Calcific bursitis of the Gruberi bursa: a case report.

BACKGROUND: Bursitis is the inflammation of a synovial bursa, a small synovial fluid-filled sac that acts as a cushion between muscles, tendons, and bones. Further, calcific bursitis results from calcium deposits on the synovial joint that exacerbates pain and swelling. The Gruberi bursa is located dorsolaterally in the ankle, between the extensor digitorium longus and the talus. Despite limited literature on its pathophysiology, the aim of this case is to discuss the bursa's association with calcific bursitis and its management via a case presented to our clinic. CASE PRESENTATION: A 47-year-old Caucasian female with no past medical or family history presents with acute right ankle pain following a minor injury 3 months prior with no improvement on analgesic or steroid therapy. Imaging demonstrated incidental calcium deposits. The day prior to presentation, the patient stated she used 1-pound ankle weights that resulted in mild swelling and gradual pain to the right dorsoanterior ankle. Physical exam findings displayed a significant reduction in the range of motion limited by pain. Imaging confirmed calcification within the capsule of the talonavicular joint, consistent with Gruberi bursitis. Initial management with prednisone yielded minimal improvement, requiring an interventional approach with ultrasound-guided barbotage that elicited immediate improvement. CONCLUSION: The presented case report highlights a rare and unique instance of acute ankle pain and swelling caused by calcific Gruberi bursitis in a young female. Although the Gruberi bursa is a relatively new discovery, it contains inflammatory components that may predispose it to calcification and should be considered in the differential of ankle swelling. Therefore, utilizing a systematic approach to a clinical presentation and considering all differential diagnoses is essential.

Imaging features of reactive bursitis secondary to osteochondroma.

PURPOSE: The purpose of this study was to determine imaging features of reactive bursitis secondary to osteochondroma. MATERIALS AND METHODS: Fourteen patients with reactive bursitis secondary to osteochondroma were retrospectively reviewed. RESULTS: The 14 patients were 11 males and 3 females ranging in age from 18 to 67 years (mean, 33.6 years). The locations were as follows: scapula (n = 2), lesser trochanter (n = 6), greater trochanter (n = 1), distal femur (n = 2), distal fibula (n = 1), iliac bone (n = 2). On CT, six bursae were hypodense and 1 was isodense compared to muscle. All bursae had a thickened wall, 6 contained multiple villous projections and septa. Five bursae contained a few calcifications. On enhanced CT, the bursa displayed mild enhancement of the wall, villous projections, and septa. On MRI, one bursa was hypointense, three were hyperintense, and 5 were isointense relative to muscles on T1-weighted images. All bursae were hyperintense relative to muscles on T2-weighted images. All bursae had a thickened wall, eight contained multiple villous projections and septa. In five bursae, a few fatty villous projections can be seen within the bursa. On enhanced MRI, all bursae displayed avid enhancement of the bursal wall, villous projections, and septa. CONCLUSIONS: Reactive bursitis secondary to osteochondroma most often occurred in young male adults. The most common involved site is lesser trochanter. The imaging features is that of an irregular, thick-walled fluid-filled bursa overlying an osteochondroma that containing multiple villous projections and septa. Calcification and/or lipoma arborescens may be developed within the bursa. On contrast-enhanced images, the bursa shows enhancement of the bursal wall, villous projections and septa.

Ultrasound Guidance Is Not Superior in Subacromial Bursa and Intraarticular Injections but Superior in Bicipital Groove: A Meta-analysis of Randomized Controlled Trials.

