Osteophytes
Athletes can develop osteophytes around the elbow, which may cause pain or reduced range of motion. One example is seen in throwers with posterome-dial impingement who develop an osteophyte on the olecranon process, occasionally with adjacent chondromalacia or spur formation of the humerus in the adjacent olecranon fossa 16 . These osteophytes sometimes can be difficult to identify on radiographs, but are shown well on MRI cross-sectional images 17 . Fig. 8. Intra-articular loose bodies. Axial...
Shoulder Magnetic Resonance Imaging
Lida Chaipat, MD, William E. Palmer, MD Musculoskeletal Imaging, Massachusetts General Hospital, 55 Fruit Street, YAW 6030, Boston, MA 02114, USA MRI provides excellent soft tissue contrast and allows for multiplanar imaging in anatomic planes. Because of these advantages MRI has become the study of choice for imaging of shoulder pathology. Some structures, such as the rotator cuff, humeral head contour, and glenoid shape, are evaluated well with conventional MRI. When more sensitive evaluation...
Tendons
Understanding the normal anatomy of the flexor tendons may be simplified by classifying them according to their location within and outside the carpal tunnel. The flexor tendons contained within the carpal tunnel, deep to the flexor retinaculum, include the flexor digitorum superficialis, flexor digitorum profundus, and flexor pollicis longus tendons Fig. 1 . A common tendon sheath surrounds the long flexor tendons of the digits, whereas the flexor pollicis longus traverses within its own...
Loose Bodies
Intra-articular bodies sometimes can be difficult to diagnose on radiographs. Some of these bodies are composed of only cartilage, whereas others are ossified but are located deep in the olecranon or coronoid fossa and therefore obscured by superimposed bone structures. CT scans are excellent at showing ossified bodies, but intra-articular contrast a CT arthrogram often is necessary for seeing chondral bodies by CT. Conventional MRI images can show even chondral intra-articular bodies 14 ,...
Nerve Abnormalities
MRI may be useful in evaluating patients with nerve disorders at the elbow. Inflammatory changes within a nerve caused by long-standing compression may alter its morphology and signal characteristics on MRI. Normal nerves Fig. 19. Complete triceps tendon rupture in a 57-year-old male with posterior elbow pain following trauma. Sagittal T2-weighted spin-echo image of the elbow shows a large fluid-filled gap arrowhead between the completely torn and retracted distal triceps tendon arrow and the...
Mechanism Of Injury And Imaging Findingsthe Deceleration Phase
During the deceleration phase, after ball release, there is strong eccentric contraction of all muscle groups to maintain the humerus within the glenoid fossa. Joint loads and compressive forces can be large enough to cause rotator cuff tears 43 . These compressive forces, combined with internal rotation and anterior displacement of the humerus, can also cause grinding of the humeral head on the biceps tendon and anterosuperior aspect of the labrum and lead Fig. 7. Bennett's lesion. Axial...
Osseous Injuries
When there is a clinical suspicion for osseous injury some surgeons prefer CT arthrography for evaluation because fractures of the glenoid are depicted better on CT compared with MRI 16,22 . These inferior glenoid fractures can contribute to recurrent instability and glenoid reconstruction may be necessary. When the posterior lateral humeral head impacts on the inferior glenoid during an anterior dislocation a fracture of the superior humeral head may occur, called a Hill-Sachs fracture. The...
Technique
Imaging is performed with the patient in the supine position, arm at the side, and the shoulder slightly externally rotated 1 . A dedicated surface coil is placed close around the shoulder to optimize signal-to-noise ratio. Imaging time usually is 1 hour or less. Specific imaging protocols vary by institution. At our hospital the standard shoulder MRI protocol includes triplanar imaging. The following sequences are obtained coronal oblique proton density PD , coronal oblique T2 with fat...
