Correction to: Distal insertional anatomy of the triceps brachii muscle: MRI assessment in cadaveric specimens employing histologic correlation and Play-doh® models of the anatomic findings.

Figures 9, 10, 11, 12 and 15 corrected.

Pectoralis major tendon and enthesis: anatomic, magnetic resonance imaging, ultrasonographic, and histologic investigation.

BACKGROUND: This study evaluates the pectoralis major (PM) tendon humeral insertion, using imaging and histologic assessment in cadaveric specimens. Current descriptions of the pectoralis major tendon depict a bilaminar enthesis, and clarification of the anatomy is important for diagnostic and surgical considerations. MATERIALS AND METHODS: Fourteen fresh-frozen whole upper extremity specimens were used in this study. Magnetic resonance (MRI) and ultrasonographic (US) imaging of the PM muscles, tendons, and entheses were performed, followed by anatomic dissection and inspection. Morphology of the lateral tendon and entheses were evaluated, focused on the presence of layers. In 11 specimens, the lateral 3 cm of the PM tendon was carefully dissected from the footprint, whereas in 3 specimens, the tendon and humeral insertion were preserved and removed en bloc. Histology was performed in axial slabs along the medial-lateral length of the tendon and also evaluated for the presence of layers. RESULTS: The superior-inferior and medial-lateral lengths of the PM footprint were 75 ± 9 mm and 7 ± 1 mm respectively. In all specimens, the clavicular and sternal head muscles and tendons were identified, with the clavicular head tendon generally being shorter. The medial-lateral length of the clavicular head tendon measured 19 ± 8 mm superiorly and 9 ± 3 mm inferiorly. The medial-lateral length of the sternal head tendon measured 38 ± 8 superiorly and 41 ± 18 mm inferiorly. All specimens demonstrated a unilaminar, not bilaminar, enthesis with abundant fibrocartilage on histology. Three specimens demonstrated interspersed entheseal fat and loose connective tissue at the enthesis on MRI and histology. CONCLUSION: The PM tendon humeral insertion consists of a unilaminar fibrocartilaginous enthesis. US, MRI, and histology failed to identify true tendon layers at the enthesis. Delaminating injuries reported in the literature may originate from a location other than the enthesis.

Distal insertional anatomy of the triceps brachii muscle: MRI assessment in cadaveric specimens employing histologic correlation and Play-doh® models of the anatomic findings.

OBJECTIVES: Assess the insertional anatomy of the distal aspect of the triceps brachii muscle using magnetic resonance imaging (MRI) in cadavers with histologic correlation and Play-doh® models of the anatomic findings. MATERIALS: Elbows were obtained from twelve cadaveric arm specimens by transverse sectioning through the proximal portion of the humerus and the midportion of the radius and ulna. MRI was performed in all elbows. Two of the elbow specimens were then dissected while ten were studied histologically. Subsequently, Play-doh® models of the anatomic findings of the distal attachment sites of the triceps brachii muscle were prepared. RESULTS: MRI showed a dual partitioned appearance of the distal attachment sites into the olecranon in all specimens. In the deeper tissue planes, the medial head muscle insertion was clearly identified while superficially, the terminal portion of the long and lateral heads appeared as a conjoined tendon. Histologic analysis, however, showed continuous tissue rather than separate structures attaching to the olecranon. CONCLUSION: Although MRI appeared to reveal separate and distinct attachments of the triceps brachii muscle into the olecranon, histologic analysis delineated complex but continuous tissue related to the attachments of the three heads of this muscle. The Play-doh® models were helpful for the comprehension of this complex anatomy and might serve as a valuable educational tool when applied to the analysis of other musculoskeletal regions.

A Rare Case of Exclusively Oncocytic Mucoepidermoid Carcinoma with MAML2 Translocation.

