Trigger 7, RAD PATHO: Fusion

Sir Kharl's Hand-Outs ++ additional information from pathology book

bone and cartilage

bone and cartilage

the skeletal system is composed of specialized connective tissues, which are:

calcium and phosphate

the bone matrix is made up of:

periosteum

• a fibrous membrane it covers the outer surfaces except for joint surfaces

• crucial to supplying blood to underlying bone

articular cartilage

joint surfaces are covered with, what?

diaphysis

• shaftlike portion

• the primary site of ossification

epiphysis

• ends of the bone

• the secondary site of ossification

skeletal system

is responsible for body support, protection, movement, and blood cell production.

206

the skeletal system is composed of, how many bones?

80

the axial skeleton is composed of, how many bones?

126

the appendicular skeleton is composed of, how many bones?

98

the skeletal system contains, how many percent of the body’s total calcium?

75

the skeletal system contains, how many percent of the body’s total phosphorus?

bone

type of connective tissue, but it differs from other connective tissue because of its matrix of calcium phosphate.

because of its matrix of calcium phosphate

bone is a connective tissue, but how does it differ from other connective tissues?

• compact (dense)

• cancellous (spongy)

the bone matrix is classified either:

compact bone

• outer layer, appears dense

• haversian systems (microscopic structure; osteon)

• thick layer for long bones (femur, tibia)

• thin for irregular bones (vertebral bodies, short bones)

medullary canal

• inner portion of bone, that is made up of cancellous (spongy) bone

• hollow, tube like structure within diaphysis

cancellous bone

• spongy bone

• weblike arrangement of marrow-filled spaces separated by this process of bone, called trabeculae

trabecular pattern

intricate, weblike bony structure is visible on a properly exposed radiograph of the skeletal system

medullary canal and is interspered between the trabeculae

where is the bone marrow located?

diploë

specific to the cancellous bone located within the skull

red bone marrow

responsible for the production of bone erythrocytes and leukocytes

bones of the trunk

in a normal adult, the red bone marrow is found primaryly, where?

yellow bone marrow

at the approximate age of 20 years, the majority of red bone marrow is replaced by BLANK, which is mainly composed of fat.

osteoblasts

• bone-forming cells that line the medullary canal and are interspersed throughout the periosteum

• responsible for bone growth and thickening, ossification, and regeneration

• produce new bone around the outer circumference

oseteoclasts

• specialized cells that break down bone to enlarge the medullary canal and allow for bone growth.

• play an important role in serum calcium and phosphorus equilibrium.

serum calcium and phosphorus equilibrium.

oseteoclasts break down bones and it play an important role in, what?

• hypercalcemia

• hypocalcemia

certain metabolic disease processes may alter the percentage of calcium, resulting in either:

metaphysis

• refers to the growth zone between the epiphysis and the diaphysis

• an area where the greatest metabolic activity happens in a bone

cartilaginous growth plate

is located between the metaphysis and the epiphysis in the bone of a growing child

radiolucent

cartilaginous growth plate radiographically appears as, what?

the more thickly the compact portion develops

the more physical stress a bone is under,

disuse atrophy

this occus when a bone is not allowed to bear weight and results in significant decalcification and thinning of the bone

• fibrous (synarthrodial)

• cartilaginous (amphiarthrodial)

• synovial (diarthrodial)

bones are connected to one another by joints, which are:

ligaments

the ends of the bones composing a synovial joint are lined with articular cartilage and are held together by, what?

synovial membrane

membrane responsible for the secretion of synovia

synovial membrane

lines the joint capsules

synovia

a lubrication fluid containing mucin, albumin, fat, and mineral salts

endosteum

inner membrane of bone

epiphyseal cartilage

• epiphyseal growth plate

• site of longitudinal growth for long bones

• cartilage epiphyseal plate diminishes if an individual reaches the end of overall growth period, and is replaced to epiphyseal line

ossification

process of bone formation

resorption

process of bone destruction

greulich and pyle method

• atlas matching method

• best known and most widely accepted method of determining skeletal bone age (skeletal maturation)

• permit an assessment of bone age based on the presence or absence of ossification centers and their configuration, and the fusion of epiphyses in various portions of the hand and wrist.

osteogenesis imperfecta

• brittle bone disease

• a quite serious and rather rare heritable or congenital disease affecting the skeletal system.

• commonly an autosomal dominant defect

• It is caused by mutations in the two structural genes that encode the α1- and α2-peptides of type I collagen

• deficient and imperfect formation of osseous tissue, skin, sclera, inner ear, and teeth is noted in individuals with this disease.

