MRI of the entire hand is relatively less common since the larger field of view can reduce spatial resolution and impede ability to detect internal derangement. This prevents healing of the UCL and leads to joint instability and osteoarthritis [13]. Coronal T2W fat-suppressed magnetic resonance image of the thumb at the MCP joint depicts an osseous avulsion of the UCL from the proximal phalangeal base (arrowhead) with subtle marrow oedema in the proximal phalangeal base and a fluid gap between the torn ligament and the proximal phalanx (shorter arrow). In conclusion, extensor digitorum brevis works in unison with other muscles to raise the toes off the ground when walking or running. Communicating tears are full thickness defects in which single injection MRA shows extension of contrast from the radiocarpal to the DRUJ (Figure 6 and and16).16). C) On a slightly proximal axial PD NFS MR image in the same finger the centrally located extensor digitorum communis tendon with the adjacent radial and ulnar sagittal bands can be seen (arrowheads). A) Illustration of the major volar extrinsic ligaments. However, they rarely present with tendon tears. B) Axial T2W FS MR image of the thumb in the same patient shows the positioning of the main and accessory bands of the UCL (arrow and arrowhead, respectively). How to cite this article: Yeo ED, Han JK, Lee HS, Won SH, Jung KJ, Chang HJ, Cha JS, Ahn H, Lee DW, Kang JK, Kim WJ. The proximal lamina attaches to the distal ulnar fovea at the base of the ulnar styloid. The muscle is usually painless although rarely it can present as a painful mass over the dorsal aspect of the hand. The most important ligaments for supporting the proximal carpal row, and those that are most commonly injured, are the scapholunate (SLL) and lunotriquetral (LTL) ligaments. The odd-numbered zones are located at the joint levels. B) Ultrasound colour Doppler short-axis image shows thrombosis of the ulnar artery more proximally at the level of the wrist (arrow). Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve. Extensor Digitorum Longus. MRI is useful for evaluating flexor tendon injuries. Now that you have learned the functions of extensor digitorum brevis, you can now check out the functions of other muscles of the foot using the following resources: Extensor digitorum brevis muscle: want to learn more about it? The most common internal derangement in this location is osteoarthritis. The flexor carpi radialis tendon has its own osteofibrous tunnel, and is separated from the carpal tunnel by the deep portion of the transverse carpal ligament, which splits along its radial border, surrounding this tendon and bridging across the trapezium. MRI - What to Expect. The extensor digitorum brevis muscle is supplied by the lateral terminal branch of deep fibular (peroneal) nerve, which arises from the L5 and S1 spinal nerves. The SLL angle < 30o and capitolunate angle > 30o are suggestive of VISI. At Fairfax Radiology, all our subspecialty trained Radiologists and state-of-the-art MRI magnets focus on one thing: you. In this finding, the string represents the aponeurosis, while the yo-yo is the thickened ligament stump [79]. Schmitt R, Frhner S, van Schoonhoven J, et al.. Idiopathic osteonecrosis of the scaphoid (Preisers disease)MRI gives new insights into etiology and pathology, The role of magnetic resonance imaging in scaphoid fractures. The EDBM muscle lies along the ulnar side of the extensor tendon of the 2nd digit (usually fourth wrist compartment 5). The origins and insertions of the wrist and hand muscles and tendons are described in Table 2. Recent evidence suggests that these ligaments, particularly the DRL, which is the thickest and strongest of the dorsal ligaments, also play a critical role in preventing dorsal metacarpal base subluxation [73]. The extensor digitorum brevis is covered by the deep dorsal fascia of the foot, which is continuous with the inferior extensor retinaculum, one of the origin points of the extensor digitorum brevis. The central slip inserts onto the dorsal base of the middle phalanx. Furthermore, they are the most commonly injured ligaments, and their disruption can lead to altered biomechanics. Although most injuries are lower grade sprains and can be managed with immobilisation, higher grade partial and complete tears have been shown to contribute to joint instability, chronic ulnar deviation, and MCP osteoarthritis. The ECU tendon can present with tenosynovitis, tendinopathy, subluxation, or dislocation due to tendon sheath disruption and tendon rupture (Figure 22). C) Coronal post contrast T1W FS MR image demonstrates no enhancement of the proximal scaphoid pole, indicating osteonecrosis (arrow). However, open injuries, displaced osseous avulsion fragments, and instability may necessitate surgical intervention. Excessive fluid accumulation and focal synovitis can be indirect signs of a tear. They observed that a TP distance of more than 1.0 mm was a sign of pulley insufficiency and at least partial tearing and an increase in palmar tendon displacement of at least 1.0 mm with forced finger flexion compared with rest was also a sign of at least partial tearing. Bateni CP, Bartolotta RJ, Richardson ML, et al.. three of the cases and there are no significant differences of it being bilateral in 54 locations between both hands. It continues anteriorly and inserts on the tendons of extensor digitorum longus of the second, third and fourth toes. It is caused by flexor tendon and pulley fibrocartilaginous metaplasia, usually the proximal margin of the A1 pulley. It has a common origin with the dorsal radioulnar ligament and inserts on the ulnar aspect of the triquetrum and lunate [26,32]. The muscle is radial and volar to the pisiform and inserts with the abductor digit minimi on the ulnar margin of the fifth metacarpal base. The extensor digitorum brevis manus (EDBM), a relatively rare anomalous muscle on the dorsal hand, may be misdiagnosed as a ganglion, a synovial nodule or cyst, or a soft-tissue tumor. The lunotriquetral articulation is usually obliquely oriented with respect to the short axis of the wrist. An SLL angle > 80o is diagnostic for DISI. Indirect MRA is much less common than direct MRA because it does not increase intra-articular pressure, which may prevent adequate visualisation of pathology. Illustrated diagrams depicting the wrist in cross-section. The ligaments are smooth and of low signal as they attach to the metacarpal and the proximal phalanx, and there is no surrounding soft tissue or bone marrow oedema. ????????????? Action: Extends medial four digits at metacarpophalangeal