Anatomy of the congenital calcaneal bursae in the bovine.

OBJECTIVE: The objective of this study was to determine the anatomical relationship of the congenital calcaneal bursae in the bovine, and describe the computed tomography (CT), endoscopic and gross anatomy of these bursae. STUDY DESIGN: Ex vivo experimental. SAMPLE POPULATION: Eighteen clinically normal cadaver bovine hindlimbs. METHODS: Intrasynovial injection of iodinated contrast and methylene blue into the intertendinous calcaneal bursa (ICB) (n = 16) or gastrocnemius calcaneal bursa (GCB) (n = 2). Limbs were imaged post-contrast injection using multidetector CT. Endoscopic examination of the ICB was performed on two randomly selected limbs. All limbs underwent gross anatomical dissection. RESULTS: The anatomy of the congenital calcaneal bursae was consistent between CT imaging, endoscopic examination and gross dissection. The ICB and GCB were two separate synovial structures with no communication in all limbs. The distal and proximal extent of the ICB, defined as the distance from the point of tuber calcanei to the distal/proximal aspect of the ICB, was (median [IQR]) 7.4 (7.4 to 7.8) cm distally and 5.4 (4.7 to 6.0) cm proximally. CONCLUSION: Positive contrast CT and gross anatomical dissection revealed no communication between the congenital calcaneal bursae in any limb. Routine bursoscopy allowed complete endoscopic examination of the ICB. The proximal extent of the ICB is shorter than the distal extent. The use of a collective term for these bursae should be avoided in the bovine, as the ICB and the GCB are two separate synovial structures with no communication. CLINICAL SIGNIFICANCE: Knowledge of distinct anatomy and relationship between the congenital calcaneal bursae in the bovine may facilitate diagnosis and treatment of disorders affecting the region of tuber calcanei, including septic bursitis and osteomyelitis.

MR Imaging of the Knee Bursae and Bursal Pathology.

The main function of the knee bursae is to provide cushioning for the many periarticular ligaments, tendons, and osseous structures. Bursae can only be visualized when distended by fluid, therefore bursal anatomy is best evaluated by MR imaging using fluid-sensitive sequences. Knowledge of the normal bursal distribution is important to avoid incorrectly interpreting a distended bursa as a periarticular fluid collection or cyst. Bursal pathology usually results from trauma, chronic overuse, or inflammation, and may be associated with an underlying intra-articular process, given the presence of synovial lining and different degrees of communication with the joint.

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.

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.

Development of a Novel Medial Synoviocentesis Approach to the Bicipital Bursa in an Equine Cadaver Model.

OBJECTIVE: To describe the volume and dimensions of the bicipital bursa and its position in relation to bony and soft tissue structures, in order to develop a novel medial synoviocentesis approach to the bicipital bursa. STUDY DESIGN: Cadaveric study. ANIMALS: Adult equine cadaver limbs (n=19). METHODS: Bicipital bursa dimensions, volume, and relationship to bony structures were obtained from positive contrast computed tomography images after distension of the bursa (n=7). Following an intra-bursal injection of polyurethane resin, the bicipital bursa (n=4) was dissected and its relationship to soft tissue structures described. After computed tomography and dissection, a novel medial bicipital bursocentesis approach was investigated on intact cadavers (n=8). RESULTS: Median (range) of measurements were: length 9.02 cm (8.48-9.45 cm); width 7.06 cm (6.71-8.01 cm); and volume 51 mL (45-58 mL). The medial aspect of the bicipital bursa was located at the junction of the subclavius and biceps muscles, which corresponds with the externally visible lateral pectoral sulcus. Needle insertion 5-10 mm craniolateral to the center of the lateral pectoral sulcus midway between the palpable distal aspect of the deltoid tuberosity and the cranial part of the greater tubercle was found to be a reliable landmark for the novel medial bursocentesis approach. This approach was successful in all cadavers. CONCLUSION: The novel approach to the bicipital bursa provided access to the medial aspect of the bursa and is an alternative to the lateral approaches. Further validation in live horses is warranted to establish the safety and efficacy of this technique.

Accessibility of extra-articular pathologies of iliopsoas tendon and bursitis of greater trochanter in hip arthroscopy.

