Diffuse Increase in Bone Density

1. Secondary to malignancy - metastases
2. Non-malignant disease - Paget's Disease
3. Myelofibrosis
4. Myelosclerosis - Sickle Cell Disease
5. Fluorosis
6. Mastocytosis
7. Osteopetrosis
8. Hypervitaminosis D

Diffuse Decrease in Bone Density

1. Osteoporosis-Multiple myeloma, Steroid administration
2. Osteomalacia
3. Hyperparathyroidism
4. Paralysis
5. Osteogenesis imperfecta

Focal lytic lesion

1. Primary malignancy -Myeloma
2. Secondary malignancy -Metastases
3. Eosinophilic granuloma
4. Brown tumors

Round Cell Lesions

1. Ewing’s sarcoma
2. Osteomyelitis
3. Multiple myeloma
4. Lymphoma and leukemia
5. Neuroblastoma

Expansile Lesion

1. 1° malignancy - Multiple myeloma
2. 2° malignancy - Mets
3. Non-malignant – Aneurysmal bone cyst
4. Fibrous dysplasia
5. Brown tumor
6. Enchondroma

Expansile Lesion of Rib

1. Primary malignancy – Plasmacytoma
2. Secondary malignancy – Mets
3. Non-malignant – Fibrous dysplasia
4. Chondrosarcoma
5. Enchondroma
6. Eosinophilic granuloma
7. Neurofibromatosis

Soap-Bubbly Lesion

1. Metastases, esp. kidney, thyroid, lung
2. Giant Cell Tumor
3. Plasmacytoma
4. Chondrosarcoma

Lesions with Associated Soft Tissue Masses

1. Multiple myeloma
2. Metastases
3. Osteomyelitis
4. Primary malignancies of bone, e.g. osteosarcoma

Sclerotic Cortical lesions

1. Osteoid osteoma
2. Brodie’s abscess
3. Healing stress fracture

Short Thumb

1. Myositis ossificans progressiva
2. Fanconi’s syndrome
3. Holt-Oram Syndrome         

Short 4th Metacarpal

1. Turner’s syndrome
2. Pseudohypoparathyroidism         

Clinodactyly

1. Down’s syndrome
2. Otopalatodigital syndrome
3. Cornelia de Lange syndrome       

Polydactyly

1. Isolated anomaly
2. Ellis-Van Creveld syndrome
3. Carpenter’s syndrome

Syndactyly

1. Carpenter’s syndrome
2. Apert’s syndrome
3. Poland’s syndrome

Erosion - Distal Clavicle

1. Rheumatoid Arthritis
2. Hyperparathyroidism          
3. Scleroderma

Acetabulo Protrusio

1. Paget’s disease
2. RA
3. Osteomalacia
4. Osteoporosis
5. Mucopolysaccharidosis

Acro-osteolysis

1. Thermal injury, burns, frostbite
2. Scleroderma
3. Hyperparathyroidism
4. Psoriasis
5. Raynaud’s disease
6. Leprosy

Avascular Necrosis

1. Idiopathic (Legg-Calve-Perthe’s Disease)
2. Steroid administration
3. Sickle cell anemia
4. Arteritis - collagen-vascular disease
5. Trauma
6. Gaucher’s
7. Pancreatitis
8. Fat embolism

Hypertrophic Osteoarthropathy

1. Carcinoma of the lung
2. Mesothelioma          
3. Chronic lung infection (TB)
4. Chronic liver disease, e.g. cirrhosis
5. Ulcerative colitis

Lesions That Affect The Spine

1. Osteoblastoma
2. Chordoma
3. Aneurysmal bone cysts
4. Metastases

Lesions That Affect The Pelvis

1. Chondrosarcoma
2. Plasmacytoma
3. Chordoma    

Posterior Scalloping

1. Neurofibromatosis
2. Achondroplasia
3. Spinal cord tumor (ependymoma)

Anterior Scalloping

1. Aortic aneurysm
2. TB
3. Neurofibroma

Lucent Metaphyseal Bands

1. Normal
2. Leukemia
3. Neuroblastoma
4. TORCH infection    

Dense Metaphyseal Bands

1. Normal
2. Lead poisoning
3. Treated leukemia
4. Healing rickets

Bone Within a Bone

1. Osteopetrosis
2. Paget’s disease
3. Thorotrast

Chondrocalcinosis

1. Pseudogout
2. Gout
3. DJD
4. Hyperparathyroidism
5. Hemochromatosis
6. Wilson’s Disease

Intramedullary Calcification

1. Enchondroma
2. Bone infarct
3. Chondrosarcoma

Thinned Ribs (Ribbon-Ribs)

1. Neurofibromatosis
2. Osteogenesis imperfecta
3. Trisomy 18
4. Gorham’s Disease

Wide Ribs

1. Achondroplasia
2. Fibrous dysplasia
3. Rickets (rosary)
4. Thalassemia
5. Mucopolysaccharidosis, esp. Hunter’s and Hurler’s
6. Gaucher’s disease

Wormian Bones

1. Normal          
2. Hypothyroidism
3. Down’s Syndrome
4. Cleidocranial dysostosis
5. Osteogenesis imperfecta

Ankylosis of SI Joints

1. Ankylosing spondylitis
2. Psoriasis
3. Reiter’s syndrome
4. Inflammatory bowel disease
5. TB