Ultrasound anatomy of the fingers: flexor and extensor system with emphasis on variations and anatomical detail.

Many anatomical details and variants occur in the finger tendons and soft tissue structures. These may lead to misdiagnosis if the radiologist is not well aware of them. We discuss the midhand extensor tendons, dorsal hood, junctura tendinea, conjoint tendons, transverse retinacular ligament, triangular ligament as well as central and distal slip anatomy and ultrasound correlation. The dorsal hood is an important structure to center the tendons at the midportion of the MCP heads, and the sagittal bands are its main components. Two tendons are present at the second digit, and two or more at the fifth digit. The extensor mechanism is anatomically interrelated with the palmar lumbricals and interosseous tendons. At the palmar side, the flexor superficialis and profundus tendons show varying relationships along the finger. The flexor profundus passes through an opening in the flexor superficialis. We also discuss the chiasma crurale, ridges at the flexor superficialis insertions and bifid flexor profundus tendon. Although a typical distribution of annular pulleys can be observed, many variants may be present of which we address some. The volar plate is a midline fibro-cartilaginous meniscus attached proximally to the well-identifiable checkrein ligaments and distally to the base of the phalanges. Knowledge of these details and variations allows for better understanding of the finger and hand ultrasound.Many anatomical details and variants occur in the finger tendons and soft tissue structures. These may lead to misdiagnosis if the radiologist is not well aware of them. We discuss the midhand extensor tendons, dorsal hood, junctura tendinea, conjoint tendons, transverse retinacular ligament, triangular ligament as well as central and distal slip anatomy and ultrasound correlation. The dorsal hood is an important structure to center the tendons at the midportion of the MCP heads, and the sagittal bands are its main components. Two tendons are present at the second digit, and two or more at the fifth digit. The extensor mechanism is anatomically interrelated with the palmar lumbricals and interosseous tendons. At the palmar side, the flexor superficialis and profundus tendons show varying relationships along the finger. The flexor profundus passes through an opening in the flexor superficialis. We also discuss the chiasma crurale, ridges at the flexor superficialis insertions and bifid flexor profundus tendon. Although a typical distribution of annular pulleys can be observed, many variants may be present of which we address some. The volar plate is a midline fibro-cartilaginous meniscus attached proximally to the well-identifiable checkrein ligaments and distally to the base of the phalanges. Knowledge of these details and variations allows for better understanding of the finger and hand ultrasound.

MR imaging-anatomical-histological evaluation of the abdominal muscles, aponeurosis, and adductor tendon insertions on the pubic symphysis: a cadaver study.

PURPOSE: To perform an MR(magnetic resonance) imaging, anatomical, and histological evaluation of the abdominal muscles and adductor tendon insertions. METHOD: Four fresh cadaveric pelvis specimens were imaged at 3 T with the following imaging parameters: TE (echo time)/TR (repetition time): 20, 4090, slice thickness: 2 mm, FOV: 270 × 90, matrix size: 512. Anatomical slices were obtained with a band saw and photographed. MR images and photographs were evaluated by an anatomist and radiologist. Selected 3 mm thick slices were placed in formalin and decalcified, cut, placed on large slides, and stained with hematoxylin eosin stain (HES). RESULTS: The main adductor tendon insertions are: the anterosuperior aspect of the pubic bone for the adductor longus, the anteroinferior aspect of the pubic bone - for the adductor brevis, and the inferior aspect of the pubic bone for the adductor magnus. On histology, the adductor longus tendon fibers inserted perpendicularly into the bone at a fibrocartilage enthesis and cross connected along the anterior pubic ligament into the controlateral tendon. The rectus abdominis-pyramidalis unit was covered by a thin anterior and posterior aponeurosis. The posterior aponeurosis inserted into the superior aspect of the anterior pubic ligament, whereas the anterior aponeurosis fused distally with the adductor longus tendons. CONCLUSION: Our findings demonstrate the insertions of the adductor tendons, on the pubic ligament and pubic bone.Histologically, the adductor longus tendon fibers inserted perpendicularly into the bone through a fibrocartilage enthesis, and cross connected along the anterior pubic ligament into the contralateral tendon.