Tendons Rhz
Digital flexor tendon injuries in the wrist include lacerations and, less commonly, closed ruptures Fig. 7 38 . The latter are usually associated with a variety of underlying chronic conditions that weaken the tendons, such as rheumatoid arthritis, osteoarthritis, scaphoid nonunion 39 , Kienbock disease, hook of the hamate fractures, nonhealed distal radial fractures 40 , and carpal dislocations. Sudden hyperextension of a flexed finger, most frequently seen in football or rugby players and...
Nerves
Proximal to the wrist joint the median nerve travels between the flexor digito-rum superficialis and FCR muscles. It then courses through the carpal tunnel along with the flexor tendons of the fingers and thumb. The carpal tunnel is a fibro-osseous canal bordered volarly by the flexor retinaculum, medially by the pisiform and the hook of the hamate, laterally by the scaphoid and trapezium, and dorsally by the carpal bones. The flexor retinaculum is composed of three parts the antebrachial...
Osteochondral Lesions of the Capitellum
Osteochondral lesions of the capitellum usually are seen in young baseball pitchers, racket sports athletes, and gymnasts 5 . The same valgus stress that in the adult throwing athlete produces MCL tears can give an impaction osteochondral lesion in the child or adolescent. When the lesion is seen in children less than 12 years old with open physes, it is called Panner osteochondrosis. When it occurs in adolescents, it is called OCD. Although there is some controversy, many authors believe that...
Mechanisms Of Injury
Osseous structures are subjected to several different types of stress during physical activities, including tensile, compressive, bending, and shear torsional forces 5 . One or more of these may result in a stress injury to bone if applied in a repetitive manner. A number of mechanisms have been suggested as possible causes for the development of stress fractures. The compressive forces that result from weight-bearing activities are undoubtedly the source of many stress injuries in the lower...
Normal Mri Appearance
The fibrous structures in the shoulder are highly organized tissues with normally low signal on all pulse sequences. These structures include the joint capsule, glenohumeral ligaments, rotator cuff tendons, and the labrum. When there is disruption of the organization structure because of tendinopathy or tear, the signal intensity increases. Unfortunately, there are confounding factors that may cause artifactually increased signal intensity in the absence of pathology. These are discussed in...
Nerves 1
The median nerve and ulnar nerve are best seen on axial MR images both display intermediate signal on T1-weighted images and mild increased signal on fluid-sensitive images. The median nerve is round to oval proximal to the carpal tunnel and flat within the tunnel. The division of the nerve into its branches is usually identified at the level of the metacarpals. Because of its smaller size, variations in the size and signal of the ulnar nerve can be difficult to assess. The nerve is highlighted...
Pathophysiology Of Nerve Disorders
The classification of nerve disorders is based on the severity of the injury and its potential for reversibility. The least severe nerve injury is neuropraxia, or first-degree nerve injury. Distortion of the myelin about the nodes of Ranvier caused by ischemia, mechanical compression, or electrolyte imbalance produces temporary loss of nerve conduction. Neuropraxia has the greatest potential for complete recovery, usually within 2 or 3 months. A more extensive injury caused by interruption of...
Subacromial Decompression
Acromioplasty refers to surgical removal of the anterior inferior hook of the acromion, which is implicated in the pathogenesis of impingement syndrome. The result is a flat acromial undersurface. Subacromial decompression involves an acromioplasty with removal of the coracoacromial ligament, bursectomy, subacromial osteophyte removal, and adhesion removal. This procedure is performed most commonly in isolation in cases of impingement syndrome, less than 50 partial thickness tears, and massive,...
Tendons 1
Magic angle effect is not uncommon in the wrist tendons, most frequently observed in the flexor pollicis longus tendon as it courses in the distal aspect of the carpal tunnel and in the palm 26 . Magic angle phenomenon has also been reported in the extensor pollicis longus and extensor carpi ulnaris tendons 27 . The absence of additional pathologic features and the presence of high signal on short TE images without signal alteration on other pulse sequences are highly suggestive of magic angle...
D
Fig. 8. Normal superior labral recess. Fast spin echo proton density coronal oblique demonstrating prominent fluid within the superior labral recess arrow but not extending into the labrum. This finding can be a normal variant. contrast tracking into the labrum 1,2,7 . Fluid or contrast within or dissecting into the labrum indicates a tear however, this criterion is less accurate when compared with that for nonoperated labra 7 . Following labral surgery, the superior labral recess may become...