PURPOSE: Different pathologies leading to psoas tendon pain and chronic bursitis of the greater trochanter are well known. The purpose of the study was to underline the accessibility of the psoas tendon at lesser trochanter, reproduce the results and measure the distances to anatomical landmarks. METHODS: Twelve hips of six human cadavers underwent hip arthroscopy. The accessibility of the iliopsoas tendon at the lesser trochanter and the bursa at the greater trochanter was documented with the camera. In addition to the usual access portals, alternative ventral ports were analysed concerning accessibility of the lesser trochanter. Afterwards, arthroscopy needles were placed along the extra-articular portals followed by dissection. The distances of the portals in relation to important anatomical landmarks were analysed. RESULTS: The accessibility to the iliopsoas tendon at the lesser trochanter and to the bursa at the greater trochanter throughout the conventional portals was reproducible. Sufficient distances to the important anatomical landmarks could be shown. The mean distance of the distal ventro-lateral and the wide distal ventro-lateral portal to the nervous cutaneous femoris lateralis was 26.8 ± 5.4 mm and 32.2 ± 3.9 mm. The mean distance from the more ventral located portals to the nervous arteria and vena femoralis was 28.3 ± 2.1 mm. CONCLUSION: This is the first study known to us that describes in detail the accessibility of the extra-articular structures underlined by anatomical preparation. In addition, it was demonstrated that a more ventrally located portal had sufficient distance to the important neurovascular structures of the ventral femur and can also be used in addendum if necessary.

MR imaging of synovial disorders of the knee.

Synovial membranes line the diarthrodial (movable) joints, bursae, and tendon sheaths of the body. The primary function of this specialized, vascular tissue is to serve as a filter system that lubricates and nourishes the articular structures as well as serving as a shock-absorber. The synovium is affected by a variety of disorders that can be localized to a specific articulation or can be systemic in nature. These include inflammatory, infectious, degenerative, traumatic, or neoplastic categories of disease. Further, MR imaging provides an excellent non-invasive tool for the evaluation of the synovium and synovial-based processes. This article will discuss technical considerations pertinent to the MR imaging evaluation of synovial processes in the knee; will review the synovial and bursal anatomy of the knee as well as the imaging characteristics of general synovial abnormalities and their diagnostic implications. In addition, it will review specific synovial processes and their characteristic MR imaging findings.

Distances to the subacromial bursa from 3 different injection sites as measured arthroscopically.

PURPOSE: The purpose of this study was to assess the distance for a standard needle to reach the subacromial bursa through 3 commonly used approaches. METHODS: Thirty patients without associated rotator cuff tears underwent arthroscopic evaluation of the shoulder. The bursa was entered without shaving or altering of the bursa. By use of standard arthroscopic portals, a spinal needle was inserted from an anterior, lateral, and posterior position and measured to define the distance to the subacromial bursa from the skin. RESULTS: The mean distance with anterior needle placement was 2.9 +/- 0.6 cm. The mean distance with lateral needle placement was 2.9 +/- 0.7 cm. The mean distance with posterior needle placement was 5.2 +/- 1.1 cm. The mean body mass index for the group of patients was 27.5. The minimum was 18.7, and the maximum was 42.8. CONCLUSIONS: The distance to the subacromial bursa from the anterior and lateral approaches appears to be consistent and within reach of a standard 22- or 25-gauge needle. The distance to the subacromial bursa from a posterior approach appears to be almost double that of the anterior and lateral approaches and may not be reachable by standard 22- and 25-gauge needles in all patients. There appears to be no correlation between distances to the subacromial bursa from the anterior, lateral, or posterior approaches and the patient's body mass index. CLINICAL RELEVANCE: Given the relative distances measured to the subacromial bursa from the anterior, lateral, and posterior positions, clinicians may choose a longer needle to improve the accuracy of placement when approaching the subacromial bursa from a posterior position. Use of a standard-length needle will provide reasonable accuracy from the anterior and lateral positions.

Clearing a blind spot in knee arthroscopy: popliteal bursa.

Each arthroscopic portal to the knee has a blind area that cannot be inspected directly. In particular, visualization of the posterior compartment is difficult to access. Although arthroscopic procedures for the posterior compartment of the knee joint have been developed through posteromedial, posterolateral and posterior trans-septal portal, the popliteal bursa remains as an area that is difficult to access and manipulate. We report a surgical procedure that can examine one of the blind spots in knee arthroscopy, popliteal bursa.

Morphology of the bursae associated with the greater trochanter of the femur.

