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A 58-year-old woman with myositis ossificans traumatica came to our trauma outpatient clinic because of cutaneous perforation of one of the ossifications. This patient developed myositis ossificans traumatica after liposuction of both upper legs 30 years ago, which condition was complicated by a chronic infection of the ossified right quadriceps muscle, a walking limitation, and a loss of range of motion. Myositis ossificans traumatica is a rare disorder associated with trauma- triggered ossification of otherwise normal muscle tissue.

This report concerns an unusual cause of sciatica. The case presented is of a young man with myositis ossificans that resulted in sciatica and was treated with en bloc excision and low-dose radiotherapy and indomethacine. The aim of this study was to explain the different diagnostic properties of myositis ossificans around the hip and non-classic causes of sciatica.

Background Context: Although traumatic myositis ossificans (MO) has been reported occasionally, MO of paraspinal muscles has been rarely seen in the cervical spine after minor injury. This is difficult to distinguish from benign and malignant soft lesions in cases of a lack of definite trauma history., Purpose: We report a case of MO in the cervical paraspinal muscle after acupuncture and describe methods for diagnosis and proper treatment, including classification, etiology, and radiologic and histologic features., Study Design: Case report., Methods: A 26-year-old woman complained of posterior neck pain that had began 2 months earlier and neck swelling after acupuncture. No abnormal finding existed on the X-ray except soft tissue swelling. Magnetic resonance imaging was evaluated because of constant neck pain. To obtain more accurate assessment, computed tomography-guided biopsy was performed and a diagnosis of MO was made., Results: The patient was conservatively treated through rest and analgesics. Posterior neck pain and swelling improved for a several months. The hyperdensity was comparable with the bony density, and the size of the calcified lesion on X-ray diminished until the last follow-up., Conclusions: Myositis ossificans that can occur after acupuncture should be recognized as a possible cause of persistent neck pain and swelling despite no definite trauma after thorough evaluation of the neoplasm and infection., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Myositis ossificans is a rare cause of pain following knee arthroplasty. We describe a 72-year-old woman who developed symptomatic early onset myositis ossificans at the femoral marker pin site following navigated knee arthroplasty., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Traditional medicines especially the herbal paste is routinely prescribed by the herb sellers. The unsupervised combinations and preparations are easily available in our part of world. The demand and supply of such irrational combination is only based on the principle that anything natural is safe. Drugs and preparations made by the people who lack the scientific knowledge of traditional herbal medicines adversely affect the consumer. We put forward few complications that resulted after herbal paste application in those who already had visited the specialist but opted the easily available unsupervised herbal preparations.

We report the case of a parosteal osteosarcoma of the distal ulna, treated with wide resection without reconstruction. The patient developed lung metastasis and a mass in the interosseus membrane of the forearm proximally to the osteotomy. The lung mass was found to be a metastasis from parosteal osteosarcoma and the biopsy of the forearm mass revealed a myositis ossificans. The suspicion of a recurrence of parosteal osteosarcoma, already metastatic, led to a second wide resection with no reconstruction. A slice of the radial cortex was taken during this second procedure. From a histological point of view, good margins were achieved and diagnosis of myositis ossificans was confirmed. Two months later, a radius fracture occurred and a synthesis, with plate and screws, as added with poly(methyl methacrylate) (PMMA) to reconstruct the bone loss, was performed. Indication of the reconstructive technique and the complication after distal ulna resection in oncologic surgery are discussed in this paper.

Myositis ossificans of the hand is very rare. We report a case of an obviously post-traumatic case and discuss the value of trauma in the etiology., (© 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.)

Myositis ossificans traumatica (MOT) is a disease in which muscular ossification develops following trauma. Almost all cases of MOT are found in skeletal muscle. The authors report in a 39-year-old man MOT involving several muscles in the head and neck, namely, bilateral masseter muscles, the left temporal muscle, the left lateral pterygoid muscle, and the left frontal muscle. Involvement of the lateral pterygoid muscle is especially rare.

We present a 10-week-old girl with myositis ossificans circumscripta (MO) of the neck secondary to nonaccidental trauma. This condition is rarely seen in infants; furthermore, the majority of MO lesions develop in the extremities rather than the head and neck region. We will detail the US-guided biopsy technique used in our case, in addition to discussing the characteristic imaging and pathological findings of MO to assist in the diagnosis and successful treatment of this condition.

