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COVID-19, the clinical syndrome produced by infection with SARS-CoV-2, can result in multisystem organ dysfunction, including respiratory failure and hypercoagulability, which can lead to critical illness and death. Musculoskeletal (MSK) manifestations of COVID-19 are common but have been relatively underreported, possibly because of the severity of manifestations in other organ systems. Additionally, patients who have undergone sedation and who are critically ill are often unable to alert clinicians of their MSK symptoms. Furthermore, some therapeutic measures such as medications and vaccinations can worsen existing MSK symptoms or cause additional symptoms. Symptoms may persist or occur months after the initial infection, known as post-COVID condition or long COVID. As the global experience with COVID-19 and the vaccination effort increases, certain patterns of MSK disease involving the bones, muscles, peripheral nerves, blood vessels, and joints have emerged, many of which are likely related to a hyperinflammatory host response, prothrombotic state, or therapeutic efforts rather than direct viral toxicity. Imaging findings for various COVID-19-related MSK pathologic conditions across a variety of modalities are being recognized, which can be helpful for diagnosis, treatment guidance, and follow-up.

Aim of study: Most sprained lateral ankle ligaments heal uneventfully, but in some cases the ligament’s elastic function is not restored, leading to chronic ankle instability. Ultrasound shear wave elastography can be used to quantify the elasticity of musculoskeletal soft tissues; it may serve as a test of ankle ligament function during healing to potentially help differentiate normal from ineffective healing. The purpose of this study was to determine baseline shear wave velocity values for the lateral ankle ligaments in healthy male subjects, and to assess inter-observer reliability. Material and methods: Forty-six ankles in 23 healthy male subjects aged 20–40 years underwent shear wave elastography of the lateral ankle ligaments performed by two musculoskeletal radiologists. Each ligament was evaluated three times with the ankle relaxed by both examiners, and under stress by a single examiner. Mean shear wave velocity values were compared for each ligament by each examiner. Inter-observer agreement was evaluated. Results: The mean shear wave velocity at rest for the anterior talofibular ligament was 2.09 ± 0.3 (range 1.41–3.17); and for the calcaneofibular ligament 1.99 ± 0.36 (range 1.29–2.88). Good inter-observer agreement was found for the anterior talofibular ligament and calcaneofibular ligament shear wave velocity measurements with the ankle in resting position. There was a significant difference in mean shear wave velocities between rest and stressed conditions for both anterior talofibular ligament (2.09 m/s vs 3.21 m/s; p

Ultrasonography (US) and dual-energy computed tomography (DECT) are useful and sensitive diagnostic tools to identify monosodium urate deposits in joints and soft tissues. The purpose of this review is to overview the imaging findings obtained by US and DECT in patients with gout, to understand the strengths and weaknesses of each imaging modality, and to evaluate the added value of using both modalities in combination.

Aim: To determine whether differences in joint and tendon stiffness as measured by ultrasound shear wave elastography are present in breast cancer patients with aromatase inhibitor- associated arthralgias compared to age-comparable healthy control women. Methods: Postmenopausal women with stage I–III breast cancer who were taking adjuvant aromatase inhibitors and complained of joint pain were enrolled (n = 6). Postmenopausal women with no history of breast cancer, hormone treatment, or joint pain served as controls (n = 7). All subjects had bilateral hands and wrists evaluated by gray-scale and power Doppler ultrasound, and shear wave elastography ultrasound. Results: Patients with AI-associated arthralgias had significantly stiffer tendons than controls in the 1st extensor compartment (long axis; p = 0.001), 4th extensor compartment (long axis; p = 0.014), 3rd metacarpophalangeal joint (p = 0.002), the pooled values of the extensor compartments, both long (p = 0.044) and short axes (p = 0.035), and the pooled values for the metacarpophalangeal joints (p = 0.002). On ultrasound, the patients (but not controls) presented with hyperemia and increased tenosynovial fluid in the flexor and extensor tendon sheaths, and the median nerves were symptomatic and bifid; however, these differences were not statistically significant. Conclusions: This is the first study to identify increased tendon stiffness as a putative physiological characteristic of aromatase inhibitor–associated arthralgias. Future studies should determine whether increased tendon stiffness is a risk factor for the development of aromatase inhibitor–associated arthralgias, or a result of aromatase inhibitor treatment.