Parsonageturner Syndrome
The hallmarks of Parsonage-Turner syndrome, also known as acute brachial neuritis, include the sudden onset of severe atraumatic pain in the shoulder Fig. 4. Quadrilateral space syndrome. Oblique sagittal T1-weighted image demonstrates selective fatty infiltration and atrophy of the teres minor muscle TMi . The deltoid muscle is spared. Fig. 4. Quadrilateral space syndrome. Oblique sagittal T1-weighted image demonstrates selective fatty infiltration and atrophy of the teres minor muscle TMi ....
Biceps Tendon Injuries
Distal biceps tendon rupture most commonly occurs in the dominant extremity of males between 40 and 60 years of age. Rupture of the distal biceps tendon may be partial or complete. Rupture of the distal biceps tendon almost always is the result of a single traumatic event in which a sudden extension force is applied to the arm with the elbow flexed 90 degrees. Most tears of the distal biceps tendon occur at the insertion site of the tendon into the radial tuberosity. Intrasubstance tears and...
Axillary Nerve
The axillary nerve, as the terminal branch of the posterior cord of the brachial plexus, receives contributions from C5 and C6 nerve roots. The nerve courses along the anterior surface of the subscapularis muscle dorsal to the axillary artery. It then makes a sharp turn posteriorly to travel along the inferior gleno-humeral joint surface. Slightly more distally, the nerve, along with the posterior circumflex artery, enters the quadrilateral space. The borders of the quadrilateral space are...
J 1
Fig. 17. Radial tunnel syndrome. Axial fat-suppressed, T2-weighted image at the level of the radial tuberosity demonstrates selective denervation edema of the supinator muscle S . Fig. 18. Posterior interosseous nerve syndrome. Axial T2-weighted image at the level of the radial tuberosity shows mild atrophy and diffuse interstitial hyperintensity of the supinator and extensor muscles with sparing of the extensor carpi radialis longus. ecu, extensor carpi ulnaris muscle edc, extensor digitorum...
Space Occupying Lesion Aberrant Nerve
The most common neuropathy of the upper extremity is the carpal tunnel syndrome, with an estimated incidence of nearly 1 annually, or almost 2.8 million new cases per year, and prevalence of 0.125 to 5.8 74 . The syndrome is most often found in patients between 30 and 60 years of age, has a male female ratio of 1 5, and is bilateral in as many as 50 of patients. Clinical complaints include often transient and reversible pain and paresthesia in the median nerve distribution. In wrist flexion, in...
Summary
A wide spectrum of abnormalities can affect the throwing shoulder. Knowledge of the athletic activity or particular phase in which pain occurs can guide the radiologist to the most likely site of involvement on the MRI examinations. 1 Beltran J, Kim DH. MR imaging of shoulder instability injuries in the athlete. Magn Reson Imaging Clin N Am 2003 11 221-38. 2 Roger B, Skaf A, Hooper AW, et al. Imaging findings in the dominant shoulder of throwing athletes comparison of radiography, arthrography,...
References
1 Kassarjian A, Bencardino JT, Palmer WE. MR imaging of the rotator cuff. Magn Reson Imaging Clin N Am 2004 12 1 39-60. 2 Greenway GD, Danzig LA, Resnick D, et al. The painful shoulder. Med Radiogr Photogr 1982 58 2 21-67. Resnick D. Arthrography, tenography, and bursography. In Resnick D, editor. Diagnosis in bone and joint disorders, vol . 1. Philadelphia Saunders 1995. p. 277-409. De Maeseneer M, Van Roy P, Shahabpour M. Normal MR imaging anatomy of the rotator cuff tendons, glenoid fossa,...