BACKGROUND: Abnormalities of the bursae in the vicinity of the greater trochanter have been implicated in the pathogenesis of lateral hip pain. The purpose of the present study was to investigate the detailed morphology of the bursae associated with the greater trochanter of the femur. METHODS: The bursae deep to the tendons of each of the gluteal muscles were examined in eighteen embalmed human hips with use of macrodissection and histological techniques. The specimens were obtained from eight female and seven male donors who had had a mean age of seventy-eight years at the time of death. RESULTS: A total of 106 bursae were identified in ten different locations, with an average of six bursae per hip. As many as four bursae were present beneath the gluteus maximus muscle and the fascia lata, including those normally thought of as the "trochanteric" bursae and the gluteofemoral bursa. Two bursae typically were found beneath the tendon of the gluteus medius muscle: the anterior subgluteus medius bursa and the piriformis (posterior subgluteus medius) bursa. In the majority of cases, a single bursa was located deep to the gluteus minimus tendon, although two different bursae were identified: the subgluteus minimus bursa and the secondary subgluteus minimus bursa. All of these bursae demonstrated a synovial lining, which was predominantly areolar in type. CONCLUSIONS: The present study revealed that numerous bursae are intimately associated with the greater trochanter and that at least two bursae are associated with each of the gluteal tendons.

An anatomic study of the calcaneal bursae in the horse.

OBJECTIVES: To establish an injection site for the gastrocnemius calcaneal bursa (GCB), to identify communication patterns between the calcaneal bursae, to estimate the proximal and distal extents of the intertendinous calcaneal bursa (ICB) and to identify variations from previous anatomic descriptions. STUDY DESIGN: Descriptive anatomic study. ANIMALS: Cadaveric equine hindlimbs (n=18) from 9 adult horses. METHODS: Communication between the ICB and GCB was determined in 18 cadaveric hindlimbs by injection of a latex mixture, followed by examination of sequential sagittal sections and documentation of the distribution of the latex mixture and communication sites. The distal and proximal extents of the ICB and subcutaneous calcaneal bursa (SCB), relative to the tuber calcanei (TC) were recorded. RESULTS: Communication between the ICB and the GCB was confirmed on the medial and lateral aspect in 100% and 50% of limbs, respectively. Communication between the SCB and the ICB, and therefore the GCB, was identified in 39% of limbs. Plantar reflections of the ICB existed in 33% of limbs. Mean extent of the ICB relative to the TC was 7.0 cm distally and 9.6 cm proximally. The SCB often occupies a more distal position than previously reported. CONCLUSIONS: The ICB and the GCB should be considered 1 synovial structure with 2 communicating compartments. CLINICAL RELEVANCE: The GCB may be an alternative site for synoviocentesis when there is septic calcaneal bursitis. Improved knowledge of calcaneal bursae anatomy may aid in diagnosis and treatment of lesions involving these structures.

The subscapular and subcoracoid bursae: descriptive and functional anatomy.

The subscapularis and subcoracoid bursae, as well as the subscapularis muscle, were studied in 42 fresh cadaveric shoulders. Fibrous bands were found in the medial part of the muscle; they were intercalated with the distal tendon-like bands. The superior distal fibrous band was always found to be thicker than the others. Strong fibrous attachments of the subscapularis muscle were found along the lateral border of the scapula as well as along the medial third of the bony crests in the subscapular fossa. Between the crests, the muscle bundles were directly attached to the bone. In the lateral part of the scapula, the subscapularis muscle had only weak connective links with the bone. The subscapularis bursa was found in all cases as a pouch strongly attached to the scapular neck and the adjacent part of the joint capsule. The top of the bursa was linked to the coracoid process by a fibrous attachment called the suspensory ligament. The subcoracoid bursa had only weak connective links with the coracoid process. In 28% of cases, the subscapularis and subcoracoid bursae merged into a unique wide bursa. The subscapular bursa had two types of links with the muscle: (1). weak connective links with the superficial muscle bundles and (2). at least 2 fibrous arcs joining the lateral tendon-like bands, the bursa, and bony crests of the subscapularis fossa. These arcs allow the bursa to follow the course of the muscle exactly. During movements of the glenohumeral joint, the subscapularis muscle sustains huge changes of orientation, particularly the upper part of the muscle that coils around the coracoid process. The strong superior fibrous band enables the muscle to maintain contact with the coracoid process. It is the function of the subscapularis and subcoracoid bursae to manage the friction of the superficial fibers against the scapular neck, the humeral head, and the coracoid process.

