Search

Objective: To demonstrate the anatomy of the extensor retinaculum (ER) of the wrist using gross anatomical correlation with magnetic resonance (MR) imaging before and after ultrasound-guided tenography in four different positions, emphasizing the morphological appearance of the ER that occurs with dorsiflexion of the wrist to define the nature of extensor tendon impingement in athletes who perform repetitive wrist dorsiflexion., Materials and Methods: Institutional policies were followed regarding cadaver use. Ten upper extremities were harvested from fresh cadavers. MR imaging before and after ultrasound-guided tenography of the wrist was performed, followed by gross anatomical correlation. Two radiologists interpreted the MR images and sections by consensus for the anatomical landmarks of the ER, and morphological changes occurring during dorsiflexion of the wrist were analyzed and measured., Results: The ER of the wrist appeared as a band of low signal intensity on T1- and PD-weighted images. Because of its orientation, axial images were best suited to depict the ER anatomy; specifically, localization of the bony landmarks and the septal attachments. On sagittal images, a consistent appearance of the ER was seen: appearing with fusiform morphology in the neutral position, and becoming shortened and thickened at the abutment point where the extensor tendons of the fourth compartment had a curved excursion during dorsiflexion. The width and thickness of the ER in neutral position averaged 13.56 mm and 1.67 mm respectively. In wrist dorsiflexion, the average width and thickness changed to 8.68 mm and 2.15 mm respectively., Conclusion: Magnetic resonance imaging is a useful technique to demonstrate the ER of the wrist, the septal attachments, and morphological changes that occur during dorsiflexion of the wrist, which potentially can lead to impingement of the extensor tendons.

The anatomy of the peroneus longus and tibialis posterior tendons is well described in literature from both anatomy and radiology. Though a slip connecting these two structures is described in the anatomic literature, its existence has not been confirmed with magnetic resonance imaging (MRI). In this study in a cadaver, such a connection is documented using high-resolution MRI with anatomic and histologic correlation. This connection can provide support to the Lisfranc joint complex and further stabilize the region of the first and second metatarsal bases.

Objective: To describe osseous landmarks that allow identification of the attachments of the ligaments and tendons in the distal medial aspect of the humerus., Materials and Methods: Reliable osseous landmarks in the distal medial aspect of the humerus were identified in 34 well-preserved specimens from a paleopathologic collection. These osseous landmarks were then sought in magnetic resonance (MR) images of ten cadaveric elbow specimens so that the ease of their visualization and optimal imaging plane could be assessed. To assign these osseous landmarks to specific attachments of the tendons and ligaments in the distal medial humerus, we cut the specimens in slices and photographed and examined them. Subsequently, the prevalence of these osseous landmarks as well as the attachment sites of the tendons and ligaments in this location was determined., Results: We determined ten reliable osseous landmarks in the distal medial aspect of the humerus, their prevalence and ease of identification, and their relationship to the attachments of the tendons and ligaments at the medial distal humerus., Conclusion: It is possible to use osseous landmarks at the distal medial humerus to facilitate identification of the different attachments of tendons and ligaments when MR images of the elbow are assessed.

Objective: The objective of our study was to document discrete bone landmarks in the lateral epicondyle of the humerus that represent the "footprints" of those tendons and ligaments that attach to it using MRI-anatomic correlation in cadavers., Materials and Methods: Thirty-three dried humeral specimens were inspected to document bone landmarks in the lateral epicondyle. MRI with anatomic correlation was performed in 10 additional cadaveric elbows. The locations of the tendinous and ligamentous attachments to the lateral epicondyle were determined with respect to the same osseous landmarks., Results: The surface of the lateral epicondyle ranged from a flat surface to a surface with up to six discrete landmarks: superior tubercle, anterior tubercle, posterior tubercle, intertubercular sulcus, rough area surrounding the tubercles, and epicondylar ridge. The radial collateral ligament attached to the superior aspect of the intertubercular sulcus and inferior aspect of the superior tubercle and was indistinguishable from the attachment of the lateral ulnar collateral ligament. The extensor carpi radialis brevis, extensor digitorum communis, and extensor digiti minimi had a common origin in the superior aspect of the lateral epicondyle. The extensor carpi ulnaris tendon arose from the posteroinferior aspect of the lateral epicondyle., Conclusion: Our investigation documents osseous landmarks that are useful in the identification of the footprints of the tendons and ligaments that attach to the lateral epicondyle. Knowledge of these structures contributes to correct interpretation of MR images in persons with tendinous and ligamentous abnormalities in this region.