Context: Neurogenic myositis ossificans or para-osteo-arthropathy are part of heterotopic ossifications. They concern mostly spinal cord injured or cerebral injured patients. They mostly target the hip and can lead to local or general inflammatory signs which can mimic severe sepsis. We detail the frequent septic like symptomatology and the relevance of echography to make the diagnosis and to start adapted therapy., Method: We conducted a retrospective study from seven patients hospitalized in infectious disease department for suspicion of septical myositis and we compared this cohort with available data., Results: They all have inflammatory syndrome and radiological signs. Diagnosis can be made early by echography, MRI or tomodensitometry. X-ray signs are delayed., Conclusion: Myositis ossificans can have a septical presentation but therapy is, at first, medical with non steroid anti inflammatory drugs and no antibiotic therapy., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Myositis ossificans traumatica (MOT) is a non-neoplastic, heterotopic bone formation within muscle or fascia, presumably due to acute trauma, a burn, surgical manipulation, or repeated injury. A 36-year-old woman presented with progressive limitation of mouth opening over the past 5 months. Computed tomography revealed an irregular ossified mass attached to the medial aspect of the left ramus, extending to the medial and lateral pterygoid plates. MOT of the medial pterygoid is rare, with only four previously reported cases in the English language literature. Surgical excision of the ossification is the main treatment modality. The authors were able to establish a cleavage plane of 3 cm between the bony mass and the medial surface of the ramus. Abdominal fat was placed as an interpositional material to prevent fibrosis and heterotopic bone formation., (Copyright © 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Purpose: The aim of this paper is to describe the sonographic (US) features of post traumatic myositis ossificans (PTMO)., Methods: Fifteen patients with histopathological diagnosis of PTMO were included. The following US parameters were evaluated: presence of a mass, calcifications, power Doppler signals, and relationship with adjacent structures., Results: Five patients (33.3%) were diagnosed as early PTMO and 10 (66.6%) as mature PTMO. In both early and mature PTMO, US showed an oval hypoechoic mass, without infiltrative borders, located in a muscular belly. In the early phase, a center of less echogenicity was observed, associated with an outer sheet-like hyperechoic peripheral rim, while, in the mature phase, peripheral calcification created more reflections and distal acoustic shadowing was observed., Conclusions: US is highly sensitive in the detection of PTMO, helps differentiate between PTMO and malignant soft tissue tumors, and can be used for follow-up of the lesions., (Copyright © 2011 Wiley Periodicals, Inc.)

Trigger point injection is a simple procedure that is widely performed for relieving pain. Even though there are several complications of trigger point injection, myositis ossificans has not been documented as one of its complications. We treated a patient who suffered from painful limitation of elbow motion and this was caused by myositis ossificans between the insertions of brachialis and supinator muscles after a trigger point injection containing lidocaine mixed with saline, and we also review the relevant medical literature.

Post-traumatic myositis ossificans is a benign condition of heterotopic ossification of unknown aetiology which typically is related to trauma from a single blow or repeated episodes of microtrauma. A case of myositis ossificans that developed after hamstring autograft harvest for an open cruciate ligament and posterolateral corner reconstruction is described, a previously unrecognised complication of this procedure.

Cranial and spinal trauma are a frequent cause of disability in the general population. Post-traumatic paraplegia or quadriplegia or hemiplegia from vascular injury (CVA) can lead to early complications (respiratory, cardiovascular, urinary, cutaneous, infectious...) that may have an impact on the immediate prognosis. Neurologic and orthopedic complications occur later and further impair the quality of life of patients. Orthopedic complications include: neurogenic paraosteoarthropathy (NPOA) or neurogenic osteoma or myositis ossificans (NMO). The nomenclature currently in use is NMO; Osseous complications: osteoporosis and secondary insufficiency fractures; Joint complications: degenerative arthropathy and stiffness; Overuse mechanical complications; Muscular complications; Infectious complications: arthritis and myositis complicating skin ulcers and bed sores. The purpose of this paper is to describe these neuro-orthopedic complications and review their imaging features.

