Maribel Miguel-Pérez

Musculoskeletal ultrasound (MSUS) is a well-established and reliable tool for the evaluation of entheses and enthesitis, particularly at larger and accessible sites. Recent technological advances, including high- and ultra-high-frequency transducers, have expanded its potential, enabling detailed assessment of distal extremity entheses. This narrative review provides a focused and updated perspective on this evolving field, highlighting three key advances. First, the identification and characterization of previously underrecognized entheseal sites in the distal extremities, such as pulley systems, retinacula, novel tendon insertions, and collateral ligaments, broadening the morphological spectrum of entheseal imaging. This is complemented by improved evaluation of vascularization through microvascular imaging and contrast-enhanced US (CEUS). Second, the emergence of interventional approaches, particularly US-guided entheseal biopsy, offers a novel means to investigate entheseal tissue in vivo and may establish a link between imaging and histopathology. Third, the integration of advanced functional imaging modalities, including elastography and multispectral optoacoustic tomography (MSOT), provides preliminary additional insights into the biomechanical and molecular properties of the enthesis beyond conventional structural assessment. Collectively, these developments support new investigational perspectives, positioning MSUS as a dynamic and integrative modality capable of exploring new anatomical territories and biological dimensions, with the potential to reshape the understanding and evaluation of entheseal involvement in rheumatology.

Background/objective: The palmaris longus muscle is a variable and often inconsistent muscle in the anterior compartment of the forearm. This fusiform-shaped muscle originates at the medial epicondyle of the humerus bone following a long and narrow tendon that inserts at the palmar aponeurosis. That tendon is used in reconstructive surgery, and for this reason, detailed information from an ultrasound is used to detect the tendon and the possible variations in the muscle. The present study aimed to investigate the palmaris longus muscle and its variations through ultrasound, anatomical, and histological analysis with clinical and surgical applications. Methods: A total of 72 upper limbs from 33 females and 39 males, 32 right and 40 left, were evaluated in ultrasound, anatomical, and histological studies. The main objective was to prove the existence of the palmaris longus muscle and its variations, as well as to measure the tendon for surgical applications. Results: Ultrasound analysis showed that it is possible to determine the existence of the muscle (76.4%) and its variations (23.6%), as well as its absence (15.3%). The anatomical results proved the ultrasound results. The width of the tendon was between 0.4 and 0.38 mm. by ultrasound and anatomical analysis. Also, normal palmaris longus tendons were not a direct cause of compression of the median nerve. Conclusions: It is important to confirm the existence and possible variations in the palmaris longus muscle and tendon through ultrasound before surgical reconstruction and for clinical diagnostics.

Background: Arterial variations in the upper limb, although infrequent, carry critical clinical implications. The presence of superficial ulnar and radial arteries, especially when originating from high levels, increases the risk of iatrogenic injury, misdiagnosis, and surgical complications. To confirm and describe, through ultrasound and anatomical dissection, the presence of a high-origin superficial ulnar artery and a superficial radial artery in a cadaver, highlighting their anatomical trajectory and clinical relevance. Methods: A cross-sectional ultrasound and anatomical study was conducted on 150 upper limbs from fresh-frozen cadavers. High-frequency ultrasound was used to scan the vasculature from the axilla to the wrist. Subsequently, dissection was performed to confirm sonographic findings. Results: One case (0.66%) of concurrent superficial ulnar artery and superficial radial artery was identified in the left arm of a 79-year-old male cadaver. The superficial ulnar artery originated from the axillary artery and coursed superficially along the forearm, anterior to the flexor muscles. The superficial radial artery emerged from the brachial artery and ran subcutaneously in the distal forearm. These arteries remained in close relation to key neural and venous structures, increasing their vulnerability to clinical error. Conclusions: The identification of high-origin superficial arteries is essential for clinical practice. Ultrasound serves as a reliable, non-invasive method for detecting such variations preoperatively. Awareness of these anomalies can prevent inadvertent vascular injuries, improve diagnostic accuracy, and inform safer surgical and anesthetic approaches in upper limb interventions.