PURPOSE: To perform a meta-analysis comparing the clinical and functional outcomes of ultrasound-guided (USG) and blind injections for shoulder pain. METHOD: The Embase, Cochrane Library, and PubMed databases were searched from database inception to April 7, 2021. Clinical and functional outcomes included the visual analog scale (VAS) pain score, abduction, flexion, American Shoulder and Elbow Surgeons Assessment Form (ASES) score, Constant-Murley Shoulder (CMS) score, Shoulder Pain and Disability Index (SPADI), Shoulder Disability Questionnaire (SDQ) score, and Shorted Disabilities of the Arm, Shoulder and Hand (Quick DASH) score. Dichotomous outcomes were assessed with mean differences (MDs) and 95% confidence intervals (95% CIs). RESULTS: Fifteen studies that compared USG and blind injections were included. No significant difference was found in the VAS score between the blind group and USG group (MD 0.41 [-0.02, 0.84]; I2 = 79%; P = .06). Subgroup analysis of the brachial bicipital groove indicated that the USG group had less pain than the blind group (MD 1.50 [0.54, 2.46]; I2 = 64; P = .002). The USG injection patients had better postoperative abduction (MD -3.08 [-5.19, -0.98], I2 = 0, P = .004) and flexion (MD -3.36 [-5.56, -1.16]; I2 = 0; P = .003) than the blind group. Additionally, the USG injection patients had better CMS scores than the blind injection patients (MD -12.95 [-25.60, -0.29]; I2 = 96; P = .04). However, subgroup analysis showed no significant difference in the subacromial bursas and glenohumeral joints of CMS score (MD -13.22 [-29.93, 3.94]; I2 = 97; P＜.0001). No significant difference was found in the SPADI, ASES score, or SDQ score between the groups. CONCLUSIONS: Ultrasound guidance is not superior in the subacromial bursa and glenohumeral joint injections in pain or function. However, injection in the brachial bicipital groove, is still superior to blind injection of pain relief. LEVEL OF EVIDENCE: Level II, meta-analysis of Level I and II studies.

Factors affecting successful ultrasound-guided injection into the podotrochlear bursa using a palmarolateral approach.

OBJECTIVE: To evaluate potential factors affecting ultrasonographic visibility of the suprasesamoidean region and the success rate of ultrasound-guided injection (USGI) into the podotrochlear bursa (PB). STUDY DESIGN: Ex vivo, experimental study. ANIMALS: 24 cadaveric forelimbs. METHODS: The PB was distended with 0, 1, or 2 ml of iodinated contrast material and saline under radiographic guidance. Ultrasonographic visibility of the suprasesamoidean region and PB was graded before and after distention with the limb loaded in three positions (vertical, cranial and caudal). Two operators with different experience levels performed an USGI into the PB with methylene blue (12 limbs each [four limbs with each of three volumes of PB distension]) using a palmarolateral approach and caudal foot placement. Limbs were frozen and sectioned to assess accuracy. RESULTS: Ultrasonographic visibility scores of the suprasesamoidean region (p = .0081) and PB (p < .0001) were improved using a caudal foot placement. Higher visibility grades of the suprasesamoidean region were associated with higher injection success rate (p = .047). The injection success was 75% (9/12) for the experienced versus 41.6% (5/12) for the less experienced operator (p = .14). PB distension improved visibility during caudal foot placement (p = .013) but not injection success rates (p = .78). CONCLUSION: Caudal foot placement enhances visibility of the PB and suprasesamoidean region. Limbs with poor visibility of the suprasesamoidean region are more likely to undergo a failed USGI. CLINICAL SIGNIFICANCE: The lateral USGI approach should be performed only in cases of optimal visibility. The reported success rates support the technical challenge of PB injections.

Safety and efficacy of image-guided retrocalcaneal bursa corticosteroid injection for the treatment of retrocalcaneal bursitis.

OBJECTIVE: To determine the safety and efficacy of image-guided retrocalcaneal bursa corticosteroid injection for retrocalcaneal bursitis. MATERIALS AND METHODS: After IRB approval, all fluoroscopically guided and ultrasound-guided retrocalcaneal bursa injections (2013-2019) were retrospectively evaluated. Pre-procedure US and radiographs were scored by 2 blinded radiologists in consensus for Achilles tendinosis and retrocalcaneal bursitis (0-3 scale), Achilles enthesopathy (present/absent), and Haglund deformity (present/absent). Pre- and post-procedure pain scores (0-10 scale) evaluated short-term response at 1-4 weeks: excellent (7-10 point decline), good (4-6 point decline), fair (1-3 point decline), or no response. Paired t-test determined significance of short-term improvement. Kaplan-Meier method analyzed time to progression to surgery or complication at 6-month minimum follow-up. Logistic regression analysis evaluated for association between demographic and imaging variables and negative outcome. RESULTS: Two hundred eighteen injections (181 female; mean 54.5 years) performed under ultrasonographic (157, 72%) or fluoroscopic (61, 28%) guidance were evaluated for complication and long-term outcomes. Injections with short-term follow-up (n = 62) yielded excellent or good response in 62.9% (p < 0.00001). Thirty patients (14%) had subsequent elective Achilles surgery. Bursal Doppler flow was associated with progression to surgery (p = 0.00042). No differences were identified in outcomes between US and fluoroscopic-guidance cohorts. Four Achilles ruptures (1.8%) were identified 15-59 days post-injection, each with immediately preceding acute injury. CONCLUSION: Image-guided retrocalcaneal bursa corticosteroid injection yields significant short-term decrease in pain score in majority (63%) of patients. Subsequent Achilles tendon rupture rate was 1.8%. Bursa Doppler flow was significantly correlated with progression to surgery and may represent a negative prognostic indicator.