In this report, we present a case of myositis ossificans traumatica (MOT) of the medial pterygoid muscle that had developed after mandibular block anesthesia administered for endodontic treatment of the lower right second molar, demonstrating typical features of this condition. MOT should be considered as a differential diagnosis when there is severe limitation of jaw opening and an associated trauma. Panoramic radiographs and axial and coronal computed tomography (CT) scans can effectively delineate the calcified mass. Other imaging studies that may be helpful include magnetic resonance imaging (MRI), bone scans, and ultrasound. As shown in our case, calcified masses were found in the right mandibular angle, which severely limited jaw opening. Some earlier reported cases of MOT were treated by extraoral surgical approaches with complete removal of the evolving muscle. The aim of this case report is to present only the diagnostic imaging aspects of myositis ossificans traumatica.

Muscle injuries of the lower leg are a common cause for time off from sports, and may also be a cause of disability in nonathletes who have a running or "pushing off" injury as part of their activities of daily living. Most injuries can be managed without imaging, but in selected cases advanced imaging techniques can demonstrate the exact site and extent of the injury and potentially modify rehabilitation and return to sports. In experienced hands ultrasonography can identify the location of muscle injuries as well as aid in hematoma aspiration. It is useful for excluding differential diagnoses such as deep vein thrombosis or Baker's cyst and may be superior for investigating certain conditions such as muscle hernia. Magnetic resonance imaging is more sensitive for injury to deeper muscles and dual injuries and is generally the modality of choice in elite athletes.

Myositis ossificans (MO) is characterized by abnormal heterotopic bone formation involving striated muscle, tendons, ligaments, fasciae, and aponeuroses. Myocardium, the diaphragm, tongue, larynx, smooth muscle, and sphincters are all spared. Several subtypes of myositis ossificans exist: posttraumatic myositis ossificans (PTMO), nontraumatic/pseudomalignant myositis ossificans, and myositis ossificans progressiva (MOP). This article reviews the clinical features and differential diagnoses of each subtype of MO and illustrates the typical imaging features demonstrated by plain radiography, ultrasound, radionuclide bone scans, computed tomography, and magnetic resonance imaging.

Myositis ossificans (MO) is a fairly common evolution in sports activity and can be due to direct trauma or to repeated micro-injuries. The traditional therapeutic approach relies on a variety of treatments, such as physical therapy but evidence of their proven clinical efficacy is lacking. The latest therapeutic option is surgical removal but this is a demolitive procedure and is frequently associated with a significant loss of functional integrity. There are few articles in literature about the treatment of post-traumatic MO, and none on extracorporeal shock wave therapy (ESWT). We illustrate a case series of 24 sportsmen treated with three sessions of electro-hydraulic shockwave therapy and an associated rehabilitation program. Only a partial reduction of the ossification was observed in the X-ray images but all the patients showed signs of functional improvement immediately after therapy. Two months after the therapy, a normal range of motion and no signs of weakness were observed. Three months after treatment, 87.5% of patients resumed regular sports activities., (Copyright 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Myositis ossificans in the head and neck is a rare heterotropic bone formation within a muscle. Besides fibrodysplasia ossificans progressiva, traumatic and neurogenic forms are described in the literature. We are presenting the case of a 35-year-old female patient with a very rare form of MO of both masseter muscles after 4 weeks of intensive care because of complications (critical illness neuropathy) after chemotherapy. Therefore, special attention should be paid to surgical trauma. As in the present case, radiotherapy, long-time intubation with immobilization and critical myopathy and neuropathy can cause MO with severe problems, such as trismus and reduced mouth hygiene, which can lead to reduced quality of life.

Study Design: A case report., Objective: To report a case of myositis ossificans in the psoas muscle after lumbar spine fracture., Summary of Background Data: Myositis ossificans is a benign condition of heterotopic bone formation in skeletal muscle. It predominantly occurs in large muscles of extremities following injury. Occurrence in the psoas muscle is rare with no previous reports of this condition associated with vertebral fracture in patients without hematologic abnormality., Methods: A 56-year-old man was referred to our hospital for a mass located in the left psoas muscle and an L3 compression fracture. He complained of low back and left leg pain after a fall 2 weeks previously. Magnetic resonance (MR) imaging obtained 12 days after trauma showed an L3 compression fracture with a left psoas mass with low T1 and high T2 signal intensity, associated edema, and enhancement. Computed tomography (CT) scans showed a suspicious slightly high-density mass in the left psoas area. The radiologic features of the mass were consistent with a hematoma., Results: After 1 week, CT scans showed calcification at the hematoma site. Histologic examination following CT-guided biopsy demonstrated new bone formation, atrophy of skeletal muscle fibers, and fibrosis. Lymphocytes were focally infiltrating. Irregularly anastomosing bony trabeculae and fibroblastic cell proliferation were noted. On follow-up MRI and CT scans 2 months later, the previous calcified mass was no longer evident., Conclusion: Myositis ossificans usually occurs in extremities and is very uncommon in the psoas muscle. We report psoas myositis ossificans that developed from hemorrhage and edema associated with a lumbar fracture and required only 2 months to regress completely. When one finds a soft tissue mass with surrounding edema in the psoas muscle combined with a vertebral compression fracture, myositis ossificans should be included in the differential diagnosis.

