DEPARTMENT OF ANATOMICAL SCIENCES

AN321 - FORENSIC OSTEOLOGY

BONE PATHOLOGY & ANOMALIES

W. B. Wood

Senior Lecturer

The University of Queensland

INTRODUCTION

Most forensic anthropologists are not experts in the recognition of bony pathology but some have made it their specialty particularly in the area of paleopathology (Brothwell & Sandison 1967; Ortner & Putschar 1981; Steinbock 1976)

When pathology or bony anomalies are observed to be present then they must be fully described, photographed, radiographed and (in the case of pathology) examined microscopically so as to identify their nature and extent. Many of the chronic infectious diseases that leave their mark on bone have overlapping morphological features that make differential diagnosis almost impossible.

Needless to say, the advice of a consultant pathologist and radiologist should always be sought before any definitive conclusion is made.

Problems may arise where postmortem artifacts of bones may mimic disease processes (eg termite or root activity) and viceversa, or where anomalies of bone may be confused with antemortem or perimortem trauma e.g. from a gunshot wound (Taylor 1974, Duflou & Oettle 1990).

The presence of bony pathology or specific anomalies may assist in individual identification if antemortem records are available for comparison. It is only rarely however that the presence of bone pathology assists in the determination of the probable cause of death.

A good modern reference text for an introduction to bony disease and abnormalities is the book Outline of Orthopaedics by Crawford Adams (1981).

Skeletal pathology may be subdivided into disorders of bones and disorders of joints.

AETIOLOGY OF PATHOLOGICAL PROCESSES

Genetic: inherited genetic defects

somatic mutations

Acquired: caused by environmental influences

TERMINOLOGY OF BONE & CARTILAGE PATHOLOGY & ABNORMALITIES

Conditions that are handed on from parent to child due to a genetic

abnormalities are called INHERITED conditions.

Conditions that are the result of abnormal growth and development of

cartilage or bone are called DEVELOPMENTAL abnormalities.

Conditions that are present at birth are said to be CONGENITAL regardless of

whether they are due to inherited genetic defects or developmental abnormalities

caused by abnormal intrauterine environmental factors.

Some bone pathology is LOCALISED while other affections are part of a

GENERALISED disease process affecting the whole body.

Diseases of bone result in abnormal bone formation, destruction, pathological

fractures, dislocations or deformity.

CLASSIFICATION

INHERITED Anomalies

ACQUIRED Diseases

Inflammatory - acute

- chronic

Neoplastic - benign

- malignant

primary

secondary

Degenerative

Nutritive

Obliterative (Circulatory)

Toxic

Metabolic (Nutritional & Endocrine)

INHERITED ANOMALIES

These conditions are usually generalized throughout the body and may or

may not be obvious at birth:

Cartilage Dysplasias: abnormal cartilage development

Achondroplasia (congenital dwarfism - marked shortening of the limbs)

Osteochondromatosis (multiple exostoses)

Bone Dysplasias: abnormal bone development

Osteogenesis imperfecta (fragilitas ossium)

Fibrous dysplasia - single or multiple cysts in bones

CONGENITAL ANOMALIES

These conditions may be inherited or acquired (secondary). They are usually localized and

obvious at birth:

Congenital dislocated hip (CDH)

Congenital genu varus/valgus (bow-leg; knock-kneed)

Reduction deformities - part or whole of a limb is absent

Fusion deformities - syndactyly; lobster claw hand, sacralization of L5

Extra digits - polydactyly

Club foot (Talipes equino varus)

Pes planus (flat-foot)

Spina bifida (absent vertebral arch)

Congenital scoliosis - usually due to a hemi-vertebra

ACQUIRED CONDITIONS

BONE & JOINT INFLAMMATION (OSTEITIS/ARTHRITIS)

Acute Inflammation

Usually due to pyogenic (pus forming) organisms

osteomyelitis

periostitis

septic arthritis

Acute Inflammation (cont.)