Hundreds of rice bodies in the subacromial-subdeltoid bursa: report of two cases and literature review.

BACKGROUND: Multiple rice bodies (RB) in the shoulder joint is a rare disorder of unknown etiology that requires percutaneous drainage or surgical operation. CASE PRESENTATION: We reported arthroscopic removal of hundreds of RB in the subacromial-subdeltoid bursa in two cases by our "chopsticks technique". One was associated with seropositive rheumatoid arthritis and the other was a rare synovial origin possibly due to microinfarction and ischemia after the radiotherapy. Radical debridement of necrotic tissue, "red tissue" and synovitis by arthroscopic radiofrequency ablation was essential for eliminating the cause of RB. A favorable clinical evolution was observed for both patients. CONCLUSIONS: We highlight the importance of patient-specific differential diagnosis and the clinical course of RB to help us further understand the pathogenesis of this uncommon disorder. Meanwhile, evacuation of RB and "red tissue" ablation by arthroscopy showed good results.

Clinical efficacy of ultrasound-guided injection in the treatment of olecranon subcutaneous bursitis.

BACKGROUND: Recent studies have shown that ultrasound-guided injection of glucocorticoids is superior to blind puncture methods. OBJECTIVE: To evaluate clinical efficacy of ultrasound-guided drug injection in the treatment of olecranon subcutaneous bursitis. METHODS: From June 2016 to September 2018, 45 patients diagnosed with obvious synovial effusion and treated with ultrasound-guided injection therapy for olecranon bursitis were included in this study. Under the guidance of ultrasound, the synovial effusion aspiration was performed and 2 ml of the compound betamethasone mixture was injected into the bursae and dressed under pressure. Ultrasound examination was performed 2 weeks after operation and the secondary fluid aspiration and drug injection treatment were performed. The depth of synovial effusion, the thickness of synovial hyperplasia and the blood flow signal were measured 4 weeks after operation to evaluate the therapeutic effect. RESULTS: After first treatment, the recurrence rate of the olecranon mass were 40%. After secondary treatment, recurrence of olecranon mass occurred in 6 of the 45 patients with a recurrence rate of 13.3%. After 4 weeks of follow-up, the depth of olecranon synovial effusion, the average thickness of synovial hyperplasia and the blood flow signal decreased significantly after treatment (P < 0.05). CONCLUSIONS: Ultrasound-guided drug injection is safe and effective in treating olecranon subcutaneous bursitis. Although the recurrence rate is high after the first treatment, the second treatment is simple and can reduce the recurrence rate. The patients have a high acceptance rate, which is worthy of clinical promotion.

Ultrasound-Guided Versus Landmark-Based Approach to the Distal Suprascapular Nerve Block: A Comparative Cadaveric Study.

PURPOSE: To compare the accuracy of distal suprascapular nerve (dSSN) blockade performed with the use of ultrasound-guided regional anesthesia (USRA) versus with a landmark-based approach (LBA). A secondary aim was to describe the anatomic features of the sensory branches of the dSSN. METHODS: USRA and LBA were performed in 15 shoulders each from 15 cadavers (total of 30 shoulders). Then, 10 mL of methylene blue‒infused ropivacaine 0.75% was injected into the dSSN. Simultaneously, 2.5 mL of red latex solution was injected to identify the position of the needle tip. The division and distribution of the sensory branches originating from the SSN were described. RESULTS: The tip of the needle was identified at 1.3 cm (range, 0-5.2 cm) and 1.5 cm (range, 0-4.5 cm) with USRA and the LBA, respectively (P = .90). Staining diffused past the origin of the most proximal sensory branch in 27 cases. The most proximal sensory branch arose 2.5 cm from the suprascapular notch. Among the 3 failures that occurred in the USRA group, the sensory branches also failed to be marked. All 30 dSSNs gave off 3 sensory branches, which innervated the posterior glenohumeral capsule, the subacromial bursa, and the coracoclavicular and acromioclavicular ligaments. CONCLUSIONS: An LBA is as reliable and accurate as US guidance for anesthetic blockade of the dSSN. Marking of the suprascapular nerve must be proximal to the suprascapular notch to involve the 3 sensory branches in the anesthetic blockade. CLINICAL RELEVANCE: The present study demonstrates that a landmark-based approach to anesthetic blockade of the distal suprascapular nerve is accurate and can be performed by orthopaedic surgeons lacking experience in ultrasound-guided anesthetic techniques.