Heterotopic ossification is defined as the formation of bone in sites where it does not normally exist. Myositis ossificans is classified as a type of heterotopic ossification, where bone formation occurs following soft tissue trauma. A case is presented of a 65-year-old female patient, diagnosed with maxillary and mandibular atrophy, in whom myositis ossificans developed secondary to iliac crest bone harvesting for preprosthetic augmentation prior to placement of maxillary and mandibular implants. Approximately 3 months after bone was harvested from the right anterior iliac crest, and despite a routine recovery from the bone grafting procedure, the patient developed persistent pain, described in her own words as "incapacitating," in the right lower quadrant of her abdomen. She was evaluated by a number of different specialists before a diagnosis of myositis ossificans was reached by her orthopedist. Management of the pain proved difficult, but eventually the symptoms improved to the extent that there was minimal disruption to her daily activities. Implant placement and prosthodontic treatment concluded to the patient's satisfaction. It may be advisable to include the possibility of occurrence of heterotopic ossification and resultant pain as a specific preoperative warning when iliac crest bone harvesting is planned to prepare patients for this potentially serious complication and to avoid litigation.

Myositis ossificans is a benign disorder of heterotopic bone formation occurring in response to soft tissue trauma. It most commonly presents in young adults and children as a painful, enlarging mass of the arm or thigh. Since there is frequently no significant history of injury, the lesion may be mistaken for a malignant bone or soft tissue tumor or infection. This article presents a case of a child in whom myositis ossificans presented with local signs and symptoms suggestive of a rapidly progressive compartment syndrome following trauma.

A 66-year-old woman presented with painful gait and a large, firm, nonmobile mass in her right foot. She had undergone four previous surgeries to remove a recurring "calcified hematoma" that resulted from an injury sustained 3 decades previously. An unusually large ossific mass (7.0 x 7.0 x 2.0 cm) consistent with post-traumatic myositis ossificans circumscripta was excised. After 3 years of follow-up, there was no return of the symptoms or the mass.

Muscle injuries are one of the most common traumas occurring in sports. Despite their clinical importance, there are only a few clinical studies on the treatment of muscle injuries. Lack of clinical studies is most probably attributable to the fact that there is not only a high heterogeneity in the severity of injuries, but also the injuries take place in different muscles, making it very demanding to carry out clinical trials. Accordingly, the current treatment principles of muscle injuries have either been derived from experimental studies or been tested empirically only. Clinically, first aid for muscle injuries follows the RICE (Rest, Ice, Compression and Elevation) principle. The objective of RICE is to stop the injury-induced bleeding into the muscle tissue and thereby minimise the extent of the injury. Clinical examination should be carried out immediately after the injury and 5-7 days after the initial trauma, at which point the severity of the injury can be assessed more reliably. At that time, a more detailed characterisation of the injury can be made using imaging diagnostic modalities (ultrasound or MRI) if desired. The treatment of injured skeletal muscle should be carried out by immediate immobilisation of the injured muscle (clinically, relative immobility/avoidance of muscle contractions). However, the duration of immobilisation should be limited to a period sufficient to produce a scar of sufficient strength to bear the forces induced by remobilisation without re-rupture and the return to activity (mobilisation) should then be started gradually within the limits of pain. Early return to activity is needed to optimise the regeneration of healing muscle and recovery of the flexibility and strength of the injured skeletal muscle to pre-injury levels. The rehabilitation programme should be built around progressive agility and trunk stabilisation exercises, as these exercises seem to yield better outcome for injured skeletal muscle than programmes based exclusively on stretching and strengthening of the injured muscle.

