Patterns of pain distribution are associated with certain musculoskeletal conditions. For example, polymyalgia rheumatica (PMR) typically affects the shoulder girdle and hips, whereas rheumatoid arthritis (RA) affects the joints symmetrical ly, with a predilection for the hands and feet. Patterns of pain distribution may overlap, especially in the elderly, who may have several conditions simultaneously. For example, hip and/or knee osteoarthritis (OA), peripheral vas cular disease, and degenerative lumbar spine all may cause lower extremity discomfort. The quality of pain Some individuals \201 nd it hard to describe pain or use descriptors of sever- ity. A description of the quality of pain can often help determine the cause. Cer tain pain descriptors are associated with nonorganic pain syndromes (see Table 1.2): \200 Burning pain, hyperpathia (i.e., an exaggerated response to painful stimuli), and allodyni a (i.e., pain from stimuli that are normally not painful) suggest a neurological cause. A change in the description of pain in a patient with a long-standing condition is worth no ting, since it may denote the presence of a second condition, e.g., a fracture or septic ar thritis in a patient with established RA. Repeated, embellished, or elaborate description (i.e., \200\234catastrophizing \200\235) m ay suggest nonorganic pain, but be aware that such a presentation may be cultural. LOCALIZATION OF PAIN AND PAIN PATTERNS 7 Table 1.1 Clinical pointers in conditions where pain is poorly localized Diagnosis Clinical pointer Periarticular shoulder pain Referred to deltoid insertion Carpal tunnel syndrome Nocturnal paresthesias and/or pain, often diffuse Trochanteric bursitis Nocturnal pain lying on affected side Hip Synovitis Groin/outer thigh pain radiating to the knee Table 1.2 Terms from the McGill pain scale that help distinguish between organic and nonorg anic pain syndromes Organic Nonorganic Pounding Flickering Jumping Shooting Pricking Lancinating ( \200\234Shooting \200\235) Sharp Lacerating Pinching Crushing Hot Searing Tender Splitting Nagging Torturing Spreading Piercing Annoying Unbearable Tiring Exhausting Fearful Terrifying Tight Tearing CHAPTER 1 Evaluating musculoskeletal pain 8 Changes in pain on examination Eliciting changes in pain by the use of different examinatio n techniques may be used to provide clues to the diagnosis: \200 Palpation and comparison of active and passive range of motion can be used to reproduce pain and localize pathology . This requires practice and a good knowledge of anatomy. Many of the classic physical exam signs and maneuvers have a high degree of interobserver v ariability. Interpretation should take into account the context in which the examination is done and the effects of suggestibility. Palpation and passive range of motion exercises are performed while the patient is relaxed. The concept of passive movement is the assumption that when t he patient is completely relaxed, the muscles and tendons around the joint are removed as p otential sources of pain; in theory, passive range of motion is limited only by pain at the true joint. This assumption has its own limitations, however, especially since passive mov ements of the joint will still cause some movement of the soft tissues. In some cases, e.g. , shoulder rotator cuff disease, the joint may be painful to move passively because of subl uxation or impingement due to a musculotendinous lesion. The clinician should be aware of myofascial pain when palpating musculotendinous structures, especially around the neck and shoulder regions. Myofascial pa in is said to occur when there is activation of a trigger point that elicits pain in a zone stereotypical for the individual muscle. It is often aching in nature. Trigger points are associated with palpable, tender bands of skeletal muscle that are hyper irritable. Trigger points are tender to palpation, and pressure may induce a stereotyped pa ttern of referred pain. This is different from the tender points characteristic of \201 b romyalgia, which tend to be present symmetrically throughout the body and do not induce ref erred pain. Local anesthetic in \201 ltration at the site of a painful structure is sometimes used to help localize pathology, e.g., injection under the acromion may provide s ubstantial relief from a \200\234shoulder impingement syndrome. \200\235 However, the tech nique is reliable only if localization of the injected anesthetic can be guaranteed. Few, i f any, rigorously controlled trials have shown it to give speci \201 c results for any con dition. THE ASSESSMENT OF PAIN IN YOUNG CHILDREN 9 The assessment of pain in young children The assessment of pain in young children is often dif \201 cult: \200 Young children often localize pain poorly. Careful identi \201 cati on of the painful area is necessary through observation and palpation. A child may not