Wrist

Ultrasound of the Hook of Hamate Region: Pictorial Review

The hook of hamate is a complex anatomical region with many small but important structures. A sound knowledge of anatomy along with a systematic ultrasound technique can help delineate a variety of disorders. In this pictorial review, we discuss the ultrasound anatomy and the possible pathologies that can be encountered in this region.

Ultrasound Imaging of Cutaneous Innervations of the Lower Extremity

Ultrasound (US) is commonly used to evaluate the cutaneous innervation of the lower extremity, owing to the following advantages: (1) US is a high-resolution soft tissue imaging modality; (2) it is feasible in patients who are deemed unsuitable to undergo magnetic resonance imaging; and (3) it enables dynamic and real-time imaging. The evaluation of cutaneous nerves requires accurate knowledge of the anatomy as well as technical details. We present a review of the US anatomy of the cutaneous nerves in the lower extremity in addition to a description of a few pathologic conditions.

Ultrasound of the ulnar-palmar region of the wrist: normal anatomy and anatomic variations

Ultrasound (US) assessment of the wrist is frequently used for the evaluation of carpal tunnel due to high frequency of local compression of the median nerve (MN), but the ulnar-palmar wrist region (UPWR) has received limited attention in the medical literature. The possibilities of US in the assessment of UPWR are therefore likely underestimated by sonologists. This review article is focused on the US assessment of the normal anatomy and anatomic variations of the UPWR. The anatomy of this region of the wrist is complex and less studied than the radial side. In an effort to simplify it and to present it didactically, we have divided this region in three parts on the basis of osseous landmarks. Our review indicates sonography is effective in identifying the UPWR and related disorders, and is thus a valuable tool for ensuring appropriate management of a variety of disorders.

Ankle and Foot Ultrasound: Reliability of Side-to-Side Comparison of Small Anatomic Structures

OBJECTIVES

In sonography of clinically relevant small structures of the ankle and foot, the healthy contralateral side can be used as a reference to identify subtle abnormalities. Intrasubject side-to-side variability must be minimal. The aim of this study was to assess the reliability of side-to-side sonographic evaluation of small structures of the ankle and foot.

METHODS

Thirty healthy volunteers were prospectively studied. Small structures of the ankle and foot were evaluated bilaterally by 2 musculoskeletal radiologists in separate sessions. The deep peroneal nerve, superior extensor retinacula, calcaneofibular ligament, superior peroneal retinacula, tibialis posterior tendon, tibial nerve, Achilles tendon, plantaris tendon, plantar fascia, and sural nerve were considered. To assess intra- and interreader agreements, 30 (100%) examinations were repeated. A nonparametric statistic was used.

RESULTS

Data were not normally distributed (P > .001). Intrareader agreement was k = 0.67 (95% confidence interval, 0.57-0.78) and interreader agreement was k = 0.73 (95% confidence interval, 0.68-0.77). The mean values and standard deviation for all the structures were 0.36 ± 1.85 mm. The overall coefficient of variation was 18.5%. The intraclass correlation coefficient was 0.93 (95% confidence interval, 0.92-0.94).

CONCLUSIONS

In ankle and foot sonography, the healthy contralateral side can be used as a reference during a real-time musculoskeletal ultrasound evaluation of small structures.

Clinical Contribution of Wrist and Hand Sonography: Pilot Study

OBJECTIVES

The purpose of this study was to evaluate the clinical contribution of wrist and hand sonography.

METHODS

This study was performed in a tertiary academic medical center. Institutional review board approval was obtained. Data collection was done retrospectively from January 2012 to December 2016 and prospectively from January 2017 to July 2017. The study included 112 consecutive patients (52 men and 60 women; mean age, 47 ± 16 years; range, 15-87 years). A total of 126 examinations were performed. All ultrasound examinations were done with high-resolution probes with up-to-date protocols. The clinical contribution of wrist and hand sonography was assessed (ultrasound examinations contributive/noncontributive). Descriptive statistic and nonparametric tests were used.

RESULTS

In 96 of 126 (76%) examinations, sonography proved to be contributive, and in 30 of 126 (24%) examinations, sonography proved to be noncontributive. The contributive/noncontributive ratio was 3.2 (96/30). A total of 51 of 126 (40%) examinations were performed in patients with a history of previous trauma. Sonography proved to be significantly more contributive in a posttraumatic setting (chi-square, 9.2; P = .0023).