Pitfalls In Rotator Cuff Imaging
Intermediate or inhomogeneous signal in the cuff tendons are causes of diagnostic difficulty. Although the signal may be because of tendinopathy or partial tearing, artifacts such as magic angle phenomenon, inhomogeneous fat suppression, and partial volume averaging also may cause an increase in signal. Magic angle phenomenon occurs on short TE sequences, such as PD sequences. Artifactually increased signal may be seen where the fibers of the cuff tendons are aligned at a 55-degree angle to the...
SportsRelated Injuries of the Elbow An Approach to MrI Interpretation
Michael J. Tuite, MDa'b' , Richard Kijowski, MDa'b aUniversity of Wisconsin Medical School, 750 Highland Avenue, Madison, WI, 53705 USA bDepartment of Radiology, University of Wisconsin Hospital and Clinics, E3 311, 600 Highland Avenue, Madison, WI 53792, USA MRI is a valuable tool for evaluating the athlete with elbow pain, particularly in those with nonlocalizable pain. MRI also is helpful in sorting out the cause of pain in athletes who may have acute trauma superimposed on tendinopathy or...
SportsRelated Injuries of the Wrist An Approach to MrI Interpretation
Jenny T. Bencardino, MDa , Zehava Sadka Rosenberg, MDb aDepartment of Radiology, Huntington Hospital, North Shore Long Island Jewish Health System, 270 Park Avenue, Huntington, NY 11747, USA bDepartment of Radiology, Hospital for Joint Diseases, New York University Medical Center, 305 East 17th Street, New York, NY 10003, USA Sports-related injuries to the wrist range from minor sprains to severe soft tissue disruption that can pose a risk to the normal functioning of the upper extremity. It is...
Injuries of the Fingers and Thumb in the Athlete
Jeffrey J. Peterson, MD , Laura W. Bancroft, MD Department of Radiology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA Hand injuries are common in athletes, accounting for up to 9 of all sports injuries 1 . Injuries to the hand are common in athletes, probably because the hand is characteristically in front of the athlete in most sports and frequently absorbs the initial contact. Furthermore, the hand is used most sports in one way or another. In many competitive team sports,...
Nondisplaced Fractures
MRI can be helpful in recognizing or characterizing nondisplaced fractures, and the imaging information may alter treatment. There are several types of fractures in which MRI can play a role. One is in identifying an otherwise radio-graphically occult fracture, such as a small radial head fracture Fig. 6 . MRI also can be helpful in avulsion fractures of the sublime tubercle in which it can help determine if the MCL is intact or if there is fibrous nonunion or a pseu-darthrosis 12 . Another...
Ulnar Collateral Ligament Tears
Tears of the ulnar collateral ligament may occur following acute valgus stress injury to the elbow or following acute traumatic elbow dislocation 18,19 .Ulnar collateral ligament tears are caused more commonly, however, by chronic repetitive stress to the elbow elicited by sports activities involving overhead throwing 20-23 . Most tears of the ulnar collateral ligament are full-thickness tears that involve the anterior bundle. The vast majority of these full-thickness tears occur in the...
Rotator Cuff Tear
The most common concern in the patient who has postoperative pain is retear of the rotator cuff repair. The patient usually presents with a known incident and details a history of acute pain associated with loss of motion. The diagnostic criteria are similar to the preoperative evaluation with the presence of fluid signal on a T2-weighted image that extends through the entire tendon substance. In the case of MR arthrography, simply seeing the contrast extend into the subacromial-subdeltoid...
Medial Epicondylitis
Medial epicondylitis is a pathologic condition of the common flexor tendon at its origin from the medial epicondyle. Medial epicondylitis is much less common than lateral epicondylitis. Unlike lateral epicondylitis, medial epicondylitis is seen mainly in athletes. Most individuals with medial epicondylitis are involved in sports activities that generate repetitive valgus and flexion forces at the elbow. Medial epicondylitis is believed to represent an incomplete healing response to an initial...
Suprascapular Nerve
The suprascapular nerve originates from the upper trunk of the brachial plexus, receiving fibers from C5 and C6 nerve roots. The nerve innervates the supraspinatus and infraspinatus muscles and provides sensation to the gle-nohumeral and acromioclavicular joints. After traversing the supraclavicular fossa, the suprascapular nerve, with its accompanying vein and artery, enters the suprascapular notch, making a sharp turn around the scapular spine. There the nerve travels within scapular notch or...