We present a comprehensive update of elbow magnetic resonance imaging, detailing the complex anatomy and pathology of the elbow. A variety of pathologies may affect the elbow joint, and many of the symptoms overlap. As such, magnetic resonance imaging of the elbow serves as an invaluable clinical tool for the clinician in the diagnosis and management of patients presenting with elbow pain.

Effusion-synovitis (ES) is recognized as a component of osteoarthritis, creating a need for rapid methods to assess ES on MRI. We describe the development and reliability of an efficient single-slice semi-automated quantitative approach to measure ES. We used two samples from the Osteoarthritis Initiative (OAI): 50 randomly selected OAI participants with radiographic osteoarthritis (i.e., Kellgren–Lawrence (KL) grade 2 or 3) and a subset from the Foundation for the National Institutes of Health Osteoarthritis Biomarker study. An experienced musculoskeletal radiologist trained four non-expert readers to use custom semi-automated software to measure ES on a single axial slice and then read scans blinded to prior assessments. The estimated intraclass correlation coefficient (ICC) for intra-reader reliability of the single-slice ES method in the KL 2–3 sample was 0.96 (95% CI: 0.93, 0.97), and for inter-reader reliability, the ICC was 0.90 (95% CI: 0.87, 0.95). The intra-reader mean absolute difference (MAD) was 35 mm3 (95% CI: 28, 44), and the inter-reader MAD was 61 mm3 (95% CI: 48, 76). Our single-slice quantitative knee ES measurement offers a reliable, valid, and efficient surrogate for multi-slice quantitative and semi-quantitative assessment.

Low back and neck pain are common and result in significant patient disability and health care expenditure. When conservative treatment fails or worrisome clinical findings are present, magnetic resonance imaging (MRI) is the imaging modality of choice to assess the cause and complicating features of spine pain. There are many potential aetiologies of spine pain with similar clinical presentation, including degenerative changes, infection, and insufficiency and pathologic fractures. MRI allows for the differentiation of these sources of spine pain and potential complicating features, permitting the appropriate direction of therapy.

Chemotherapy-induced peripheral neuropathy (CIPN) is caused by drug-induced damage to the axons which is not detected easily due to lack of reliable, clinically applicable modalities. Diffuse tensor imaging (DTI) allows for quantitative measurements of fractional anisotropy (FA) and apparent diffusion coefficient (ADC), which have been shown to detect nerve injury by Magnetic Resonance Imaging (MRI). We sought to evaluate if DTI could be used for detection of CIPN in patients with breast cancer treated with a taxane. Patients with h/o exposure to neurotoxic chemotherapy, diabetes, or peripheral neuropathy were excluded. Patients completed pre- and post-chemotherapy MRI of bilateral legs and FACT&GOG-Ntx. Genotyping of single-nucleotide variations (SNVs) was performed to detect known associations with CIPN. We had 14 evaluable patients in this prospective trial. Mean FA values post-chemotherapy were significantly lower than baseline at mid-calf (p

Ultrasound elastography (USE) is becoming an important adjunct tool in the evaluation of various musculoskeletal (MSK) traumatic conditions and diseases, with an increasing number of applications and publications in recent years. This rapidly evolving technique enhances the conventional ultrasound (US) examination by providing information on the elastic properties of tissue alongside the morphological and vascular information obtained from B-mode US and Doppler imaging. Those performing USE must have basic knowledge of its proper imaging techniques and limitations. In this review article, we place the USE in historical perspective and discuss basic techniques and current applications of USE in the evaluation of various traumatic and pathologic conditions of fasciae, nerves, muscles, tendons, ligaments, and MSK soft tissue masses.