Purpose: To determine the precise anatomy and magnetic resonance (MR) imaging appearance of the chiasma crurale in cadavers, paying special attention to degenerative changes, Material and Methods: Twelve fresh human ankles were harvested from 11 nonembalmed cadavers (mean age at death 77 years) and used according to institutional guidelines. MR imaging and MR tenography were used to investigate the anatomy of the chiasma crurale using proton density-weighted sequences. The gross anatomy of the chiasma crurale was evaluated and compared to the MR imaging findings. Histology was used to elucidate further the structure of the chiasma crurale., Results: Above the chiasma, five specimens had a small amount of fat tissue between the tibialis posterior and flexor digitorum longus tendon. In all specimens both tendons had a sheath below the chiasma but not above it. At the central portion of the chiasma there was no soft tissue between the tendons, except in two specimens that showed an anatomic variant consisting of a thick septum connecting the tibial periosteum and the deep transverse fascia of the leg. In MR images, eight specimens showed what were believed to be degenerative changes in the tendons at the level of the chiasma. However, during gross inspection and histologic analysis of the specimens, there was no tendon degeneration visible., Conclusion: At the central portion of the chiasma, there is no tissue between the tibialis posterior and flexor digitorum longus tendons unless there is an anatomic variant. At the chiasma crurale, areas with irregular tendon surfaces are normal findings and are not associated with tendon degeneration (fraying).

Objective: The purpose of our study is to describe and define an anatomic variation located close to the bicipital groove using MRI with gross anatomic and histologic correlation in cadavers., Materials and Methods: Ten fresh male human shoulders were harvested and used in this investigation. They were derived from persons with a mean age of death of 78.9 years (age range, 58-92 years). MR arthrography using proton density-weighted sequences was used to obtain images in axial, coronal, and sagittal planes. After imaging, the specimens were cut in axial, coronal, and sagittal sections using a band saw. The slices were then photographed to allow correlation with the MR arthrographic images, followed by histologic analysis., Results: Two anomalous tendons, both intimate with the tendon of the long head of the biceps brachii muscle in the bicipital groove, were recognized. The origin of both tendons was in the greater tuberosity near the articular capsule. These structures had a muscular belly that was joined with the other biceps bellies. At the level of the bicipital groove, the anomalous tendons appeared as hypointense structures in proton density-weighted images, with a mostly flat morphology in axial and coronal planes. The average dimensions of these structures were 45.5 (craniocaudal)x6.2 (anteroposterior)x0.85 (mediolateral) mm., Conclusion: The MR images, gross anatomic inspection, and histologic information led us to conclude that these anomalous structures were accessory heads of the biceps brachii muscle.

Objective: The purpose of this study was to use MRI and anatomic correlation in cadavers to delineate the anatomic features of the distal attachment of the brachialis muscle., Materials and Methods: MRI was performed on 13 cadaveric elbows. The MRI findings were compared with those in anatomic sections and histologic preparations. The brachialis muscle of one cadaver was dissected., Results: The dissected brachialis muscle had two heads, superficial and deep. The attachment of the superficial head to the ulnar tuberosity was farther distal than that of the deep head. The attachments of all aspects of the muscle included a tendinous layer rather than purely muscular structures. Histologic analysis showed no direct communication between the brachialis and biceps brachii tendons or between the brachialis tendon and joint capsule., Conclusion: Familiarity with the anatomic features of the distal brachialis muscle and tendon is essential for accurate assessment of these structures.

Objective: The purpose of this cadaveric study was to describe the normal MR anatomy of the triceps brachii tendon (TBT) insertion, to correlate the findings with those seen in anatomic sections and histopathologic analysis, and to review triceps tendon injuries., Materials and Methods: Twelve cadaveric elbows were used according to institution guidelines. T1-weighted spin-echo MR images were acquired in three planes. Findings on MR imaging were correlated with those derived from anatomic and histologic study., Results: On MR images, the TBT had a bipartite appearance as it inserted on olecranon in all specimens. The insertion of the medial head was deeper than that of the long and lateral heads and was mainly muscular at its insertion, with a small amount of the tendon blending with the muscle distally, necessitating histologic analysis to determine if there was tendon blending with the muscle at the site of insertion and if the medial head inserted together with the common tendon or as a single unit. At histopathologic analysis, the three heads of the triceps tendon had a common insertion on the olecranon. The bipartite aspect of the tendon that was identified in the MR images was not seen by histologic study, indicating that there was a union of the medial and common tendons just before they inserted into bone., Conclusion: TBT has a bipartite appearance on MR images and inserts on olecranon as a single unit.

