Week 1 - MSK Basic Sciences Formative Flashcards
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The lines that are often visible surrounding the osteon are termed cement lines.
The radiographic features of which biochemical bone disorder include: bone enlargement, thickened cortices, thickened trabeculae with mixed areas of lysis and sclerosis? Select one: * Osteomalacia * Osteoporosis * Osteogenesis imperfecta * Paget’s disease * Renal osteodystrophy
Paget’ disease of the bone is correct
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This slide shows skeletal muscle. Note the features of striations (visible on the longitudinally sectioned fibres) and the peripheral nuclei (seen on the transversely sectioned fibres).
Match the correct bone tumours to the descriptions * Osteosarcoma * Ewing’s sarcoma * Fibrosarcoma
* Statement 1 - FIBROSARCOMA - tends to occur in abnormal bone and affects young adults * Statement 2 - OSTEOSARCOMA - malignnat tumour producing bone, most cases in adolescents and 60% involve the knee (Tx - resection of tumour + adjuvant chemo) * Statement 3 - EWING’S SARCOMA - occurs in adolescents, fever, riased inflammatory markers, warm swelling (Onion peel sign on xray) - surgery _ adjuvant radiochemotherapy
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Muscle fibres are grouped into bundles called fascicles and a muscle typically contains several fascicles. The connective tissue around a single fascile is the PERIMYSIUM
True or False: The striations present in skeletal muscle result from the orientation of the myofibrils, which run across the fibre. Select one: True False
False
True or false: Osteochondromas are always benign. Select one: True False
FALSE Beware a question which states something is ‘always’ the case! * The commonest benign bone tumour is an osteochondroma which produces a bony outgrowth on the external surface with a cartilaginous cap. * These do not usually case any problems but can produce local pain. * However, there is a very small (1%) risk of malignant transformation and any lesion growing in size orproducing pain may require excisional biopsy.
Which biochemical disorder of bone is being described below? Condition X is a quantitative defect of bone characterised by reduced bone mineral density and increased porosity.
Osteoporosis is a quantitative defect of bone characterised by reduced bone mineral density and increased porosity (i.e. the bone is of normal quality, there is just not enough of it). The WHO defines osteoporosis as bone mineral density less than 2.5 standard deviations below the mean peak value of young adults of the same race and sex
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OSTEOCHONDROMA
The commonest benign bone tumour is an osteochondroma which produces a bony outgrowth on the external surface with a cartilaginous cap (which isn’t visible on the x-ray). These do not usually cause any problems but can produce local pain.
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HAVERSIAN CANAL
* Bone is constantly undergoing remodelling. In this process, a number of osteoclasts will congregate and begin to ‘drill’ into the bone, forming a tunnel. * A blood vessel will grow into the tunnel bringing with it osteoblasts which line the tunnel and begin laying down new lamellar bone. * This process continues until only the space of a Haversian canal remains.
Bone is constantly undergoing remodelling. In this process, a number of _____ will congregate and begin to ‘drill’ into the bone, forming a tunnel. A blood vessel will grow into the tunnel bringing with it X, which line the tunnel and begin laying down new lamellar bone. This process continues until only the space of a Haversian canal remains. The cells responsible for the destruction of bone during remodelling are:?
OSTEOCLASTS Osteoprogenitor cells: located on bone surfaces, for example under the periosteum, these cells serve as a pool of reserve osteoblasts Osteoblasts: bone forming cells found on the surface of developing bone. They have plentiful RER and prominent mitochondria. Osteocytes bone cell trapped within the bone matrix Osteoclasts: large multinucleated cells. Found on surface of bone &are responsible for bone resorption
Malignant soft tissue tumours arising from the connective tissues are known as sarcomas. Sarcomas are relatively uncommon accounting for less than 1% of all malignant tumours. Sarcomas can arise from and are named according to the tissue type from which they arise. State the tissue names of these malignant soft tissue tumours * Fat * Muscle * Blood vessels
Fat - liposarcoma Muscle - rhabdomyosarcoma Blood vessel - angiosarcoma
Avascular necrosis is an ischaemic necrosis of bone predominantly in adults. Several sites are particularly prone to AVN including the femoral head, the femoral condyles, the head of the humerus, the capitellum, the proximal pole of the scaphoid and the proximal part of the talus. From the following list, select the risk factors associated with AVN: * Manual occupations * Sickle cell disease * Deep sea diving * Sedentary jobs * Excessive red wine and cheese consumption
Sickle cell disease Deep sea diving Steroids and alcholism are two of the commonest identified causative factors
Of the following features of a soft tissue swelling, select those which are more reassuring of a malignant swelling: Select one or more: * Soft/fatty lesions * Systemic upset with weight loss and fatigue * Larger lesions (>5cm) * A history of fluctuation in size * An irregular surface
* Features suggestive of a benign soft tissue neoplasm include smaller size, fluctuation in size (malignant tumours don’t regress in size), cystic lesions, well‐defined lesions, fluid filled lesions and soft / fatty lesions. * Features suggestive of a potential malignant soft tissue neoplasm include larger lesions (>5cm), rapid growth in size, a solid lesion, an ill‐defined lesion, an irregular surface, associated lymphadenopathy & systemic upset (weight loss, los of appetite, fatigue)
Benign bone tumours: State the correct bone tumours to the following radiological descriptions: * A single lucent lesion, often an incidental finding, found most commonly within metaphyseal regions * A tumour extensively involving the proximal femur with cortical thinning and a ‘Shepherd’s crook’ deformity. * Tumour often occuring arround the knee and distal radius with a ‘soap bubble’ appearance
A single lucent lesion, often an incidental finding, found most commonly within metaphyseal regions - SIMPLE BONE CYST A tumour extensively involving the proximal femur with cortical thinning and a ‘Shepherd’s crook’ deformity. - FIBROUS DYSPLASIA Tumour often occuring arround the knee and distal radius with a ‘soap bubble’ appearance GIANT CELL TUMOUR
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An outer shell of dense cortical bone makes up the shaft (diaphysis). Cancellous or trabecular bone occupies the ends of the bone (the epiphyses).
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LACUNA
Chondrocytes live within a space in the extracellular matrix termed a lacuna. Chondrocytes are active cells, which not only secrete but also maintain the extracellular matrix around them.
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A simple bone cyst was the answer
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Endomysium