Instability
Two main categories of instability include multidirectional atraumatic instability and traumatic instability 11 . Multidirectional instability usually is seen in young patients, is often bilateral, and is believed to be because of capsular laxity, which is not evaluated well with MRI. These patients typically are not sent for imaging 12 . Traumatic instability most commonly occurs after a shoulder dislocation and is usually unidirectional. Because anterior shoulder dislocation is much more...
Mechanism Of Injury And Imaging Findingsthe Late Cocking Phase
The extreme positioning of the humerus in maximum external rotation and 90 of abduction can, over time, stretch the anterior capsule and ligaments, leading to anterior capsular laxity and resultant microinstability or even frank anterior humeral translation. Microinstability may be assessed clinically by a positive ''apprehension test'' in which the patient has a sense of apprehension as his or her arm approaches the ABER position. Posterosuperior or ''internal'' impingement, in which the...
Type 3 Ulnar Styloid Nonunion
Fig. 16. Ulnar styloid impaction. Frontal radiograph of the wrist demonstrates a curved, or ''parrot beak,'' ulnar styloid, with subchondral changes in both the ulnar styloid and the trique-trum arrows . Soft tissue swelling at the ulnar aspect of the wrist is also seen. Fig. 18 63-69 . Ulnar styloid nonunion is classified as type I or type II. Type I nonunion involves the tip of the ulnar styloid. The TFCC remains intact, and the DRUJ is stable. Type II nonunion involves the base of the ulnar...
Stenosing Tenosynovitis Extensor Pollicis Longus
Fig. 9. De Quervain's tenosynovitis. Coronal fat-suppressed T2-weighted image demonstrates tendon sheath effusion, peritendinous edema, and tendon thickening of the first extensor compartment arrowheads . 47 . MRI can be useful in mapping the course of the superficial radial nerve before surgery and also in identifying causes for postsurgical failure. The intersection syndrome is characterized by pain and swelling approximately 4 to 8 cm proximal to Lister's tubercle of the radius where the...
Approach To Rotator Cuff Evaluation
One approach to evaluating the rotator cuff on MRI is to begin by reviewing the coronal oblique PD images to get an overview of the anatomy Fig. 1 . Proton density images are weighted intermediately between T1 and T2 signal. They provide superior signal-to-noise ratio and spatial resolution, albeit at the expense of soft tissue contrast. Large cuff tears and distortions of the anatomy may be identified. Shoulder alignment may be evaluated also. Occasionally because of improper positioning or...
Ulnar Nerve
The ulnar nerve continues directly from the medial cord of the brachial plexus, and contains motor and sensory fibers arising from the C8 and T1 roots. The ulnar nerve crosses from the anterior to the posterior compartment at mid-arm level, piercing the intermuscular septum. The ulnar nerve may pass under the arcade of Struthers, present in 70 of individuals, approximately 8 cm proximal to the medial epicondyle 35 . The arcade of Struthers, made of fibers from Fig. 6. Parsonage-Turner syndrome....
Cubital Tunnel Syndrome
Physiologic and compressive cubital tunnel syndromes have been described. Compressive cubital syndrome may have acute, subacute, or chronic presentation. Normal loss in volume and increased pressure within the tunnel during elbow flexion result in physiologic cubital tunnel syndrome. This can be seen in ''sleep palsy,'' as the arm is held in flexion for prolonged periods of time. Blunt trauma to the cubital tunnel is a typical cause of acute external compression syndrome of the ulnar nerve....
Imaging of UlnarSided Wrist Pain
Department of Radiology, Virginia Commonwealth University, Main Hospital, 3rd Floor, Room 3-343, 1250 East Marshall Street, Richmond, VA 23298, USA Ulnar-sided wrist pain has long been a diagnostic dilemma for both radiologists and hand surgeons. The small size of the anatomic structures, the diversity of disorders that can cause symptoms, and the high rate of asymptomatic findings at the ulnar aspect of the wrist are some of the factors that contribute to the difficulty of diagnosis and...