Posttraumatic osteoarthritis of the ankle and hindfoot is a common and frequently debilitating disorder. 70% to 90% of ankle osteoarthritis is related to prior trauma that encompasses a spectrum of disorders including fractures and ligamentous injuries that either disrupt the articular surface or result in instability of the joint. In addition to clinical evaluation, imaging plays a substantial role in the treatment planning of posttraumatic ankle and hindfoot osteoarthritis. Imaging evaluation must be tailored to specific clinical scenarios and includes weight bearing radiography that utilizes standard and specialty views, computed tomography which can be performed with a standard or a weight bearing technique, magnetic resonance imaging, and ultrasound evaluation. This review article aims to familiarize the reader with treatment rationale, to provide a brief review of surgical techniques and to illustrate expected imaging appearances of common operative procedures performed in the setting of posttraumatic ankle and hindfoot osteoarthritis, such as joint-preserving procedures, ankle fusion, subtalar fusion, tibiotalarcalcaneal fusion and ankle arthroplasty. Preoperative findings will be discussed along with the expected postoperative appearance of various procedures in order to improve detection of their complications on imaging and to provide optimal patient care.

Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple organs and organ systems. Musculoskeletal (MSK) involvement is one of the most frequent and the earliest locations of disease. This disease affects joints and periarticular soft tissues, tendon sheaths and tendons, bones, and muscles. Multimodality imaging, including radiography, ultrasound (US), and magnetic resonance imaging (MRI), plays a significant role in the initial evaluation and treatment follow up of MSK manifestations of the SLE. In this paper, we illustrate MSK imaging features in three clinical forms of SLE, including nondeforming nonerosive arthritis, deforming nonerosive arthropathy, and erosive arthropathy, as well as the other complications and features of SLE within the MSK system in adults and juveniles. Advances in imaging are included. Conventional radiography primarily shows late skeletal lesions, whereas the US and MRI are valuable in the diagnosis of the early inflammatory changes of the soft tissues and bone marrow, as well as late skeletal manifestations. In nondeforming nonerosive arthritis, US and MRI show effusions, synovial and/or tenosynovial hypertrophy, and vascularity, whereas radiographs are normal. Deforming arthritis clinically resembles that observed in rheumatoid arthritis, but it is reversible, and US and MRI show features of inflammation of periarticular soft tissues (capsule, ligaments, and tendons) without the pannus and destruction classically observed in RA. Erosions are rarely seen, and this form of disease is called rhupus syndrome.

We provide a comprehensive review of the clinical presentation, imaging evaluation, classification, and management of adolescent idiopathic and adult degenerative scoliosis.

This article discusses instrumented spinal surgeries, the radiologic assessment of spinal fixation hardware, and the potential complications of spinal hardware. Radiography is the standard for the postoperative assessment of spinal hardware. Computed tomography and magnetic resonance imaging play a valuable role in the detection of hardware and postsurgical-related complications such as infection, pseudarthrosis, and malpositioned instrumentation. Familiarity with the normal imaging appearance of implanted spinal hardware along with the expected progression of normal postoperative osseous arthrodesis enables recognition of potential complications and helps facilitate appropriate clinical management.

Radiologists should be familiar with basic principles of fracture fixation and the normal imaging appearances of implant constructs and their complications. The surgeon's selection of external fixation, intramedullary nail fixation, open reduction and internal fixation, or some combination depends on patient factors, fracture configuration, injury to the soft tissue envelope, and surgeon experience. Complications including loss of fixation with resultant malalignment, nonunion, infection, and posttraumatic osteoarthritis present additional challenges for the surgeon as well as the radiologist. This article reviews the rationale behind fracture fixation in fractures of the lower leg, ankle, and foot. Examples of postoperative complications are also reviewed.