joints; Extends hand at wrist joint. Harper MT, Chandnani VP, Spaeth J, et al.. Gamekeeper thumb: diagnosis of ulnar collateral ligament injury using magnetic resonance imaging, magnetic resonance arthrography and stress radiography, Radial collateral ligament injury of the thumb with a Stener-like lesion, https://creativecommons.org/licenses/by-nc-nd/4.0/, Anterior surface of radius and interosseous membrane, Volar aspect of the thumb distal phalangeal base, Common flexor tendon (ulnar epicondyle of the humerus). First metacarpophalangeal (MCP) ulnar collateral ligament osseous avulsion with Stener lesion in a 39-year-old female with left thumb valgus injury. Class IIC lesions demonstrate even more progressive change than IIB lesions with a frank perforation of TFC, and Class IID lesions demonstrate LTL perforation as well as all of the findings of class IIC lesions. Coronal T2W fat-suppressed magnetic resonance image shows partial tearing of the triangular ligament of the peripheral TFCC at its ulnar styloid attachment (arrow) and a small distal radioulnar effusion with synovial proliferation, which commonly accompanies TFCC tears (arrowhead), consistent with a Palmer 1B lesion. The middle and distal phalanges of each digit articulate to form the distal interphalangeal (DIP) joints. It attaches to the distal margin of the sigmoid notch at the ulnar aspect of the distal radius over the articular cartilage. A rare cause of ulnar-sided pain is hypothenar hammer syndrome, which is secondary to thrombosis of the ulnar artery overlying the hamate bone as it exits Guyons canal. Axial T2W fat-suppressed magnetic resonance image of a 37-year-old female with pain and swelling dorsal to the left third metacarpophalangeal joint shows partial tearing of the EDC tendon with tendon thickening consistent with tendinopathy. . A T2-weighted axial MRI of the hand showing, just as in T1, an ovoid mass of an intermediate signal intensity (arrow). Illustrated diagram of the triangular fibrocartilage complex. According to these findings in sonography and MRI scan, the final diagnosis made was that of a right extensor digitorum brevis manus muscle. These muscles are covered by the deep dorsal fascia of foot. The intrinsic ligaments connect and are interposed between the carpal bones, and are important for maintaining the integrity of the proximal carpal row. As a result, this condition is commonly called skiers thumb. Two methods of MRA have been described: direct, in which dilute gadolinium contrast is percutaneously injected into the target joint (Figure 6), and indirect, in which contrast is injected intravenously, allowed to circulate systemically (Figure 7), and recruited to a specific joint via exercise-induced hyperaemia [5]. However, no synovial inflammation at the left MCP joints was seen. There is localised enhancement related to focal synovitis (arrow), and the patient was diagnosed with radial styloid impingement. Clinical symptoms include pain over the dorsoradial aspect of the hand [62]. Approximately 125% of patients have recurrence of symptoms after surgery [61]. Additionally, these two muscles cooperate to aid the lumbrical muscles of the foot to extend the same interphalangeal joints. This is the most commonly missed tear. The anatomy of the wrist and hand is complex and contains numerous small structures. Clinical importante of the extensor digitorum brevis manus muscle. There may be a gap between the bone and the ligament stump, and the ligament stump may be retracted and globular. It is a syndrome characterised by a shortened distal ulna (negative ulnar variance) that impinges on the distal radius proximal to the sigmoid notch. Osseous avulsion from the dorsal base of the distal phalanx can occur. The distal carpal row is composed of the trapezium, trapezoid, capitate, and hamate. Otherwise, early osteonecrosis demonstrates low signal intensity of necrotic bone with respect to surrounding normal bones on T1W images and variable signal on fluid-sensitive, FS images. and transmitted securely. Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster. Tears of the dorsal SLL band at its lunate attachment are usually symptomatic and traumatic rather than degenerative. Extensor carpi ulnaris (ECU) interstitial tear. As a result, many institutions have elected to perform imaging with the patient supine and the arm at the side, which brings the hand away from the isocentre of the magnetic field and may lead to decreased signal throughout the image with poor and inhomogeneous fat suppression. The dorsal bands of the SLL (long arrow) and LTL (curved arrow) are seen. The extensor digitorum brevis manus (EDBM) muscle is an accessory muscle in the hand and is a normal anatomical variant. These ligaments contribute to the stability of the TFCC [26,34]. These injuries are usually due to a biting mechanism and involve the extensor tendon with either a complete or partial tear. The median nerve can bifurcate into two nerve bundles in the distal forearm and appear as a bifid median nerve in the carpal tunnel. Finally, the IP joint is a true hinge joint, allowing flexion and extension. Although division of the retinaculum may provide symptomatic relief, the excision of the muscle is usually recommended. Reviewer: A) Coronal T1W fat-suppressed (FS) gradient echo magnetic resonance (MR) image of the MCP joint shows a fracture fragment off the ulnar aspect of the proximal phalangeal base (arrow) that is displaced by 6 mm. Occasionally it may be associated with exercise-induced pain or tenosynovitis of the extensor tendons. This is significant because it can allow the spread of infection proximally into the forearm [36]. Alongside the tibialis anterior and the extensor hallucis longus, the extensor digitorum longus is known as one of the leg extensors. Osseous coalitions of the lunate and triquetrum are typically asymptomatic. Tendinosis and tenosynovitis of the flexor carpi radialis tendon. Normal anatomy of the finger at the metacarpophalangeal (MCP) joint. The posterior interosseus nerve is situated between the extensor digitorum longus and abductor pollicis longus (or extensor pollicis brevis) muscles. The LTL is V-shaped and also made of three components: dorsal, central, or membranous, and volar or palmar bands. These tears are in the avascular portion of TFC and are usually debrided due to poor healing [53]. The volar bands of the SLL (short arrow) and LTL (arrowhead) are also noted. The most frequent mechanism of injury is extension, ulnar deviation, and carpal supination. The muscle also courses over the lateral terminal branch of deep fibular (peroneal) nerve. This is associated with a focal tear of the ulnar sagittal band as it attaches onto the tendon (arrow). Occasionally, contrast can be helpful to detect areas of granulation tissue or hyperaemia associated with soft tissue injuries that may be less conspicuous on routine, non-contrast imaging. MRI findings of lunate osteonecrosis are those described previously when discussing scaphoid osteonecrosis (Figure 14). Injury location, percentage of tendon involvement and any adjacent osseous or soft tissue involvement should be described with detail in the report. 