Myositis ossificans traumatica is a pathological condition characterized by extraskeletal bone formation, induced by major or repeated minor trauma to the muscles. Our objective is to report an unusual case of myositis ossificans traumatica in a paraplegic patient. Bilateral swelling and erythema on the thighs of a 1-month paraplegic inpatient was diagnosed as myositis ossificans traumatica in the quadriceps muscles due to low-molecular-weight heparin injections for deep vein thrombosis prophylaxis. As a result, repeated injections under the spinal cord injury level should be avoided when possible because of the risk of myositis ossificans traumatica.

Traumatic muscular pathology is frequent in the athlete. Usually, these lesions heal spontaneously leaving no sequelae. One must be able to predict how long the healing process will last in order to avoid a long period of inactivity and to protect the patient from a recurrent tear. Medical imaging can define the precise location and severity of muscle traumas and detect critical elements that will delay complete repair. Sonography is the most useful and the least expensive imaging technique for analyzing muscular trauma. It provides a good study of muscle fibers, tendons, and aponeurosis but is limited in its poor visualization of the deep structures such as hamstring tendons and the difficulty in detecting muscular scar. MRI is the most sensitive imaging technique for analyzing muscular trauma. However, muscular fibers themselves are not visualized with MRI. It remains a secondary technique, adapted to the insufficiencies of sonography. Nevertheless, the exact place of medical imaging in traumatic muscular pathology remains and leaves the door open to many later studies.

We report two cases of this rare postoperative condition. Both patients having undergone extensive surgery to their hips, developed increased bone growth in the soft tissue of the hip, accounting for the reduced range of movement, pain and stiffness. Plain x-rays taken confirmed the presence of heterotopic ossification, also known as a variant of myositis ossificans. We review the literature and discuss treatment options of this rare condition in patients with end-stage haemophilic arthropathy.

Unlabelled: FOP is a disabling disorder in which skeletal muscle is progressively replaced with bone. Lymphocytes, our model system for examining BMP signaling, cannot signal through the canonical Smad pathway unless exogenous Smad1 is supplied, providing a unique cell type in which the BMP-p38 MAPK pathway can be examined. FOP lymphocytes exhibit defects in the BMP-p38 MAPK pathway, suggesting that altered BMP signaling underlies ectopic bone formation in this disease., Introduction: Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by progressive heterotopic ossification of connective tissues. Whereas the primary genetic defect in this condition is unknown, BMP4 mRNA and protein and BMP receptor type IA (BMPRIA) protein are overexpressed in cultured lymphocytes from FOP patients, supporting that altered BMP signaling is involved in this disease. In this study, we examined downstream signaling targets to study the BMP-Smad and BMP-p38 mitogen-activated protein kinase (MAPK) pathways in FOP., Materials and Methods: Protein phosphorylation was assayed by immunoblots, and p38 MAPK activity was measured by kinase assays. To examine BMP target genes, the mRNA expression of ID1, ID3, and MSX2 was determined by quantitative real-time PCR. Statistical analysis was performed using Student's t-test or ANOVA., Results: FOP lymphocytes exhibited increased levels of p38 phosphorylation and p38 MAPK activity in response to BMP4 stimulation. Furthermore, in response to BMP4, FOP cells overexpressed the downstream signaling targets ID1 by 5-fold and ID3 by 3-fold compared with controls. ID1 and ID3 mRNA induction was specifically blocked with a p38 MAPK inhibitor, but not extracellular signal-related kinase (ERK) or c-Jun N-terminal kinase (JNK) inhibitors. MSX2, a known Smad pathway target gene, is not upregulated in control or FOP cells in response to BMP, suggesting that lymphocytes do not use this limb of the BMP pathway. However, introduction of Smad1 into lymphocytes made the cells competent to regulate MSX2 mRNA after BMP4 treatment., Conclusions: Lymphocytes are a cell system that signals primarily through the BMP-p38 MAPK pathway rather than the BMP-Smad pathway in response to BMP4. The p38 MAPK pathway is dysregulated in FOP lymphocytes, which may play a role in the pathogenesis of FOP.

An unusual case of recurrent myositis ossificans (MO) bilaterally in the hamstring muscles of a 47-year-old athlete secondary to trauma is presented with a review of the literature of current treatment options. MO is a common condition that occurs among athletes in association with muscle and/or tendon strain or contusion. After an extensive literature review, we believe this to be the first case reported of recurrent and bilateral MO in a nonsurgical setting from recurrent hamstring strains. Plain radiographs and physical examination revealed the appearance and chronology of this pathology. Treatment options to improve flexibility and decrease morbidity are discussed along with prophylaxis for future injury. Treatment of mobility and flexibility, rehabilitation goals and treatment with nonsteroidal anti-inflammatory drugs, bisphosphonates, and magnesium are discussed along with prophylaxis.