Mucoepidermoid carcinoma is the most common malignant tumor of the salivary gland. The oncocytic variant of mucoepidermoid carcinoma (OMEC) is rare and a small subset shows exclusive oncocytic morphology. Here we report an OMEC case of the parotid gland in a 74-year-old woman with exclusive oncocytes and rare mucocytes. The oncocytes showed diffuse nuclear positivity with p63 immunostaining. The MAML2 translocation was present, supporting the diagnosis of OMEC. Distinguishing OMEC with exclusive oncocytes from oncocytoma and oncocytic carcinoma can be very challenging for pathologists and is critical for proper clinical management. Our experience suggests that appropriate ancillary studies, especially the MAML2 translocation, may provide the essential evidence in difficult cases. Our literature review shows that the presence of mucocytes in an oncocytic neoplasm might be an important morphologic clue of OMEC.

Carpal bone cysts: MRI, gross pathology, and histology correlation in cadavers.

PURPOSE: Intraosseous cysts of carpal bones are frequently observed on routine imaging examinations of the wrist. There is controversy regarding the underlying pathogenesis of these cysts. In this study, we aimed to investigate the magnetic resonance imaging (MRI) appearance of intracarpal bone cysts in correlation with histologic analysis, using cadaveric wrists. METHODS: Five freshly frozen cadaveric wrist specimens (from three women and two men; mean age at death, 80 years) were studied. Imaging was performed with T1-weighted fast spin-echo, and proton density-weighted fast spin-echo with and without fat-suppression. The existence of cysts was confirmed by comparing MRI and histology findings. Hematoxylin and eosin stain was performed on tissue slices of 3 mm thickness to analyze the structure of cysts and their communication with the joint cavity. RESULTS: Ten cysts were observed. In all cases, cysts were eccentrically located either in the subchondral bone or beneath the cortex. On histologic examination, there were regions of fat necrosis without inflammation or increased vascularity, surrounded by fibrous walls. There were no giant cells, cholesterol granules, or a true synovial lining. Mucoid change was rare. Fibrous component of cysts varied from small fibrous septa to well-formed walls. Some cysts communicated with the joint cavity. Two cysts were adjacent to ligamentous attachments. Those cysts with fibrous tissue demonstrated variable hypointensity on T2. CONCLUSION: In contrast to previous reports that described a mucoid composition of intracarpal bone cysts with occasional foamy macrophages, our observations support the concept that these lesions reflect a spectrum of fat necrosis and fibrous changes, without inflammation or hypervascularity. These cysts are typically surrounded by fibrous walls without a true synovial lining.

Relationship between the degeneration of the cruciate ligaments and calcium pyrophosphate dihydrate crystal deposition: anatomic, radiologic study with histologic correlation.

To investigate the association of calcium pyrophosphate dihydrate (CPPD) crystal deposition and cruciate ligament (CL) degeneration, 10 cadaveric knees were studied with 1.5-T magnetic resonance imaging and sectioned in three planes. The slices were evaluated with high-resolution Faxitron radiography. The images and specimens were evaluated by two radiologists. Histologic sections were obtained from eight that contained calcifications and from two without calcifications. Radiographs and histologic analysis demonstrated CPPD crystal deposition in 80% of specimens and 75% of CLs in these eight specimens. Degenerative changes were observed in 75% of them. Such analysis demonstrated no evidence of CPPD crystals or degeneration in the control specimens.

Hypercalcemia in disseminated coccidioidomycosis: expression of parathyroid hormone-related peptide is characteristic of granulomatous inflammation.

BACKGROUND: Hypercalcemia is an uncommon complication of disseminated granulomatous infections. The pathogenesis of hypercalcemia associated with infection is not clear. METHODS: We investigated a case of disseminated coccidioidomycosis with hypercalcemia. We used a sensitive radioimmunoassay to measure serum parathyroid hormone-related peptide (PTHrP) and a mouse monoclonal antibody to PTHrP to immunostain biopsies. RESULTS: We found elevated serum levels of PTHrP while the patient was hypercalcemic that became undetectable when serum calcium normalized. We also found that the inflammatory cells and some surrounding tissues in skin biopsies expressed PTHrP. PTHrP was expressed by all biopsied lesions of patients with coccidioidomycosis that we examined, whether localized to the lung or disseminated, but no other cases were hypercalcemic. PTHrP was also expressed by the 3 mycobacterial granulomas we examined, and in a lymph node from a patient with sarcoidosis. CONCLUSIONS: The expression of PTHrP is a property of infectious granulomas regardless of etiology or the tissue involved, suggesting that PTHrP expression is part of the normal granulomatous immune response. Hypercalcemia may result if there is disseminated infection and multiple granulomas. We propose that excess production of PTHrP is the cause of hypercalcemia in granulomatous infections.