Ankle and midfoot ligaments: Ultrasound with anatomical correlation: A review.

We present a detailed overview of anatomical and US features of ankle and midfoot ligaments based on our own dissections and cadaver studies as well as US imaging in cadavers and volunteers. The ligament anatomy about the ankle and midfoot is complex. Most ligaments are superficial and hence very well accessible for US. US technique to obtain optimal visualization however is difficult and requires a learning curve. We discuss US technique in detail for each individual ligament. We divided the ligaments in different groups: tibiofibular ligaments, Bassett's ligament, lateral collateral ligament complex (anterior talofibular ligament, calcaneofibular ligament, lateral talocalcaneal ligament, posterior talofibular ligament), medial collateral ligament complex, spring ligament, Chopart joint ligaments (bifurcate ligament, dorsal talonavicular ligament, lateral calcaneocuboid ligament, long and short plantar ligaments), Lisfranc ligaments, sinus tarsi ligaments.

Normal Anatomy and Compression Areas of Nerves of the Foot and Ankle: US and MR Imaging with Anatomic Correlation.

The anatomy of the nerves of the foot and ankle is complex, and familiarity with the normal anatomy and course of these nerves as well as common anatomic variants is essential for correct identification at imaging. Ultrasonography (US) and magnetic resonance (MR) imaging allow visualization of these nerves and may facilitate diagnosis of various compression syndromes, such as "jogger's heel," Baxter neuropathy, and Morton neuroma. It may be difficult to distinguish the nerves from adjacent vasculature at MR imaging, and US can help in differentiation. The authors review the normal anatomy and common variants of the nerves of the foot and ankle, with use of dissected specimens and correlative US and MR imaging findings. In addition, the authors illustrate proper probe positioning, which is essential for visualizing the nerves at US. The authors' discussion focuses on the superficial and deep peroneal, sural, saphenous, tibial, medial and lateral plantar, medial and inferior calcaneal, common digital, and medial proper plantar digital nerves.

Ultrasound of the knee with emphasis on the detailed anatomy of anterior, medial, and lateral structures.

OBJECTIVE: To describe the detailed ultrasound anatomy of the anterior, medial, and lateral aspects of the knee and present the ultrasound examination technique used. MATERIALS AND METHODS: We present ultrasound using images of patients, volunteer subjects, and cadaveric specimens. We correlate ultrasound images with images of anatomical sections and dissections. RESULTS: The distal quadriceps tendon is made up of different laminas that can be seen with ultrasound. One to five laminas may be observed. The medial retinaculum is made up of three anatomical layers: the fascia, an intermediate layer, and the capsular layer. At the level of the medial patellofemoral ligament (MPFL) one to three layers may be observed with ultrasound. The medial supporting structures are made up of the medial collateral ligament and posterior oblique ligament. At the level of the medial collateral ligament (MCL), the superficial band, as well as the deeper meniscofemoral and meniscotibial bands can be discerned with ultrasound. The posterior part, corresponding to the posterior oblique ligament (POL), also can be visualized. Along the posteromedial aspect of the knee the semimembranosus tendon has several insertions including an anterior arm, direct arm, and oblique popliteal arm. These arms can be differentiated with ultrasound. Along the lateral aspect of the knee the iliotibial band and adjacent joint recesses can be assessed. The fibular collateral ligament is encircled by the anterior arms of the distal biceps tendon. Along the posterolateral corner, the fabellofibular, popliteofibular, and arcuate ligaments can be visualized. CONCLUSION: The anatomy of the anterior, medial, and lateral supporting structures of the knee is more complex than is usually thought. Ultrasound, with its exquisite resolution, allows an accurate assessment of anatomical detail. Knowledge of detailed anatomy and a systematic technique are prerequisites for a successful ultrasound examination of the knee.

Ultrasound of the sural nerve: normal anatomy on cadaveric dissection and case series.