Imaging Findings In Osseous Stress Injuries
Conventional radiographs are notoriously insensitive for detecting stress injuries in bone. The sensitivity of initial radiographs, obtained at the time of presentation, has been reported to be as low as 15 and will become positive over time in only 50 of patients 17,18 . The earliest radiographic finding in a stress reaction involving cortical bone is the ''gray cortex'' sign 19 . This is an area of subtle, ill-defined intracortical lucency, related to the osteoclastic tunneling that occurs in...
Ulnolunate Impaction Syndrome
Fig. 4. Ulnar TFCC tear. Coronal fat-suppressed T1-weighted image from an MR arthrogram radiocarpal joint injection only demonstrates contrast extravasating into the DRUJ asterisk and through the ulnar aspect of the TFCC arrows , consistent with an ulnar-sided TFCC tear. Contrast is also noted extending into the midcarpal joint through a torn lunotriquetral ligament curved black arrow . Tears of the LTL are much less common than scapholunate ligament SLL tears, occurring only about one sixth as...
Median Nerve
The median nerve supplies the radial side of the flexor portion of the forearm and hand, and is formed by the blending of the lateral and medial cords of the brachial plexus. It contains both motor and sensory fibers from the C5, C6, C7, C8 and T1 nerve roots. The median nerve descends in the arm in close relationship to the brachial artery. It has no branches at the level of the arm. At Fig. 12. Subcutaneous anterior transposition of the ulnar nerve. Axial T1-weighted image shows a mildly...
Radial Nerve
The radial nerve, a terminal branch of the posterior cord of the brachial plexus, supplies the extensor musculature of the arm and forearm as well as the overlying skin. The radial nerve carries motor and sensory fibers from the C5, C6, C7, C8, and T1 nerve roots. The nerve descends between the medial and long heads of the triceps muscle in the proximal arm. At the proximal humeral shaft, the radial nerve traverses within the humeral spiral groove. In the distal arm, the nerve perforates the...
The Triangular Fibrocartilage Complex
The triangular fibrocartilage complex TFCC is the primary stabilizer of the distal radioulnar joint DRUJ . It also absorbs stress during axial loading of the wrist and limits lateral deviation of the carpus. The main components of the TFCC are the triangular fibrocartilage, the dorsal and volar radioulnar ligaments, the volar ulnolunate and ulnotriquetral ligaments, the meniscus homologue, the ulnar collateral ligament, and the extensor carpi ulnaris tendon sheath 15-19 . The complex anatomy of...
Normal Variants
There are several normal osseous features of the elbow that are important to recognize because they may be more striking on MRI images than at arthros-copy. One of the most common is the pseudodefect of the capitellum, a normal anatomic feature that mimics an osteochondral lesion on MRI images 3 . The pseudodefect of the capitellum occurs posterolaterally where the normal articular surface of the capitellum ends abruptly giving a stepoff at the interface with the nonarticular portion of the...
Ligaments
The extrinsic ligaments are capsular ligaments that tie the radius and ulna to the carpal bones and traverse the radiocarpal joint, midcarpal joint, or both. The extrinsic ligaments may be divided into volar and dorsal components. The volar radiocarpal ligaments are stronger and thicker than the dorsal ligaments and are the major stabilizers of wrist motion. Significant variations have appeared in the descriptive anatomy and nomenclature of these ligaments 6-9 , resulting in some confusion in...
Nondisplaced Tear
Fig. 2. Subcortical cysts and posterior capsular stripping in a 16-year-old male who had right shoulder pain when throwing for 3 months. A Subcortical cysts arrow in the greater tuberosity at the insertion of the supraspinatus tendon are seen as high signal intensity on a fat-suppressed T2-weighted image. B Axial gradient echo T2-weighted image shows a nondisplaced tear of the posterior labrum and capsular stripping arrow . Fig. 3. Posterosuperior labral tear and impaction of the greater...