Background: The purpose of this study was to evaluate plantar fasciae of healthy subjects and patients with plantar fasciitis by shear wave velocity (SWV) and stiffness with correlation to B-Mode and color Doppler ultrasonography (CDUS) and to establish cut-off values. Methods: This observational study was conducted with the approval of the Institutional Review Boards (IRBs) of our institution. 108 unilateral plantar fasciae were evaluated by including 87 consecutive patients (mean age 51.7, range: 29–82) (66 women and 21 men) with plantar fasciitis and 21 asymptomatic age matched healthy volunteers (mean age 47.3, range: 32–58) (15 women and 6 men). All patients were prospectively imaged between July 2018 and March 2019. B-mode US was used to measure thickness and CDUS to grade vascularity. SWE measurements were repeated 3 times and mean was used for statistical analysis. Results: Mean SWV value in healthy subjects was 6.94 m/s and in patients 4.98 m/s with a mean stiffness value of 152.88 kPa and 93.54 kPa respectively (p &lt, 0.001). For SWV a cut-off value of 6.16 m/s had a specificity of 80.95% and sensitivity of 79.31%. For stiffness a cut-off value of 125.57 kPa had a specificity of 80.95% and sensitivity of 80.46%. No correlation to CDUS was found. The mean thickness of healthy fascias was 3.3 mm (range 2.4–3.9) compared to 6.1 mm (range 2.0–22.0) in plantar fasciitis (p &lt, 0.001) with no correlation to SWV or to stiffness (r² = 0.02, p = 0.06). Conclusion: SWE allows quantitative assessment of plantar fascia stiffness, which decreases in patients with plantar fasciitis. No correlation to the thickness of the plantar fascia was found, therefore it represents an independent factor for the diagnosis of plantar fasciitis and could be helpful in addition to thickness measurement in unclear cases.

Tendon injuries represent the second most common injury of the hand (after fractures) and are a common scanning indication in radiology. Pulley injuries are very frequent in rock climbers with the A2 pulley the most commonly affected. Tendon and pulley injuries can be reliably evaluated using ultrasound (US) and magnetic resonance imaging (MRI). US can be postulated as a first-line imaging modality, allowing dynamic examination. MRI is essential for cases with ongoing diagnostic doubt post-US and also for preoperative pulley reconstruction assessment.

Elbow pain can cause disability, especially in athletes, and is a common clinical complaint for both the general practitioner and the orthopaedic surgeon. Magnetic resonance imaging (MRI) is an excellent tool for the evaluation of joint pathology due to its high sensitivity as a result of high contrast resolution for soft tissues. This article aims to describe the normal imaging anatomy and biomechanics of the elbow, the most commonly used MRI protocols and techniques, and common MRI findings related to tendinopathy, ligamentous and osteochondral injuries, and instability of the elbow.

Aromatase inhibitor-induced arthralgia (AIA) comprises significant, activity-limiting musculoskeletal symptoms, including joint pain, myalgia, and joint stiffness. We conducted a prospective feasibility study in postmenopausal women diagnosed with early-stage (0–3) hormone receptor positive (HR+) breast cancer who were candidates for treatment with adjuvant AI therapy (n = 16). Tendons of the hands and wrists and the median nerve were imaged using gray-scale and power Doppler ultrasound (US) and US SWE. Arthralgia symptoms were evaluated using the Breast Cancer Prevention Trial (BCPT) Symptom Checklist musculoskeletal subscale (MS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and stiffness subscales. At baseline, there were significant differences in the SW velocities of tendons between dominant and nondominant hands. Increased velocity in 2 of 6 tendons and the median nerve was associated with greater pain at baseline, whereas slower velocity of the extensor digitorum tendon (suggesting decreased stiffness) was associated with a higher WOMAC stiffness score. Increased SW velocity (suggestive of increased stiffness) at baseline in the abductor pollicis longus tendon was associated with a worsening of all three pain and stiffness measures by 6 months. Future studies should evaluate SWE scores related to AIA outcomes in a larger sample size.

