Disorders of Muscles and Soft Tissues

Muscular Dystrophy, Myotonic Dystrophy, Polymyositis and dermatomyositis, myositis ossificians, poliomyelitis, contractures



Osteochondritis Dissecans

Osteochondritis dissecans is a localized form of ischemic necrosis that most frequently affects young males and is probably caused by trauma. It occurs primarily about the knee, usually on the lateral aspect of the medial femoral condyle. Other common locations are the ankle, femoral head, elbow, and shoulder. In this condition, a small, round or oval necrotic segment of bone with its articular cartilage detaches and lies in a depression in the joint surface. Often denser than the surrounding bone, the necrotic segment is well-demarcated by a crescentic lucent stone. The necrotic segment may separate from the joint to form […]

Contractures

A contracture refers to the permanent shortening and rigidity of muscles, joints, and fascial structures that may be a sequel to joint immobility due to disease or severe pain. Congenital contractures include clubfoot, torticollis, and the deformities associated with arthrogryposis (see the section “Arthrogryposis Multiplex Congenita” later in this chapter). Acquired contractures may reflect primary muscle, fascia, or ligamentous disturbances or be secondary to neural disorders (poliomyelitis, cerebral palsy), primary connective tissue diseases, or injuries to the skin (scarring, trauma, burns).       Volkmann’s contracture is a rare complication of fracture that is caused by muscle ischemia resulting in […]

Poliomyelitis

The radiographic manifestations of poliomyelitis reflect muscular weakness and paralysis due to necrosis and a loss of motor nerve cells in the spinal cord, brain, or cranial nerves. Decreased peripheral muscle tone causes a loss of muscular soft tissue volume and secondary bone atrophy; this produces thinning and demineralization of the bones of the extremities. Severe scoliosis of the thoracolumbar spine can develop. In patients with severely paralyzed extremities, calcification and ossification may form in the periarticular soft tissues and appear to bridge across the joints. This finding is most common about the hip.   Involvement of the phrenic nerve can […]

Myositis Ossificans

Myositis ossificans refers to the development of calcification or ossification within injured muscles that is usually related to acute or chronic trauma to the deep tissues of the extremities. Persons in certain occupations and sports are prone to develop myositis ossificans. Thus heterotopic bone often arises in the adductor longus (rider’s bone), brachialis (fencer’s bone), and soleus (dancer’s bone) muscles.   The earliest radiographic change in myositis ossificans is a soft tissue mass that develops soon after injury. After about 1 month, faint calcification appears as a hazy shadow of increased density. Over a period of several weeks, the calcification […]

Polymyositis and Dermatomyositis

Polymyositis is an inflammatory disease of skeletal muscles in which a lymphocytic infiltration produces muscle fiber damage and degeneration. In dermatomyositis, polymyositis is associated with skin inflammation and a characteristic rash. Adults with dermatomyositis have a relatively high incidence of underlying malignancy. The musculoskeletal changes are most severe in childhood dermatomyositis. Diffuse edema of the subcutaneous and muscular tissues leads to increased muscular bulk and density, poor delineation of the normally sharp subcutaneous-muscular interface, and edema of subcutaneous tissue septa. In chronic disease, there is decreased muscle bulk and joint contractures. A characteristic finding is extensive calcification in the muscles and […]

Myotonic Dystrophy

Myotonic dystrophy is an inherited disease in which an anatomic abnormality of the motor end plate and striated muscle leads to atrophy and an inability of the contracted muscle to relax (myotonia). Associated findings include cataracts, frontal baldness and testicular atrophy in men, and a characteristic facial expression (myopathic facies). In addition to severely disturbed pharyngeal peristalsis associated with the pooling of contrast material within the valleculae and pyriform sinuses, patients with myotonic dystrophy have a reduced or absent resting pressure of the cricopharyngeus muscle. Because a major function of this upper esophageal sphincter is to prevent esophageal contents from […]

Muscular Dystrophy

Replacement of muscle by fat in the muscular dystrophies results in a characteristic radiographic appearance of the extremities. Although the total muscle mass is not decreased, the extensive accumulation of fat within the remaining muscle bundles produces a fine striated, or striped, appearance. In the pseudohypertrophic dystrophy of Duchenne, enlargement of specific muscle groups (calves, shoulder girdles) suggests muscular strength, though the patient is actually extremely weak. In wasting diseases, most of the muscle tissue is replaced by fat, so the fascial sheath bounding the muscle stands out as a thin shadow of increased density as it is visualized on […]

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