Bony changes of the tibia secondary to pes anserine bursitis mimicking neoplasm.

OBJECTIVE: To describe the radiological features of pes anserine bursitis with intramedullary extension and cortical scalloping and to determine the prevalence of these bony changes among patients with pes anserine bursitis. MATERIALS AND METHODS: Reports of knee magnetic resonance imaging (MRI) examinations performed at our institution between July 2007 and June 2017 in patients with pes anserine bursitis were retrospectively reviewed, and a total of 542 cases showing MR evidence of pes anserine bursitis were identified. From these, cases of pes anserine bursitis with intramedullary extension and cortical scalloping were identified. Two experienced musculoskeletal radiologists evaluated the MRI by consensus. The medical records of these patients were also reviewed. RESULTS: Eight patients were diagnosed with pes anserine bursitis with bony changes (prevalence, 1.47% [8 out of 542]), over the study period. All of these patients had a history of chronic knee pain. Seven patients also underwent radiography at the time of diagnosis; these images demonstrated variable appearances depending on the depth of the cortical scalloping and intramedullary extension. On MRI, all patients demonstrated a mass-like fluid extension around the pes anserine bursa and into the bone. None of the patients underwent biopsy; diagnosis was based on MRI features alone. CONCLUSION: Pes anserine bursitis with intramedullary extension is an unusual presentation of bursitis that may simulate a neoplasm clinically and radiologically. To avoid misdiagnosis, radiologists should be aware of the occurrence of osseous changes in the tibia confluent with pes anserine bursitis.

Factors associated with pain in nonsurgically treated rotator cuff tears -A study with magnetic resonance imaging.

BACKGROUND: In rotator cuff tears, some cases become asymptomatic with nonsurgical treatment, others remain symptomatic. The purpose of this study was to identify factors associated with pain in nonsurgically treated rotator cuff tears using magnetic resonance imaging (MRI). METHODS: In total, 108 shoulders diagnosed with supraspinatus (SSP) tendon tears using MRI were nonsurgically treated, and MRI was repeated after more than a year. The patients were divided into pain or improvement group according to whether the pain persisted or disappeared. Bursal fluid accumulation; SSP tendon retraction; subscapularis (SSC) tendon tears; infraspinatus (ISP) tendon tears; and Goutallier classification into SSC, SSP, and ISP were included as evaluation factors. Predictive factors for persistent pain on initial MRI and factors associated with persisting pain after nonsurgical treatment on repeat MRI were statistically analyzed using multivariate logistic regression analysis. RESULTS: The improvement group showed a significant decrease in bursal fluid accumulation compared with the pain group (p < 0.01). SSC tendon tears (OR, 4.42; 95% CI, 1.16-16.9; P = 0.03) on initial MRI were significantly associated with persistent pain. Bursal fluid accumulation (OR, 2.44; 95% CI, 1.18-5.07; P = 0.02) and SSC tendon tears (OR, 2.25; 95% CI, 1.15-4.39; P = 0.02) on repeat MRI were significantly associated with persistent pain. CONCLUSIONS: Bursal fluid accumulation decreased when pain improved. The involvement of SSC tendon tears can serve as a predictive factor for persistent pain. Pain may persist although patients with rotator cuff tears including SSC tendon tears are nonsurgically treated. LEVEL OF EVIDENCE: Level IV case-control study.

Huge Bursitis and Bursal Synovial Osteochondromatosis Associated With Scapular Osteochondroma Mimicking a Giant Calcific Mass of the Chest Wall.

Osteochondroma is the most common benign bone tumor, but it rarely arises from the scapula. Scapulothoracic bursitis is quite rare and osteochondroma is one of the unusual causes of this condition. Synovial chondromatosis may occur extremely uncommonly in this bursa. We reported an unusual case of scapulothoracic bursitis with synovial chondromatosis, which is caused by osteochondroma. To the best of our knowledge, there is no defined chondromatosis in the scapulothoracic bursa secondary to scapular osteochondroma in the literature.

Primary synovial osteochondromatosis of the shoulder: a rare cause of shoulder pain.

