinal cord, and will con \201 rm evidence of cord c ompression or myelomalacic signal change within the spinal cord. The disadvantage of MRI is that a static assessment is provided, so the most important screening test remains \202 exion-extension views of the cervical spine. CT remains an important tool in the preoperati ve assessment of patients with cervical spine involvement in rheumatoid arthritis. MRI does not adequately visualize the bony architecture which must be fully visualized prior to sta bilization and decompression of the cervical spine. CT imaging is particularly useful in as sessing the course of the vertebral artery within the C2 lateral masses and aids identi \201 cation of those patients in whom transarticular screw \201 xation is not feasible. Treatment Treatment aims to alleviate pain and restore stability of the cervical spine. In patients with severe medical co-morbidities, such as ischaemic heart disease and multi-orga n impairment, surgical treatment may be deemed too risky. Immunosup- pressed patients carry an increased risk of post-operative complications, such as infection and wound break-down, so the decision to operate on these patients is made on an individual case-by-case basis f ollowing consultation between rheumatologist, anesthetist, and surgeon. Surgical techniques \200 Amongst the earliest techniques described for C1 \200\223C2 stabilization were sublaminar w iring techniques as described by Gallie and Brooks. Modern plate and screw techniques allow solid reconstruction of the occipitocer- vical or atlanto-axial articulations. Coexisting osteoporosis is technically challenging at surgery. Prophylactic surgery prior to neurologi cal de \201 cit remains controversial. There is good evidence to show that those who prese nt with a more advanced neurological de \201 cit have a poorer postoperative outcome in te rms of restoration of func- tion. In patients with Ranawat grade 2b disease only 20% of pat ients showed one grade of improvement following surgery versus 58% of patients with Ranawat grade 3a disease. Procedures for pain relief, such as atlanto-axial stabiliza- tion for oc cipital neuralgia, have a success rate of around 80%. Modern stabilization techniques often negate the use of postoperative halo immobilization and often only a cervical collar is re quired until fusion is achieved. This is obviously a bene \201 t in this population which is usually frail. There is recent evidence to show that good results can be anticipated eve n in those patients who do not achieve a good radiographic fusion, probably because of the lower functional demands of rheumatoid patients. Intervertebral disciitis Cervical and thoracic disciitis are less common than lum- bar disc iitis (see Chapter 16 p. 454, Infection, and lumbar disciitis). Tumors related to the cervical spine Tumors of the cervical spine may present in the spinal cord, the meninges, a peripheral nerve, for example, a neu- ro \201 broma, or from the ve rtebral column itself. Metastatic malignancy is commoner than primary malignant tumors. Bra chial plexus involvement may result from a Pancoast tumor in the apex of the lung. Presenta tion is with spinal cord compression, symptoms attributable to local destruc- tion or progr essive nerve symptoms. Torticollis in children Torticollis is derived from the Latin and literally translates as \200\230twisted neck \200\231. Causes Torticollis may be congenital or acquired. \200 The congenital causes may be due to an underlying muscular abnormality, accounting for 80% of congenital torticollis. Causes include a sternocleidomastoid mass, sternocleidomastoid t ightness or may occur despite a normal sternocleidomastoid. The remaining 20% of con- genit al torticollis results from bony abnormalities. These include failure of formation of the u pper cervical bones (for example, a congenital hemi-atlas) or due to failure Figure 5.6 This lateral plain radiograph of the neck in \202 exion demonstrates an increa sed atlanto-axial distance. CHAPTER 5 Regional musculoskeletal anatomy and conditions 127 of segmentation of the upper cervical spine bony ele- ments (such as occurs in Kippel \200 \223Feil syndrome). A com- bination of these bony abnormalities may be present. Acquired to rticollis is best classi \201 ed as painful or non- painful. The most common cause of pain ful acquired torticollis is trauma resulting in atlanto-axial rotatory subluxation. Tumors such as eosinophilic granuloma and osteoid osteoma may cause painful torticollis, and need to be entertained in the differential diagnosis in a child presenting with pain and an abno rmal attitude of the head and neck. In \202 ammatory causes include JIA and post-infectiou s torticollis. Gastro-oesophageal re \202 ux may be associated with painful torticollis an d is referred to as the Sandifer syndrome. The most important differ- ential diagnosis in t he older child presenting with a non- painful torticollis is an underlying central nervous system tumor or a syrinx, although the commonest cause is ocular, with the child compensati ng for weakness of the ocular muscles. Hysterical torticollis is a diagnosis of exclusion. Treatment Treatment is normally conservative with regular follow-up. Orthoses do not seem t o be helpful. Exercise and stretch- ing have been demonstrated to yield good results and up to 90% improve with this method. The best results are obtained in patients less than 3 mon ths of age with less successful results in children over 18 months of age. Indications for surgery Surgery is indicated in patients with signi \201 cant head tilt an d