The sural nerve is a small sensory nerve innervating the lateral aspect of the ankle and foot. Clinical symptoms of pathology may present as atypical sensory changes in this region. We present the normal anatomy and ultrasound technique for examination of the sural nerve based on an anatomical dissection, as well as imaging in a normal volunteer. We also present a case series (n=10) of different conditions of the sural nerve that we encountered based on a review of interesting cases from 4 institutions. The pathological conditions included neuropathy related to stripping or venous laser surgery, compression by abscess, Lyme disease, nerve tumors, traumatic transsection, and encasement by fibrous plaque and edema. Ultrasound with its exquisite resolution is the preferred imaging method for examining the sural nerve in patients with unexplained sensory changes at the lateral aspect of the ankle and foot.

Ultrasound of the elbow: a systematic approach using bony landmarks.

The use of bony landmarks can be helpful in performing an ultrasound study of the elbow. We discuss bony landmarks that can be used for evaluation of the common extensor tendon, ulnar collateral ligament and common flexor tendon, coronoid and olecranon fossa, ulnar nerve, and biceps tendon. We discuss bony landmarks for each of these structures.

Ultrasound findings in injuries of dorsal extensor hood: correlation with MR and follow-up findings.

OBJECTIVE: The aim of this study was to use ultrasound to examine the dorsal hood in nine patients with a clinical suspicion of dorsal hood injuries. MATERIAL AND METHODS: Clinical and imaging files from interesting case logbooks of nine patients were reviewed. Ultrasound was performed by one of the three radiologists experienced in musculoskeletal ultrasound. The examinations were also performed in flexion and in flexion with resistance. MR correlation was obtained in six patients. One patient underwent surgery. To obtain anatomical correlation of the normal dorsal hood 2 embalmed hand specimens were dissected. RESULTS: The sagittal bands were easily depicted in the transverse plane on ultrasound images and presented as hypoechoic bands on both sides of the extensor communis tendons. Injuries of the sagittal bands were seen on ultrasound as hypoechoic thickening of the sagittal bands at the side of the extensor tendons. The normal shape of the sagittal bands was also no longer recognizable. Subluxations or dislocations of the extensor tendons were also seen. When the injuries were located in the fibrous slips between the extensor indicis and the extensor communis of the second finger, subluxations with an increased distance between these 2 tendons were seen, especially in flexion, or in flexion with resistance. CONCLUSION: Ultrasound is a valuable tool for the assessment of the injuries of the dorsal hood and is an easily available method for the diagnosis of the fine soft tissue components of the dorsal hood region.

The thickness of the sagittal bands in volunteers: high resolution ultrasound of the fingers.

PURPOSE: A sign of injury of the sagittal bands is thickening. The normal values for the thickness of the sagittal bands has not been described before. Our purpose was to measure the thickness of the sagittal bands with ultrasound in normal volunteers and compare differences between radial and ulnar band, dominant and non-dominant hand, different fingers, and men and women. MATERIALS AND METHODS: In 21 volunteers (10 men, 11 women), high resolution ultrasound imaging of the fingers was performed by two radiologists. The index, mid finger, ring finger and little finger were analyzed. The mean values were obtained for each finger. Statistical differences were calculated with a two-tailed Student's t test. RESULTS: The thickness of the sagittal bands showed a wide range of variations. Statistically significant differences were not found between the radial and ulnar band, dominant and non-dominant hand, and different fingers. Between men and women a significant difference was found for the ulnar band of index and ring finger of the dominant hand. CONCLUSION: The measurements of the sagittal bands show a wide range of values. Statistically significant differences for the means were only found for the ulnar band of index and ring finger of the dominant hand between men and women.

Spectrum of normal and pathologic findings in the region of the first extensor compartment of the wrist: sonographic findings and correlations with dissections.

OBJECTIVE: The purpose of this presentation is to review pathologic conditions that lead to pain at the radial aspect of the distal radius and to address anatomic variations of the first extensor compartment that exist and may have diagnostic and therapeutic implications. METHODS: Our presentation is based on a review of cases from teaching files and observations made in anatomic specimens. RESULTS: The discussed conditions include de Quervain tenosynovitis, intersection syndrome, and Wartenberg syndrome. Sonographic diagnosis of these conditions is addressed, and correlations are provided with anatomic specimens. CONCLUSIONS: Sonography is able to depict and differentiate between these conditions.

