Ultrasound of the Month Diagnosis Index

Case 77 Painful Os trigonum

25-year-old female with intermittent posterior ankle pain. MRI showed the presence of an os trigonum, but without bone marrow edema. Ultrasound-guided anesthetic injection of the os trigonum was requested to assess whether it was a symptom generator.

Discussion: Os trigonum is a fragment of bone of the lateral tubercle of the posterior process of the talus that has failed to fuse with the remainder of the talus. The incidence is said to be 7% of the population. Although it may be an incidental finding, it can be the source of pain in individuals who do activities requiring repetitive plantarflexion of the ankle, such as ballet dancers or soccer players. A painful os trigonum is often called "os trigonum syndrome", and it is one of a few conditions that can result in posterior ankle impingement.

Radiological studies play a pivotal role in evaluating patients with clinical symptoms of posterior ankle impingement.

MRI can identify an os trigonum as well as the extent of soft tissue involvement such as synovial scarring and FHL tenosynovitis. On MRI, bone marrow edema (high signal intensity on inversion recovery sequences) in the os trigonum and posterior process of talus are suggestive of a symptomatic os trigonum, but it is not 100% sensitive.

Ultrasound can also identify an os trigonum, but more importantly, it can be used to guide needle placement for a targeted injection of anesthetic with or without cortisone. If the patient feels symptomatic relief after injection of anesthetic around the os, it can increase the diagnostic confidence of the foot and ankle specialist that the os trigonum is the symptom generator.

Case 76 Flexor carpi radialis tenosynovitis

76-year-old woman with right wrist pain and palpable mass at the volar radial wrist. The patient was referred for a wrist ultrasound to assess for a ganglion cyst.

Discussion: The flexor carpi radialis (FCR) tendon has a complex insertion at the wrist, with the majority of the tendon (80%) inserting at the base of the 2nd metacarpal. 20% of the tendon insert on the 3rd metacarpal, and a few tendon slips attach to the trapezium.
The FCR tendon is encased in a sheath from the musculotendinous junction to the trapezium, and it is outside the carpal tunnel. When the tendon sheath is distended with fluid, this is called tenosynovitis.

FCR tenosynovitis is generally associated with two main conditions:

  • Overuse: Manual labor, golf or racquet sports
  • Arthritis: Radiocarpal or basilar joint arthritis

Post-traumatic FCR tenosynovitis can also be seen after a scaphoid or distal radius fracture.

Treatment is usually non-operative and includes immobilization, non-steroidal anti-inflammatory medication (NSAIDs) and peritendinous corticosteroid injection. Ultrasound guidance is ideal for safe and accurate FCR peritendinous corticosteroid injection.

Case 75 Biceps long head tenosynovitis with loose body in the tendon sheath

68-year-old female with progressively worsening left anterior shoulder pain.

Discussion: The biceps tendon long head is a common source of anterior shoulder pain.Usually due to repetitive overuse, the biceps tendon can undergo various pathologies, including tendinosis, tenosynovitis, split tears, dislocations, and ruptures. All of these conditions can be accurately assessed on ultrasound. Cortisone injection into the biceps tendon sheath is a percutaneous treatment option for anterior shoulder pain due to the biceps tendon long head.Under ultrasound guidance, the position of the needle with respect to the target can be visualized in real time so that tendon sheath injection can be performed accurately and puncturing adjacent structures such as vessels, the subscapularis tendon, or the biceps tendon long head itself can be avoided.Ultrasound also allows the radiologist to identify and address unexpected findings, such as soft tissue masses and fluid collections.

Case 74 Parameniscal cyst of the knee

22-year-old female with progressive lateral knee pain after prior ACL reconstruction and lateral meniscal repair. MRI showed a large multilobulated lateral parameniscal cyst.

Discussion: Parameniscal cyst is a ganglion cyst arising from the meniscus due to a chronic tear of the meniscus. Fluid leaks out from the meniscal tear into the extraarticular soft tissues and becomes confined by a pseudocapsule. As the cyst slowly enlarges, it can become symptomatic as it causes mass effect on surrounding soft tissues. Definitive treatment for parameniscal cysts is to surgically treat the underlying meniscal tear. A non-invasive percutaneous treatment option is aspiration and fenestration under ultrasound guidance. Performing the procedure under ultrasound allows the radiologist to directly visualize the cyst, needle, and relevant soft tissues including the popliteal artery in the current case. Cortisone is often injected at the end of the procedure, although the extra benefit of cortisone in preventing recurrence of parameniscal as well as ganglion cysts in general is controversial.