Synovial osteochondromatosis is a benign neoplastic condition which manifests as multiple cartilaginous or osteocartilaginous nodules within a joint, bursa and tendon sheath. It typically results in pain and stiffness of the affected joint, and is thought to arise as a result of synovial membrane proliferation and metaplasia. 1 We report the diagnosis and management of a 36-year-old man who presented with a long history of shoulder pain, which had been managed conservatively prior to referral to orthopaedics. Following investigation and subsequent diagnosis, he underwent successful surgical treatment of primary synovial osteochondromatosis, in the form of open synovial debridement and excision of nodules, with no recurrence demonstrated at 1-year follow-up. This case illustrates the diagnosis and management of primary synovial osteochondromatosis, and emphasises the importance of serial imaging and specialist referral for cases of diagnostic uncertainty or failure to respond to treatment as expected.

Synchronous bilateral lipoma arborescens of bicipitoradial bursa-a rare entity.

Lipoma arborescens is a rare non-neoplastic condition that affects the synovial lining of joints and bursae accounting for less than 1% of all lipomatous lesions. Characterized by villous proliferation of the synovium, it is an uncommon cause of intra/periarticular mass presenting as a painless, slowly progressive longstanding swelling, and is sometimes accompanied by intermittent monoarticular effusions. We describe a rare case of bilateral lipoma arborescens in the bicipitoradial bursae in a young male referred for MRI evaluation of spontaneous bilateral elbow swelling. We chose to bring this case to light because of the rare simultaneous involvement of the bicipitoradial bursae bilaterally and the role of MR in providing a definite diagnosis, hence obviating the need for biopsy and avoiding consideration of other complex intra/periarticular masses.

Outcomes and cost-effectiveness of ultrasound-guided injection of the trochanteric bursa.

We hypothesized that ultrasound (US) guidance improves outcomes of corticosteroid injection of trochanteric bursitis. 40 patients with greater trochanteric pain syndrome defined by pain to palpation over the trochanteric bursa were randomized to injection with 5 ml of 1% lidocaine and 80 mg of methylprednisolone using (1) conventional anatomic landmark palpation guidance or (2) US guidance. Procedural pain (Visual Analogue Pain Scale), pain at outcome (2 weeks and 6 months), therapeutic duration, time-to-next intervention, and costs were determined. There were no complications in either group. Ultrasonography demonstrated that at least a 2-in (50.8 mm) needle was required to consistently reach the trochanteric bursa. Pain scores were similar at 2 weeks: US: 1.3 ± 1.9 cm; landmark: 2.2 ± 2.5 cm, 95% CI of difference: - 0.7 < 0.9 < 2.5, p = 0.14. At 6 months, US was superior: US: 3.9 ± 2.0 cm; landmark: 5.5 ± 2.6 cm, 95% CI of difference: 0.8 < 1.6 < 2.4, p = 0.036. However, therapeutic duration (US 4.7 ± 1.4 months; landmark 4.1 ± 2.9 months, 95% CI of difference - 2.2 < - 0.6 < 1.0, p = 0.48), and time-to-next intervention (US 8.7 ± 2.9 months; landmark 8.3 ± 3.8 months, 95% CI of difference - 2.8 < - 0.4 < 2.0, p = 0.62) were similar. Costs/patient/year was 43% greater with US (US $297 ± 99, landmark $207 ± 95; p = 0.017). US-guided and anatomic landmark injection of the trochanteric bursa have similar 2-week and 6-month outcomes; however, US guidance is considerably more expensive and less cost-effective. Anatomic landmark-guided injection remains the method of choice, but should be routinely performed using a sufficiently long needle [at least a 2 in (50.8 mm)]. US guidance should be reserved for extreme obesity or injection failure.

Increased expression of type 1 cannabinoid (CB1) receptor among patients with rotator cuff lesions and shoulder stiffness.