Functional anatomy of the dorsal hood or the hand: correlation of ultrasound and MR findings with cadaveric dissection.

The main aim of this study was to provide an overview of the anatomy of the dorsal hood (DH) based on the dissection of sixteen cadaver hands, correlated with magnetic resonance (MR) and ultrasound findings. A secondary aim was to assess the function of components of the DH. Sixteen embalmed hands were evaluated by MRI and ultrasound before being dissected. Each hand was photographed during each stage of dissection. Secondly we evaluated the role of the different structures of the DH in the stability of the extensor tendon by transection of the different components alternatively at the ulnar and radial sides. MR, ultrasound, and dissection showed that the extensor tendon (ET) is stabilized by the sagittal band (SB) at the level of the metacarpophalangeal (MCP) joint and more distally by the transverse and the oblique bands, respectively. Transection of the radial SB of the second finger leads systematically to ulnar dislocation of the ET. The transection of the ulnar DH does not lead to instability of the ET. The SB is the most important structure of the DH in the stability of the ET at the MCP level. Rupture of the radial SB of the second finger leads systematically to ulnar dislocation of the ET.

Improved visualization of the radial insertion of the biceps tendon at ultrasound with a lateral approach.

We report a new lateral approach for ultrasound visualization of the distal biceps tendon. A cadaver specimen was dissected to study distal biceps anatomy relevant to this approach. Sonograms obtained in volunteers and patients are provided to illustrate this alternative method.

Sonography of the normal ankle: a target approach using skeletal reference points.

OBJECTIVE: Sonographic examination of the ankle depends on exact knowledge of the specific probe positions to acquire the best images. CONCLUSION: In this article, we discuss these positions and illustrate them with drawings, anatomic slices or dissection, and sonograms. Positions studied include those for best imaging of the anterior tibiotalar joint, anterior tibiofibular ligament, anterior talofibular ligament, calcaneofibular ligament, peroneal tendons, Achilles tendon, flexor hallucis longus, posterior deltoid ligament, anterior deltoid ligament, and posterior medial tendons.

Sonography of the finger flexor and extensor system at the hand and wrist level: findings in volunteers and anatomical correlation in cadavers.

We present a review of sonography of the flexor and extensor system of the hand and wrist in volunteers and cadavers. CT tenography also was performed in cadaveric specimens. Anatomical structures of the extensor system that were assessed with sonography included the extensor tendons and insertions, retinaculum, and dorsal hood. On the flexor side, the variable relationship between the flexor superficialis and profundus could be appreciated. Volar plates, tendon insertions, and annular pulleys could also be investigated. Sonography can show details of the finger flexor and extensor system.

US diagnosis of UCL tears of the thumb and Stener lesions: technique, pattern-based approach, and differential diagnosis.

The thumb is a central component supporting the intricate movements of the hand. Patients with acute thumb pain, particularly after trauma, require prompt evaluation of structural integrity, thus avoiding long-term morbidity such as instability, chronic pain, and osteoarthritis. Injury to the ulnar collateral ligament (UCL) of the thumb requires imaging for diagnosis of surgically important entities such as the Stener lesion. Historically, routine radiography including stress views does not allow such diagnosis and is potentially detrimental to patient care. Both magnetic resonance imaging and ultrasonography (US) are currently used for direct evaluation of the UCL of the thumb and are safe and accurate. US is more dynamic and less time-consuming and may be easier to perform. Furthermore, other disorders such as tenosynovitis, tendon tears, and articular pathologic conditions can involve the thumb and thenar region and may also be diagnosed with US. In this context, US is an underused tool because it is potentially an adjunct to the clinical examination in the appropriate setting. A sound knowledge of the regional anatomy and basic training in the principles of US should equip the imager with the skills necessary to evaluate the UCL of the thumb and its surrounding structures.