Case 73 Chronic left superior peroneal retinaculum rupture and anterior subluxation of the peroneus brevis tendon

38-year-old man with chronic left posterior lateral ankle pain and snapping sensation.

Discussion: The superior peroneal retinaculum (SPR) extends from the lateral periosteum of the lateral malleolus and attaches posteriorly on the Achilles and/or calcaneus.A normal SPR acts to keep the peroneal tendons in place within the peroneal groove at the posterior aspect of the lateral malleolus.A chronically torn SPR can result in recurrent peroneal tendon subluxation or dislocation, presenting as painful lateral ankle snapping or popping usually when walking up or down stairs.Ultrasound can efficiently evaluate for peroneal tendon subluxation or dislocation using real-time and dynamic imaging.Conservative management involves cast immobilization. If symptoms persist, surgical repair is highly successful.

Case 72 Lipoma of the antecubital fossa of the elbow

50-year-old female with slowly-growing palpable mass along the antecubital fossa of the elbow. An ultrasound was requested to rule out a soft tissue mass.

Discussion: Soft tissue lipomas are benign tumors composed of mature adipocytes that usually present as an incidental soft palpable mass.Although they are benign, they may require imaging to confirm that it is a lipoma and not an aggressive neoplasm.MRI is the most accurate modality for characterizing fat-containing tumors that are located in the deep soft tissues.For superficial lesions, ultrasound is also an accurate modality for confirming that a palpable mass is indeed a lipoma. Compared to MRI, ultrasound is more cost effective, faster, and better tolerated by patients.

Case 71 Stenosing FHL tenosynovitis

26-year-old female ballet dancer with left posterior ankle pain and difficulty dancing en pointe.

Discussion: The FHL tendon, because of its function to plantarflex the great toe and because of its particular course along the posterior ankle, is susceptible to irritation particularly in ballet dancers. Chronic irritation of the tendon can result in both tendinosis and tenosynovitis of the FHL posterior to the ankle. Like all tendons in the foot and ankle, because the FHL courses relatively superficially in the soft tissues, it is a structure that is optimally evaluated by ultrasound. Stenosing tenosynovitis, in which hypertrophic scarring of the tendon sheath can have a constricting effect on the tendon, can result in pain and diminished excursion of the FHL.

Case 70 Partial thickness laceration injury of the palmaris longus tendon

35-year-old woman with laceration injury to the volar wrist and paresthesias with palpation of the laceration.

Discussion: The palmaris longus is variably absent in between 5%-27% of the patient population. When present, the palmaris longus tendon can be found as a long and flat tendon at the volar wrist, coursing over then inserting on the central flexor retinaculum. Its superficial location makes it particularly susceptible to laceration injury. The palmaris longus tendon is a common source of tendon graft given its length and lack of functional deficit with harvest. Given its close proximity to the median nerve, injury or irritation to the palmaris longus tendon may cause paresthesias and the median nerve should be closely evaluated for concomitant injury. When harvesting the palmaris longus tendon, nerve stimulation is performed to confirm the median nerve is left intact.

Case 69 Quadriceps tendon rupture

53-year-old male with hyperflexion injury to the knee 6 days prior.

Discussion: Quadriceps tendon rupture usually occurs during rapid contraction of the muscle while the knee is flexed. Ultrasound is a useful imaging modality for diagnosing acute quadriceps ruptures, and its quicker exam time, cost-effectiveness, and lack of contraindications are advantages of ultrasound compared to MRI.
In the acute phase, fluid associated with the injury will outline the torn tendon and increase the conspicuity of the tear. In the chronic phase, the tear is often harder to detect due to the presence of scar tissue that may appear similar to tendon.

Case 68 Muscle herniation of the anterior tibialis muscle

35-year-old male with painful swelling over the anterior shin during exercise, noticed several months prior.

Discussion: Focal herniation of muscle through a defect of the fascia can be symptomatic, causing either a palpable lump beneath the skin or vague compartment-syndrome-like pain. Onset of symptoms upon exercise is classic. Ultrasound allows direct visualization of the herniating muscle, which can usually be elicited upon active muscle contraction by the patient. Because of this dynamic component to the evaluation, ultrasound is the best modality for diagnosing this entity; MRI, because it is a static exam, may not be able to identify the herniating muscle.