BACKGROUND: Shoulder stiffness is a disease manifested by pain, limited range of motion, and functional disability. The inflammatory and fibrosis processes play a substantial role in the pathogenesis of shoulder stiffness. The CB1 receptor has been recognized to mediate the processes of pathologic fibrosis. This study investigated the role of the CB1 pathway in pathogenesis of rotator cuff lesions with shoulder stiffness. METHODS: All of the patients undergoing repair surgery for rotator cuff lesions were recruited and subcategorized into subjects with and without shoulder stiffness. Reverse transcription-polymerase chain reaction assay was used to evaluate the expression level of CB1 and interleukin 1ß (IL-1ß) in the subacromial bursae, and enzyme-linked immunosorbent assay was used to measure the concentration of CB1 and IL-1ß in the subacromial fluid. Tenocytes treated with CB1 agonists and antagonists were also studied for the relationship of CB1 and the inflammatory cytokine IL-1ß. RESULTS: The patients with shoulder stiffness had higher messenger RNA (mRNA) expression (P = .040) and immunohistochemistry staining (P < .001) of CB1 in the subacromial bursa and higher CB1 concentration in the subacromial fluid (P = .008). Tenocytes treated with the CB1 agonist WIN 55,212-2 and antagonist AM251 showed increased expression of IL-1ß mRNA (P = .049) and suppressed expression of IL-1ß mRNA (P = .001), respectively. DISCUSSION: The CB1 pathway is involved in the pathogenesis of shoulder stiffness. It may be a promising target for the treatment of rotator cuff lesions with shoulder stiffness.

Lipoma arborescens of the bicipitoradial bursa.

Lipoma arborescens (LA) is a rare, benign articular lesion that is most commonly found within the suprapatellar recess of the knee. An extremely rare case of LA involving unilateral bicipitoradial bursa is described in this study. A 58-year-old male presented with a superficial soft mass on the volar aspect of the left forearm. The magnetic resonance imaging (MRI) examination demonstrated a lobulated complex mass containing multiple frond-like fatty nodules, along the distal biceps tendon in the bicipitoradial bursa. Ultrasound-guided biopsy of the lesion confirmed the diagnosis of LA and patient was scheduled for surgical excision. Recognizing the characteristic imaging of LA, particularly on MRI, is essential for accurate pre-procedural diagnosis.

Treatment and outcome with traumatic lesions of the olecranon and prepatellar bursa: a literature review apropos a retrospective analysis including 552 cases.

BACKGROUND: Traumatic lesions of the olecranon bursa (OB) and prepatellar bursa (PB) are injuries commonly seen in orthopaedic trauma units. These injuries are associated with a high rate of complications. At present, only little is known about the incidence, complication rate, and treatment approaches in patients with acute open bursae. MATERIALS AND METHODS: A total of 552 patients who had been treated for acute traumatic lesions of either the olecranon bursa or the prepatellar bursa, or both at our department were retrospective identified in the years between 2009 and 2014. An analysis of the medical history of these patients was carried out to investigate the incidence of bursa injuries, circumstances, concomitant injuries, complication rate, and treatment approaches. In addition, a systematic literature search on PubMed was conducted. RESULTS: The incidence of traumatic lesions of the OB or PB in trauma patients was 0.2% (198/100,000; 62% OB, 38% PB). Bursectomy was performed in 83.7%. Concomitant injuries were present in 41% of the cases, with no significant influence on the complication rate (P = 0.367). The overall complication rate was 19.7%. Revision surgery was necessary in 4.5% of the patients. No significant differences between OB and PB injuries were noted with regard to the complication rate (P = 0.221). There were also no significant differences in the complication rate between patients who received bursectomy and those with conservative treatment (P = 0.364). Regression analyses showed that prophylactic antibiotic administration significantly reduced the risk of infection (P = 0.04). CONCLUSIONS: Traumatic lesions of the OB and PB are associated with a high risk of complications. Prophylactic antibiotic therapy can potentially reduce the risk of infection and the need for revision surgery.

Ultrasound evaluation of bursae: anatomy and pathological appearances.

A bursa is an extra-articular sac that may communicate with a joint and functions to decrease friction between tendons and either bone or skin. Bursae can be classified as native and non-native (adventitious) bursae. The native bursae are lined with a synovial membrane and occur at predictable anatomical sites; knowledge of these normal structures can help distinguish them from other pathological entities. An adventitious bursa can form at sites of friction rather than at predictable anatomical sites, but otherwise have imaging features similar to native bursae. Bursal distention can occur from many pathological processes, most commonly resulting from chronic overuse injury. When imaging bursal pathological conditions, there is often an overlap of imaging findings, regardless of the cause. In general, ultrasound of a distended bursa reveals a fluid collection with either simple anechoic or more complex hypoechoic fluid. Bursal distention is characteristically unilocular and compressible, unlike other structures such as ganglion cysts, which are usually multilocular and non-compressible. This article reviews the anatomical locations of common bursae and shows pathological examples using ultrasound. Knowledge of typical locations and imaging appearances of bursae can aid in narrowing the differential diagnosis and guiding further management and treatment decisions.