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RADIOLOGICALVARIENTS INIMMATURE SKELTON

Dr.RAJEEV.K.S

NORMAL BONY VARIANTS FREQUENTLY CONFUSEs WITH PATHOLOGIC CHANGES

SYNCHONDROSIS

An infant is born with three synchondroses of the sphenoid bone. The frontosphenoid synchondrosis the intersphenoid synchondrosis ( close by several months to 1 year of life.) The spheno-occipital synchondrosis, , may remain patent until early adulthood

Sphenoid Bone Synchondroses

These synchondroses generally are not attended to by the orthopaedic surgeon except when assessing the cervical spine for trauma. The most common question then asked is Do these synchondroses represent basilar skull fractures Knowing the existence of these synchondroses and when they close eliminates the need to do other time-intensive and expensive studies

Body of C2 and Odontoid Synchondrosis

The synchondrosis between the odontoid and body of C2 may simulate a fracture from birth until it closes, between ages 3 and 7 years When it is partially fused it may appear as an incomplete fracture of the odontoid

Body of C2 and Odontoid Synchondrosis

. Assessment of the odontoid's alignment with the body of C2 then becomes extremely important. If the alignment is not anatomic, further evaluation with computed tomography (CT) or magnetic resonance imaging (MRI) is indicated

Synchondroses between Vertebral Bodies and Neural Arches

These synchondroses appear as lucent lines between the vertebral bodies and neural arches from birth until mid-childhood, They become particularly noticeable on oblique views of the infant's cervical spine and may mimic fractures.

Cervical Spine Pseudosubluxation

Owing to ligamentous laxity and horizontally positioned facet joints the upper cervical spine in infants and children may appear to subluxate during flexion. When multiple cervical vertebral bodies are involved, physiologic subluxation is clearly the diagnosis

Cervical Spine Pseudosubluxation

. Subluxation limited to C2 on C3, however, may be physiologic or associated with a hangman's fracture. To differentiate these conditions, Swischuk[9] devised the posterior cervical line. This line is drawn from the anterior cortex of the C1 posterior ring to the anterior cortex of the spinous process of C3 (Fig. 10-7). If the line misses the anterior cortex of the spinous process of C2 by more than 2 mm, a true dislocation is present. This line should be used only to assess C2-3 subluxation and should not be applied at any other level. Moreover, a normal posterior cervical line does not exclude significant ligamentous injury

ISCHIOPUBIC SYNCHONDROSIS: COMMONLY CONFUSED WITH INFECTION OR NEOPLASTIC CHANGE

The ischiopubic synchondroses may have irregular mineralization and may be asymmetrically expanded The asymmetry is unusual because most normal variants tend to be symmetric. Complete bilateral ossification occurs as early as age 4 years or as late as 14 years. Pain and tenderness may be associated with an irregularly mineralized and expanded ischiopubic synchondrosis, but without positive laboratory findings, further workup is unnecessary. A biopsy of this synchondrosis should not be obtained because false-positive results for neoplastic changes frequently occur. Not uncommonly, however, osteomyelitis may involve the ischiopubic synchondrosis, with positive blood cultures, elevated erythrocyte sedimentation rates, or increased Creactive protein levels confirming the diagnosis. With adequate antibiotic therapy, the prognosis is good.

Osteosclerosis of the Newborn

A neonate's long bones may appear very dense, which can be mistaken for pathologic conditions such as osteopetrosis significant clinical findings are associated with pathologic osteosclerotic conditions. jaundice, hepatosplenomegaly, anemia, and pancytopenia are associated with osteopetrosis manifesting in the newborn period. Normal osteosclerosis of the newborn has no associated signs or symptoms and resolves several weeks after birth.

Physiologic Periosteal New Bone Formation of the Newborn.

Physiologic periosteal new bone is not present before 1 month of life and is most commonly noted between 1 and 6 months of life. It is almost always bilateral and symmetric, involving the femur, humerus, and tibia most frequently. The periosteal new bone formation is thin and separated by a lucent line from the diaphyseal cortex . The patient's age, the bilateral symmetry, and the benign radiographic image differentiate this condition from pathologic entities such as trauma, congenital syphilis, osteomyelitis, prostaglandin therapy, infantile cortical hyperostosis (Caffey's disease), leukemia, and neuroblastoma.

Dense Transverse Metaphyseal Lines.