Pericruciate fat pad of the knee: anatomy and pericruciate fat pad inflammation: cadaveric and clinical study emphasizing MR imaging.

OBJECTIVE: The pericruciate fat pad is located in the intercondylar fossa, intimate with the cruciate ligaments. With MR imaging, signal abnormality of the pericruciate fat pad has been observed in patients with posterior knee pain. The purpose of this study was to describe the anatomy of the pericruciate fat pad in cadaveric specimens and to document the clinical spectrum of pericruciate fat pad inflammation. MATERIALS AND METHODS: Twelve cadaveric knees underwent MR imaging with T1 and T2 multiplanar images. Cadaveric sections were then prepared for macroscopic evaluation, with additional histologic analysis performed in four cases. MR images in seventeen patients (ten males, seven females; average age, 31.5 years; age range, 19-57 years) involved in intensive sporting activity and with posterior knee pain were reviewed. RESULTS: MR images in cadaveric specimens showed a fat pad that was located above and between the cruciate ligaments, near their attachment sites in the inner portion of the femoral condyles, within the intercondylar fossa. Fatty tissue covered by a thin layer of synovial membrane was confirmed at histology. Seventeen patients with posterior knee pain and without gross cartilage, meniscal, or ligamentous abnormalities all revealed an increased signal in this fat pad in fluid-sensitive fat-suppressed images, mainly in the sagittal and axial planes. In eight cases, enhancement of this fat pad was demonstrated following intravenous gadolinium administration. CONCLUSIONS: The pericruciate fat pad is a structure located in the intercondylar fossa, intimate with both the anterior and posterior cruciate ligaments. Inflammatory changes in this fat pad may be found in patients, especially athletes with posterior knee pain.

Capsular ligaments of the hip: anatomic, histologic, and positional study in cadaveric specimens with MR arthrography.

PURPOSE: To demonstrate the anatomy of the capsular ligaments of the hip by using magnetic resonance (MR) arthrography. MATERIALS AND METHODS: Institutional policies were followed regarding cadaver use. MR arthrographic images of 10 fresh human cadaveric hips were obtained by using a positioning device to arrange the hip joint in different controlled positions. MR appearances of the capsular structures were noted and correlated with those seen on anatomic slices and dissections. Two readers working in consensus graded the visibility of these structures. Tissue samples were collected for histologic analysis. An MR positional study was performed to evaluate the length of these capsular ligaments and the subjective classification of their appearance as either taut or lax in extension, flexion, abduction, adduction, and internal and external rotation. RESULTS: The hip capsule inserts proximally and continuously to the acetabular rim periosteum. Distally, it has a firm anterior insertion at the femoral intertrochanteric line and no posterior osseous insertion. The inferior band of the iliofemoral ligament was best evaluated in the sagittal, axial, and axial oblique planes, and it serves a restrictive function in extension; the superior band of the iliofemoral ligament was best evaluated in the coronal and axial oblique planes, and it serves a restrictive function in external rotation; the ischiofemoral ligament was best evaluated in the axial and axial oblique planes, and it serves a restrictive role in internal rotation; the pubofemoral ligament was best evaluated in the sagittal plane, and it serves a restrictive function in abduction; and the zona orbicularis could be evaluated equally well in any imaging plane. CONCLUSION: MR arthrography enables visualization of the capsular ligaments of the hip.

High origin of the anterior band of the inferior glenohumeral ligament: MR arthrography with anatomic and histologic correlation in cadavers.