admit to pain but will withdraw the limb or appear anxious when the painful area is examined. Observing a child \200\231s facial expression during an examination is very important, as is the parent \200\231s response. Quanti \201 cation of pain often requires nonverbal clues, such as the child \200\231s behavior. Pain rating scales are often helpful (see Figure 1.1). \200 Tur ning the examination into a form of play may put the child at ease and assist with the exam ination. For example, asking the child to imitate your own movements may help you gauge ran ge of motion. \200 The trappings of a clinic setting may make young children nervous, and removing a white coat or stethoscope from sight may also help place the patient at ease. 0 1 2 3 4 5 Fig. 1.1 Pain assessment in children \200\224the faces rating scale. This page intentionally left blank 11 Chapter 2 Regional musculoskeletal conditions: making a working diagnosis Introduction 12 Neck pain 14 Shoulder pain 22 Pain around the elbow 34 Wrist pain 40 Sympto ms in the hand 46 Upper limb peripheral nerve lesions 58 Thoracic back and chest pain 64 Lo w back pain and disorders in adults 70 Spinal disorders in children and adolescents 84 Pelv ic, groin, and thigh pain 92 Knee pain 104 Lower leg and foot disorders (adults) 118 Child and adolescent foot disorders 132 Corticosteroid injection therapy 142 Principles of rehabi litation 146 CHAPTER 2 Regional musculoskeletal conditions 12 Introduction This chapter provides a guide to constructing an appropriate differential diag nosis for the patient who presents with regional musculoskeletal symp- toms. It does not ma ke reference to all possible diagnoses, only to the most common. This section is divided in to discussions of the neck, upper limb (shoulder, elbow, wrist), hand, thoracolumbar spine, lower limb (pelvis, groin, thigh, knee), and foot. General considerations \200 Findings from conventional clinical examination and imaging o f the musculoskeletal system usually occur when the patient is at rest, and therefore only minima lly symptomatic. Examination in the context of function (i.e., carrying, lifting, walking, bending, etc.) is not easy, although it is arguably more appropriate. Therefore, a thorough history utilizing deep knowledge of functional anatomy is the best alternative and an inva luable way of obtaining good information about abnormal function and its causes. Time spent obtaining a detailed account of the onset of symptoms is often helpful, regardless of whether the symptoms are of recent onset, or chronic, or obvio usly associated with trauma. Patients usually have a clearer concept of injury-induced dise ase and may try to rationalize the appearance of nontrauma-related symptoms by association with an event or injury. Weakness (as a symptom) may be due to a neuropathic or myopathic condition or it may be per ceived according to the impact of other symptoms such as pain. With children, it is important to obtain a history from both the child and a care provider. Second-hand information, even if provided by the mother, may be less r eliable than direct information from someone who has the opportunity to observe the child d uring the day. \200 Regional musculoskeletal lesions may be a presenting feature of a sys temic disorder such as an autoimmune rheumatic disease, malignancy or infection. Clinical s uspicion should guide the evaluation. Screening for disseminated malignancy, lymphoma, myeloma, and infection should at least include a CBC, CMP, serum and urine protein electrophoresis with immuno \201 xation, ESR and CRP. Thereafter, tests should be directed speci \201 cally to ward the clinical scenario. Corticosteroid injections and rehabilitation, as part of regional pain treat- ment, are dis cussed in general terms at appropriate points in the text. The practical approach to these therapies is presented at the end of this chapter. This page intentionally left blank CHAPTER 2 Regional musculoskeletal conditions 14 Neck pain Background epidemiology \200 About 10% of the adult population has neck pain at any one time, although many people do not seek medical help. About 1% of adult patients with neck pain develop neurologic de \201 cits, but overall lev els of disability are lower than for patients with low back pain. Isolated neck pain in children and adolescents is unusual. More commonly, it accompanies th oracic spine pain or pathology. \200 A continuum of radiological appearances exists in re lation to age: intervertebral disc narrowing, marginal end-plate osteophytes, and facet joi nt changes. The appearances are often termed degenerative; however, their correlation with the presence and severity of pain is poor. Functional anatomy \200 The neck is the most mobile (37 separate articulations) but least stable part of the spine. There are seven vertebrae (C1 \200\223C7) and \201 ve interver tebral disks (C2/3 \200\223C6/7). The C5/6 disc is most often associated with radicular sym ptoms. If it occurs, cord compression is most likely in this region, although atlantoaxial (C1 \200\223C2) subluxation may produce the same picture, especially among patients with RA . \200 Minor congenital abnormalities are not infrequent and increase the risk of degenerative changes. Nerve roots C2 and C3 cover sensation over the back of the head, the lower jaw line, and the neck. Nerve roots C4 \200\223T1 leave the spine in dural root sleeves, traverse the intervertebral foramina, and form the brachial plexus. Cervical nerves have a dermatomal representation (see Figure 2.1) and supply the upper limb musculature in a predictable way. Taking a history The site, radiation, and description of pain \200 Nerve root (radicular) pain is usually sharp and reasonably well localized in the arms. It is often described as \200\234burning \200\235 and associated with paresthesias and numbness. Nerve root irritat ion and compression by an intervertebral disc are common causes of radicular pain. However, in older adults and those who suffer recurrent bouts of pain, it is usually due to stenosi s of the exit foramen caused by vertebral end-plate osteophytes, facet joint osteophytes, t hickened soft tissue, or \201 brosis. Pain from deep cervical structures is common. It often localizes poorly across the upper ba ck. It can be referred to the upper arms, is typically described as \200\234heavy \200\235 or \200\234aching, \200\235 and is more diffuse than nerve root pain. Muscle spasm often accompanies various lesions. It can be very painful. \200 Pain from th e upper cervical spine (C1 \200\223C3) can be referred to the temporomandibular joint (TMJ) or retro-orbital regions. Conversely, NECK PAIN 15 Table 2.1 The major causes of neck pain in adults Soft tissue lesions (posture, psychogenic issues, and overuse as modi \201 ers) Neck strain Torticollis Myofascial pain Trauma (e.g., acute \202 exion \200\224extension injury [whiplash])) Cervicothoracic interspinous bursitis Degenerative and mechanical lesions Spondylosis Disc prolapsed Thoracic outlet syndrome Diffuse idiopathic skeletal hyperostosi s (DISH) In \202 ammatory conditions Rheumatoid arthritis (RA) Spondyloarthropathy (associated with fracture and in \202 ammato ry discitis) (Chapter 8) Juvenile idiopathic arthritis (Chapter 7) Polymyalgia rheumatica ( PMR) (Chapter 14) Myelitis Bone lesions Traumatic fracture Osteomyelitis (e.g., TB) Osteoporosis (fragility fracture) (Chapter 16) Osteomalacia (bone disease or muscle pain) Paget \200\231s disease Nonosseous infections General systemic infection (general/cervical myalgias) Meningitis Discitis Malignancy Primary (rare) or primary tumors (and pathological fracture) Myeloma, lymphoma, leukemias Brachial plexus lesions Trauma Thoracic outlet syndromes (e.g., cervical rib) Referred pain from Acromioclavicular or temporomandibular joint Heart and major arteries (e.g., angina, thorac ic aorta dissection) Pharynx (e.g., infection, tumors) Lung and diaphragm (e.g., Pancoast t umor, subphrenic abscess) Abdomen (e.g., gallbladder, stomach, esophageal, or pancreatic di sease) Shoulder (e.g., adhesive capsulitis) (Chapters 2 and 19) CHAPTER 2 Regional musculoskeletal conditions 16 Ophthalmic v C2 v C2,C3 Maxillary v C3 C4 Mandibular v C5 C6 T1 C2,3 C3 C4 T2 T3 T4 T5 T2 C5 T3 C6 T2 C5 T4 T2 T5 T1 T1 C6 C7 C8 C6 C8 C7 Fig. 2.1 Dermatomal distribution of the cervical and upper thoracic nerves re \202 ecting the radicular pattern of nerve root lesions. pain from TMJ disorders or as a result of dental malocclusion can be referred to the neck. Pain from the lower neck may be referred to the interscapular and anterior thoracic wall regions. The latter may mimic cardiac ischemic pain. Florid descriptions of the pain and of its extent and severity ( \200\234catastrophizing \200\235) are associated with prominent psychological modulators of pain. Evaluation of the shoulder joint is often necessary as pathology there often coexists and s ymptoms around the shoulder often complicate neck evaluation. Occipital headache is a common manifestation. Acute neck pain with trauma \200 Acute neck pain with trauma requires urgent assessment even if there are no obvious neurologic symptoms. Acute trauma requires urgent evaluation and consideration of fracture, spinal cord damage, and vertebral instability. About 80% of serious injuries occur from an accelerating head hi tting a stationary object. \200 An abrupt \202 exion injury may fracture the odontoid ( this occurs less commonly with extension); however, fewer than one in \201 ve injuries at C1/C2 produce neurologic de \201 cit because of the wide canal at this level. If not traumatic or osteoporotic (the latter being relatively rare in the cervical spine), fractures may occur in bone invaded by malignancy. NECK PAIN 17 New and/or