Case 67 Anconeus epitrochlearis muscle (accessory anconeus muscle)

42-year-old woman with numbness in the left fourth and fifth fingers. The patient was referred for an ultrasound (US) of the elbow to assess for ulnar nerve pathology.

Discussion: The anconeus epitrochlearis is an accessory muscle which originates from the olecranon and inserts on the medial epicondyle.This accessory muscle at the elbow may be asymptomatic but has been implicated as a cause of cubital tunnel syndrome which leads to ulnar neuritis. The anconeus epitrochlearis may be unilateral or bilateral. The anconeus epitrochlearis, also known as the accessory anconeus, is not to be confused with the anconeus muscle which is found at the lateral aspect of the elbow.

Case 66 Pedunculated osteochondroma of the distal femur

14-year-old girl with history of hard palpable mass along the anterior thigh, which was first noticed several months prior.

Discussion: Osteochondromas are benign cartilaginous tumors that manifest as bony excrescences with a cartilage cap, most commonly occurring around the knee. Treatment is usually conservative, although surgical resection may be considered in symptomatic patients, as in our patient. Intraoperative radiographs show the osteochondroma in our patient before (a) and after (b) surgical excision.

Case 65 Complete laceration of the flexor digitorum profundus and superficialis tendons with a tendinous gap

39-year-old female with inability to flex either the proximal or distal interphalangeal joints of the left pinky after finger laceration with a glass.

Discussion: Penetrating injuries such as accidental lacerations from a glass or knife are relatively common in the wrists and hands, and the laceration can cause a tendon tear if deep enough. The superficial location of these tendons and relative thinness of the overlying soft tissues make ultrasound a quick and ideal modality for assessing the integrity of these tendons.

Case 64 A4 pulley rupture of the right ring finger

30-year-old woman with pain in the right middle and ring fingers following rock-climbing injury. The patient was referred for an ultrasound (US) to assess for tendon injury.

Discussion: There are 5 pulleys associated with the flexor tendon sheath of the finger. The most important for biomechanical function are the A2 and A4 pulleys. The A2 is the strongest pulley but most commonly injured. Pulley rupture is an overuse injury commonly seen in rock-climbers. Sonography is effective in the evaluation of pulley rupture and can be useful to assess for the integrity of the flexor tendon.

Case 63 SPN stump neuroma due to latrogenic nerve transection

39-year-old man with history of prior ORIF of tibial fracture and multiple subsequent surgeries including fasciotomy.

Discussion: One of the complications of a nerve transection, either post-traumatic (eg. due to penetrating injury) or deliberate (as part of limb amputation) is the development of a stump neuroma. Stump neuroma can result in pain and parasthesia in the distribution of that nerve. Ultrasound can be a very accurate modality for evaluating the integrity of nerves, particularly nerves that course superficially in the extremities.

On ultrasound, a stump neuroma manifests as a heterogenous soft tissue/scar at the end of a transected nerve. As in this case, ultrasound-guided injection of anesthetic around the nerve and the scar can be helpful for confirming that the patient's symptoms are related to the stump neuroma.

Case 62 Impingement of the FHL tendon

Impingement of the FHL tendon by the proud tip of distal tibial screw causing irritation and tenosynovitis of the tendon.

Discussion: MRI and ultrasound play complementary roles in assessing for complications after surgery. Because of the outstanding soft tissue contrast and overall spatial resolution, an MRI is usually a good first line test in detecting complications such as infection, synovitis, and tenosynovitis. Ultrasound is valuable for evaluating soft tissues, and when evaluating the positioning of hardware in relation to anatomic structures, ultrasound is not susceptible to metal artifact to the same degree that MRI is. In addition, dynamic maneuvers on ultrasound may reveal information such as tendon subluxation or soft tissue herniation that static exams such as MRI will not detect.

Case 61  Right hip joint synovitis

Hip joint synovitis is a common cause of hip pain and limping in the pediatric population.

Radiographic evaluation usually shows no abnormality.

Sonography is useful to determine the presence or absence of a joint effusion.

The benefits of sonography include the ability to evaluate the contralateral side and the lack of ionizing radiation, particularly advantageous in the pediatric population.