Objective: Abnormalities of the plantar aponeurosis are commonly encountered in patients with subcalcaneal heel pain. Understanding normal anatomy is required to accurately diagnose some disorders of the foot. The purpose of our study was to describe the normal anatomy of the plantar aponeurosis, using ultrasonography and MRI with close anatomic correlation in cadavers., Materials and Methods: After MRI and ultrasonography of 10 cadaveric foot specimens, the thickness of the central and lateral portions of the plantar aponeurosis displayed by imaging studies was measured by three radiologists. One specimen was sectioned in the transverse plane, one in the coronal plane, one in the sagittal plane, and two in a sagittal oblique plane. Normal anatomy was identified and similar measurements of the plantar aponeurosis were also made. An average value was determined and a statistical analysis was accomplished., Results: The calcaneal insertions of the plantar aponeurosis were better visualized than its distal portions with both MRI and ultrasonography. The measurements of the plantar aponeurosis made by three different radiologists were different, but without statistical significance. The average measurements for the central and lateral portions of the plantar aponeurosis with both imaging methods were different from each other because of differences in the morphology of these structures. The values obtained with ultrasonography and MRI, were also different from each other for both the central and lateral portions of the plantar aponeurosis, but with no statistical significance., Conclusions: We have described the detailed anatomy of the plantar aponeurosis with emphasis on the more distal structures that can be visualized with MRI. There was no statistically significant difference between the accuracy of ultrasonography and MRI regarding the measurements of the thickness of the central and lateral portions of the plantar aponeurosis. Knowledge of the normal anatomy of these structures enables the radiologist to identify early alterations, providing timely diagnosis and treatment.

Purpose: The purpose of this report was to demonstrate the normal complex insertional anatomy of the tibialis posterior tendon (TPT) in cadavers using magnetic resonance (MR) imaging with anatomic and histologic correlation., Material and Methods: Ten cadaveric ankles were used according to institutional guidelines. MR T1-weighted spin echo imaging was performed to demonstrate aspects of the complex anatomic distal insertions of the TPT in cadaveric specimens. Findings on MR imaging were correlated with those derived from anatomic and histologic study., Results: Generally, the TPT revealed a low signal in all MR images, except near the level of the medial malleolus, where the TPT suddenly changed direction and "magic angle" artifact could be observed. In five out of ten specimens (50%), a type I accessory navicular bone was found in the TPT. In all cases with a type I accessory navicular bone, the TPT had an altered signal in this area. Axial and coronal planes on MR imaging were the best in identifying the distal insertions of the TPT. A normal division of the TPT was observed just proximal to the insertion into the navicular bone in five specimens (100%) occurring at a maximum proximal distance from its attachment to the navicular bone of approximately 1.5 to 2 cm. In the other five specimens, in which a type I accessory navicular bone was present, the TPT directly inserted into the accessory bone and a slip less than 1.5 mm in thickness could be observed attaching to the medial aspect of the navicular bone (100%). Anatomic inspection confirmed the sites of the distal insertions of the components of the TPT., Conclusion: MR imaging enabled detailed analysis of the complex distal insertions of the TPT as well as a better understanding of those features of its insertion that can simulate a lesion.

Objective: The purpose of this anatomic imaging study was to illustrate the normal complex anatomy of tendons of the plantar aspect of the ankle and foot using magnetic resonance (MR) imaging with anatomic correlation in cadavers., Design: Seven fresh cadaveric feet (obtained and used according to institutional guidelines, with informed consent from relatives of the deceased) were studied with intermediate-weighted fast-spin-echo MR imaging. For anatomic analysis, cadaveric specimens were sectioned in 3-mm-thick slices in the coronal and axial planes that approximated the sections acquired at MR imaging., Results: The entire courses of the tendons into the plantar aspect of the foot were analyzed. The tibialis posterior tendon has a complex distal insertion. The insertions in the navicular, second, and third cuneiforms bones were identify in all cases using axial and coronal planes. A tendinous connection between the flexor hallucis longus and the flexor digitorum longus tendons was identified in five of our specimens (71%). The coronal plane provided the best evaluation. The peroneus longus tendon changes its direction at three points then obliquely crosses the sole and inserts in the base of the first metatarsal bone and the plantar aspect of the first cuneiform., Conclusions: MR imaging provides detailed information about the anatomy of tendons in the plantar aspect of the ankle and foot. It allows analysis of their insertions and the intertendinous connection between the flexor hallucis longus and the flexor digitorum longus tendons.

