1 Alterations of Musculoskeletal Function in Children Chapter 43

Mosby items and derived items © 2006 by Mosby, Inc. 2 Bone Formation  Bone formation begins in two phases at about the eighth week of gestation Delivery of bone cell precursors to sites of bone formation Aggregation of the bone cell precursors at primary centers of ossification

Mosby items and derived items © 2006 by Mosby, Inc. 3 Bone Formation  Intramembranous formation On or within the mesenchyme  Endochondral formation Cartilage anlage Perichondrium Periosteal collar Secondary centers of ossification

Mosby items and derived items © 2006 by Mosby, Inc. 4 Bone Formation

Mosby items and derived items © 2006 by Mosby, Inc. 5 Bone Growth  Until adult stature is achieved, bone growth occurs at the epiphyseal plate through endochondral ossification  Factors affecting bone growth Growth hormone Nutrition General health Many growth factors and regulators

Mosby items and derived items © 2006 by Mosby, Inc. 6 Skeletal Development  In the newborn, the entire spine is concave anteriorly (kyphosed)  In the first 3 months of life, the cervical spine begins to arch (lordotic)  Curve of the lumbar spine develops with sitting  Compared to an adult, a newborn has a large head, long spine, and short extremities

Mosby items and derived items © 2006 by Mosby, Inc. 7 Skeletal Development  Genu varum (peaks by 2½ years) Bowleg  Genu valgum (5-6 years) Knock-knee

Mosby items and derived items © 2006 by Mosby, Inc. 8 Muscle Development  Between birth and maturity, muscle nuclei in the body increase 14 times in boys and 10 times in girls  The composition and size of muscles vary with age

Mosby items and derived items © 2006 by Mosby, Inc. 9 Congenital Defects  Syndactyly Webbing of the fingers Fusion of the soft tissues of the fingers True syndactyly also includes fusion of the bones and nails  Vestigial tabs Extra digit

Mosby items and derived items © 2006 by Mosby, Inc. 10 Syndactyly

Mosby items and derived items © 2006 by Mosby, Inc. 11 Congenital Defects  Developmental dysplasia of the hip Abnormality of the proximal femur, acetabulum, or both Risk factors  Female sex, metatarsus adductus, torticollis, oligohydramnios, first pregnancy, and breech presentation The hip can present as subluxated, dislocatable, or dislocated

Mosby items and derived items © 2006 by Mosby, Inc. 12 Congenital Defects  Developmental dysplasia of the hip Manifestations  Asymmetry of gluteal or thigh folds  Limb length discrepancy  Limitation of hip abduction  Positive Ortolani sign  Positive Barlow test  Positive Trendelenburg gait  Pain

Mosby items and derived items © 2006 by Mosby, Inc. 13 Developmental Dysplasia of the Hip

Mosby items and derived items © 2006 by Mosby, Inc. 14 Congenital Defects  Deformities of the foot Metatarsus adductus Equinovarus deformity  Positional equinovarus  Idiopathic congenital equinovarus  Tetratologic equinovarus  Pes planus

Mosby items and derived items © 2006 by Mosby, Inc. 15 Osteogenesis Imperfecta  “Brittle bone disease”  Defect in collagen production Bone and vessel collagen  Sillence classification  Results in osteoporosis, bowed and deformed limbs, short stature, spine curvature, and bluish sclera  Can be evident before birth (in utero fractures)

Mosby items and derived items © 2006 by Mosby, Inc. 16 Osteogenesis Imperfecta

Mosby items and derived items © 2006 by Mosby, Inc. 17 Rickets  Disorder causing mineralization failure, “soft” bones, and skeletal deformity  Causes Insufficient vitamin D Insensitivity to vitamin D Renal wasting of vitamin D Inability to absorb calcium or vitamin D in the gut

Mosby items and derived items © 2006 by Mosby, Inc. 18 Rickets

Mosby items and derived items © 2006 by Mosby, Inc. 19 Scoliosis  Scoliosis is a rotational curvature of the spine Nonstructural  The curvature is from a cause other than the spine Structural  Spine curvature associated with vertebral rotation  Skeletal abnormalities, neuromuscular disease, trauma extraspinal contractures, bone infections of the vertebrae, metabolic bone disorders, joint disease, and tumors