Obturator externus bursa: anatomic origin and MR imaging features of pathologic involvement.

PURPOSE: To investigate the anatomy of the obturator externus bursa of the hip and describe the magnetic resonance (MR) imaging features of pathologic involvement. MATERIALS AND METHODS: The authors dissected eight cadaver hemipelvises to assess for the presence of periarticular bursae of the hip and bursal communication with the fascial plane of the obturator externus muscle. In addition, 10 consecutive patients with obturator externus bursa enlargement were prospectively identified with MR imaging. A bursa was considered present when a fluid collection was seen extending along the obturator externus muscle, continuous with the posterior inferior hip joint. The direction, extent, contour, and thickness of the bursa and hip capsule were recorded. Surgical findings were available for eight of the 10 patients, with histopathologic correlation between the bursal lining and hip capsule. RESULTS: At cadaveric dissection, one specimen showed a bursa communicating with and extending from the posteroinferior aspect of the hip joint deep to the obturator externus tendon. In all 10 patients, MR images showed a hip joint effusion with a continuous bursa extending medially and displacing the obturator externus inferiorly. At surgery, a bursa was seen displacing the obturator externus muscle inferiorly and originating from the posteroinferior aspect of the hip joint in all eight patients. Results of pathologic analysis confirmed disease identical to the primary hip abnormality in all eight patients. CONCLUSION: The obturator externus bursa is a potential posteroinferior communication of the hip joint capsule, can be a site of disease spread from the hip joint, and can be accurately identified with MR imaging.

Ultrasonographic evaluation of the canine shoulder.

The aim of this study was to determine the normal ultrasonographic anatomy of the canine shoulder. Fourteen shoulders from 7 clinically normal mid-sized dogs were radiographed and imaged using high frequency ultrasound. Each shoulder was isolated postmortem, and the ultrasonographic and gross anatomy was studied during dissection. The ultrasonographic appearance of the shoulder specimens was similar to that found in the live dogs. Twenty-four shoulders isolated postmortem from 12 variably sized dogs were also used to characterize the normal ultrasound anatomy over a range of sizes. Important anatomic structures that could be consistently evaluated were the biceps tendon and bursa, the bicipital groove surface, the supraspinatous tendon, the infraspinatous tendon, the teres minor tendon, and the caudal aspect of the humeral head. Results of ultrasonographic examination of 4 dogs with shoulder lameness are described to illustrate some applications of canine shoulder ultrasonography in the evaluation of the canine shoulder. In these dogs, ultrasound was a valuable tool to evaluate effusion and synovial proliferation within the bicipital bursa, supraspinatous and biceps tendinitis, biceps tendon strain, and dystrophic calcification.

Endoscopy of the intertubercular bursa in horses.

Forelimbs from 3 anesthetized horses and 16 fresh cadaver horses were used to describe the endoscopic anatomy of the intertubercular bursa and outline the surgical portals that provide the greatest access to structures within the bursa. A lateral arthroscopic portal was made proximal to the deltoid tuberosity of the humerus into the distal bursal recess. A second portal was created proximal to the humeral tubercles that entered the proximal bursal space. These approaches provided consistent viewing and instrument access to the lateral intertuberal groove, the greater and intermediate humeral tubercles, and the synovial membrane of the proximal and distal bursal recesses. The intermediate tubercle and heavy muscle mass restricted access to the medial intertuberal groove and lesser tubercle. This technique may provide a less invasive alternative to bursotomy in the surgical management of selected horses with intertubercular bursitis. Clinical applications include cartilage debridement, fragment removal, partial synovectomy, and high-volume lavage.

Useful boundaries of the subacromial bursa.