(18)F-FDG PET imaging of rheumatoid knee synovitis correlates with dynamic magnetic resonance and sonographic assessments as well as with the serum level of metalloproteinase-3.

PURPOSE: The aim of this study was to assess rheumatoid arthritis (RA) synovitis with positron emission tomography (PET) and( 18)F-fluorodeoxyglucose ((18)F-FDG) in comparison with dynamic magnetic resonance imaging (MRI) and ultrasonography (US). METHODS: Sixteen knees in 16 patients with active RA were assessed with PET, MRI and US at baseline and 4 weeks after initiation of anti-TNF-alpha treatment. All studies were performed within 4 days. Visual and semi-quantitative (standardised uptake value, SUV) analyses of the synovial uptake of FDG were performed. The dynamic enhancement rate and the static enhancement were measured after i.v. gadolinium injection and the synovial thickness was measured in the medial, lateral patellar and suprapatellar recesses by US. Serum levels of C-reactive protein (CRP) and metalloproteinase-3 (MMP-3) were also measured. RESULTS: PET was positive in 69% of knees while MRI and US were positive in 69% and 75%. Positivity on one imaging technique was strongly associated with positivity on the other two. PET-positive knees exhibited significantly higher SUVs, higher MRI parameters and greater synovial thickness compared with PET-negative knees, whereas serum CRP and MMP-3 levels were not significantly different. SUVs were significantly correlated with all MRI parameters, with synovial thickness and with serum CRP and MMP-3 levels at baseline. Changes in SUVs after 4 weeks were also correlated with changes in MRI parameters and in serum CRP and MMP-3 levels, but not with changes in synovial thickness. CONCLUSION: (18)F-FDG PET is a unique imaging technique for assessing the metabolic activity of synovitis. The PET findings are correlated with MRI and US assessments of the pannus in RA, as well as with the classical serum parameter of inflammation, CRP, and the synovium-derived parameter, serum MMP-3. Further studies are warranted to establish the place of metabolic imaging of synovitis in RA.

Sonography of a rupture of the tendon of the extensor pollicis longus muscle: initial clinical experience and correlation with findings at cadaveric dissection.

OBJECTIVE: The objectives of our study were to report our initial clinical experience with sonography of the wrist for diagnosing a proximal rupture of the tendon of the extensor pollicis longus (EPL) muscle and to perform sonographic-anatomic correlation of the EPL tendon. MATERIALS AND METHODS: Clinical and imaging files of five patients who underwent sonography and subsequent open wrist surgery were reviewed retrospectively. Imaging was performed by four radiologists experienced in musculoskeletal sonography. Tendon retraction was evaluated on sonography and at surgery. In cadavers, sonography was performed in concert by two musculoskeletal radiologists during progressive stages of dissection of four embalmed specimens. One specimen was sliced in the transverse plane. RESULTS: In cadavers, the EPL tendon was located on or adjacent to Lister's tubercle and extended to the base of the thumb. The EPL tendon crossed over the extensor carpi radialis tendons where it exhibited a flattened aspect. In the five patients in the study, a tubular-shaped hypoechoic area was evident at the position of the ruptured EPL tendon on sonograms. At surgery, this area corresponded to fluid, hemorrhage, and scar tissue in the EPL tendon sheath. The assessment of tendon retraction on sonography correlated with findings at surgery. CONCLUSION: Sonography may aid in diagnosing a rupture of the EPL tendon and in the preoperative assessment of gap size and position of the retracted tendon ends. A characteristic tubular hypoechoic area may be seen crossing over the extensor carpi radialis tendons.

Assessment of disease activity in rheumatoid arthritis with (18)F-FDG PET.