42-year-old male with left wrist pain after a fall. The palmaris longus tendon is present in 86% of the population and is located superficially to the flexor retinaculum [38]. This translates to a more accurate diagnosis and a better-tailored treatment . Each volar plate attaches to the collateral ligaments, and to the sagittal bands and deep palmar transverse ligaments at the MCP joint [64]. The condition is associated with rowing and racquet sports and is less commonly from direct trauma [26,57]. Normal scapholunate (SLL) and lunotriquetral (LTL) ligament anatomy. Zone 4 injuries at the level of the proximal phalanx often result from lacerations and can involve the central slip, lateral slips, medial and lateral lumbrical bands, and extensor hood. dorsum of the right hand, more exactly in the distal part of the wrist, between the extensor tendons of the index and middle fingers, was detected. Type III injuries are present when there is an avulsed bone fragment, with the fragment held in place by the A4 pulley; type IV injuries occur when the bony fragment is present, but the tendon has been avulsed from the fragment [64]. 24-year-old male with mildly displaced scaphoid waist fracture nonunion, and persistent pain. The bifid median nerve can also appear with an accessory artery, the persistent median artery, which lies between the two nerve bundles. Scaphoid nonunion with osteoarthritis requires salvage procedures such as limited or total wrist arthrodesis, proximal row carpectomy, scaphoid excision, or arthroplasty. Preisers disease is the idiopathic form of osteonecrosis of the scaphoid bone, although most cases have a history of repetitive micro-injuries or overloading [11]. Anatomy of the Human Body (20th ed). found the mean measurement of the SLL angle on sagittal MRI to be closely correlated with measurements taken on lateral radiographs when the wrist was positioned in 15o of radial deviation. MRI is an imaging tool that uses a strong magnet field combined with radio waves to produce images of the inside of the body. Coronal images are perpendicular to the long axis of the metatarsals. Zone 2 injuries are the most common and are associated with the highest rate of complications. Surgical repair is required. When placed under tension, extension of the middle finger was observed. On MRI, tendinopathy is characterised by heterogeneous high signal intensity and thickening on fluid-sensitive sequences, and active tenosynovitis will demonstrate tendon sheath effusions with enhancement [57]. Nakano M, Watanabe Y, Masutani M. A case of extensor digitorum brevis manus. Type II injuries occur when the tendon is retracted to the PIP joint level. Zone IV injures are rare due to the protective nature of the transverse carpal ligament. AJR Am J Roentgenol. As a result, these muscles work in unison to extend the corresponding digits of the foot. [Google Scholar] 74. The extensor tendons are highly superficial in this region. The canal it begins at the proximal margin of the transverse carpal ligament at the level of the proximal pisiform and ends at the aponeurotic arch of the hypothenar musculature at the level of the hook of the hamate. However, the pulley fibres appear intact, uniform in thickness, and low in signal (arrow). However, when the wrist was placed in the neutral position the measurement could differ from the radiographic measurement by 14o, and when the wrist was placed in 15o of ulnar deviation, the measurement could differ by 32o [54]. Osteonecrosis may result from repetitive microtrauma, interruption of blood supply including acute fracture, hypercoagulability, steroid use, altered biomechanics in association with negative ulnar variance, decreased radial inclination, and type I lunate morphology. The peripheral TFC appears normal. Shereen R, Loukas M, Tubbs RS. Injuries in zones 2 through 5 can involve the neurovascular bundle and require emergency surgery [27]. However, fibrous tissue ingrowth can result in some enhancement and lead to false negative interpretation [48-50]. In order to generate diagnostic images in a reasonable time, patient positioning, scanner and coil selection, and MRI parameters must be optimised, and imaging should be tailored to best address the clinical question. The trapezoid and hamate have two non-articular nutrient arteries but lack consistent intraosseous anastomosis, which also places fracture fragments at risk for osteonecrosis. Wrist position can alter the degree of ulnar variance. and grab your free ultimate anatomy study guide! Extensor Digitorum. How Does Ankle MRI Work? Palmar pole fractures can result in osteonecrosis due to interruption of the single arterial supply, which is observed in up to 20% of the population [26,31]. Ulnar nerve compression can occur proximal to Guyons canal (Type I) or within the canal (Type II) resulting from mass effect related to ganglion cysts, neuromas, or accessory muscles. However, these sequences often suffer from poor contrast resolution, which may make articular cartilage and TFCC injuries less conspicuous [7]. Become a Gold Supporter and see no third-party ads. On clinical examination, there is focal tenderness between the extensor digitorum and extensor carpi radialis tendons with provoked pain on extension. Just proximal to the FDS insertion, fibres from each tendon slip extend to the other, which is known as Campers chiasm [27]. Its greatest importance can be to serve as a donor for tendon grafting [39]. The wrist is composed of zone IV, the tendons within the carpal tunnel, and Zone V, the tendons extending from the myotendinous junction to the proximal aspect of the carpal tunnel. (PMID: 14996394), [3] Newer three-dimensional spin echo techniques allow thin section imaging with isotropic voxels and no interslice gaps. Isolated FDS avulsions are rare, and FDS injuries usually occur in conjunction with FDP injuries. Radiography is the primary tool for assessing osteoarthritis, but MRI can be useful to look for ligament injuries, such as to the AOL, which can result in joint instability. On MRI, oedema surrounding the ligaments and volar plates typically indicates acute injury of that structure. Torn ligaments demonstrate discontinuity of fibres, while partial tears would show irregularity of the fibres and/or increased signal on fluid-sensitive sequences (Figure 19) [55]. 