CONCLUSION

Wrist and hand sonography significantly influences the diagnostic and therapeutic path, especially in a posttraumatic setting.

Wrist and Hand Ultrasound: Reliability of Side-to-Side Comparisons of Very Small (<2-mm) Clinically Relevant Anatomic Structures

OBJECTIVES

In ultrasound (US) examinations of clinically relevant very small structures of the wrist and hand, the healthy contralateral side can be used as a reference to identify subtle abnormalities. Intraindividual side-to-side variability must be minimal. The aim of this study was to assess the reliability of side-to-side US evaluations of very small structures of the wrist and hand.

METHODS

Forty-one healthy volunteers were prospectively studied. Small structures of the wrist and hand were evaluated bilaterally by 2 musculoskeletal radiologists in separate sessions. The first annular pulleys of the second finger and the thumb, sagittal band of the third finger, extensor and flexor retinacula, ulnar collateral ligament of the thumb, radial collateral ligament of the second finger, and palmar cutaneous branches of the median and ulnar nerves were considered. To assess intra- and inter-reader agreement, 10 of 41 (24%) examinations were repeated. Nonparametric statistics were used.

RESULTS

Data were not normally distributed (P > .001). Intra-reader agreement was κ = 0.674 (95% confidence interval [CI], 0.57-0.78), and inter-reader agreement was κ = 0.935 (95% CI, 0.92-0.95). The mean value ± SD for all of the structures was 0.78 ± 0.44 mm. The overall coefficient of variation was 9.8% ± 0.07%. The intraclass correlation coefficient was 0.97 (95% CI, 0.96-0.98).

CONCLUSIONS

In clinical practice, the healthy contralateral side can be used as a reference during a real-time musculoskeletal US evaluation of small (<2-mm) structures.

Ultrasound versus MRI in common fibular neuropathy

INTRODUCTION

We prospectively compared ultrasound (US) and MRI in patients with common fibular neuropathy.

METHODS

Forty adult patients with clinical suspicion of common fibular neuropathy and 40 healthy controls underwent both US and MRI. US and MRI datasets were randomized for prospective reading.

RESULTS

The overall sensitivity of US and MRI for diagnosing fibular neuropathy was 90% (95% confidence interval [CI], 79.7%-97.3%) and 87.5% (95% CI, 71.55%-93.1%), respectively. The overall specificity of US and MRI was 92% (95% CI, 77.45%-96.1%) and 85% (95% CI, 73.3%-94.4%), respectively. The overall sensitivity and specificity of US combined with MRI were 94% (95% CI, 0.80%-0.99%) and 84% (95% CI, 0.70%-0.91%), respectively. Overall intra- and inter-observer agreements among 3 readers were 0.76% (95% CI, 0.62%-0.85%) and 0.74% (95% CI, 0.65%-0.81%).

CONCLUSIONS

US diagnostic accuracy for common fibular neuropathy was slightly higher than that of MRI. Muscle Nerve 55: 849-857, 2017.

Normal Sonographic Anatomy of the Wrist With Emphasis on Assessment of Tendons, Nerves, and Ligaments

Sonography allows for rapid, cost-effective, noninvasive, and dynamic evaluation of soft tissue structures, thus representing a valuable tool for ruling out musculoskeletal disorders of the wrist. Because of the complexity of the wrist joint, sonographic training and familiarity with normal and variant anatomy are needed to avoid misdiagnosis and improper treatment. The aim of this article is to enlighten readers about the structures representing normal findings or common variants during sonographic evaluations of the wrist. The main text reviews the pertinent gross anatomy and procedures that are recommended to assess the soft tissue structures of the wrist, with particular emphasis given to tendons, nerves, and ligaments. Detailed explanations of the scanning techniques and sonographic appearance of the wrist structures are provided in the figure legends.

Use of contrast-enhanced sonography to investigate intraneural vascularity in a cohort of Macaca fascicularis with suspected median mononeuropathy

OBJECTIVES

The purpose of this study was to provide clinical evidence of the use of contrast-enhanced sonography in detecting and quantifying changes in intraneural vascularity due to median mononeuropathy.