associated symptoms Ask about associated leg weakness and new bladder or bowel s ymptoms. New onset acute neck pain with neurologic features needs urgent evalua- tion. Neur ologic symptoms may also accompany chronic neck pain: \200 Spinal osteomyelitis, meningit is, discitis (infection or in \202 ammation), myelitis, and fracture may all present with acute or subacute neck pain. All may cause cord compression. Myelopathy due to spondylosis typically presents with a slowly progressive disability over weeks to months, although it c an be acute, particularly if associated with central disc prolapse. Subacute pain, \202 accid paralysis, and profound distal neurologic signs may suggest mye litis, a condition caused mainly by infections and autoimmune diseases. Tinnitus, gait disturbance, blurring of vision, and diplopia associated with neck pain are all ascribed to irritation of the cervical sympathetic nerves. The vertebral arteries pass close to the facet joints just anterior to emerging nerve roots. Disruption of vertebral blood \202 ow may cause dizziness in severe cases of neck spondylosis. Previous trauma Ask about previous trauma \200\224it often precedes and in \202 uences chr onic pain: \200 Acute and occupational (chronic overuse) trauma is a common antecedent of chronic neck pain. Cervical dystonia (torticollis) can occur 1 to 4 days after acute trauma. It responds poorl y to treatment and can be longstanding. It may also complicate arthropathy such as in RA or Parkinson \200\231s disease. Whiplash injury is associated with chronic myofascial pain. \200 In some patients with ch ronic pain following (sometimes trivial) trauma, there may be dissatisfaction with the quality of care received at the time of the i njury. Unresolved litigation associated with trauma correlates with the persistence of neck pain and reported disability. Occupational and leisure activities Some occupations and sports/activities are associated w ith recurrent neck pain: \200 Neck pain (and early spondylosis) is prevalent among people whose occupations require persistent awkward head and neck postures, e.g., professional da ncers. Although biomechanical factors may be an important in \202 uence in initiating and aggravating neck pain, there may also be an underlying genetic predispositio n to OA and/or hypermobility. Other points Establish whether the pain started or varies with any nonmusculoskeletal sympt oms: \200 Cardiac ischemia, dyspepsia, or abdominal pain can result in referred pain to the neck (see Table 2.2). CHAPTER 2 Regional musculoskeletal conditions 18 Examination Functionally, the neck is part of the upper limb, and symptoms in the arms and legs may be relevant. Neurologic examination of the arms is important to the assessment of the neck. \200 An adequate examination cannot be performed in a clothed patient. Despite the inconvenience, it is important to have the patient change into an examination gown to a void missing potentially relevant clues. \200 Inspection from front and back may reveal s peci \201 c muscle wasting or spasm and poor posture. Observing active movements reveals little if the patient has severe pain or muscle spasm. I nability to move the neck even small distances is characteristic in advanced ankylosing spo ndylitis (AS) (Chapter 8). \200 Tenderness often localizes poorly in degenerative disease . Exquisite tenderness raises the possibility of a disc lesion, osteomyelitis, or malignanc y (the latter two are rare). There may be trigger points in neck stabilizer and extensor muscles. Activation of a trigge r point elicits myofascial pain in a zone that is stereotypical for the individual muscle. Tender points (localized, nonradiating pain elicited by pushing with the thumb), notably at the occipital origin of the trapezius, the medial scapular border, a nd the mid-belly of the trapezius, are features of \201 bromyalgia (FM) (Chapter 18). It is not clear whether tender and trigger points are the same. Examination of passive mobility may be helpful primarily if it reveals gross asymmetry. The normal range of movement varies depending on age, sex, and ethnicity. Generally, at least 45 * of lateral \202 exion and 70 * of rotation should be achieved in a middle-aged adult. Global loss of passive mobility is nonspeci \201 c and occurs with i ncreasing age. The range of movement that might indicate hypermobility has not been establi shed. Care should be taken if neck instability is a possibility (e.g., after trauma, or in a pati ent with a history of RA). Vigorous passive examination of forward \202 exion may exacerb ate disc lesions. Examination of the shoulder is important to evaluate any referred pain or associated articu lar lesion (e.g., adhesive capsulitis) (Chapter 19). Neurologic examination of upper and lower limbs is important in all cases in which pain is referred to the arms and/or the legs if cord compression