Intraabdominal myositis ossificans (IMO) is a rare benign disorder characterized by reactive bone formation in intraabdominal soft tissue that should be distinguished from a malignant condition. We retrospectively searched our patient records and report 9 new cases of IMO. The lesions occurred in 7 men and 2 women with a mean age of 50 years (range, 24--76 years), 5 of whom had previous abdominal surgery. Histologically, all the cases were similar, consisting of a reactive mesenchymal process in adipose tissue. Mitosis was observed, but with no atypical forms, and the lesions lacked malignant cytologic features. IMO is an uncommon benign lesion that develops relatively rapidly. The pathogenesis is related to intraabdominal surgical procedures, but the exact mechanism remains to be determined., (Int J Surg Pathol 14(1):37-41, 2006.)

Myositis ossificans of the hand is extremely rare. We report an unusual case of myositis ossificans of the thenar muscles and discuss the diagnostic pitfalls whereby this condition can be mistaken for malignancy or infection.

Heterotopic ossification is the formation of bone in the soft tissues. Soft tissue bone deposition may range from the minimal and inconsequential to massive and clinically significant. In some clinical settings it is a predictable finding with an unpredictable course and in other settings it may be diagnostically confounding. Heterotopic ossification may be encountered in clinically disparate disease processes and circumstances. We review the genetic, neurogenic, post-traumatic, post-surgical and "reactive" causes of heterotopic ossification and discuss some current concepts of its pathogenesis.

Inflammatory myofibroblastic pseudotumour (IMFPT) is a rare condition. The clinical presentation can be indistinguishable from that of a malignant neoplasm. The most frequently affected organ is the lung; a much less common site is the larynx and subglottic involvement is particularly rare. Trauma is purportedly one potential aetiological factor, although there have been no previous reports of IMFPT occurring in the larynx secondary to external laryngeal trauma. We present a case of IMFPT of the subglottis which occurred subsequent to external trauma of the neck sustained during air bag inflation in a road traffic accident. This mechanism has not been previously reported. Furthermore, the lesion progressed uniquely to show myositis ossificans-like maturation over time. The patient was ultimately treated by means of complete local excision.

Muscle injuries are one of the most common traumas occurring in sports. Despite their clinical importance, few clinical studies exist on the treatment of these traumas. Thus, the current treatment principles of muscle injuries have either been derived from experimental studies or been tested only empirically. Although nonoperative treatment results in good functional outcomes in the majority of athletes with muscle injuries, the consequences of failed treatment can be very dramatic, possibly postponing an athlete's return to sports for weeks or even months. Moreover, the recognition of some basic principles of skeletal muscle regeneration and healing processes can considerably help in both avoiding the imminent dangers and accelerating the return to competition. Accordingly, in this review, the authors have summarized the prevailing understanding on the biology of muscle regeneration. Furthermore, they have reviewed the existing data on the different treatment modalities (such as medication, therapeutic ultrasound, physical therapy) thought to influence the healing of injured skeletal muscle. In the end, they extend these findings to clinical practice in an attempt to propose an evidence-based approach for the diagnosis and optimal treatment of skeletal muscle injuries.

Restriction of the mouth opening from a pathologic condition outside the temporomandibular joint is called a pseudo- or extra-articular ankylosis. The authors report two cases of severe post-traumatic pseudoankylosis. One case showed fibrous degeneration of the bilateral masseter muscles without a facial bone fracture, which caused severe trismus, a mouth opening of less than 2 mm, and gradually appeared after blunt injuries to the face. The other was a rare case accompanied with the bone formation in the masseter muscle and was diagnosed as myositis ossificans traumatica, which also presented as severe trismus, with a maximal mouth opening of 5 mm after facial violence. Both were surgically treated with dissection of the affected muscles. In addition, a hemicoronoidotomy was performed in the case of myositis ossificans traumatica. Although a conservative therapy with physical rehabilitation is the basic policy for the management of pseudoankylosis of the temporomandibular joint, a surgical treatment should be considered when the origin of the problems is an osteogenic character or severe extra-articular ankylosis resistant to conservative therapy before completion of true temporomandibular joint ankylosis.