Signs: redness, heat, pain, swelling, loss of function

pus formation, bone and cartilage destruction

The bony lesions of acute osteomyelitis typically demonstrate an

involucrum of coarsely woven bone overlying or surrounding the surface of

the original bone and perforated by one or more sinuses (fistulae) for the

escape of pus from the medullary cavity. Embedded in the involucrum may be one or more pieces of dead bone (sequestra).

Acute septic arthritis may lead to total joint disruption with fibrous or bony

ankylosis.

In acute periostitis, woven bone is laid down on the surface of the bony

cortex but there is no involvement of the medullary cavity and no formation

of sinuses.

Chronic Inflammation

Pyogenic organisms (chronic osteomyelitis)

Signs:

recurrent or continuing symptoms and signs of inflammation persistent pus draining from sinuses

destruction of bone and cartilage (osteolysis/chondrolysis) or

abnormal bone formation and thickening (osteogenesis)

Tuberculosis

a chronic infection of bone which results in bone and joint

destruction

usually there is little or no evidence of bony reaction

attacks especially the vertebral column resulting in vertebral collapse and the development of kyphosis (sharp posterior angulation of the

spine)

no associated evidence of sequestra formation, involucrum, or fusion

of joints

Syphilis & yaws

these are chronic infections of bone caused by related organisms.

usually the disease focuses on the bones of the cranial vault, the facial skeleton or the tibia.

there may be localized (fusiform swelling) of the shaft of a bone or

generalized subperiosteal new bone formation due to periostitis,

localised areas of bony destruction or rarefaction with dense

thickening of the overlying cortex, diffuse sclerotic thickening of the

whole bone. Radiologically the appearances vary from severe

osteoporosis to dense sclerosis.

BONE & CARTILAGE NEOPLASMS (TUMOURS)

True bony neoplasms result from the uncontrolled growth of bone, bone marrow

and cartilage cells.

Benign neoplasms are self limiting and tend to remain localised.

Malignant neoplasms tend to spread throughout the body via tissue planes, body

cavities and via blood and lymphatic vessels.

Benign:

osteoma - occur in about 1% of people

especially common on the ectocranial surface

as a discrete mound of compact bone

osteochondroma - arise at epiphysial lines, project at right angles and

resemble ossified tendons

NOTE: auditory exostoses (osteomata) may occur in the external

auditory canal

Malignant:

These may be either primary or secondary (metastatic)

Metastatic neoplasms with primary centers located in other organs or tissues

of the body are much more common in bone than primary bony neoplasms.

Primary: osteosarcoma/blastoma/clastoma

chondrosarcoma/blastoma

multiple myeloma

Ewing's tumour

Secondary: these are usually of epithelial origin

breast

bronchus

thyroid

kidney

prostate

Most malignant neoplasms cause swelling of the affected bone associated with

bone resorption (destruction or lysis). Radiographically they demonstrate localized

radiolucency of bone tissue.

Others may stimulate bone formation so that radioopaque areas may be present in

the bone radiograph.

DEGENERATIVE BONE & CARTILAGE PATHOLOGY

Osteoarthritis

most commonly associated with aged individuals and better termed

degenerative joint disease

characterized by periarticular bony lipping (osteophytes) and spur formation

often associated with eburnation (a polished ivory-like appearance of

synovial joint articular surfaces) due to the exposure of subchondral bone.

may be localized (post traumatic) or more generalized and affecting

especially the vertebral column and large limb joints.

severe degrees may lead eventually to bony ankylosis of joints

Rheumatoid Arthritis

this is a chronic non-bacterial inflammation of joints that nearly always

affects several joints at the same time (polyarthritis).

the cause is unknown but may be associated with autoimmune disease.

the condition often starts in the young adult and occurs more frequently in

females.

the condition causes thickening of the articular capsule, softening and erosion of the articular cartilage.

eventually erosion and destruction of the subchondral bone and secondary

osteoarthritis may develop.

Ankylosing spondylitis

a chronic disease of the vertebral column in which the ligaments of the

vertebral column become ossified and the intervertebral joints become

immobilized.