The anatomic boundaries the subacromial bursa may serve as a useful guide for surgical orientation and safety. The goals of this study were to measure the minimum distance between the subdeltoid reflection of the subacromial bursa and the circumflex branch of the axillary nerve and to identify relationships between the margins of the subacromial bursa and the acromion, rotator cuff, and acromioclavicular joint. Seventeen fresh-frozen cadavers (mean age, 69 years), were included. Eleven cadavera were dissected only after the subacromial bursa was injected with a latex solution to define the peripheral boundaries of the bursa. The bursal margins were always 2 cm or more from the anterolateral corner of the bursal acromial surface and the bursa lined the anterior half of the anteroposterior distance of the acromion. The mean distances from all points of the acromion to the axillary nerve averaged approximately 5 cm. The mean minimum distance from the subdeltoid bursal reflection to the axillary nerve was 0.8 +/- 0.5 cm with a range of 0.0 to 1.4 cm. In the unelevated extremity, the inferior bursal reflection was always cephalad to the axillary nerve even when the two structures were apposed. Surgeons should exercise caution when approaching the inferior boundary of the subdeltoid bursal reflection because of the proximity to the axillary nerve. We recommend coupling previously reported "safe deltoid-split" distances to this useful anatomic landmark to prevent nerve injury. Furthermore, the central location of the anterolateral corner of the acromion within the bursal space can be applied to needle placement for injection, arthroscopic diagnosis or treatment and mini-open rotator cuff repairs.

The anatomy of the deep infrapatellar bursa of the knee.

Disorders of the deep infrapatellar bursa are important to include in the differential diagnosis of anterior knee pain. Knowledge regarding its anatomic location can aid the clinician in establishing a proper diagnosis. Fifty cadaveric knees were dissected, and the deep infrapatellar bursa had a consistent anatomic location in all specimens. The deep infrapatellar bursa was located directly posterior to the distal 38% of the patellar tendon, just proximal to its insertion on the tibial tubercle. There was no communication to the knee joint. Its average width at the most proximal margin of the tibial tubercle was slightly wider than the average distal width of the patellar tendon. It was found to be partially compartmentalized, with a fat pad apron extending down from the retropatellar fat pad to partially divide it into anterior and posterior compartments. The recommended approach to this bursa, either for aspiration, injection, or surgery, is along the lateral edge of the patellar tendon just proximal to the tibial tubercle.

The lateral synovial recess of the knee: anatomy and role in chronic Iliotibial band friction syndrome.

The tissue deep to the iliotibial band (ITB) and its relationship to the lateral knee joint capsule was studied anatomically and the histopathology of this tissue in chronic iliotibial band friction syndrome (ITBFS) was examined. Findings show that the tissue under the ITB consists of a synovium that is a lateral extension and invagination of the actual knee joint capsule and is not a separate bursa as described in the literature. Additionally, in cases of chronic ITBFS seen in young elite athletes, synovial tissue taken from this lateral synovial recess reveals histological evidence of inflammation and hyperplasia that suggests its involvement in the pathological process.

The semimembranosus-tibial collateral ligament bursa. Anatomical study and magnetic resonance imaging.

A bursa that was deep to the tibial collateral ligament and adjacent to the semimembranosus tendon was studied in fifty cadaveric knees; a vinyl solution was injected into four of the specimens in order to facilitate a study of the relationship between the bursa and its surrounding structures. The bursa had the shape of an inverted U: the superficial arm was an elliptical pocket that was located between the semimembranosus tendon and the tibial collateral ligament, and the deep arm was a triangular pocket that was located between the semimembranosus tendon and the medial tibial condyle. The bursa measured, on the average, twenty-one millimeters in its greatest anteroposterior dimension and ten millimeters in its greatest superoinferior dimension. Magnetic resonance images were made of two patients, and they showed fluid in the bursa.

Communication of the ulnaris lateralis bursa with the equine elbow joint and evaluation of caudal arthrocentesis.

Elbows from cadaver limbs were evaluated to determine the presence of a communication between the ulnaris lateralis bursa (ULB) and the joint and the extent of the bursa. Thirty-two pairs of joints were studied: 12 pairs were frozen, then transversely sectioned and 20 pairs were injected with methyl methacrylate. The 12 frozen-section pairs revealed a communication between the ULB and the elbow joint in 9/24 joints (37.5%) and a true bursa (absence of communication) in 15/24 joints (62.5%). The mean bursal length in adult horses was 3.8 cm. There was no significant difference in the length of the bursa or presence of bursa-joint communication between the right and left limbs. In the acrylic specimens a communication between the ULB and the joint was found in 19/40 specimens (47.5%). There was no significant correlation between age or sex and frequency of communication. There was a significantly greater prevalence of communications present in Quarter Horse than in non-Quarter Horse (P < 0.05) joints. A communication between the ULB and the joint is not always present, and therefore injection of the elbow joint via the ULB may be unreliable.