8600 Rockville Pike Pathologic conditions of the wrist tendons include de Quervain tenosynovitis, extensor carpi ulnaris tendinopathy, rheumatoid tenosynovitis, infectious synovitis, tendon tears, hydroxyapatite deposition disease, intersection syndrome, tenosynovial giant cell tumor, and fibroma of the tendon sheath. For fractures involving the articular surface, the amount of involvement should be quantified because it can be an indicator of joint stability. Rock climbing is a common cause of pulley injury, most frequently involving the A2 pulley of the ring finger [27]. 31-year-old male with one-year history of ulnar-sided wrist pain after an injury. The bones and joints are typically evaluated for contusion, fracture, malalignment, dislocation, or joint effusion in the setting of injury. DeQuervains tenosynovitis. The origin of the muscle can be variable, although it most commonly arises from the dorsal wrist capsule deep to the extensor retinaculum [42]. However, it can indirectly affect the triquetrum. When possible, MRI of the fingers should be performed on 3T systems to obtain superior spatial resolution, and the fingers should be placed in a dedicated hand/wrist coil. Federal government websites often end in .gov or .mil. The MCP joint capsule is partially composed of fibrocartilage that is thickened dorsally and volarly and forms the dorsal and volar plates, respectively. The distal conjoined tendons are connected by the triangular aponeurosis. Some authors have noted that an intact accessory band or sesamoid-metacarpal ligament may prevent the development of a Stener lesion [80]. If the avulsed osseous fragment is displaced by more than 5 mm, or if it involves more than 25% of the articular surface, surgery is indicated. A case report. If incomplete or heterogeneous fat saturation impacts diagnostic quality, chemically selective fat suppression techniques can be switched to a short tau inversion recovery (STIR) sequence. Class IC lesions are traumatic avulsions from the peripheral volar attachments at the lunate or triquetral bones, specifically the ulnolunate and ulnotriquetral ligaments. MRI findings include erosive changes at the level of the radius with osseous remodelling. Some institutions have advocated placing traction on the wrist during the MRA with finger traps connected to a pulley and weight system. Insertion: Extensor expansions of medial four digits. Clinically, patients present with fourth and fifth finger sensory loss and weakness. This is best measured on true lateral wrist radiographs. These findings may be present with or without widening of the SLL interval. AJR Am J Roentgenol. GENERAL CONSIDERATIONS Clinical Indications for Foot US Patients with TFCC pathology present with ulnar-sided wrist pain, variable instability, and often a clicking or snapping sensation with rotation [26,32]. MRI of Extensor Tendons of the Wrist Musculoskeletal Imaging Review. Higher grade injuries usually require surgical intervention. Clin Anat 2002; 15: 286-292. A) Axial T2W fat-suppressed (FS) magnetic resonance (MR) image of the wrist at the level of the ulnar groove with the wrist in neutral position shows increased signal in the ECU tendon with a small tenosynovial effusion (arrow). Bilateral extensor digitorum brevis manus. At surgery, there were a central TFC tear and an SLL tear. Clin Anat. The most medial tendon of extensor digitorum brevis (extensor hallucis brevis) extends the great toe at the metatarsophalangeal joint. Melville DM, Taljanovic MS, Scalcione LR, et al.. The most important ones are the volar radioscaphocapitate ligament, which prevents rotatory subluxation of the scaphoid and the radiolunatotriquetral ligament (also known as the long radiolunate ligament), which connects the distal radius with the proximal carpal row (Figure 12A and andC).C). Within the bones there are variant morphologies of some of the carpal bones, including developmental coalitions and numerous reported developmental ossicles. Klauser et al. Patients present with pain and swelling over the radial styloid process with increased pain during thumb extension and abduction [26,57]. Sookur PA, Naraghi AM, Bleakney RR et-al. Additionally, on axial imaging of the wrist a ratio measurement between the long axis of the median nerve seen in cross section and its short axis at the carpal tunnel inlet of greater than 3:1 may also help to detect cases of carpal tunnel syndrome suggested on nerve conduction testing [60]. There are rare reports of a Stener-like lesion involving interposition of the abductor aponeurosis and the RCL, which also requires surgical intervention [81]. Half a century of flexor tendon surgery. Entrapment neuropathy of the deep peroneal nerve associated with the extensor hallucis brevis. B) Illustration of the major dorsal wrist extrinsic ligaments and collateral ligaments. B) Axial proton density (PD) non-fat suppressed (NFS) magnetic resonance (MR) image of the finger at the level of the metacarpal head in a 42-year-old female shows the fibrocartilaginous thickening of the volar plate (arrowhead). The Lichtman staging of Kienbck disease is important for patient management (Table 3). The ulnar styloid process can be variable in length and is independent of ulnar variance. The second and third extensor compartment tendon sheaths communicate via a foramen, which can allow the spread of inflammation between the two. T1W hyperintense contrast is seen extending through the defect and into distal radioulnar joint, consistent with a Palmer 1A lesion, Peripheral triangular fibrocartilage complex (TFCC) tear. Zone 3 injuries can be open or closed and occur at the PIP joint level. Axial T1W fat-suppressed post-contrast MRI shows intense synovial enhancement of the right second and fourth metacarpophalangeal (MCP) joints (shorter arrows) with marginal erosions of the second metacarpal head (arrowhead). However, MRI is more sensitive in detecting radiographically occult fracture lines and bone marrow oedema. The radial and ulnar collateral ligaments resist varus and valgus angular forces, respectively. The Verdan system is most commonly used, which includes eight zones (Figure 20) [66]. All rights reserved. When this occurs in the thumb, it may spontaneously resolve. Therefore, determination of subtle ulnar variance on MRI should be done