is a po ssibility: look for increased tone, clonus, pyramidal weakness, and extensor plantar respon se. It is also important to check for a cervicothoracic sensory level. Diagnostic procedures Radiographs Radiographs should be requested with speci \201 c object ives in mind: \200 A lateral neck \201 lm may demonstrate soft tissue thickening (characteristic of infection or synovitis), spondylitis (i.e., syndesmophytes, discitis, an d periosteal apposition), and the severity of spondylosis. Oblique views centered on the suspected level may show nerve root foramen stenosis from bon y encroachment in patients with radiculopathy. There may be underlying OA (Chapter 6). NECK PAIN 19 High cervical \202 exion and extension views and a \200\234through-the-mouth \200\235 (odontoid) view are useful to demonstrate odontoid pathology. \200 In a patient with RA, if the distance between the anterior arch of the atlas and odontoid process is >3 mm on a l ateral \201 lm taken in \202 exion, there is likely to be C1/C2 AP subluxation. On a lateral \201 lm, superior odontoid subluxation in RA can be judged from a reduced distance from the anteroinferior surface of C2 to a line drawn between the h ard palate and base of the occiput (McGregor \200\231s line). The distance should be >34 mm in men and >29 mm in women. Lateral odontoid subluxation is best demonstrated with magneti c resonance (MR) imaging. Stepwise vertebral subluxation throughout the cervical spine demonstrated on a lateral \201 lm is characteristic of advanced RA. There may be only a few but important signs of spinal infection such as a soft tissue mass or isolated loss of joint space. Magnetic resonance (MR) and computed tomography (CT) \200 MR has largely superseded CT, a rthrography, and CT \200\223arthrography in assessing cervical spine/nerve, dural, vertebra l, disc, and other soft tissue lesions in the neck. In many cases the relevance of some MR \201 ndings is still being established \200\224patterns of signal abnormality do occur in asymptomatic people. The fre quency of these effects increases with age. MR is the technique of choice for imaging disc prolapse, myelopathy (Plate 1), myelitis, and for excluding infection or tumors. MR is used to help evaluate the need for neurosurgical intervention in RA patients with high cervical instability. MR may show soft-tissue swelling around the odontoid in CPPD disease (Chapter 15) but the diagnosis is best made with CT, which shows calci \201 cation around the odontoid and of adjacent ligaments ( \200\234crowned dens syndrome \200\235). In patients with the combination of unexplained radiographic signs and generalized symptoms, MR is an important investigation. Cases of spinal infection (such as TB or brucellosis) and lymphoma and can be detected using MR (Chapter 17). Bone scan \200 Scintigraphy has little role in diagnosing neck lesions. \200 Despite im proved image quality and tomographic images, the neck is poorly imaged by bone scan. Treatment Figure 2.2 shows the principles of treating mechanical cervical syndromes and the timing of MR scanning. \200 Remember to review the diagnosis if pain is persistent despi te treatment and symptoms seem disproportionate to the results or reports of imaging. In our e xperience, in \202 ammatory psoriatic-related neck pains are often mistaken for cervical s pondylosis. This may be because the clinician too readily assumes the latter diagnosis and/ or radiologists misinterpret radiographs. 2 0 MECHANICAL CERVICAL SPINE LESION C H A P T E R NO NEUROLOGICAL SIGNS WITH NEUROLOGICAL SIGNS ACUTE CHRONIC OR RECURRENT MYELOPATHY RADICULOPATHY 2 R e g i o n a l FIRST Collar \200\224firm or soft Pain control* Muscle relaxant ? rest or bedrest Collar \200\224firm or soft Pain control* Muscle relaxant Tricyclic agent at night ?rest or bedrest Rest or bedrest Soft collar Pain control* Muscle relaxant Physiotherapy \200\224heat, etc. Tricyclic agent at night Mobilization physiotherapy Other physiotherapy \200\224traction, hydrotherapy postural advi ce and home exercise cervical pillow Pain control* intermittent soft collar m u s c u l o s k e l e t a l URGENT MR SCAN THEN Tricyclic agent at night Inject \200\230trigger \200\231 points Gentle traction Gentle mobilization Other physiotherapy Scan abnormal \200\224neurosurgical referral or review diagnosis Scan normal \200\224review diagnosis walking aid MR SCAN Scan normal \200\224further traction and/or epidural injection Scan abnormal \200\224neuros urgical referral or review diagnosis IF NO BETTER c o n d i t i o n s Pain clinic Pain clinic MR SCAN MR SCAN Scan normal \200\224epidural injection Scan abnormal \200\224neurosurgical referral or revi ew diagnosis Scan normal \200\224epidural injection Scan abnormal \200\224neurosurgical referral or revi ew diagnosis =simple analgesics and/or anti-inflammatory IF STILL NO BETTER Pain clinic Pain clinic