INTRODUCTION: The anterior band of the inferior glenohumeral ligament has been described to arise from the anteroinferior labrum, but we have observed that in some persons its origin is from the anterior or anterosuperior labrum, creating diagnostic difficulties. MATERIALS AND METHODS: Ten fresh unembalmed cadaveric shoulders underwent magnetic resonance arthrography (MRA) using a posterior approach with a 1.5 T GE magnet, with the following sequences: T1-weighted fast spin-echo in axial, coronal and sagittal planes, and T1 fat-suppressed spin-echo in the axial plane (TR/TE 600/20, section thickness 2.5 mm, 0.5 mm interslice space, number of signals acquired, two, field of view 12 × 12 cm, and matrix 512 × 256 pixels). Following imaging, the shoulders were frozen and later sectioned using a band saw into 3-mm sections corresponding to the axial imaging plane. Histological analysis was also performed to determine the origin of the anterior band. RESULTS: Four of the ten shoulders had an origin of the anterior band above or at the 3 o'clock position: one at the 1 o'clock position, two at the 2 o'clock position, and one at the 3 o'clock position. In another shoulder, the anterior band of the inferior glenohumeral ligament originated from the middle glenohumeral ligament, and in five other shoulders, the anterior band originated from the anteroinferior labrum as has been described in the literature. CONCLUSIONS: This finding is of clinical significance as a high origin of the anterior band of the inferior glenohumeral ligament leads to MR arthrographic finding that can simulate those of labral tears or detachments.

A slip connecting the peroneus longus and tibialis posterior tendons at the forefoot: MRI, anatomic, and histologic findings in a cadaver.

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.

Edematous processes within Kager fat pad: magnetic resonance imaging, gross anatomical, and histological studies in cadavers with clinical correlation.

OBJECTIVE: To demonstrate the anatomical features of Kager fat pad (KFP) and its fasciae using magnetic resonance imaging, gross anatomy, and histology in cadavers; and to correlate the data with image findings in patients. METHODS: The KFP was analyzed in 10 fresh human cadavers and 152 clinical cases. The retrospective clinical study was institutional review board approved. The specimens were studied by magnetic resonance imaging and sectioned for anatomical/histological correlation. Clinical cases were selected to evaluate the frequency, distribution, and patterns of edema/inflammation in KFP. The square of the Pearson product moment correlation coefficient and Student t tests were performed. RESULTS: Fasciae about KFP are double layered and derived from the union of the fascia of the leg and flexor and peroneal retinacula. Edema in KFP could be divided into diffuse, confined anteriorly, confined posteriorly, and confined externally. Confined patterns of edema were associated with paratenonitis and fluid in the Achilles bursae (P < 0.05). CONCLUSIONS: Four patterns of edema occur in KFP. Paratenonitis and bursal fluid were associated with confined edematous patterns. The double layer about KFP may contain edema that affects this region.

Morphology of the distal radioulnar joint: cadaveric study with MRI and MR arthrography with the forearm in neutral position, pronation, and supination.

OBJECTIVE: The purpose of this study was to evaluate the physiologic extent and thickness of the cartilage and bare areas of the distal radioulnar joint with gross anatomic examination, MRI, and MR arthrography with the forearm in neutral position, maximal pronation, and maximal supination. MATERIALS AND METHODS: MRI and MR arthrography were performed on 10 cadaveric specimens (mean age at death, 82.9 years; range, 56-97 years) with the forearm in neutral position, maximal pronation, and maximal supination. Cartilage surface and thickness were assessed, and degenerative changes and bare areas were evaluated in consensus by two musculoskeletal radiologists. Gross anatomic and histologic examinations were used as the reference standard. RESULTS: MRI in maximal pronation and supination was helpful in evaluation of the ulnar cartilage. In the axial plane, any change in cartilage thickness in the ulnar head was related to chondral degeneration. In the coronal plane, cartilage thickness proved to be an unreliable sign in the assessment of chondral degeneration. The presence of osteophytes in the proximal aspect of the joint was easily detected and proved to be a reliable criterion for joint degeneration. Bare areas were found at the proximal and volar attachments of the joint capsule. CONCLUSION: Detailed knowledge of the anatomy of the distal radioulnar joint should allow more accurate assessment of degenerative changes and localization of erosions in inflammatory joint disease. Imaging with the forearm in maximal pronation and supination can improve visualization of the cartilage of the ulnar head.