Mosby items and derived items © 2006 by Mosby, Inc. 20 Scoliosis

Mosby items and derived items © 2006 by Mosby, Inc. 21 Osteomyelitis  Osteomyelitis in children frequently begins as a blood abscess in the metaphysis of the bone  The abscess ruptures under the periosteum and spreads along the bone shaft or into the bone marrow Sequestra  Sections of dead bone due to periosteal separation Involucrum  Periosteal new bone

Mosby items and derived items © 2006 by Mosby, Inc. 22 Osteomyelitis

Mosby items and derived items © 2006 by Mosby, Inc. 23 Juvenile Rheumatoid Arthritis  Childhood form of rheumatoid arthritis  The basic pathophysiology of JRA is the same as the adult form  One difference is the mode of onset Arthritis in fewer than five joints Arthritis in more than five joints Systemic disease

Mosby items and derived items © 2006 by Mosby, Inc. 24 Juvenile Rheumatoid Arthritis  Differences in JRA and adult RA Large joints are affected Subluxation and ankylosis of the cervical spine Joint pain is not as severe Positive antinuclear antibody test Chronic uveitis Low detection of rheumatoid factor Limited subcutaneous rheumatoid nodules  Common in the heart, lungs, eyes, and other organs

Mosby items and derived items © 2006 by Mosby, Inc. 25 Osteochondrosis  Avascular diseases of the bone  Legg-Calvé-Perthes disease Interrupted blood supply to the femoral head Self-limiting disease Deformation due to ischemia is permanent  Osgood-Schlatter disease Tendinitis of the anterior patellar tendon and osteochondrosis of the tubercle of the tibia

Mosby items and derived items © 2006 by Mosby, Inc. 26 Legg-Calvé-Perthes Disease

Mosby items and derived items © 2006 by Mosby, Inc. 27 Cerebral Palsy  A static disorder of muscle tone and balance caused by an ischemic insult to the brain  Perinatal disorder  Disease patterns Hemiplegia, diplegia, quadriplegia

Mosby items and derived items © 2006 by Mosby, Inc. 28 Muscular Dystrophies  Group of disorders that cause degeneration of skeletal muscle fibers  The muscular dystrophies cause progressive, symmetric weakness and wasting of skeletal muscle groups

Mosby items and derived items © 2006 by Mosby, Inc. 29 Duchenne Muscular Dystrophy  Most common of the muscular dystrophies  X-linked recessive inheritance Deletion of a segment of DNA or a single gene defect on the short arm of the X-chromosome  Duchenne muscular dystrophy gene Encodes for the dystrophin protein Dystrophin mediates the anchorage of the actin cytoskeleton of the skeletal muscle fiber to the basement membrane

Mosby items and derived items © 2006 by Mosby, Inc. 30 Duchenne Muscular Dystrophy  Manifestations of the disorder begin to appear by approximately 3 years of age Slow motor development Progressive weakness Muscle wasting Sitting and standing are delayed The child is clumsy, falls frequently, and has difficulty climbing stairs

Mosby items and derived items © 2006 by Mosby, Inc. 31 Muscular Dystrophy

Mosby items and derived items © 2006 by Mosby, Inc. 32 Muscular Dystrophies  Becker muscular dystrophy  Fascioscapulohumeral muscular dystrophy  Scapuloperoneal muscular dystrophy  Limb girdle muscular dystrophy

Mosby items and derived items © 2006 by Mosby, Inc. 33 Bone and Muscle Tumors  Nonossifying fibroma  Simple bone cysts  Aneurysmal bone cysts  Osteoid osteoma  Fibrous dysplasia  Osteosarcoma  Ewing sarcoma  Rhabdomyosarcoma

Mosby items and derived items © 2006 by Mosby, Inc. 34 Nonaccidental Trauma  “Corner” metaphyseal fractures Long bone fractures caused by a twisting force Transverse tibial fractures are the most common Associated with child abuse, but osteogenesis imperfecta must be ruled out

Mosby items and derived items © 2006 by Mosby, Inc. 35 Nonaccidental Trauma