Fig. 2.2 The principles of treating mechanical neck syndromes and the timing of MR scanning . This page intentionally left blank CHAPTER 2 Regional musculoskeletal conditions 22 Shoulder pain Anatomy of the shoulder (see Figure 2.3) \200 The glenohumeral joint is a b all and socket joint. The shallow glenoid cavity permits a wide range of movement. The circ ular \201 brocartilagenous labrum sits on the glenoid, increases the articular surface ar ea, and acts as a static joint stabilizer. Normal glenohumeral movements include depression, then glide and rotation of the humeral he ad under the coracoacromial (CA) arch to enable elevation of the arm. As the arm elevates, there is smooth rotation and elevation of the scapula on the thoracic wall. (a) Supraspinatus muscle Acromion Subacromial (subdeltoid) bursa Labrum Glenohumeral joint space Greater tuberosity of humerus Glenoid fossa (scapula) Deltoid muscle Axillary recess Joint capsule Humerus (b) Acromioclavicular joint Clavicle Acromion Coracoclavicular ligament Coracoid process Coracoacromial ligament Transversehumeral (intertubercular) ligament Subscapularis bursa Scapula Tendon and synovial sheath of the long head of the biceps Humerus Fig. 2.3 (a) Major shoulder structures. (b) The relationship of the joint capsule to its bo ny surround and the coracoacromial arch. SHOULDER PAIN 23 Shoulder movements are a synthesis of four joints: glenohumeral, acromioclavicular (AC), st ernoclavicular (SC), and scapulothoracic. Movements at AC and SC joints enable slight clavicular rotation, shoulder elevation/depression, and protraction/retraction. The rigid CA arch protects the glenohumeral joint from trauma; it and the overlying deltoid are separated from the capsule by the subacromial (subdeltoid) bursa. A cuff of muscles surrounds the glenohumeral joint capsule. These rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis. The supraspinatus initiates abduction by depressing the humeral head, then elevating the ar m alone for the \201 rst 10 of movement. The more powerful deltoid then takes over abdu ction. The infraspinatus/teres minor externally rotates the arm, and the subscapularis inte rnally rotates the arm (see Figure 2.4). Production of powerful shoulder movements requires some degree of arm elevation, since the larger muscles such as the deltoid, latissimus dorsi (extensor), and teres major (adductor) work inef \201 ciently with the arm in the anatomical position. The rotator cuff muscles act synchronously as joint stabilizers throughout the range of shoulder movement. The long head of biceps tendon originates above the glenoid (usually attached to the labrum) and runs within the glenohumeral joint capsule anteromedially in a bony groove. Pain and shoulder lesions (see Chapter 19) \200 Shoulder pain is common and may have its origin in articular or periarticular structures or may be referred from the cervical or tho racic spine, the thoracic outlet, or subdiaphragmatic structures (see Table 2.2). Shoulder lesions often produce pain referred to the humeral-deltoid insertion, which the pa tient will interpret as pain in the upper arm. \200 Periarticular disorders, mainly subac romial/shoulder impingement (SAI) disorders, are the most common cause of shoulder pain in adults (>90% of cases). Traumatic or in \202 ammatory lesions of many different shoulder structures and conditions that result in neuromuscular weakness of the rotator cuff or scap ular stabilizers may result in impingement pain. Pain from subacromial impingement syndrome is thought to be generated by the \200\234squas hing \200\235 of subacromial structures between the greater tuberosity of the humeral head and the ca arch during rotation/elevation of the humeral head. Taking a history When did the pain start? Shoulder injuries are common and may be acute or chronic (overuse). \200 Rotator cuff lesions (in \202 ammation, degenerative weakness, o r tear) are often associated with activities and occupations that involve straining the arm in abduction or forward \202 exion. A history of an acute CHAPTER 2 Regional musculoskeletal conditions 24 (a) Subscapularis Deltoid Pectoralis major (b) Supraspinatus Deltoid Infraspinatus Teres minor Teres major Latissimus dorsi Fig. 2.4 The muscles of the shoulder: (a) anterior view; (b) posterior view. SHOULDER PAIN 25 Table 2.2 The most common causes of shoulder pain Periarticular lesions (often manifest as subacromial impingement pain) Rotator cuff tendonitis/tears (very common age 40y+) Calci \201 c tendonitis Bicipital tendonitis Subacromial bursitis Milwaukee shoulder (basic calcium phosphate crystal periarthritis) Periarticular muscle weakness Articular lesions Synovitis (glenohumeral or acromioclavicular joint) OA (glenohumeral or acromioclavicular joint) Glenohumeral instability (e.g., labral tears) Adhesive capsulitis ( \200\234frozen shoulder \200\235) Neurologic