with caution [31]. All content published on Kenhub is reviewed by medical and anatomy experts. The location of the tear is in the well-vascularised periphery of TFC and may heal. The site is secure. However, the thumb is generally extended, rotated, and abducted with respect to the hand and lesser fingers. Crossref, Medline, Google Scholar; 29 Cavdar S, Dogan T, Bayramicli M, Sehirli U, Yuksel M. An unusual variation of extensor digitorum brevis manus: a case report and literature review. Lippincott Williams & Wilkins. This can produce a locked digit that must be manually unlocked. No matter which condition you have, if you're in pain or can't move a part of your body as well as you usually can, talk to your healthcare provider. MRI is also useful in detecting other, less frequent fractures involving the carpal bones. This is generally due to ligamentous laxity related to repetitive movements such as pinching or a single traumatic event. The first MCP joint is a diarthrodial joint that has features of both a condyloid (ellipsoid) joint and a hinged (ginglymus) joint, which allows a greater range of motion than a typical hinge joint. Current protocols utilise 2-D fast spin echo imaging in a combination of chemically-selective fat-suppressed (FS), fluid-sensitive sequences, such as T2-weighted (T2W) or proton density (PD) sequences in three orthogonal planes, to look for marrow and soft tissue oedema (Figure 3), in addition to a coronal T1-weighted (T1W) non-fat suppressed (NFS) sequence, which is often used to detect osseous alignment, fracture lines, and marrow replacement [5]. In indirect arthrography, the synovium begins to excrete gadolinium at about 10-11 minutes, and postcontrast imaging is usually performed at about 25-30 minutes following the injection to allow enough gadolinium to enter the joint [23,24]. It is estimated to be two to The pain is likely to be a consequence of muscle hypertrophy and of impingement of the muscle against the extensor retinaculum. has suggested a CSA > 15 mm2 either proximal or distal to the carpal tunnel as a cut-off for detecting carpal tunnel syndrome, and CSA > 19 mm2 as a cut-off for severe carpal tunnel syndrome [59]. Author: 2008;191 (6): 1767-75. Magnetic resonance arthrography of the wrist and elbow. The lateral 3 tendons also course anteriorly over the tarsal and metatarsal bones, to insert at the lateral aspect of the tendons of extensor digitorum longus. On rare occasions, ulnar artery pseudoaneurysm, hypertrophy of the flexor carpi ulnaris tendon, osteoarthritis of the pisotriquetral joint, or hamate/pisiform fractures can lead to compression. Low-grade A1 flexor tendon pulley injury. Curated learning paths created by our anatomy experts, 1000s of high quality anatomy illustrations and articles. The extensor hood is located primarily over the dorsal aspect of the proximal phlangeal base in each lesser digit and serves to stabilise the extensor tendon from abnormal transverse movement. A transverse gray-scale sonograph of the dorsum of the hand showing anomalous muscle with a typical echo texture (straight arrow), located between the extensor tendons of the third and fourth digits (curved arrows). Register now Each digit contains a metacarpal, a proximal phalanx, a middle phalanx, and a distal phalanx. Many injuries can be treated conservatively by splinting with the PIP joint in extension. As a result, although ulnar variance can be suggested on MRI, using this modality to diagnose and measure the degree of variance is inappropriate. An important calcaneal fracture is an avulsion of the origin of the extensor digitorum brevis (EDB) muscle [24, 32]. This decreases volume averaging and allows the generation of multiplanar reformatted imaging in any desired plane [8]. The stabilising ligaments may be thickened and intermediate in signal, indicating chronic scarring and degeneration. The TFC is thicker peripherally than centrally, giving it a biconcave appearance on sagittal images. Significant improvement in synovitis, osteitis, and bone erosion following golimumab and methotrexate combination therapy as compared with methotrexate alone: a magnetic resonance imaging study of 318 methotrexate-naive rheumatoid arthritis patients, Key MR imaging features of common hand surgery conditions. Direct MRA has the highest accuracy in detecting TFC tears, especially for central and radial-sided (Palmer IA, ID, and II) tears. To do this the coronal sequence should be planned from the axial images through the first metacarpal head and metacarpophalangeal (MCP) joint [29]. MRI can demonstrate an abnormal flow void of the ulnar artery to help suggest this diagnosis (Figure 25). B) Coronal T1W non-fat suppressed MR image of the same region shows replacement of the normal fat in the scaphoid proximal pole (arrow). We studied the tendons in cadavers and volunteers with ultrasound. 2D fast spin echo T2W fat-suppressed magnetic resonance image at the level of the mid carpus shows mild flexor carpi radialis tendinosis (arrow), mild tendon sheath distension and ill-defined soft tissue oedema deep to the tendon consistent with tenosynovitis (arrowhead), 3D gradient echo (GRE) imaging showing a central triangular fibrocartilage disc (TFC) perforation. Tear of the extensor digitorum longus and its fascia is a very rare acute ankle injury. Radial/central communicating tears are often bilateral and can be asymptomatic [26,32,33]. Peripheral tears of the TFCC can result in injury to the volar ulnolunate and ulnotriquetral ligaments. Untreated fractures can progress to nonunion and may rarely require surgical excision for symptomatic relief [47]. Origin: Lateral condyle of tibia, upper 2/3 - 3/4 of medial fibular shaft surface, upper part of interosseous membrane, fascia cruris, and anterior intermuscular septum. In our practice, the most common indications for imaging include the following: detecting radiographically occult osseous injuries (Figure 1), assessment of the triangular fibrocartilage complex (TFCC) and intrinsic ligaments of the wrist, ligament tears involving the fingers, and flexor and extensor tendon injuries. The FDS tendon splits at the base of the proximal phalanx of each lesser digit into two distinct tendon slips; it subsequently passes around and eventually deep to the FDP tendon at its insertion onto the volar plate of the PIP joint and at the volar base of the middle phalanx (Figure 28). Check for errors and try again. Normal metacarpophalangeal (MCP) ligaments of the thumb. However, there is generally poorer SNR and spatial resolution compared to chemically selective FS spin-echo techniques. Location