• eight types of OI: type I to type VIII

  • type I, mildest

  • type VIII, most severe

type I collagen

main collagen of bone, tendon, and skin

• COL1A1

• COL1A2

• CRTAP

• LEPRE1

the specific mutations in osteogenesis imperfecta occur in the following genes:

• osteogenesis imperfecta congenita

• osteogenesis imperfecta tarda

main clinical groups of osteogenesis imperfecta:

the age of onset and the severity of the disease

main clinical groups of osteogenesis imperfecta are based on, what?

osteogenesis imperfecta congenita

classification of osteogenesis imperfecta

• present at birth

• Infants with this disease usually have multiple fractures at birth that heal only to give way to new fractures

• results in limb deformities, dwarfism, death

osteogenesis imperfecta tarda

classification of osteogenesis imperfecta

• present after birth

• fractures might not appear for some years after birth and then generally stop once adulthood is reached

• otosclerosis

otosclerosis

• hearing disorder

• is the formation of abnormal connective tissue around the auditory ossicles

achondroplasia

• most common inherited disorder aftecting the skeletal system

• results in bone deformity and dwarfism

• occurs in 1 in 15,000 to 40,000 newborns

• is caused by an autosomal dominant gene (FGFR3) at the 4p chromosome location, and this gene does not skip generations.

• disturbance in endochondral bone formation, epiphyseal cartilage of the long bones does not convert to bone in the normal manner, impairing the longitudinal growth of the bones

• a type of osteochondrodysplasia

• have normal trunk size and shortened extremities

• ultrasonography is used for prenatal diagnosis

normal trunk size and shortened extremities

achondroplasia is a type of osteochondrodysplasia, and patients with this disorder have, what?

autosomal dominant gene (FGFR3) at the 4p chromosome location

achondroplasia is caused by, what gene and its chromosome location?

FGFR3

individuals with this gene have about a 50% chance of transmitting it to their children.

• no more than 4ft in height

• lower extremities usually less than half the normal length

• extreme lumbar spine lordosis

• bowed legs

• bulky forehead with midface hypoplasia

• narrowing of the foramen magnum within the skull (neutral compression)

clinical manifestations of achondroplasia:

orthopedic surgery

occasionally, this surgery may be necessary in the management of complications associated with achondroplasia

ilizarov procedure

• procedure used to attempt to lengthen the shorten limbs

• this procedure was perfected by Dr. Gavriil Ilizarov and has been used for over 30 years

• It consists of a corticotomy of the limb, followed by attachment of an ilizarov fixator, which consists of two circular frames that surround the limb, wires, and rods.

• using this method, bones may be made to grow at a rate of approximately 1 mm per day.

cardiovascular system

early research indicates that introduction of growth hormones (GHs), will have adverse fects on, what body system?

osteopetrosis

• marble bone disease

• used to characterize a variety of disorders involving an increase in bone density and defective bone contour, often referred to as skeletal modeling

• mutations of CLCN7 gene

• bones are abnormally heavy and compact but nevertheless brittle.

CLCN7

osteopetrosis involve mutuations at, what gene?

• infantile malignant CLCN7-related autosomal recessive osteopetrosis (ARO)

• intermediate autosomal osteopetrosis (IAO)

• autosomal dominant osteopetrosis type II (ADOII)

the spectrum of osteopetrosis:

infantile malignant CLCN7-related autosomal recessive osteopetrosis (ARO)

spectrum of osteopetrosis

• which has its onset in infancy

intermediate autosomal osteopetrosis (IAO)

spectrum of osteopetrosis

• develops in childhood

autosomal dominant osteopetrosis type II (ADOII)

spectrum of osteopetrosis

• occurs in late childhood or adolescence

• osteocleroses

• craniotubular dysplasias

• craniotubular hyperostoses

disorders characterizing osteopetrosis:

craniotubular dysplasias

• are a group of rare autosomal recessive hereditary diseases

• a disorder characterizing osteopetrosis, which affects the cranium and tubular long bones

• manifest in childhood

Albers-Schönberg disease

• a fairly common form of osteosclerotic osteopetrosis

• this autosomal dominant, delayed, benign skeletal anomaly involves increased bone density in conjunction with fairly normal bone contour.