Case 60 Glomus tumor

45-year old female with pain in the fingertip of the middle finger.

The patient did not want an MRI due to claustrophobia, thus an ultrasound was requested.

Case 59 Gamekeeper's thumb

Gamekeeper's thumb (or skier's thumb) describes a UCL avulsion fracture or rupture, usually off the base of the first proximal phalanx.

These injuries at the ulnar aspect of the 1st MCP joint may lead to significant instability, at times requiring surgical intervention.

As the structures about the 1st MCP joint are superficial, ultrasound is a useful and efficient modality to assess for the integrity of ligamentous structures following trauma to the thumb.

Case 58 Plantar fibromatosis.

Plantar fibromatosis, also known as Ledderhose disease, is the development of fibrous nodules, often multiple, in the plantar fascia. It can co-exist with palmar fibromatosis (Dupuytren’s contracture).

Case 57 Arterial pseudoaneurysm after knee replacement.

Pseudoaneurysm is an uncommon complication after total knee arthroplasty, with a reported incidence of 0.03% to 0.2%.
Symptoms of a pseudoaneurysm include pain, gait disability, cold foot, pulsatile mass and recurrent hemarthrosis.
Ultrasound is a cheap, sensitive modality for patients suspected of a pseudoaneurysm.
If a pseudoaneurysm is detected by ultrasound, MRA may be indicated to more accurately delineate the parent artery for possible embolization.

Case 56 Common peroneal nerve scar encasement.

Trauma is the most common cause of acquired peripheral neuropathy, occurring as either direct injury to the nerve (e.g. laceration, contusion) or indirect injury (e.g. scar encasement, entrapment).

Peripheral nerves have a characteristic appearance on US which helps in their identification.

Scar tissue usually appears as hypoechoic/dark tissue on US, and can cause encasement or entrapment of adjacent nerves.

US is useful in the evaluation of peripheral nerves, particularly when there is adjacent metallic hardware that can limit MRI evaluation.

Case 55 Diagnosis: Birth-related clavicle fracture

The clavicle is the most common site of birth-related fracture, reported to occur in up to 1% of vaginal deliveries.
Risk factors for fracture of the clavicle include large size of the baby, forceps delivery, and shoulder dystocia.
Although easily diagnosed by radiographs, ultrasound is an ideal alternative as it is fast, accessible, and most importantly, lacks ionizing radiation.
Additional value of ultrasound is that it can evaluate the soft tissues surrounding the clavicle should the patient’s palpable abnormality be caused by an entity other than a clavicle fracture.

Case 54 Diagnosis: DeQuervain’s tenosynovitis

Painful inflammation of the abductor pollicis longus and extensor pollicis brevis tendons. Most common in women and often in the 30-50 year age group Tendon tears are relatively uncommon. Associated with repetitive activities such as racquet sports, golf, manual labor and frequently lifting and holding a newborn child (as in the case presented). May also be associated with conditions such as rheumatoid arthritis. Treatment options include NSAIDs, physical therapy, reduction in the activities causing pain, and cortisone injections. Cortisone injections should be done with ultrasound guidance to confirm accuracy. Severe cases without response to more conservative measures may require surgery.

Case 53 Diagnosis: Peri-patellar bursitis:

Involves inflammation of the synovial-lined bursa between the skin and the patella or the patellar tendon. Common condition, often related to repetitive kneeling (carpenters, maids, gardeners, etc.) Also associated with gout, rheumatoid arthritis, diabetes, uremia, etc. With any clinical suspicion for infection, ultrasound-guided aspiration should be performed.

Case 52 Diagnosis: Metatarsal stress fracture:

Radiographs remain the initial diagnostic study of choice in evaluating for a metatarsal fracture. If radiographs are normal but the diagnosis is still suspected, MRI is the gold standard. In patients who cannot have an MRI and in other selected circumstances, an ultrasound of the area may confirm the presence of a fracture. However, if the ultrasound imaging is normal, fracture cannot be excluded and further imaging and follow-up is necessary.

Case 51 Primary synovial chondromatosis

The core biopsy samples obtained demonstrated findings compatible with primary synovial chondromatosis. This is a relatively rare condition with proliferation of islands of irregularly hypercellular cartilage seen microscopically.

Most commonly seen in the knee, this process may arise from joint synovium or less likely a tendon sheath. The condition is twice as common in men and in the primary form has no known precipitating factors.