of the tear and any tendinous retraction should be clearly described, in addition to the presence of any osseous avulsions and any displacement of the bony fragment. However, it may not be very helpful in improving characterisation of TFCC injuries [25]. HHS Vulnerability Disclosure, Help The other two bands show intermediate signal resulting from the presence of fibrovascular components. On the palmar side the flexor digitorum superficialis and flexor digitorum profundus tendons are also visible (shorter arrow and longer arrow, respectively). Unable to process the form. Flexor Digiti Minimi Brevis. Dorsal intercarpal extrinsic ligament sprain. Trigger thumb. It contains deep and superficial bands and is a chief restraint to dorsal radial subluxation. Sookur PA, Naraghi AM, Bleakney RR, et al.. Accessory muscles: anatomy, symptoms, and radiologic evaluation. B) Coronal T2W FS MR image of the same area shows a Stener lesion with a yo-yo on the string appearance. Full-thickness tears will allow abnormal communication of contrast between the radiocarpal and midcarpal joints [26,33,34]. However, fibrocartilaginous LTL coalitions can be associated with atypical ulnar-sided wrist pain. A transverse gray-scale sonograph of the dorsum of the hand obtained during active finger extension, showing a muscle protruding dorsally between the third and fourth digits. Complications related to carpal tunnel release are estimated at between 3 and 19%, and surgical re-exploration is necessary in up to 12% of cases [61]. Read more. Abbreviations: EDB = extensor digitorum brevis, EDL = extensor digitorum longus, EHL = extensor halluces longus, MRI = Magnetic resonance imaging, MTP = metatarsophalangeal. The authors report no conflict of interest. It is composed of the distal radius and ulna, carpal bones, and five metacarpal bases. MRI scans can help to distinguish EDBM from tumors. Most MRI studies are currently performed at higher field strength (ideally 3T), which significantly improves spatial and contrast resolution to enable the assessment of joint internal derangement [4]. A consequence of pulley tearing is bowstringing of the flexor tendon, which is variable depending on the number of pulleys torn and the positioning of the finger [27]. There is a slight predominance of occurrence in males. Illustrated diagram of the extensor mechanism of the finger including the tendons, extensor hood ligaments, and extensor sagittal bands. As a result, these injuries are commonly treated surgically [79]. In about 93% of cadaveric specimens there is also a variable pulley (Av) located between the A1 and Ao pulleys. Crossref, Medline, . These findings are not specific for osteonecrosis but may suggest it. The angulated dorsal surface of the scaphoid forms the palpable humpback [47]. 1) that Radiographics. The space between the proximal and distal laminae of the triangular ligament is termed the ligamentum subcruentum, which represents loose, vascularised tissue. 3. Additionally, the structures are evaluated for the presence of partial or full-thickness tearing. The dorsal band of the SLL is the most important for stability of the wrist [34] and is homogenously low in signal intensity on MRI (Figure 11). Rutgers - New Jersey Medical School Training Specialty: Diagnostic Radiology 6/1/2002 - 6/30/2006 Rheumatoid arthritis (RA) frequently presents with tenosynovitis and tendinopathy because the wrist tendons are surrounded by a synovial sheath or bursa. Anatomic snuff box tenderness is a sensitive test for scaphoid fractures, but pain and tenderness over the scaphoid tubercle are more specific. National Library of Medicine 2002;15 (4): 286-92. Extensor digitorum brevis projects anteriorly to the lateral malleolus and passes over the lateral aspect of the calcaneocuboid joint. These bones form an arch that supports the metacarpals and is considered more stable than the proximal row. Extensor digitorum brevis is a thin muscle found on the dorsum of the foot. A positive Tinel test, or tingling sensation in the distribution of the nerve elicited by light percussion over the nerve, is an additional sign that supports diagnosis of the disease. Received 2020 May 7; Accepted 2020 Jul 22. There are usually two palmar sesamoid bones surrounded by the volar plate, which attaches to the metacarpal head and proximal phalangeal base and helps stabilise the flexor pollicis longus tendon. The thumb is composed of the proximal and distal phalanges, the first metacarpal and CMC joint, and trapezium with four basal joints, including its articulations with the scaphoid, trapezoid, and first and second metacarpal bases. Brought to you by the European Society of Radiology (ESR) -. They extend around the joint from the extensor hood to the volar plate and serve to stabilise the extensor tendon at the MCP joint level. The flexor and extensor tendons dynamically stabilise the thumb and contribute to its motion. Non-communicating tears comprise partial-thickness defects. The information we provide is grounded on academic literature and peer-reviewed research. Patients should be placed prone with the arm extended over head in the Superman position to put the wrist as close to the isocentre of the magnetic field as possible, in order to obtain the highest signal-to-noise ratio (SNR) and most homogeneous signal. The A1, A3, and A5 pulleys are located at the level of the MCP, PIP, and DIP joints, respectively, and attach to the volar plates. There are numerous accessory ossicles of the wrist that can be mistaken for pathology or occasionally be a source of symptoms. Proximal intersection syndrome is a usually chronic, overuse, inflammatory condition affecting the dorsal radial aspect of the distal forearm 45 cm proximal to the radiocarpal joint, where the first and second extensor compartment tendons cross each other. Scand J Plast Reconstr Surg Hand Surg. The scaphoid is important for carpal stability and acts as a stabiliser between the two carpal rows. Extensor digitorum brevis manus muscle. Disruption of the LTL results in volar intercalated segmental instability (VISI) with volar tilting of the lunate. Secondary signs include muscle oedema and enhancement of the hypothenar muscles, third and fourth lumbricals, and interosseous muscles related to denervation [26,62]. According to these findings in sonography and MRI scan, the final diagnosis made was that of a right extensor digitorum brevis manus muscle. The wrist consists of many ligaments, classified as intrinsic (interosseous) and extrinsic (capsular). The wrist is perhaps the most complex joint in the body and is affected by a wide