CIRCULATORY BONE DISEASE

This is usually due to a disturbance of the blood supply (reduced or absent) to

bone or cartilage.

This may lead to avascular necrosis of bone or cartilage.

Keinbock's disease of the wrist (necrosis of the lunate bone)

Perthe's disease of the hip (necrosis of the proximal epiphysis of the hip)

Anaemias may also affect bone leading to a widening of the haematopoietic

marrow spaces in bones (or the diploe in the cranium vault).

Porotic hyperostosis (spongy hyperostosis) is a condition affecting the cranial

vault which is probably anaemia related. There is a thinning and often

complete destruction of the outer table of the cranial vault (especially in the

parietal bones) with exposure of the spongy (sieve-like) diploe. Similar affects

may appear in the orbital roof (cribra orbitalis) or endocranial surface (cribra

cranii).

METABOLIC BONE DISEASE

NUTRITIVE &/OR ENDOCRINE

In these conditions there is a generalized reduction in bone mass as a result of

inadequate osteoid production or mineralization, or of excessive demineralisation of

bone.

Osteoporosis:

a generalized loss of calcium from the bones especially in

postmenopausal women.

multifactorial in aetiology, with hormonal, dietary and reduced activity all

playing a part.

Osteomalacia:

Due to deficient calcium absorption and/or metabolism

Rickets (lack of vitamin D) causes softening and bending of bones

due to excessive production of osteoid and a failure of osteoid tissue to ossify (calcify).

Skeletal effects are most obvious in the long bones, which become

bent and distorted.

Adult osteomalacia - causes generalized osteoporosis & crush

fractures of vertebrae, or stress fractures of ribs, sternum & pelvis.

Renal rickets

Scurvy:

Due to insufficient intake of Vitamin C which is essential for the production

of collagen and therefore of osteoid.

Usually presents as cortical thinning and pathological fractures especially in

infants and young children.

Hyperparathyroidism (Osteitis Fibrosa Cystica)

Due to excess production of parathyroid hormone.

There is loss of mineralized bone due to overactive osteoclastic resorption

There is generalized osteoporosis and the development of cystic lesions

throughout the bones.

Hyperpituitarism:

Gigantism:

Due to overproduction of somatotrophic hormones (e.g. growth hormone) in

the growing child.

All the bones become excessively large.

Acromegaly:

Similar cause as for gigantism but only when it develops in adult

individuals after the growth epiphyses have closed.

Results in an individual with excessively large mandible, hands and feet.

Paget's disease:

a very common bone disease (4% over 50yr olds in the UK)

uncertain aetiology

characterized by disordered bone architecture associated with:

bone thickening, deformity,

pathological fractures

Gouty arthritis:

a metabolic disease due to abnormal urate metabolism. Results in the

deposition of urate crystals in the periarticular tissues associated with acute

inflammatory arthritis.

TOXIC DISEASE

Metal poisoning eg lead, mercury, bismuth, and phosphorus, often cause

metaphysial (and occasionally diaphysial) bands of increased density.

Fluoride intoxication may cause diffuse sclerosis with undulating periosteal

reaction.

REFERENCES

Brothwell D & AT Sandison 1967 Diseases in Antiquity CC Thomas Springfield Illinois

Crawford Adams J 1981 Outline of Orthopaedics 9th Edition, Churchill Livingstone

Crawford Adams J 1978 Outline of Fractures 7th Edition, Churchill Livingstone

Duflou J & THG Oettle 1990 "Bony Foramina in Forensic Medicine". Paper (No A553)

presented at the 12th Meeting of the International Association of Forensic Science Adelaide 1990

Ortner DJ & WGJ Putschar 1981 Identification of Pathological Conditions in Human Skeletal Remains Smithsonian Contributions to Anthropology No 28 Smithsonian Institution Press Washington DC

Steinbock RT 1976 Paleopathological Diagnosis and Interpretation. CC Thomas

Taylor HL 1974 "The Sternal Foramen: The Possible Forensic Misinterpretation of an Anatomic Abnormality" JFS 19(4):730-734