Case 50 Bicipitoradial Bursitis

Bicipitoradial bursitis is a relatively uncommon condition resulting in inflammation and distention of the bicipitoradial bursa. This enlarged bursa may impinge upon the adjacent radial nerve bifurcation and posterior interosseous nerve.

Bicipitoradial bursitis is most commonly secondary to repetitive activity and may be associated with biceps tendon tears or tendinosis. In rare cases, the bursa may be infected and require antibiotic therapy and possible surgical intervention.

As demonstrated in this case, ultrasound is valuable in evaluating the distal biceps tendon for tear/tendinosis and in confirming the presence of an enlarged and inflamed bursa. Also, ultrasound allows safe needle aspiration and injection of the bursa as indicated.

Case 49 Intramuscular lipoma of the vastus lateralis muscle

Microscopic pathologic review of the core specimens obtained demonstrated Adipose tissue containing small bands of bland fibrous tissue and numerous skeletal muscle fibers. No evidence of mineralization.

Case 48 Plantar foot abscess following puncture injury

Costal cartilage fractures may be a difficult clinical diagnosis.

Gram stain with culture and sensitivity of the fluid obtained from aspiration yielded gram-positive cocci (Staph Aureus).

Case 47 Costochondral junction fracture

Costal cartilage fractures may be a difficult clinical diagnosis.

Radiographs are generally normal in the absence of an associated rib fracture.

While, as demonstrated, the diagnosis may be made by either CT or ultrasound imaging (as well as MRI), ultrasound is less expensive, faster, and like MRI avoids the use of radiation.

Case 46 Ganglion cyst

Ganglion cyst extending from the tibial tunnel into the adjacent soft tissues in the setting of prior ACL reconstruction.

MRI is the examination of choice in evaluating the integrity of the ACL in the setting of prior reconstruction and easily demonstrates the presence of ganglion cysts

Ultrasound may be used to confirm the diagnosis and more importantly to guide the safe and complete aspiration of these ganglion cysts

Ganglion cyst fluid is often extremely thick, requiring the use of larger (16-18 gauge) needles for complete aspiration

As clinically indicated, the fluid may be sent for laboratory analysis to exclude the possibility of infection.

Case 45 Complete tear of the ulnar collateral ligament with avulsion

Complete tear of the ulnar collateral ligament of the thumb with avulsion

While MRI has historically been the imaging study of choice for evaluating the ulnar collateral ligament, ultrasound will often quickly make the diagnosis and should be considered when this diagnosis is suspected.

It is important that complete tears are detected early so that prompt surgical correction may be performed.

Case 44 Temporal (giant cell) arteritis

Case 43 Full-thickness tear of the anchilles tendon

Case 42 Lateral ankle sprain

Case 41 Patellar tendon rupture

The interval elevation of the patella and increased patella-tibial tubercle distance as consistant with patellar tendon rupture.

Case 40 Giant cell tumor of tendon sheath

Giant Cell Tumor of Tendon Sheath involving the extensor tendon of the 2nd digit of the hand, also referred to as localized nodular tenosynovitis. Pathologically, the tissue is identical to PVNS. Lesions contain histiocyte-like multinucleated cells and fibroblastic cells. Frequently, they contain hemosiderin deposits.

Case 39 Calcium hydroxyapatite deposition disease

Case 38 Sciatic nerve stump neuroma

Case 37 Foreign Bodies

Case 36 Paralabral cyst

Paralabral cyst extending posteriorly and impinging the sciatic nerve.

Case 35 Post-traumatic seroma

Post-traumatic seroma interposed between the medial gastrocnemius and soleus muscles following partial medial gastrocnemius tear. Ultrasound-guided seroma aspiration may allow prompt resolution of symptoms and rapid improvement in patient mobility. The use of ultrasound during these procedures allows safe and accurate needle placement and ensures complete evacuation of the fluid collection.

Case 34 Ganglion cyst

Immediately following aspiration of the ganglion cyst, the patient was able to painlessly perform the ballet maneuvers and great toe flexion that had previously elicited discomfort. As clinically indicated, cortisone injection into the ganglion could also be performed at the time of the initial cyst aspiration. Due to the relatively high recurrence rate of ganglion cysts, the patient will be monitored clinically for evidence of symptom recurrence.