restriction of movement, where a tight band is palpable in the sternocleidomastoid. Surge ry is usually delayed until the patient is over age 1 year and where there has been a failu re of non-operative treatment. Surgery may involve a release of the muscle from one or two sites of its attach- ment, and may involve complete division of the tendon or Z-plasty. Par tial or complete muscle resection has also been performed. In general, 90% of patients unde rgoing surgery have a good result. Further reading Clarke CR (ed.). The Cervical Spine, 4th edn. The Cervical Spine Clinical presentation The appearance of the deformity may be variable, but usually the chil d demonstrates a restricted range of movement of the cervical spine. There may be associate d plagiocephaly or facial asymmetry depending on the duration of symptoms. A mass is palpab le in the sterno- cleidomastoid on the ipsilateral side of the head tilt before 6 weeks of life in up to one-third of patients. Torticollis that corrects on covering one of the eyes is due to an underlying ocular cause, and a compensatory maneuvering of the head and neck. Research Society/Lippincott, Williams and Wilkins, 2004. Hildingsson C, Toolanen G. Outcome after soft tissue injury of the cervical spine: Prospect ive study of 93 car-accident victims. Acta Orthop Scand 1990; 61: 357 \200\2239. Riise T, Jacobsen BK, Gran JT. High mortality in patients with Rheumatoid Arthritis and atl anto-axial subluxation. J Rheumatol. 2001; 61: 357 \200\2239. Roche CJ, Eyes BE, Whitehouse GH. The rheumatoid cervical spine: signs of instability on pl ain cervical radiographs. Clin Radiol 2002; 57: 241 \200\2239. Santavirta S, Slatis P, Kankaanpaa U, Sandelin J, Laasonen. Treatment of the cervical spine in rheumatoid arthritis. J BJS(a) 1988; 70: 658 \200\22367. Investigations Investigations should include anteroposterior and lateral radiographs of the cervical spine to exclude underlying bony abnormalities. In children presenting with painf ul tor- ticollis a CT scan should be undertaken to exclude under- lying tumor, such as oste oid osteoma. An MRI scan is useful to exclude underlying central nervous system tumors in p atients with painless torticollis. Cheung JCY, Wong MWN, Tang SP, Chen TMR, Shum SLF, Wong EMC. Clinical determinates of the o utcome of manual stretching in the treatment of congenital muscular torticollis in infants. JBJS (a) 2001; 83; 679 \200\22387. Demirbilek S, Atayurt H. Congenital muscular torticollis and ster- nomostoid tumor: results of non-operative treatment. J Pediatr Surg 1999; 34: 549 \200\22351. Natural history The natural history is variable. If there is a sternocleido- mastoid mass p alpable there is a 50 \200\22370% chance of resolu- tion by 1 year. A small sub-group of ab out 10% of patients require surgical intervention. THORACIC SPINE AND CHEST WALL: REGIONAL MUSCULOSKELETAL CONDITIONS 128 Thoracic spine and chest wall: regional musculoskeletal conditions bodies, at either single or multiple levels in the spine, most commonly involving the thora cic spine. This process results in wedging of the vertebral body and multiple vertebral bod y involvement results in kyphosis. The cause is unclear but Scheuermann \200\231s disease i s a risk factor for developing osteoarthritis in later life. Main differential diagnosis of thoracic and chest wall pain Thoracic vertebral body \200 \200 Fracture, e.g. osteoporotic fracture. Tumors, e.g. pathological fracture, metastases, osteo id osteoma. Metabolic bone disease, e.g. Paget \200\231s disease, osteomalacia. Pathology Ossi \201 cation of the vertebral bodies occurs in three places, the primary cen ter being the middle of the vertebral body and the other, secondary centers being in the up per and lower margins of each vertebral body. The secondary cen- tres are also known as rin g epiphyses, and these appear around puberty in the adolescent within the cartilaginous end plates that lie between the developing vertebral body and the intervertebral disc. In Sche uermann \200\231s disease, the cartilaginous end plate and ring epiphysis do not develop no rmally, and the disc protrudes through the cartilage into the vertebral body. The anterior surface is that portion of the vertebral body, which is exposed to the greatest weight-bear ing force and is, therefore, that portion most likely to be involved. The disc space narrow s anteriorly and wedging of the vertebral body occurs. Mechanical \200 \200 \200 \200 \200 Osteoarthritis of the thoracic spine. Scoliosis. Costovertebral joint disease. Diffuse idio pathic skeletal hyperostosis. Olecranon bursitis. Nerve derived \200 Nerve root compression by herniated disc or osteophyte. Pathology of intercostal nerve, e.g . herpes zoster, neuroma. In \202 ammatory/infection \200 Spondylarthropathy. \200 Disciitis osteomyelitis. \200 Crystal, e.g. calcium pyrophosphate deposition. History Pain in the thoracic spine in children aged between 13 and 16 is typical, although this pain is usually self-limiting after a few months. Pain may recur at a later stage as s econdary degenerative change develops. Chest wall lesions \200 \200 Examination Examination reveals a tender kyphosis during the \200\230active \200\231 phase of Scheuermann \200\231s disease, although this tenderness settles, leaving a pain free ky phosis. Rib, e.g. fracture, tumors, osteomalacia. Costochondral pathology, e.g. degenerative, rheum atoid arthritis. Soft tissue, e.g. intercostal muscle tear, myofascial pain, \201 bromyal gia, enthesitis. Pleural disease, e.g. infection, in \202 ammation, in \201 ltration. Bre ast pathology, e.g. mastitis.