• patients with this disease are asymptomatic

• hereditary disorder, byt bone sclerosis is not radiographically visible at birth

craniotubular hyperostoses

• include a variety of fairly rare hereditary diseases, causing both an increase in bone density and abnormal bone modeling

• manifest in childhood

syndactyly

hand and foot malformation

• failure of the fingers or toes to separate

• appears webbed digits

• associated with apert syndrome

apert syndrome

• syndactyly is associated with this syndrome

• it is a genetic syndrome involving mutations of fibroblast growth factor receptor 2

• is responsible for crainosynostosis

fibroblast growth factor receptor 2

apert syndrome is a genetic syndrome involving mutations of, what?

polydactyly

hand and foot malformation

• refers to the presence of extra digits

clubfoot (talipes)

hand and foot malformation

• congenital malformation of the foot that prevents normal weight bearing

• foot is turned inward at the ankle

• more common in males than in females and may occur bilaterally.

casting or splinting the foot

clubfoot is generally corrected by, how?

developmental dysplasia of the hip (DDH)

• a malformation of the acetabulum

• often results to the head of the femur being displaced superiorly and posteriorly

• may be unilateral or bilateral

• occurs frequently in female than males

• affects 1 in 1000 births

• breech position in utero

• being the first child

• low levels of amniotic fluid

risk factors in developmental dysplasia of the hip (DDH):

• cerebral palsy

• myelomeningocele

• arthrogryposis

• larsen syndrome

developmental dysplasia of the hip (DDH) may be associated with:

larsen syndrome

association with DDH

• is a mutation of the FLNB gene affecting the production of filament B protein.

• sonography may be used to diagnose

• this anomaly should be treated early with immobilization through casting or splinting the affected hip to allow the acetabulum to grow and form a normal joint.

FLNB

what gene is mutated in larsen sydrome?

filament B protein

larsen syndrome is a genetic mutation of the FLNB gene that affects the production of, what?

• uneven limb length

• hip muscle weakness

• uneven gait

if the larsen syndrome is left untreated, it will result to what?

scoliosis

• abnormal lateral curvature of the spine

• does not generally become visually apparent until adolescence

• affects girls more frequently

• cardiopulmunary complications

• degenerative spinal arthritis

• fatigue

• joint dysfunction syndromes

scoliosis may cause numerous complications like:

structural scoliosis

• associated with vertebral rotation

• are idiopathic

nonstructural scoliosis

the primary issue is not vertebral rotation, usually results from unequal leg lengths or compensatory postural changes affected by chronic pain elsewhere in the body.

25 to 35 degrees

scoliosis may be corrected by placing the individual in a brace or body cast in patients with curves of, what degrees?

greater than 40 degrees

surgical treatment with spinal fusion is prescribed for curves greater than, what degree?

transitional vertebra

• one that takes on the characteristics of both vertebrae on each side of a major division of the spine

• occurs between the thoracic and lumbar spine or at the junction between the lumbar spine and the sacrum

spina bifida

• incomplete closure of the vertebral canal that is particularly common in the lumbosacral area

• no visible abnormality or neurologic deficit, but failure of fusion of the two laminae is visible radiographically

• treatment: determined on the basis of the extent of the anomaly and requires service of a variety of physicians

cervical rib

• most commonly occurs at C7

• may exert pressure on the brachial nerve plexus or the subclavian artery, requiring surgical removal of the rib.

• usually unilateral, but can be bilateral

spina bifida occulta

• much more common

• generally asymptomatic unless the underlying spinal cord is affected

• associated with a hairy patch or birthmark on the back, and a few children develop mild spastic gait or bladder problems

mild spastic gait or bladder problems

an individual with spina bifida occulta has a hairy patch or birthmark on the back, and a few children develop, what?

spina bifida cystica

• spinal-wall defect is accompanied by a protrusion of the spinal cord

• this may take two forms:

  • meningocele

  • meningomyelocele

meningocele

spina bifida cystica

• meninges and cerebrospinal fluid (CSF), protrude through the defect

meningomyelocele

spina bifida cystica

• protrusion of meninges, CSF, and functional neural elements (nerve or spinal cord contents)

• 90% cases

crainiosynostosis

• premature or early closer of any of the cranial sutures

• congenital anomaly causes an overgrowth of the unfused sutures to accommodate brain growth, which alters the shape of the head

• associated with apert syndrome

• corrected with surgery, but brain damage may occur

apert syndrome

a genetic disorder that is caused by a mutation of FGRF2 gene on chromosome 10

FGRF2 gene on chromosome 10

apert syndrome is a genetic disorder that is caused by a mutation of, what gene?

anencephaly

• congenital abnormality in which the brain and cranial vault do not form

• only facial bones are formed

• this abnormality results in death shortly after birth

• may be diagnosed before birth by ultrasonography.

• a neural tube defect, and the cause is unknown