Background: Suprascapular neuropathy is a known cause of shoulder pain. Although neurodynamic techniques are widely used to treat peripheral neuropathies, the mechanical behavior of the suprascapular nerve in the shoulder region remains poorly understood. Objectives: This study aimed to analyze the mechanical behavior of the suprascapular nerve during a contralateral cervical glide and an infraspinatus muscle contraction. Methods: The study was conducted in two phases. First, nerve movement was analyzed in 12 cryopreserved cadaveric shoulders using anatomical dissection. Second, suprascapular nerve displacement was assessed in 34 shoulders from 17 healthy volunteers using ultrasound imaging. Results: In cadaveric dissections, the contralateral cervical glide produced a proximal nerve displacement of 1.85 mm at the suprascapular notch. In the ultrasound study, this maneuver resulted in horizontal and vertical displacements of 1.18 mm and 0.39 mm, respectively. In contrast, infraspinatus muscle contraction caused a distal displacement of 3.21 mm in the cadaveric study, and ultrasound imaging showed horizontal and vertical displacements of 1.34 mm and 0.75 mm, respectively. All reported displacements were statistically significant (p < 0.05). Conclusions: The findings of both phases of the study contribute to a better understanding of suprascapular nerve biomechanics and may inform clinical neurodynamic interventions.

Objectives: This study aimed to examine the differences in shoulder ultrasonographic parameters between overhead aquatic athletes and their relationship with shoulder pain. Methods: Sixty-four healthy junior subjects (n = 128 shoulders) participated in the study, including 17 healthy controls, 25 elite junior swimmers, and 22 elite junior water polo players. An ultrasonographic study of the shoulder was carried out to measure the thickness of the rotator cuff structures in sex- and age-paired groups. Results: Compared to controls, female and male swimmers and water polo players had thicker values in the rotator cuff tendons, including the subscapularis (SSB) (p < 0.001), supraspinatus (p < 0.001), infraspinatus (p < 0.001) and teres minor (Tm) (p < 0.025). The female swimmers had thicker values than the water polo players in the SSB (p < 0.001) and Tm (p < 0.011). In the comparison by sexes, the female controls had a thinner LHBB, SSB and Tm (p < 0.019), the female swimmers had a thinner ISP (p = 0.001), and the female water polo players had a thinner LHBB, SSB, ISP and acromiohumeral distance than their group-paired counterparts (p < 0.018). Finally, the females had a lower incidence of positive Jobe test results compared to the males (p = 0.018), which was associated with lower pain scores at rest (p < 0.034) and during training (p < 0.036). Conclusions: The rotator cuff tendon structures were larger in the healthy overhead aquatic athletes compared to the age- and sex-paired controls. The females had smaller values in the shoulder ultrasonographic tendon parameters compared to the age- and sport-paired males, except for the supraspinatus tendon.

Background: Injuries of the proximal attachment of the hamstring muscles are common. The present study aimed to investigate the relationship of the proximal attachment of the hamstring muscles with neighboring structures comprehensively. Methods: A total of 97 hemipelvis from 66 cryopreserved specimens were evaluated via ultrasound, anatomical and histological samples. Results: The proximal attachment of the hamstring muscles presents a hyperechogenic line surrounding the origin of the semimembranosus and the long head of the biceps femoris muscles, as well as another hyperechogenic line covering the sciatic nerve. The anatomical and histological study confirms the ultrasound results and shows different layers forming the sacrotuberous ligament. Furthermore, it shows that the proximal attachment of the semimembranosus muscle has a more proximal origin than the rest of the hamstring muscles. Moreover, this muscle shares fibers with the long head of the biceps femoris muscle and expands to the adductor magnus muscle. The histological analysis also shows the dense connective tissue of the retinaculum covering the long head of the biceps femoris and semimembranosus muscles, as well as the expansion covering the sciatic nerve. Conclusions: These anatomical relationships could explain injuries at the origin of the hamstring muscles.

The semimembranosus muscle inserts into several tendons that are associated with some pathologies. Although ultrasound is useful for studying, diagnosing, and managing these pathologies, the correct interpretation of any images requires a clear knowledge of the related anatomical structures and the inter-related functions. We studied 38 cryopreserved non-paired knees from adult anatomical specimens and 4 non-paired knees from 29 to 38-week-old fetuses. The semimembranosus muscle and its tendons were located, observed, and injected under ultrasound guidance. The macroscopic anatomy was studied using dissection and anatomical cuts and the tendons were analyzed histologically. Measurements of muscle were taken 10 cm from the medial epicondyle and just before the tendon divided. The ultrasound facilitated the identification of the different divisions of the tendon of semimembranosus muscle and the rotation of the muscle and tendon from medial to posterior. An anatomical study confirmed this rotation and revealed an average width, thickness, and diameter of 38.29 mm, 14.36 mm, and 112.64 mm, respectively. Important relationships were observed between the divisions of the main tendons and the medial collateral ligament, the posterior side of the knee and popliteus muscle. This information can help to explain knee pathologies and facilitate rehabilitation after surgery.