spectrum of disorders. Degenerative perforations of the central SLL and LTL increase with age and can be asymptomatic. Repetitive stress to the SLL from crutch walking and ulnar impingement of the LTL can also result in injury [26,33,34]. The carpal bones are also labelled (U ulna, R radius, Tri triquetrum, L lunate, S scaphoid, H hamate, C capitate, T trapezoid, Tra trapezium), Indirect magnetic resonance arthrography showing localized synovitis in an area of symptomatic impingement in a 46-year-old female with chronic scaphoid fracture with nonunion and persistent radial-sided wrist pain. Acute ligamentous injuries of the thumb can occur but are much less common than at the MCP joint. These findings most commonly occur with ulnar positive variance but can occasionally occur with neutral or negative variance [52]. Clinical examination cannot alone detect complications of scaphoid fractures. . The deep fibres of this ligament blend with the LTL and attach to the triquetrum [34]. Infection from the thumb and little finger tendon sheaths can spread into the radial and ulnar bursae and communicate with each other, resulting in a horseshoe abscess. 60-year-old female with chronic numbness in her hand. Imaging key wrist ligaments: what the surgeon needs the radiologist to know. B) Coronal T2W FS MR image shows the normal intermetacarpal (arrowhead) and ulnar collateral ligaments (arrow). However, the intermediate to increased T2W signal of the ligamentum subcruentum can mimic a tear in this region [26,53]. the presence of a soft-tissue mass with muscle-like echo texture, which suffers morphological changes during the active extension of the fingers. It can even have one or more tendons absent. 3 and 4) in the dorsum of the hand. The primary differential consideration is a chronic hook of hamate fracture; however, if the bone has smooth, well-corticated, and rounded margins it more likely represents an accessory ossicle. Sonography may reveal a soft-tissue mass with muscle echotexture; in real time, it usually undergoes morphologic changes during active finger extension. Although it can be seen in normal individuals, ECU tendon subluxation can also be related to an acute injury, and the patient history and physical examination may be needed to diagnose pathologic subluxation [26,57]. Surgical repair for these injuries ideally is performed within 24 hours in current practice [27]. All imaging planes are used for their assessment. Similar to the SLL, the dorsal band is best seen on axial imaging and the membranous component is best seen on coronal imaging [26,33,34]. 7. The exception is the abductor digiti minimi, which forms the ulnar lateral band of the fifth digit [65]. Zanetti et al. In scaphoid nonunion with preserved vascularity, a non-vascularised bone graft fixated with screws is able to achieve successful union. The extensor mechanism of the lesser fingers is formed by a combination of extrinsic and intrinsic tendons (Figure 26). Closed space infection of the flexor tendon sheaths can result in pyogenic flexor tenosynovitis. Anderson MW, Benedetti P, Walter J et-al. Hafezi-Nejad N, Carrino JA, Eng J, et al.. Scapholunate interosseous ligament tears: diagnostic performance of 1.5 T, 3 T MRI, and MR arthrographya systematic review and meta-analysis. Important imaging findings include whether the tear is partial-thickness (with an estimate of the cross-sectional percentage of tendon involvement) or full-thickness. Any imaging evidence of ligamentous/volar plate malpositioning or trapping should be described in the report to aid clinical management. 47-year-old female with right-side dorsal wrist pain after fall. Bull Hosp Jt Dis. The anatomical basis of clinical practice. The superficial radial nerve provides sensory function of the dorsolateral aspect of the hand (Figure 13). As a library, NLM provides access to scientific literature. In addition, the most medial tendon of extensor digitorum brevis crosses the dorsalis pedis artery over the calcaneocuboid joint, and the lateral tarsal artery over the navicular bone. It is thought to be present in ~3% of the population 1. Ulnolunate abutment. These injuries can involve the distal central tendon slip with possible osseous avulsion of the dorsal middle phalangeal base, but they can also involve the lateral slips. Scaphoid fractures account for approximately 60-90% of all wrist fractures, and 12% of scaphoid fractures fail to heal and require surgical treatment [26,46]. An additional dorsal capsular wrist ligament is the dorsal intercarpal ligament which extends from the scaphoid to the dorsal tubercle of the triquetrum and variably to the second metacarpal base (Figure 12B) [26,34]. Illustrated schematic of the flexor and extensor tendon zone injuries. It inserts onto the central part of the flexor retinaculum and lower part of the palmar aponeurosis. Its volar surface is the flexor retinaculum, which extends from the distal radius to the metacarpal bases. The most medial slip and tendon of extensor digitorum brevis usually constitute a distinct muscle named extensor hallucis brevis. A review. the dorsal radiocarpal ligament, or the wrist-joint capsule. B) Axial T2W FS MR image of the wrist at the level of the ulnar groove with the wrist in supination shows an abnormal boomerang shaped morphology of the ECU tendon, which is draped around the ulnar margin of the groove (arrow). Historically, the most important of these was felt to be the anterior oblique ligament (AOL or beak ligament), which is a palmar structure traveling between the palmar tubercle of the trapezium and the ulnar margin of the first metacarpal base. Injuries in this zone are usually treated conservatively with splinting with the PIP joint in extension. Clinical symptoms include pain, tingling, and numbness in the thumb, and index and middle fingers. Palastanga, N., & Soames, R. (2012). Radiographs are typically useful for aiding in evaluation. Coronal T1W non-fat suppressed MR image of the wrist shows a transverse fracture of the capitate waist (arrow) that was not visible radiographically (not shown), Detection of peripheral neuropathy on magnetic resonance (MR) imaging. Ulnar impingement is a distinct entity from ulnolunate abutment. Philadelphia, PA: Lippincott Williams & Wilkins. Coronal T1W fat-suppressed magnetic resonance image of the wrist depicts a non-united scaphoid waist fracture with enhancing bone marrow oedema in the distal pole about the fracture site. MR appearance of the extensor digitorum manus brevis muscle: a pseudotumor of the hand. Similar to imaging of the wrist, many routine MRI protocols contain a