Cervical nerve root and radicular referred pain Neuralgic amyotrophy Spinal cord lesions: tumors, syringomyelia Neurovascular Complex regional pain syndrome (see Chapter 18) Thoracic conditions (referred pain) Mediastinal tumors Angina Systemic and diffuse conditions Polymyalgia rheumatica (see Chapter 14) Myositis (see Chapter 13) Chronic pain disorders (see Chapter 18) Polyarticular synovitis Bone disorders Tumors Osteonecrosis (see Chapter 16) Paget \200\231s disease (see Chapter 16) Subdiaphragmatic (referred pain) Gallbladder disease Subphrenic abscess injury, however, is not always obtained. Subsequent calci \201 cation in the tendon follow ing a supraspinatus injury can be asymptomatic or present with acute pain. Manual labor is a risk factor for rotator cuff lesions. There is typically no acute injury; instead, there is a history of repetitive movements over years that lead to injury. Athletes involved in throwing and racket sports are at risk of rotator cuff tendinopathy an d labral tears. Football players are at risk of clavicle fracture, shoulder dislocation (wh ich may lead to long-term instability), and disruption of the acromioclavicular (AC) joint. CHAPTER 2 Regional musculoskeletal conditions 26 Pain from degenerative glenohumeral or AC joint arthritis might be a long-term sequelae of a bone or joint injury. The shoulder girdle is one of the most common sites for a chronic pain syndrome. Myofascial pain of the shoulder girdle is common and may mimic the symptoms of cervical rad iculopathy, re \202 ux esophagitis, or ischemic heart disease. Severe, persistent, sleep-disturbing pain of recent onset may be indicative of avascular ne crosis, osteomyelitis, or bony tumors. Although uncommon in the shoulder region, these cond itions should not be missed. Where is the pain? \200 Pain from the shoulder may be referred to the deltoid insertion. \200 Well-localized pain may occur with AC joint arthritis \200\224the patient will have no trouble pointing out the affected joint \200\224 but remember that referred C4 nerve roo t pain and pain from bone lesions of the distal clavicle is maximal in the same area. Glenohumeral articular and capsulitis pain are not well localized (e.g., the patient covers his shoulder with his hand). Pericapsular pain may be associated with SAI syndromes but may also be myofascial (typicall y) or referred from the cervicothoracic spine. \200 Bilateral shoulder pain should increa se suspicion of the presence of an in \202 ammatory polyarthritis such as RA (see Chapter 5), juvenile idiopathic arthritis (JIA, Chapter 7), psoriatic arthritis (see Chapter 8) or CPPD arthritis (see Chapter 15) \200\224 but these would be rare without other joint sympt oms. Diffuse pain across the shoulder girdle muscles in those over 55 years of age raises the po ssibility of PMR (see Chapter 14). This pain is often associated with immobility and stiffn ess, particularly early in the day. A deep aching pain associated with stiffness is characteristic of adhesive capsulitis (frozen shoulder). The use of the term frozen shoulder is popular, but often incorrectly applied. It is a condition that is rare in patients under 40 years of age . The condition occurs in three phase: a painful phase, an adhesive ( \200\234frozen \200 \235) phase, and a resolution phase. Phases often overlap and the duration varies, but long -term limitation of shoulder movement remains in up to 15% of patients. It is associated wi th diabetes. Does the pain vary? Movement- or posture-related pain may be a clue to its cause: \200 Ro tator cuff lesions often present to rheumatologists with an SAI pattern of pain \200\224tha t is, pain reproducibly aggravated by speci \201 c movements during each day such as reach ing up (overhead) with the arm. Articular, bone, and adhesive capsulitis pain is more likel y to be persistent. A history of recurrent bouts of shoulder pain in children and adolescents may suggest glenohumeral instability due to hypermobility SHOULDER PAIN 27 or previous trauma, e.g., a labral tear. In an unstable shoulder, pain may result from syno vitis, subchondral bone damage, or an SAI disorder. The frequency of recurrent anterior sub luxation is inversely proportional to the age at which the initial dislocation occurs. Are there spinal symptoms? There is an association between neck conditions and shoulder pai n. C4 nerve root pain is referred to the shoulder, while adhesive capsulitis is associated with cervical nerve root symptoms (the nature of the link is unknown). In \202 ammatory ne ck lesions caused by CPPD and psoriatic spondylitis can lead to pain referred to the should ers, mimicking PMR. Examination Visual inspection Inspect the neck, shoulders, and arms from the front, side, a nd back with the patient standing. \200 Abnormality of the contour of the cervicothoracic spine could indicate muscle imbalance/spasm or might