This study aimed to describe the shoulder anatomy, together with the anatomical relationships in adults and early stages of development. The shoulder muscles were studied from ultrasound, anatomical, and microscopic perspectives in a sample of 34 human shoulders. Thickness measurements were taken of the tendons and fasciae of the subscapularis, long head tendon of the biceps brachii, supraspinatus, infraspinatus, and teres minor. Ultrasound and dissection techniques are strongly correlated. However, the measurements obtained from the dissection technique were superior to those obtained from the ultrasound in all cases, except for the thickness of the long head tendon of the biceps brachii, the teres minor tendon, and the fascia thickness of the infraspinatus. In addition, the study of shoulder anatomy revealed no differences between females and males. Relevant findings from dissection included a clear overlap between the infraspinatus and supraspinatus, which shared tendon fibers, and a similar connection between the transverse ligament of the long head tendon of the biceps brachii and the subscapularis, which created a more interconnected shoulder function. The study of the anatomical measurements shows an underestimation of the shoulder measurements in the ultrasound compared with the dissection technique, but a high correlation between the measurements made by the two techniques. We present reference values for the tendon and fascia thicknesses of the rotator cuff, with no differences observed by gender. The relationships between shoulder structures described in the anatomical study imply as well that, in the event of an injury, adjacent tissues may be affected. This extended information may facilitate future optimal clinical explorations.

Adhesive capsulitis is an idiopathic and disabling disorder characterized by intense shoulder pain and progressive limitation of active and passive glenohumeral joint range of motion. Although adhesive capsulitis has been traditionally considered a diagnosis of exclusion that can be established based on a suggestive medical history and the detection of supporting findings at the physical exam, imaging studies are commonly requested to confirm the diagnostic suspicion and to exclude other causes of shoulder pain. Indeed, clinical findings may be rather unspecific, and may overlap with diseases like calcific tendinitis, rotator cuff pathology, acromioclavicular or glenohumeral arthropathy, autoimmune disorders, and subacromial/subdeltoid bursitis. Magnetic resonance imaging, magnetic resonance arthrography, and high-resolution ultrasound have shown high sensitivity and accuracy in diagnosing adhesive capsulitis through the demonstration of specific pathological findings, including thickening of the joint capsule and of the coracohumeral ligament, fibrosis of the subcoracoid fat triangle, and extravasation of gadolinium outside the joint recesses. This narrative review provides an updated analysis of the current concepts on the role of imaging modalities in patients with adhesive capsulitis, with the final aim of proposing an evidence-based imaging protocol for the radiological evaluation of this condition.

Purpose: Compartment syndrome is a surgical emergency that can occur in any part of the body and can cause cell necrosis when maintained over time. The resulting defects can affect the nerves, muscle cells, bone tissue, and other connective tissues inside the compartment, and fasciotomy has to be performed. The anatomical and histological characteristics of the leg make acute, chronic, and exertional compartment syndrome more likely in this limb. For these reasons, knowledge of the ultrasound, anatomical, and histological features of the crural fascia can help in the treatment of leg compartment syndrome. Methods: Twenty-one cryopreserved lower limbs from adult cadavers and from one 29-week-old fetus were obtained from the dissection room. They were examined by ultrasound and a subsequent anatomical dissection and microscopy to study the crural fascia and its relationship with the different muscles. Anthropometric measurements were taken of the distances from the head of the fibula and lateral malleolus to the origin of the tibialis anterior muscle in the crural fascia, the exit of the superficial fibular nerve, and the fascia covering the deep posterior muscles of the leg. Results: The crural fascia has very important clinical relationships, which can be identified by ultrasound, as the origin of the tibialis anterior muscle at 16.25 cm from the head of the fibula and the exit of the superficial fibular nerve that crosses this fascia at 21.25 cm from the head of the fibula. Furthermore, the presence of a septum that fixes the deep posterior muscles of the leg and the vessels and nerve can be seen by ultrasound and can explain the possible development of a posterior compartmental syndrome of the leg. Awareness of these features will help to keep these structures safe during the surgical treatment of compartment syndrome. Conclusion: The ultrasound study allows identification of anatomical structures in the leg and, thus, avoids damage to them during surgery for compartmental syndromes.