Objective: Under the hypothesis that the anatomic relationship of the tibialis anterior tendon and extensor retinaculum of the foot and ankle is relevant to the clinical aspects of a tear in that tendon, we assessed the anatomic details of these structures using MRI in cadavers and evaluated MRI in patients with a tibialis anterior tendon tear., Materials and Methods: Seven cadaveric feet underwent detailed MRI using standard and oblique coronal planes with respect to the course of the tibialis anterior tendon and extensor retinaculum. Cadaveric sections subsequently provided an anatomic correlation. MR images of seven patients with tibialis anterior tendon tear were analyzed by consensus of two musculoskeletal radiologists., Results: Imaging-anatomic correlations allowed identification of the tibialis anterior tendon and extensor retinaculum. The tendon passed through three tunnels formed by the superior extensor retinaculum, oblique superomedial, and oblique inferomedial limbs of the inferior extensor retinaculum. Of seven patients with the tendon tear, three patients had complete tears and four patients had partial tears. In all partial tears, the level of the tear was at the ankle joint, corresponding to the approximate level of the oblique superomedial limb. In all complete tears, the proximal ends of torn tendons were retracted to a level below the oblique superomedial limb. In all tears, the oblique superomedial limb surrounding the torn tendon was seen with thickening in four patients and enhancement after IV gadolinium injection in two patients. Other findings included a bulbous appearance or swelling of the torn tendon in two complete and two partial tears and fluid collections within the tendon sheath and in an area confined by the extensor retinaculum in four patients., Conclusion: The relationship of the tibialis anterior tendon and extensor retinaculum is well depicted on MRI, even in patients with a tibialis anterior tendon tear, and is clinically relevant to the tear of this tendon.

Purpose: To determine if passive positioning of the ankle influences the MR imaging appearance of ankle tendons and ligaments., Methods: A positioning device was used during imaging of 10 volunteers. Axial and coronal T1-weighted images were acquired in six positions of the ankle, and the appearance of the tendons and lateral ligaments was subjectively evaluated., Results: The peroneus longus (PL), peroneus brevis (PB), anterior tibialis (AT), extensor digitorum longus (EDL), and extensor hallucis longus (EHL) tendons were best visualized in 20 degrees of plantarflexion and 20 degrees of inversion (p < 0.0001). The anterior talofibular (ATF) and calcaneofibular (CF) ligaments were best seen in 20 degrees of plantarflexion (p < 0.0001). Ten degrees of dorsiflexion was the least useful imaging plane for all of the aforementioned structures., Conclusion: When there is clinical concern regarding pathology of a specific structure about the ankle, passive positioning may allow optimal evaluation.

Purpose: The purpose of this work was to demonstrate the normal ligamentous and tendinous anatomy of the intermetacarpal (IMC) and common carpometacarpal (CCMC) joints with MRI and MR arthrography., Method: MR images of 22 wrists derived from fresh human cadavers were obtained before and after arthrography. The MR imaging features of the ligaments and tendons about the CCMC and IMC joints and the joints themselves were analyzed in a randomized fashion and correlated with those seen on anatomic sections., Results: Six CCMC ligaments were visualized. The dorsal and palmar CCMC ligaments and the pisometacarpal ligament were best visualized in the sagittal plane. The radial and ulnar CCMC collateral ligaments and the capito-third metacarpal ligament were best visualized in the coronal plane. Three main IMC ligaments were observed: a dorsal and a palmar ligament and an interosseous ligament complex. All three ligaments were best visualized in the axial plane. Four tendinous insertions to the metacarpal bases were evident., Conclusion: The anatomy of the ligaments and tendinous insertions about the second to fifth IMC and the CCMC joints is well demonstrated by MR imaging and MR arthrography. MR arthrography does not significantly improve the visualization of these complex structures.

Objective: The purpose of this study was to provide a detailed description of the anatomy of the coronoid process of the ulna and to use magnetic resonance (MR) images and anatomic correlation with cadavers to show the macroscopic configuration of this structure.Materials and Methods: Photography and high-resolution radiography were performed in 26 ulna specimens from the collection of a local museum. MR imaging of the coronoid process of 11 cadaveric elbows was performed. The images were compared with those seen on anatomic sectioning.Results: The anteromedial rim of the coronoid process of the ulna had a regular surface, without osseous irregularities or facets in 69.2% of the specimens. In 30.8% of the specimens, the anteromedial rim was not regular and a small ridge could be identified. The insertion site of the joint capsule was onto the anterior aspect of the coronoid process, at an average distance of 5.9 mm distal to the tip. The attachment of the anterior band of the ulnar collateral ligament at the sublime tubercle was flush with the articular margin in 63.6% of the specimens. In 36.4% of the specimens, a more distal attachment, with a separation between the undersurface of the ligament and the adjacent tubercle, was seen. The brachialis tendon was attached to the coronoid process at a mean distance of 12.1 mm distal to the tip.Conclusion: The coronoid process of the ulna is a small osseous structure with a complex anatomy and presents some anatomical variations. [ABSTRACT FROM AUTHOR]