Postoperative infections of the knee are uncommon but may occur with joint arthroplasties, fracture fixation, or after arthroscopic procedures. The ultimate diagnosis is made by joint aspiration or tissue sampling. Joint aspiration and tissue sampling can be performed under imaging guidance or intraoperatively. Imaging is an important adjunct to clinical and laboratory findings and should start with radiographs. Cross-sectional imaging including magnetic resonance (MR) imaging, computed tomography (CT), nuclear studies, and ultrasound (US) are frequently used if the diagnosis is in doubt and to evaluate the extent of disease. We discuss the current algorithm in the diagnosis of various postoperative infections of the knee joint. The article addresses the utility of radiography, MR imaging, CT, US, and the most commonly used nuclear studies in the diagnosis of various postoperative knee infections and the imaging appearances of these infections on each of these diagnostic modalities.

Radiographs are indicated as the first imaging test in all patients with chronic wrist pain, regardless of the suspected diagnosis. When radiographs are normal or equivocal, advanced imaging with MRI (without or without intravenous contrast or following arthrography), CT (usually without contrast), and ultrasound each has a role in establishing a diagnosis. Furthermore, these examinations may contribute to staging disease, treatment planning, and prognostication, even when radiographs are diagnostic of a specific condition. Which examination or examinations are best depends on the specific location of pain and the clinically suspected conditions. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Gout, a crystalline arthropathy caused by the deposition of monosodium urate crystals in the articular and periarticular soft tissues, is a frequent cause of painful arthropathy. Imaging has an important role in the initial evaluation as well as the treatment and follow up of gouty arthropathy. The imaging findings of gouty arthropathy on radiography, ultrasonography, computed tomography, dual energy computed tomography, and magnetic resonance imaging are described to include findings of the early, acute and chronic phases of gout. These findings include early monosodium urate deposits, osseous erosions, and tophi, which may involve periarticular tissues, tendons, and bursae. Treatment of gout includes non-steroidal anti-inflammatories, colchicine, glucocorticoids, interleukin-1 inhibitors, xanthine oxidase inhibitors, uricosuric drugs, and recombinant uricase. Imaging is critical in monitoring response to therapy; clinical management can be modulated based on imaging findings. This review article describes the current standard of care in imaging and treatment of gouty arthropathy.

In the past 2 decades, sonoelastography has been progressively used as a tool to help evaluate soft-tissue elasticity and add to information obtained with conventional gray-scale and Doppler ultrasonographic techniques. Recently introduced on clinical scanners, shear-wave elastography (SWE) is considered to be more objective, quantitative, and reproducible than compression sonoelastography with increasing applications to the musculoskeletal system. SWE uses an acoustic radiation force pulse sequence to generate shear waves, which propagate perpendicular to the ultrasound beam, causing transient displacements. The distribution of shear-wave velocities at each pixel is directly related to the shear modulus, an absolute measure of the tissue's elastic properties. Shear-wave images are automatically coregistered with standard B-mode images to provide quantitative color elastograms with anatomic specificity. Shear waves propagate faster through stiffer contracted tissue, as well as along the long axis of tendon and muscle. SWE has a promising role in determining the severity of disease and treatment follow-up of various musculoskeletal tissues including tendons, muscles, nerves, and ligaments. This article describes the basic ultrasound physics of SWE and its applications in the evaluation of various traumatic and pathologic conditions of the musculoskeletal system.