Case 33 Osgood-Schlatter disease

Case 32 Mucin-secreting adenocarcinoma

Moderately differentiated mucin-secreting adenocarcinoma, consistent with a pulmonary origin. This matched the previous pathology of the patient's primary lung tumor.

Case 31 Peripheral nerve sheath tumor

Peripheral nerve sheath tumor of the ulnar nerve.

Case 30 Congenital muscular torticollis

Congenital Muscular Torticollis.

Case 29 Meralgia paresthetica

Based on the clinical presentation, the diagnosis of meralgia paresthetica was considered most likely. Ultrasound evaluation of the lateral femoral cutaneous nerve was requested with peri-neural anesthetic injection to confirm the diagnosis.

Case 28 Calcific tendinosis

Calcific tendinosis of the proximal hamstring tendons.

Case 27 Infected olecranon bursitis

Case 26 Tarsal tunnel syndrome secondary to tibial nerve compression

Tarsal tunnel syndrome secondary to tibial nerve compression from a perineural ganglion cyst.

Treatment of choice is ultrasound-guided aspiration of the cyst with resulting nerve decompression.

Case 25 Ganglion cyst

Ganglion Cyst.

Case 24 Spinoglenoid notch cyst

Spinoglenoid notch cyst causing denervation atrophy and fatty replacement of the infraspinatus muscle.

Case 23 Partial thickness tear of the proximal patellar tendon

Partial thickness tear of the proximal patellar tendon.

Case 22 Nodular Pigmented Villonodular Synovitis

Nodular Pigmented Villonodular Synovitis arising from the lateral tibiotalar joint.

Case 21 Myxomatous tumors of the soft tissues

Myxomatous tumors of the soft tissues are a heterogeneous group of lesions, both benign and malignant, that show an overproduction of mucopolysaccharide substances. Characterized by a mixture of primitive mesenchymal cells and myxomatous stroma.

Case 20 Paralabral cyst compressing the femoral nerve

Following the ultrasound-guided aspiration of the paralabral cyst compressing the femoral nerve, the patient experienced symptomatic relief of her femoral nerve symptoms.

Case 19 Calcific tendinosis

Calcific tendinosis of the long head of the rectus femoris tendon at the Anterior Inferior Iliac Spine

Case 18 Schwannoma

Case 17 Epidermoid inclusion cyst

Case 16 Giant cell tumor with ABC formation

Case 15 Sindig-Larson-Johansson syndrome

Case 14 Right rectus abdominus hypertrophy

Right rectus abdominus hypertrophy with strain common in tennis players.

Case 13 Traumatic peroneus brevis tear

Traumatic peroneus brevis tear status post ultrasound guided PRP injection with healing response.

Case 12 Glomus tumor of the terminal tuft

Case 11 Lateral epicondylitis with deep surface tear of extensor tendon

Lateral epicondylitis with deep surface tear of extensor tendon origin/lateral collateral ligament with seroma formation. Ultrasound guided seroma aspiration and platlet rich plasma injection.

Case 10 Early osteoarthritis with lateral hip impingement

Case 9 Scar encasement/neuroma formation about ulnar nerve

Case 8 Lateral femoral cutaneous nerve entrapment

Initial imaging shows hypoechoic scarring surrounding the nerve near the Iliac crest and Sartorius origin. Ultrasound guided perineural injection was Performed resulting in symptomatic relief.

Case 7 Linear calcification in anterior joint capsule

Linear calcification in anterior joint capsule producing anterior impingement and pain.

Case 6 Large foreign body granuloma

Large foreign body granuloma containing multiple foreign bodies.

Case 5 De Quervain’s tendinitis/tenosynovitis

Large tendon sheath effusion, inhomogeneity of the first dorsal compartment tendons with marked hyperemia on power Doppler imaging.

Case 4 Isolated teres minor atrophy

Isolated teres minor atrophy:

  • Atrophic muscle appears echogenic and and diminutive in size
  • Normal muscle is hypoechoic on ultrasound
  • Teres minor atrophy often due to injury of the axillary nerve as it passes through the quadrilateral space

Case 3 Peroneal tenosynovitis

Ultrasound shows fluid and nodular soft tissue surrounding the peroneal tendons giving rise to the soft tissue swelling seen on radiographs.

Case 2 Osteomylitis

Case 1 Gout

Sonographic appearances suggestive of gout. Confirmed on ultrasound guided aspiration.