combination of fat-suppressed, fluid-sensitive sequences and NFS T1W and PD sequences. Ng AW, Griffith JF, Taljanovic MS, et al.. Is dynamic contrast-enhanced MRI useful for assessing proximal fragment vascularity in scaphoid fracture delayed and non-union? Indirect wrist MR arthrography: the effects of passive motion versus active exercise, Accuracy of pre-and postcontrast, 3 T indirect mr arthrography compared with wrist arthroscopy in the diagnosis of wrist ligament injuries, Magnetic resonance arthrography of the wrist with axial traction: an iconographic review, Internal derangement of the hand and wrist, High-resolution 3-T MRI of the fingers: review of anatomy and common tendon and ligament injuries. extensor digitorum brevis manus muscle (rare) Radiographic features Accessory muscles look like other muscles in imaging studies. Focal extensor digitorum communis (EDC) tendon tear at extensor tendon zone 5 with tearing of the ulnar sagittal band. 2. This tendon is stabilised by the extensor hood at the MCP joint, which has radial and ulnar sagittal bands, and slightly more distal triangular expansions, which extend distally to insert on the distal phalangeal base [75]. Reus M, Martnez F, Abelln D, Alonso J, Vzquez V, [1] TFCC injuries can be organised by Palmers Classification (Table 4) into either traumatic/acute (Class 1) or degenerative/chronic (Class 2). 9 (8): e1568. The first extensor compartment is composed of the abductor pollicis longus tendon, which has a dominant insertion on the radial margin of the first metacarpal bone, and the extensor pollicis brevis tendon, which inserts on the proximal phalangeal base or the dorsal first MCP joint capsule. However, if this ligament is completely absent, arthrodesis may be necessary [53]. Single compartment magnetic resonance (MR) arthrography in a 31-year-old male with ulnar-sided wrist pain. At our institution, the most common indication for intravenous contrast is to better characterise suspected infections. I would honestly say that Kenhub cut my study time in half. The splitting of the FDS tendon provides a passage for the FDP tendon to continue distally within the digit and insert onto the volar plate of the DIP joint and the volar distal phalangeal base. Origin: Lateral epicondyle of humerus. The carpal vascular anatomy is considered atypical because the blood vessels often enter the bones distally. The .gov means its official. In this manuscript we describe the normal anatomy, imaging techniques, and MRI findings of various traumatic and pathologic conditions of the wrist and hand including occult fractures, osteonecrosis, ligamentous and tendon injuries, and entrapment neuropathies. Patients who are unable to tolerate surgery for scaphoid nonunion may be candidates for non-operative management with casting for 4-6 weeks. These ligaments do not play a significant role in wrist stability (Figure 12B). Meyer P, Lintingre PF, Pesquer L, et al.. The volar component blends with the TFCC and is the strongest. Furthermore, some institutions have used contrast to assess whether bones, such as the scaphoid following a proximal pole or a waist fracture, demonstrate signs of osteonecrosis (Figure 5). Similar to the thumb MCP joint, the IP joint has dorsal and volar plates consisting of fibrocartilage [74]. The tendon of the extensor of the index is absent in the cases in which the EDBM muscle inserts into the second finger. The extensor digitorum brevis (EDB) muscle is a muscle on the dorsal surface of the foot which helps extend digits 2 through 4. At physical examination, a prominence in the First, it is invasive and can cause a reactive synovitis that can produce pain for several days following the injection. Most commonly it is useful in the setting of palpable soft tissue abnormalities to differentiate solid from cystic lesions, and to detect areas of active synovitis in the setting of inflammatory arthropathy, either in the initial diagnosis of an inflammatory arthropathy or to follow therapeutic response [11,12]. In acute UCL injuries there is commonly periligamentous oedema seen on fluid-sensitive sequences. 2003 Nov;181(5):1224-6. Additionally, MRI is very helpful in characterising palpable abnormalities, such as ganglion cysts, soft tissue masses, and osseous excrescences [1,2], as well as assessing for causes of peripheral neuropathies of the median and ulnar nerves within the wrist and hand (Figure 2) [3]. ganglion or soft-tissue tumors. Zone 2 injuries are usually due to a laceration and occur at the level of the middle phalanx. Furthermore, increasing the intra-articular pressure can cause extravasation of the dilute gadolinium, either along the needle tract or through weaker areas of the joint capsule, which can either obscure or mimic pathology. It has been reported that the sensitivity for complete proper UCL tears is 96%, while the specificity is 95% [78]. Some institutions may separate the hands slightly with a block or towel, while others place the hands with the palms touching. Distal flexor digitorum profundus (FDP) tendon laceration in flexor zone 1. Origin: Hook of hamate and flexor retinaculum. The extensor digitorum brevis manus is an accessory muscle that occurs in the fourth extensor compartment and can be unilateral or bilateral. In these cases, the adductor aponeurosis can lie deep to the UCL stump, which forms the classic yo-yo on a string appearance described in the Stener lesion (Figure 37). Class IIA lesions represent degenerative wear and thinning of the articular disk without perforation. Schweitzer ME, Natale P, Winalski CS, et al.. The proximal pole of the lunate can be predisposed to ischaemia because it lacks soft tissue attachments. Hook of hamate fractures can occur by direct trauma or avulsive force from the transverse carpal ligament. Magnetic resonance imaging (MRI) has high spatial and contrast resolution, and can characterise bone and soft tissue without using ionising radiation, making it an ideal imaging modality to assess pathologic conditions affecting joints. Historically, direct wrist arthrography used a two- or three-compartment approach, whereby contrast was injected into multiple compartments of the wrist, and imaging (MRI or radiography) was performed to determine whether there was abnormal communication between the compartments that indicated a tear in the intervening supporting structures [19]. A T1-weighted axial MRI of the hand showing an ovoid mass of an intermediate signal intensity, similar to normal muscle, surrounding the extensor digitorum communis tendons (arrow).
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