The objective of our study was to retrospectively assess for differences in imaging appearances of Morton neuromas before and after laser therapy using diagnostic ultrasound (US).A retrospective review was performed to identify patients who underwent US imaging to evaluate for Morton neuroma during the study period (June 1, 2013-July 1, 2014); of the 42 patients identified, 21 underwent US evaluations before and after laser therapy. US reports and images were reviewed and correlated with clinical history. The final study group consisted of 21 patients who had a total of 31 Morton neuromas evaluated using US after treatment. A retrospective review was then performed to characterize the appearances of these lesions before and after therapy followed by an analysis of variables.Retrospective US review of 31 pretreatment Morton neuromas showed fusiform, heterogeneously hypoechoic masses with well-defined borders in most cases and that pain was reported when transducer pressure was applied in 97% (30/31) of cases. After treatment, lesions showed ill-defined borders (23/31), and pain with application of transducer pressure was either significantly decreased or absent (29/31); these findings were concordant with the clinical findings. Both of these characteristics were statistically significant (p0.0001). In addition, more Morton neuromas occurred in the second intermetatarsal space than in the third intermetatarsal space (p0.0001).US may be used to identify posttreatment changes after laser therapy of Morton neuromas. Posttreatment changes include ill-defined borders and less pain or the absence of pain with the application of transducer pressure. These criteria may be applied in future clinical studies evaluating the efficacy of laser therapy for Morton neuroma.

OBJECTIVE. The objective of our study was to compare ultrasound (US) tophus and monosodium urate (MSU) deposit detection and US tophus size in the metatarsophalangeal (MTP) 1 joint with dual-energy CT (DECT) using two DECT postprocessing protocols in patients presenting with podagra. SUBJECTS AND METHODS. Seventy-five consecutive patients with podagra (66 men and nine women; mean age, 65.6 years; age range, 33-88 years) and 75 control subjects with MTP 1 joint osteoarthritis (49 men and 26 women; mean age, 63.0 years; age range, 35-87 years) prospectively underwent US and DECT between 2016 and 2018 to assess the MTP 1 joint. Two Syngovia postprocessing DECT protocols with different minimum attenuation thresholds of 150 HU (DECT 150 protocol) versus 120 HU (DECT 120 protocol) and the same maximum attenuation threshold (500 HU) and constant kilovoltage setting of tubes A and B at 80 and 140 kVp were evaluated. Interobserver variability of the two DECT protocols was calculated and compared with that of US. RESULTS. The postprocessing DECT 150 protocol was positive for tophus detection in 55 of 75 patients (73.3%) with podagra, whereas the postprocessing DECT 120 protocol detected MSU deposits in all 75 patients (100%). Tophus size assessed using the DECT 120 protocol showed an improved correlation with tophus size detected on US (p < 0.01). Interobserver variability of DECT was improved when using the DECT 120 protocol (p < 0.01). CONCLUSION. The postprocessing DECT 120 protocol enables improved visualization of MSU deposits and provides more accurate information about tophus size that better correlates with tophus size on US compared with the standard postprocessing DECT 150 protocol.

Purpose Our hypothesis in this study is that the radial and ulnar collateral ligaments of the wrist exist and are true ligaments which can be visualized by high-resolution ultrasonography (US). Methods High-resolution US examination of the radial and ulnar collateral ligaments of the wrist was performed on 56 fresh cadaveric wrists. The visibility of these ligaments was assessed by four observers who classified the ligaments in consensus as well seen, adequately seen, or not seen. Surgical dissections of 12 radial collateral ligaments and 12 ulnar collateral ligaments were then performed and the ligaments were classified as present or absent. The US and dissection results were then compared. To confirm that the dissected structures represent true ligaments a histologic examination of the ligaments was performed. Results All examined radial and ulnar collateral ligaments were seen on the US examination. The radial collateral ligament was seen between the radial styloid and radial aspect of the scaphoid. The ulnar collateral ligament was seen between ulnar styloid process and the triquetrum. On all surgical dissections, the radial collateral ligament was present at the floor of the first extensor compartment and the ulnar collateral ligament was at the floor of the sixth extensor compartment. Both ligaments were proven to be true capsular ligaments on both dissection and histologic examinations. Conclusion The radial and ulnar collateral ligaments of the wrist are true ligaments and can be seen at the floor of the first and the sixth extensor compartments, respectively, using high-resolution US. Based on their anatomic location, they most likely provide static stability to the wrist joint.