Normal children have dense transverse metaphyseal lines, especially between 2 and 6 years of age, that may be confused with radiodense metaphyseal bands associated with lead poisoning Two radiographic findings, however, may help to distinguish normal radiodense metaphyseal lines from those seen in lead poisoning: (1) normal dense metaphyseal lines are no denser than the metaphyseal or diaphyseal bony cortex, whereas the dense metaphyseal bands associated with lead poisoning are usually denser than the metaphyseal or diaphyseal bony cortex; and (2) a dense metaphyseal line commonly involves the proximal fibula with lead poisoning, but the proximal fibula is usually not involved in the normal patient with dense metaphyseal lines.[1] Lead poisoning, however, cannot be definitively diagnosed from radiographic findings. Chemical tests of blood and urine are required to diagnose plumbism

Avulsive Cortical Irregularity

The avulsive cortical irregularity usually involves the posterior aspect of the medial femoral condyle, appearing as an irregular and concave defect that may simulate malignancy The lesion most probably results from repetitive avulsive-type trauma

Avulsive Cortical Irregularity

. This defect is most frequently seen in 10- to 15-year-olds, ismore common in boys, and is often bilateral. An avulsive cortical irregularity should not be sampled for biopsy because a misdiagnosis of osteosarcoma may be made. A correct diagnosis is made by knowing the general age ranges as well as the characteristic location and radiographic features of the avulsive cortical defect.

leukemia lines

It is extremely important to examine the bones carefully when leukemia (most commonly acute lymphoblastic leukemia) is considered because the bone marrow and peripheral blood smear may initially be negative, with only radiographic changes present.

TRUNK

Rhomboid fossa of the clavicle (N)It is an excavation that it is located on the underside of the sternal end of clavicle wherethe costoclavicular ligament attaches, which serves to stabilize the sternoclavicular joint.

Posterior arch rib fracturesPosterior arch rib fractures in abused children (P)These fractures are often located in the posterior arch, which follow a straight line. Theyare produced by chest compressions, direct blows and falls on hard surfaces

Resleor sign (P)Bone erosions in the lower edges of the ribs caused by pressure from dilated intercostal arteries in aortic coarctation

Limbus vertebrae (N-P)The limbus vertebrae originates in childhood and is caused by an intervertebral disc displacement causes a separation of a small segment of the vertebral ring from the rest of the vertebral body, remaining isolated. The most common location is in the lumbarregion, followed by the cervical region. This defect is often seen in the supero-anterior margin. This anomaly may be confused with a fracture, infection or a tumor resulting in unnecessary invasive procedures. It is postulated that the limbus verterbae is a sequel to a previous unnoticed injury on a immature skeleton. We must differentiate from a spectrum of disorders such as osteochondrosis deformans Schmorl nodules This skeletaldisorder usually causes no symptoms treatment is conservative

Spondylolysis (P)In children, spondylolysis usually occurs between the fifth lumbar and first sacralvertebrae, and is often due to a birth defect in that area of the spine . an slippage of the upper over the lower vertebrae, it would be a spondylolisthesis

Ischiopubic synchondrosis (N)

The ossification of cartilage located between the ischium and the pubis is very variable.The total bone fusion occurs in only 6% of children 4 years and 83% of those 12years. There may be an expansion and irregular ossification of this synchondrosis intheprepubertal period. The bone fusion usually preceded by an intermittent increase in size of radiolucent component of cartilage, which gives it a globular shape We must not confuse this entity with other tumors such as osteomyelitis or eosinophilic granuloma

Bone island (enostosis) (N)

Injuries are often diagnosed as incidental findings. They look like lumps in sclerotic cancellous bone of variable size and irregular surface contours of 2mm to 2cm in diameter,on the bone scan are not active, although there may be some in the larger ones. can occur in any bone, preferably in long bones (femur), and at any age, but more often after puberty. We must not confuse this finding with metastatic osteosarcoma that may look similar the clinical history may guide us toward one or another diagnosis

Femoral epiphyseal growth retardation (N)This entity is also called Meyer dysplasia, although a strict dysplasia is a defective development of the hip joint the shape or the organization of the hip joint.This delay of ossification of the femoral head, goes subsequent editing and serial radiographs, which demonstrate a secondary nucleus ossified and normal, without sequelae or deformities, although there may be minor changes that do not alter the relationship head - acetabulum.The differential diagnosis must be made with septic arthritis, Perthes disease, multiple epiphyseal dysplasia and hypothyroidism