METHODS

Five Macaca fascicularis monkeys were exposed to 20 weeks of repetitive work to increase their risk of developing median mononeuropathy. Contrast-enhanced sonograms were obtained in 30-second increments for 7 minutes while a contrast agent was being delivered. Data were collected immediately at the conclusion of the 20-week work exposure and then again during a recovery phase approximately 3 months after the completion of work. Quantitative analysis and trend graphs were used to analyze median nerve perfusion intensity. This study also compared the use of both manual counting of pixels and semiautomatic measurement using specialized software.

RESULTS

Based on the average data, maximum intensity values were identified as the best indicators of nerve hyperemia. Paired t tests demonstrated significantly higher maximum intensities in the working stage for 4 of the 5 subjects (P < .01).

CONCLUSIONS

This study provides preliminary evidence that (1) in a controlled exposure model, a change in intraneural vascularity of the median nerve between working and recovery can be observed; (2) this vascular change can be measured using an objective technique that quantifies the intensity of vascularity; and (3) contrast-enhanced sonography may improve the ability to reliably capture and measure low-flow microvascularity.

Ultrasound case report of a palmar lipoma causing carpal tunnel syndrome

Ultrasound as an imaging technique is well established for the assessment of patients presenting with a palpable lump. Lipomata of the hand are relatively rare and are rarely the cause of neuropathy. Previous case reports of these rare types of lipomata have primarily involved imaging with magnetic resonance imaging in order to provide diagnostic information. This case report of a deep-seated lipoma of the flexor digitorum superficialis tendon sheath causing carpal tunnel syndrome and trigger wrist demonstrates that ultrasound can play a key role in the diagnosis and can provide vital diagnostic information for ongoing management and surgical resection without the need for further imaging.

Utilization of Sonography Compared With Magnetic Resonance Imaging in Determining the Cross-Sectional Area of the Median Nerve in a Sample of Working Macaca fascicularis

A preclinical study of 15 Macaca fascicularis monkeys was conducted to determine (1) the ability of detecting median mononeuropathy (MMN) within the median nerve after a work intervention and (2) the relationship between the layers of the median nerve during an acute inflammatory process by using sonography in conjunction with magnetic resonance imaging (MRI). Cross-sectional areas (CSAs) were imaged using MRI and sonography proximal to the carpal tunnel inlet (defined by the most distal portion of the radius) and further distal into the carpal tunnel (defined by the most proximal portion of the pisiform) at the prework exposure stage. CSAs measured on the outer edge of the median nerve were obtained from both modalities, at both anatomical locations. An intermodality t test demonstrated no statistical differences between the two sets of measurements (radius, P ≤ .15; pisiform, P ≤ .46). At the postwork exposure stage, sonographic measurements were obtained on the outer and inner borders of the median nerve at both anatomical levels. A two-tailed t test showed statistically significant differences within the carpal tunnel comparing pre- and postwork CSA measurements (radius, P ≤ .01; pisiform, P ≤ .297). The epineurial layer area was then determined as the difference between outer-border and inner-border CSAs. Pearson correlations between the epineurial layer and overall median nerve CSA within the carpal tunnel demonstrated a strong positive correlation that was statistically significant ( r = 0.97; P ≤ .01) after postwork exposure. Possible factors contributing to this acute phase of MMN could be hyperemia within the layers of the nerve and the development of Renault bodies. This work would need to be translated to human studies for further confirmation of the anatomic and clinical significance of this effect.

Sonographic Representation of Bifid Median Nerve and Persistent Median Artery

Bifid median nerve and persistent median arteries are natural anatomic variants that exist in a small percentage of the population. This case describes a young woman who was referred for electrodiagnostic (EDX) testing of her right upper extremity because of a one-year history of numbness, tingling, and discomfort in her right upper extremity consistent with carpal tunnel syndrome. Careful sonographic scanning (gray scale and power Doppler) and dynamic investigation revealed a bifid median nerve and associated persistent median artery (PMA). The awareness of a bifid median nerve and PMA is important when evaluating patients sonographically for diagnosis of upper extremity pathology, including enlargement due to carpal tunnel syndrome. Furthermore, as musculoskeletal sonography increases in clinical practice, it is important to raise awareness of this dual anatomic variant to ensure that appropriate evaluation and treatment are provided. The sonographic presentation of anatomic variations in this case along with a review of these anomalies is provided for translational clinical use.