be associated with a nerve root origi n of pain. Scapular asymmetry at rest is especially relevant when examining children and may indicate a congenital bony deformity. Subtle degrees of asymmetry are comm on and are not usually due to speci \201 c pathology. Diffuse swelling of the whole shoulder may suggest a shoulder effusion/hemarthrosis or subacromial bursitis. In the elderly, Milwaukee shoulder should be considered. Swelling of the AC joint occurs with joint diastasis, arthritis, and distal cl avicular bone lesions. Arm swelling and skin changes distally could indicate a complex regional pain syndrome (see Chapter 18). Elicit any tenderness Eliciting tenderness of discrete shoulder structures is often unrewar ding: \200 Tenderness of the AC joint, humeral insertion of the supraspinatus tendon, and the long head of biceps tendon may be clues to pathology, but palpation may not yield a speci \201 c diagnosis. An appreciation of trigger points associated with myofascial pain and tender points in \201 bromyalgia (see Chapter 18) is important in the interpretation of regional soft tissue tenderness. Document bilateral shoulder movements This aids diagnosis but also gives an indication of t he level of functional impairment and can help in monitoring changes over time (see Table 2 .3). The movements are \201 rst tested actively (the patient does the movement) and then passively (the clinician supports the limb). Muscle strength can also be assessed while tes ting active movement. \200 Observe arm elevation in the scapular plane from behind, notin g symmetry of scapular movement, the pattern of pain during elevation, and the range of eleva tion. Hunching of the shoulder at the outset of arm elevation often occurs with an impingem ent problem. A painful arc may suggest a rotator cuff lesion. Inability to lift the arm sug gests CHAPTER 2 Regional musculoskeletal conditions 28 a rotator cuff tear or weakness, capsulitis, or severe pain, e.g., acute calci \201 c supr aspinatus tendonitis. Observe and compare internal rotation of shoulders, which can be judged by how far up the back the hand can reach. Poor performance may be due to rotator cu ff weakness, weakness of the scapular stabilizing muscles, or pain (generally from shoulder impingement syndrome). This maneuver assumes normal elbow function. Observe the range of external rotation of the humerus from the front. Ask patients to \202 ex their elbows as if they were holding a tray, and then rotate the arms outwards. Min or degrees of restriction caused by pain are not speci \201 c, but severe restriction is c haracteristic of adhesive capsulitis. Passive range of motion should be tested with two hands: one hand guides the movement while the second rests on the shoulder. Many patients will subconsciously \202 ex the spine to compensate for restricted range of motion at the shoulder; using both hands can help detec t this and other abnormalities in movement at the joint. Test for subacromial impingement \200 Always compare the affected with the asymptomatic s ide and make conservative judgments about muscle weakness if there is pain impeding volunta ry effort. Most tests rely on their ability to narrow the distance between the humeral head and the CA arch, by driving the greater tuberosity under the CA arch as the hu merus rotates (see Figure 2.5). Whether the tests are speci \201 c for lesions of the subacromial structures or for the si te of impingement are unknown. Movement of the glenohumeral joint Move the glenohumeral joint passively in all directions by moving the upper arm with one hand and placing the other over the shoulder to feel for \200\234clunks \200\235, crepitus, and resistance to movement: \200 If the humeral head c an slide anteriorly (often with a \200\234clunk \200\235) without rotation in the glenoid it suggests instability. Grossly reduced passive shoulder movement (notably external rotation, with or without pain) is the hallmark of adhesive capsulitis. Pull down on both (hanging) arms. If the humeral head moves inferiorly (sulcus sign), there may be glenohumeral instability. Stress the acromioclavicular joint Stressing the AC joint may reproduce the pain. This is c onventionally done by compression or shear tests: \200 These tests should not normally be painful. Although painful tests have not proved to be speci \201 c for AC pathology (pain from SAI may also be present), a positive test may provide a clue that the AC joint is art hritic or dynamically unstable, or that impingement of structures in the subacromial space under the AC joint is occurring. Hold the patient \200\231s arm in forward \202 exion (90 ) and draw it across the top of the patient \200\231s chest. The resulting compression of the AC joint may produce pain. A C joint pain can also be elicited by passively SHOULDER PAIN 29 Table 2.3 Isolated muscle testing of shoulder girdle muscles