Chiasma crurale: intersection of the tibialis posterior and flexor digitorum longus tendons above the ankle. Magnetic resonance imaging-anatomic correlation in cadavers.

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).

Accessory head of biceps brachii muscle: anatomy, histology, and MRI in cadavers.

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.

Degenerative changes in the ligamentum teres of the hip: cadaveric study with magnetic resonance arthrography, anatomical inspection, and histologic examination.

OBJECTIVE: Review and classify the pathologic abnormalities of the ligamentum teres in degenerative hip joints. MATERIAL AND METHODS: Eleven cadaveric hip joints were examined with magnetic resonance arthrography and were then sectioned. The appearance of the ligamentum teres and its attachment seen by inspection of the anatomical sections was correlated with findings seen at magnetic resonance imaging. Histologic evaluation was done. RESULTS: Magnetic resonance arthrographic and histologic findings showed a spectrum of ligamentum teres degeneration. The thickest ligamentum teres revealed mucoid and fibromatous degeneration with microscopic tear. Ligamentum teres with intermediate thickness revealed fatty replacement with and without fibromatous degeneration, fibromatous degeneration with and without mucoid degeneration, and eosinophilic change. The thinnest ligamentum teres was near-complete disruption of the ligament. CONCLUSIONS: The ligamentum teres revealed degenerative changes that were similar histologically to degenerative changes in tendons. Magnetic resonance arthrography provided a sensitive technique for demonstration of the ligamentum teres and various patterns of degeneration.

Ulnomeniscal homologue of the wrist: correlation of anatomic and MR imaging findings.

PURPOSE: To evaluate the anatomy of the ulnar side of the wrist in the region of the triangular fibrocartilage (TFC) complex, with special focus on the ulnomeniscal homologue (UMH) and its relationship to surrounding structures. MATERIALS AND METHODS: Institutional review board approval and informed consent were not required. Ten upper extremities were harvested from the nonembalmed cadavers of four women and six men (age range at death, 56-97 years; mean age at death, 83 years) and used according to institutional guidelines. Magnetic resonance (MR) imaging and MR arthrography of the wrist were performed with the wrist in neutral position, maximal ulnar deviation, and maximal radial deviation by using intermediate-weighted sequences. The specimens were cut into 4-mm-thick sections that corresponded to the MR imaging planes. The gross anatomic features of the UMH and its relationship to adjacent structures were evaluated and compared with imaging findings. UMH variants, as described in previous articles on purely anatomic studies, were sought on MR images. MR findings of the wrist in neutral position were compared with those of the wrist in maximal ulnar and radial deviations. Histologic examination was used to further elucidate the structure of the UMH. RESULTS: The UMH displayed complex anatomic features because of its obliquely oriented course. However, it could be divided into styloid, radioulnar, and collateral components and a distal insertion. The UMH variants described in previously published studies could be identified, but evaluation results were highly dependent on the wrist position at imaging. CONCLUSION: The anatomy of the UMH is complex. For assessment of the UMH and the ulnar side of the TFC complex, coronal MR arthrography with the wrist in neutral position or radial deviation might be superior to standard MR imaging.

Annular ligament of the elbow: MR arthrography appearance with anatomic and histologic correlation.