UNLABELLED: The aim of this study was to assess synovitis by (18)F-FDG PET in an individual joint analysis and in a global analysis of rheumatoid arthritis (RA) disease activity and to compare (18)F-FDG PET parameters with clinical, biologic, and sonographic (US) rheumatoid parameters. METHODS: Three hundred fifty-six joints were assessed in 21 patients with active RA: the knees in all subjects and either wrists as well as metacarpophalangeal and proximal interphalangeal joints in 13 patients, or ankles and the first metatarsophalangeal joints in the remaining 8 patients. PET analysis consisted of a visual identification of (18)F-FDG uptake in the synovium and measurements of standardized uptake values (SUVs). Independent assessors performed the clinical and US examinations. RESULTS: PET positivity was found in 63% of joints, whereas 75%, 79%, and 56% were positive for swelling, tenderness, and US analysis, respectively. Both the rate of PET-positive joints and the SUV increased with the number of positive parameters present (swelling, tenderness, US positivity) and with the synovial thickness. The mean SUV was significantly higher in joints where a power Doppler signal was found. In a global PET analysis, the number of PET-positive joints and the cumulative SUV were significantly correlated with the swollen and tender joint counts, the patient and physician global assessments, the erythrocyte sedimentation rate and C-reactive protein serum levels, the disease activity score and the simplified disease activity index, the number of US-positive joints, and the cumulative synovial thickness. CONCLUSION: (18)F-FDG PET is a unique imaging technique that can assess the metabolic activity of synovitis and measure the disease activity in RA.

Ultrasound during dissection of cadaveric specimens: a new method for obtaining ultrasound-anatomic correlations in musculoskeletal radiology.

We report a new technique for ultrasound-anatomic correlations consisting of dissection of embalmed specimens during ultrasound examination. Our method consists of performing ultrasound during the different stages of dissection. The technique was developed by making observations of selected structures in two embalmed and two non-embalmed cadaver hands. The image quality was subjectively graded by consensus of two investigators, before and after denudation of the selected structures of the hand. As an example, the technique is demonstrated for the flexors at the metacarpophalangeal joint level, the extensor complex at the level of the proximal phalanx, and the dorsal hood of the second to fourth fingers. Before dissection the image quality in fresh specimens was graded moderate, and in embalmed specimens good. After dissection the image quality was good in fresh specimens and excellent in embalmed specimens. Our method is simple and does not require sophisticated material. Our results indicate that embalmed specimens could be better than non-embalmed specimens, because of the presence of artefacts in the non-embalmed specimens (gas deposits). The described methodology can yield excellent results regarding precise identification of different interfaces and structures, as observed at ultrasound.

Rheumatoid hand joint synovitis: gray-scale and power Doppler US quantifications following anti-tumor necrosis factor-alpha treatment: pilot study.

PURPOSE: To evaluate by using B-mode and power Doppler ultrasonography (US) and clinical assessment the response of hand joint synovitis in patients with active rheumatoid arthritis (RA) to treatment with the anti-tumor necrosis factor-alpha agent infliximab. MATERIALS AND METHODS: Wrists, metacarpophalangeal (MCP) joints, and proximal interphalangeal (PIP) joints in 11 patients with active RA were assessed before and 6 weeks after three infliximab infusions. US assessment was performed at a single site in the MCP and PIP joints and at two sites (radiocarpal and intercarpal) in the wrists. Twenty measurements were performed in the wrists; 110 measurements, in the MCP joints; and 103 measurements, in the PIP joints. Two wrists and seven PIP joints were excluded owing to complete joint destruction. US parameters (synovial thickness, number of US-positive joints [ie, with synovial thickness > or = 1 mm], cumulative synovial thickness index, and presence of Doppler signal) and clinical parameters (swollen joint count) were independently assessed and compared with baseline values by using the McNemar chi2 and paired Student t tests. RESULTS: After infliximab treatment, there was a significant decrease in the mean numbers of swollen and US-positive joints and in the cumulative synovial thickness (P <.05). The mean synovial thickness decreased in all joints swollen at baseline and in the MCP and PIP joints not swollen at baseline (P <.01). Change from baseline cumulative synovial thickness correlated significantly with change in disease activity score (r = 0.69, P <.05). The number of positive Doppler US signals decreased significantly (in 13 US-positive joints at baseline, in five after treatment; P <.05). CONCLUSION: US is a feasible imaging modality for measurement of the response of RA small-joint synovitis to therapy.