ApophysitisThe term refers to that Osteochondrosis and apophyseal extra-articular location and have a high prevalence in children who play sports regularly

Avulsion fractures (P)In them there is a commitment to the vertebral bone and joint. Traction mechanismsinvolved acute tendon or ligament elementsinserted into the apophysis. There are ageof onset characteristics. Its severity and treatment depends on the area affected and thedegree of displacement

Metaphyseal bands (N-P)Normal metaphyseal endochondral bone growth (in the zone of provisional calcification) requires the maintenance of a delicate balance between osteoblastic bone deposition and osteoclastic bone remodeling . Whenever growing bone is subjected to toxic, metabolic, neoplastic, or infectious stressors, proper osteogenesis is compromised. Stress on growing bone leads to poor endochondral bone formation. In general, when the stress is eliminated, rapid deposition of new bone at the metaphysis produces dense bands.

Metaphyseal bands (N-P)They may be sclerotic, usually in relation to growth stops differential diagnosis between different entities such as: normal newborn, any severe disease, metaphyseal fracture, leukemia, lymphoma,metastases,congenital infections, scurvy

Physiological periosteal reaction (N)You have to make a differential diagnosis with other causes of periosteal reactionsuch as child abuse, infections (syphilis), metastatic neuroblastoma, treatmentwith prostaglandins and Caffey disease. The periosteal new bone formationoccurssymmetrically in the bodies of the long bones of infants and resolves within 3months of age. It is believed due to the handling of the newborn. There are no associatedfractures (Fig.

Distal femoral cortical irregularity (N)

This is a normal variant consisting of a periosteal fibrous proliferationpredilection for the posterior cortex of the distal femoral medial metaphysis.distal femoral metaphyseal defect, cortical desmoid, irregular or defective cortical avulsion medial supracondylar femur The age of onset is between 12 and 20 years andpreferably in males. Usually resolves spontaneously in the second decade of life.

Distal femoral cortical irregularity (N)Radiographically similar to fibrous cortical defect, except as specific location. radiolucent lesion with sclerosis at the base, the cortex may be irregular and may have spicules that can be interpreted as a sign of aggression. MRI showedhypointensity and hyperintensity on T2-T2, with a dark rim on both sequences and near the insertion of the gastrocnemius muscle .A bone scan is usually normal. Radiological differential diagnosis: fibrous cortical defect, periosteal chondroma , # osteosarcoma.Bone abscess secondary to osteomyelitis

Poor radiographic technique (N)

Sometimes the anomalous position of the pediatric patient during the acquisition of theX-ray can show us false images that can confuse in establishing a diagnosis and

Irregularity of the tibial tuberosity (N)The tibial tuberosity is an anterior extension of the epiphysis of the tibial cartilage.It is usually ossified from several sites.Ossification usually occurs between 8 and 12 years in girls and between 9 and 14 in males The ossicles can mimic fragments produced by avulsion. Their appearance is usually not symmetrical.The soft tissue edema and thickening of the patellar tendon in a preteen, suggests thediagnosis of Osgood-Schlatter disease

Dorsal defect of the patella (N)It is a normal variant that should not be confused with patellar osteochondritis dissecansand a clue to differentiate both is that the former does not produce or produces very little pain and does not dissect any osteochondral fragments

Accessory bones (P) and sesamoid (N)

Peroneum Os (N): Os peroneum is an ossicle or sesamoid bone, oval or rounded locatedin the thickness of the distal peroneus longus tendon near the cuboid .establish a differential diagnosis of fractures , nonfused ossification centers or pathologic calcification of soft tissues

Os peroneum

Medial cuneiform (left image) and accesory navicular bone (right image)

Khler: Necrosis of the navicular tarsal (P)Described by Khler in 1908 as a navicular self-limiting disease characterized by flattening, sclerosis and irregular ossification of this bone.has caused more controversy regarding its possible etiology, some authors label it as a development variant. It affects children between 3 and 10 years.When radiographs are obtained we can find obvious alterations in the navicular boneossification which appears flattened, with fragmentation and increased density. In early disease it may keep the space with neighboring bones, but may suffer a collapse in its evolution

Abused child (P):This are quite typical fractures that should be not to be confused with other normalfindings such as the proximal radius step

Supracondylar humeral process (N)It is a phylogenetic vestige-atavism that can be found in some peoplecorresponds to a asympthomatic normal variant to have caused median nerve compression. Differential diagnosis should be made with osteochondroma

THANK YOUDR.RAJEEV