The diagnosis of nerve entrapment at osteofibrous tunnels relies primarily on clinical and electrodiagnostic findings. Recently, the refinement of high-frequency broadband transducers with a range of 5-15 MHz, sophisticated focusing in the near field, and sensitive color and power Doppler technology have improved the ability to evaluate peripheral nerve entrapment in osteofibrous tunnels with ultrasonography (US). In the upper limb, osteofibrous tunnels amenable to US examination include the carpal tunnel for the median nerve and the cubital and Guyon tunnels for the ulnar nerve. In the lower limb, these tunnels include the fibular neck for the common peroneal nerve, the tarsal tunnel for the posterior tibial nerve, and the intermetatarsal spaces for the interdigital nerves. High-resolution US allows direct imaging of the involved nerves, as well as documentation of changes in nerve shape and echotexture that occur in compressive syndromes. A spectrum of extrinsic causes of entrapment, such as tenosynovitis, ganglia, soft-tissue tumors, bone and joint abnormalities, and anomalous muscles, can also be diagnosed with US. With continued experience, it is likely that this technique will be increasingly used to evaluate nerve entrapment syndromes.

The progressive refinement of broadband transducers with frequencies higher than 10 MHz and improved near-field resolution has enhanced the potential of sonography to evaluate a variety of nerve entrapment syndromes occurring in the upper limb, such as suprascapular neuropathy in the area of the spinoglenoid-supraspinous notch, the quadrilateral space syndrome (axillary neuropathy), radial neuropathy in the area of the spiral groove, the supinator syndrome (posterior interosseous neuropathy), the cubital tunnel syndrome (ulnar neuropathy), and the Kiloh-Nevin syndrome (anterior interosseous neuropathy). In these settings, high-resolution sonography can depict changes in the nerve's shape and echotexture and can depict many extrinsic causes of nerve entrapment.

Tendons and nerves represent probably one of the best application of musculoskeletal US due to the high lesion detection rate and accuracy of US combined with its low cost, wide availability, and ease of use. The refinement of high-frequency broadband linear-array transducers, and sensitive color and power Doppler technology, have improved the ability of US to detect fine textural abnormalities of these structures as well as to identify a variety of pathological conditions. Characteristic echotextural patterns, closely resembling the histological ones, are typically depicted in these structures using high US frequencies. In tendon imaging, US can assess dislocations, degenerative changes and tendon tears, including intrasubstance tears, longitudinal splits, partial and complete rupture, inflammatory conditions and tendon tumors, as well as postoperative findings. In nerve imaging, US can support clinical and electrophysiological testing for detection of compressing lesions caused by nerve entrapment in a variety of osteofibrous tunnels of the limbs and extremities. Congenital anomalies, nerve tears, and neurogenic tumors can also be diagnosed. Overall, US is an effective technique for imaging tendons and nerves. In most cases, a focused US examination can be performed more rapidly and efficiently than MR imaging.

Objective. To compare magnetic resonance imaging (MRI), conventional radiography, and ultrasonography in identifying bone erosions in patients with juvenile idiopathic arthritis (JIA), and to determine the validity and reliability of an MRI scale in detecting and grading joint damage. Methods. In 26 JIA patients, the clinically more affected wrist was studied with MRI, radiography, and ultrasonography, coupled with standard clinical assessment and biochemical analysis. MR images were assessed independently by 2 readers according to an apposite devised scoring system. Results. Of 26 patients, 25 (96.1%) had 1 or more erosions as detected by MRI, whereas conventional radiography and ultrasonography revealed erosions in 13 (50%) of 26 and 12 (50%) of 24 patients, respectively. The ability of MRI to detect erosive changes was significantly higher with respect to conventional radiography (P ‫؍‬ 0.002 with Bonferroni correction [P B ]) and ultrasonography (P B ‫؍‬ 0.0002) in the group of patients with <3 years' disease duration. Ultrasonography and conventional radiography were of equivalent value for the detection of destructive changes. Wrist MRI score correlated highly with radiographic erosion score (r s ‫؍‬ 0.82) and with wrist limited range of motion score (r s ‫؍‬ 0.69). The interreader intraclass correlation coefficient (ICC) for MRI score was excellent (0.97); intrareader ICCs were good for both investigators (0.97 and 0.79). Conclusion. MRI seems to be a powerful tool to detect early structural damage in JIA. The proposed MRI scale for bone erosions appears promising in terms of reliability and construct validity. The pathophysiologic meaning and the prognostic value of bone erosions revealed only by MRI remain to be established in longitudinal studies.

The most common indication for shoulder ultrasonography (US) is the diagnosis of rotator cuff disease. However, there is a spectrum of non-rotator cuff abnormalities that are amenable to US examination, including instability of the biceps tendon, glenohumeral joint, and acromioclavicular joint; arthropathies and bursites (inflammatory diseases, degenerative and infiltrative disorders, infections); nerve entrapment syndromes; and space-occupying lesions. Many of these conditions may be overlooked clinically or can even mimic rotator cuff tears, and US can help redirect the diagnosis if a complete shoulder examination rather than a simple rotator cuff assessment is performed. In addition, US can be remarkably helpful in guiding either needle aspiration procedures or local injection therapy in patients with synovial processes. Although radiography, magnetic resonance (MR) imaging, and computed tomographic and MR arthrography are effective modalities for the evaluation of non-rotator cuff disorders, US is both less costly and less invasive and will likely be used more frequently in this setting as experience increases. Once adequate radiographs have been obtained to exclude apparent bone disorders, high-resolution US should be the first-line imaging modality in the assessment of non-rotator cuff disorders of the shoulder, assuming the study is performed with high-end equipment by an experienced examiner.

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Poland syndrome (PS) has been described as unilateral pectoral muscle deficiency variably associated with ipsilateral thoracic and upper limb anomalies. Bilateral hypoplasia/aplasia of the pectoralis muscle and upper limb defects in association with variable thoracic muscles, chest wall deformities and lower limb defects have been infrequently reported in the literature. We report on a 3(1/2)-year-old girl with clinical features consisting in bilateral asymmetric pectoral muscle defects (complete agenesis on the left side and agenesis of the sternocostal head on the right side), nipple hypoplasia, left rib defect, and right hand symbrachydactyly. In this study, we reviewed the bilateral features present in our patient and those described in the literature. Hypotheses explaining bilateral features in PS are reviewed.

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