Chapter 12 discusses glenohumeral joint trauma. The shoulder is one of the most frequently dislocated joints in the body. The glenohumeral joint is ball and socket articulation between the humeral head and scapular glenoid. The humeral head is significantly larger than the glenoid fossa, which predisposes this joint to instability. Anterior shoulder dislocations are more common than those occurring posteriorly, and true inferior dislocations are rare. Bone injuries associated with anterior glenohumeral joint dislocations are the bony Bankart and Hill-Sachs lesions. The diagnosis of dislocation is made on radiographs. CT examination is useful in the evaluation of associated bone lesions and glenoid bone loss. Magnetic resonance arthrography (MRA) is the study of choice in the evaluation of associated glenolabral and rotator cuff injuries. Initial treatment is closed reduction with immobilization and subsequent physical therapy. Surgical treatment is indicated for complicated dislocations with instability.

Chapter 10 reviews acromioclavicular joint trauma. The acromioclavicular (AC) joint represents the articulation between the acromion process and lateral clavicle and is a synovial joint stabilized by 3 ligaments. AC joint injuries are most common in active/athletic young adults. The most common injury is AC joint dislocation sustained during contact sports. This injury usually happens from a fall on an outstretched arm. The degree of separation can be evaluated by radiography and, if needed, CT and MRI. The injury is divided into 6 types by the Rockwood classification based on degree of separation of the acromion from the clavicle.

Chapter 8 discusses clavicle fractures. Clavicle fractures are common and are usually displaced. The frequent rate of injury to the clavicle at various age groups is likely because of early ossification and its superficial anatomical location. Causes of injury include direct impact because of direct fall or blow to the shoulder. Injury from indirect trauma is less common and usually is because of a fall on an outstretched arm. The midshaft of the clavicle is the most common site of fractures. Radiographs are the mainstay of diagnosis, whereas CT examination and MRI can aid in complex or pathologic fractures. Fractures of the clavicle often heal with prominent initial callus formation and subsequent remodeling.

Chapter 6 on rib trauma reviews the mechanism of injury and clinical features, imaging strategy, imaging characteristics, and treatment of rib fractures. Blunt chest trauma is a common cause of rib injury. This injury can vary in severity and cause respiratory compromise. Ribs usually fracture at the point of impact or posteriorly, where their anatomy renders them structurally weakest. Most rib fractures are stable and are treated conservatively. Flail chest occurs when 3 or more contiguous ribs are fractured in 2 or more places, separating a segment that is free-floating and moves independently, and which may be associated with life-threatening situations.

Chapter 7 provides an overall look at sternum fracture. The sternum is a flat bone at the anterior center of the chest, which protects the mediastinum. The sternum along with the ribs and vertebrae form the thoracic cage, which protects the thoracic organs and vessels. Fractures are usually associated with direct blunt trauma which most commonly occurs during motor vehicle accidents or from vigorous cardiopulmonary resuscitation. Significant mortality may be associated with displaced sternal fractures because of aortic, cardiac, or pulmonary injury. CT examination has surpassed radiographs in the assessment of sternal fractures and adds identification of secondary findings. It has superior sensitivity to radiography and is valuable in diagnosing serious associated injuries.

Chapter 17 discusses hand trauma. Metacarpal and phalangeal fractures are common, as are dislocations of the interphalangeal and metacarpophalangeal joints. These injuries may be related to sports or work trauma or result from a fall. Osseous injuries are frequently associated with ligamentous or tendon injury. Most hand injuries are stable and can be treated with closed reduction and immobilization. Significantly displaced fractures and those with substantial intraarticular extension often require operative repair including Kirschner-wire stabilization or open reduction and internal fixation. Generally, the treatment option that achieves the desired reduction and degree of fixation, allows early motion, and minimizes soft-tissue injury should be preferred.