OBJECTIVE: As part of the lateral ligament complex of the elbow, the annular ligament has an adjunctive role in stabilizing the proximal radioulnar joint. Knowledge of the anatomy of this ligament may enhance our understanding of its functional role in maintaining integrity of the elbow joint in fracture and dislocation. The purpose of this study is to provide a detailed analysis of the anatomy of the annular ligament using MR arthrography with anatomic and histologic correlation in cadavers. MATERIALS AND METHODS: MR arthrography of six fresh cadaveric elbows using coronal, axial, and sagittal planes was performed after injection of intraarticular contrast material. The MR arthrography appearance of the annular ligament was correlated with anatomic sectioning and histologic analysis. RESULTS: On MR arthrography, the axial and sagittal planes provided the best evaluation of the annular ligament. Although the anterior attachment of annular ligament was a single band, the posterior attachment was fenestrated in two of six specimens. Anatomic inspection confirmed the MR observations. On histology, the annular ligament appeared to be part of a complex supporting structure continuous with the elbow joint capsule, adjacent ligaments, and muscles. CONCLUSION: The annular ligament is a complex structure formed from the capsule, lateral collateral ligamentous complex, and supinator muscle that act in unison to stabilize the proximal radioulnar joint. Its posterior attachment to the ulna can be fenestrated normally. A detailed analysis of anatomy of this ligament allows us to better understand its functional role in fractures and dislocations of the elbow joint.

Changes in the acetabular fossa of the hip: MR arthrographic findings correlated with anatomic and histologic analysis using cadaveric specimens.

OBJECTIVE: The objective of our study was to determine the morphologic and histologic pattern of tissue changes in the acetabular fossa and evaluate its association with osteoarthritis of the hip joint. MATERIALS AND METHODS: Eleven cadaveric hip joints derived from elderly persons were examined using MR arthrography. All 11 joints were then sectioned. The pattern of acetabular fossa changes determined during inspection of the anatomic and histologic sections in all cadaveric specimens was correlated with MR arthrographic findings. We classified acetabular fossa changes into three stages. Imaging findings of osteoarthritis were reviewed to assess for an association between acetabular cartilage changes and acetabular fossa changes. RESULTS: MR arthrographic findings of changes in the acetabular fossae included low signal intensity related to multiple thin or thick fibrous strands in the acetabular fat and a decrease in the amount of peripheral fatty tissue. Histologic findings revealed fat necrosis, fibrous strands, a decrease in the amount of fat, fibrocartilaginous metaplasia of fat, and chondroid metaplasia at the bony surface of the acetabular fossa. There was a statistically significant correlation between the advanced stage (stage IV) of acetabular cartilage degeneration and the advanced stage (stage 3) of acetabular fossa change (p < 0.001). CONCLUSION: In a small number of specimens, MR arthrographic findings and histologic analyses showed fibrofatty tissue changes and chondroid metaplasia in the acetabular fossae of cadavers derived from an elderly population. The advanced stage of acetabular fossa change was correlated statistically with the advanced stage of acetabular cartilage degeneration.

Ligaments of the posterior and lateral talar processes: MRI and MR arthrography of the ankle and posterior subtalar joint with anatomic and histologic correlation.

OBJECTIVE: MRI and combined ankle and posterior subtalar MR arthrography in cadavers were used to evaluate the ligaments of the posterior and lateral talar processes. Subsequent anatomic and histologic correlation was performed. MATERIALS AND METHODS: Ten cadaveric ankles were used. Routine radiography and MRI were initially performed. Ankle and posterior subtalar MR arthrography, followed by anatomic and histologic analysis, was then performed to allow better assessment of the ligaments of the lateral and posterior talar process. RESULTS: In all subjects, MR arthrography provided superior delineation of the articular and periarticular structures, as well as the ligaments. The lateral talocalcaneal and medial talocalcaneal ligaments were best seen in the axial and coronal planes, respectively. The axial plane was best for visualizing the fibulotalocalcaneal ligament, and the sagittal plane was best for evaluating the posterior talocalcaneal ligament. The anterior and posterior talofibular ligaments and the posterior tibiotalar ligament (superficial and deep portions) were best seen in the axial plane. Histologic analysis was correlated to anatomic sectioning and showed the attachment sites of these ligaments. CONCLUSION: Combined ankle and posterior subtalar MR arthrography enhances visualization of the ligaments attaching to the posterior and lateral talar processes, including the posterior, lateral, and medial talocalcaneal and fibulotalocalcaneal ligaments.