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Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Bone Tumors (Benign and Malignant)


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Overview

Bone tumors are abnormal growths of cells within the bone that may be noncancerous (benign) or cancerous (malignant); they often occur in areas of rapid bone growth. For most bone tumors the cause is unknown. Possible causes include genetic defects passed down through families, radiation, and injury. A bone tumor may be primary, originating within the bone itself, or secondary, resulting from the spread (metastasis) of cancer elsewhere in the body, such as from the lung, breast, or prostate.

Benign bone tumors occur more frequently than malignant bone tumors. Benign bone tumors remain localized within the bone and do not metastasize to other tissues or organs, but can enlarge in the bone or the surrounding tissue. Benign tumors are named according to the cell type of origin: bone cells (osteoblasts) may produce osteomas, cartilage cells (chondroblasts) may produce chondromas, and tumors arising from both bone and cartilage produce osteochondromas. Benign bone tumors do not always enlarge, nor do they always impact surrounding tissue or joints. However, benign bone tumors that are at risk for fracture (pathological fracture) may require surgery. Local recurrence depends on the type of benign bone tumor. Osteochondromas are the most common benign bone tumors. Other benign bone tumors include non-ossifying fibroma, unicameral (simple) bone cyst, giant cell tumor, enchondroma, and fibrous dysplasia.

Malignant bone tumors are classified as primary and secondary. The most common types of primary bone cancer—those cancers that originate in or near bone—are multiple myeloma (however, multiple myeloma is often considered a bone marrow tumor rather than a bone tumor), chondrosarcoma, osteosarcoma, and Ewing's sarcoma. Fibrosarcomas arise from connective tissue (muscle, ligament, or tendon) but may affect the bones of the jaw, arms, and legs.

Multiple myeloma is a malignant tumor of plasma cells, a type of white blood cell produced by the bone marrow. Non-Hodgkin's lymphoma of the bone is another malignant tumor that develops in the bone marrow.

Chondrosarcomas are the second most common bone cancer in adults. They arise from cartilage cells and develop in the legs, shoulders, arms, hips, pelvis, or ribs. (They may also arise from benign enchondromas and osteochondromas ("Detailed Guide").)

Osteosarcomas are bone-forming tumors that develop primarily at the ends of the bones in the growth plates of children and young adults (most cases occurring in teenagers), and affect the knee, hip, and shoulder, in that order. Ewing's sarcoma, a rare malignant tumor of the bone which is the second-most-common type of bone cancer in children, develops most frequently in the middle (shaft) of long bones, and affects the hips, long bones in the upper and lower leg, pelvis, upper arm, and ribs.

There are several other types of sarcoma, such as malignant giant cell tumors and chordoma. These rare tumors occur most often in adults over the age of 30.

Secondary bone cancer occurs when malignant cells from a primary cancer site, such as the kidney, lung, prostate, breast, or thyroid, metastasize to the bones; although cancer is present in the bones, the malignant cells are those of the organ of origin. Therefore, these secondary cancers are not referred to as bone cancer but are instead named for the original organ from which they spread (e.g. metastatic lung cancer). Common sites of secondary bone cancer include the ribs, skull, pelvis, and vertebrae. These bone tumors may not be treated in the same way as primary bone tumors because they occur in the later stages of metastatic cancer of other organ systems. Sometimes, when metastasis of the primary tumor involves bone and other organ systems, only palliative treatment is given.

Malignant bone tumors are staged using the American Joint Commission on Cancer (AJCC) tumor/node/metastasis staging system. Stages for tumor characteristics, the possible spread to lymph nodes, and metastasis to distant organs (TNM) are shown in increments, including T0 (no tumor evident), T1 (tumor smaller than 8 cm), T2 (tumor larger than 8 cm), and T3 (tumor in more than one place on the same bone); N0 (no spread) to N1 (spread to lymph nodes); and M0 (no distant spreading) or M1 (distant metastasis) ("Detailed Guide"). An alternate grouped TNM staging system uses Roman numerals I through IV, ranging from the absence of to incremental increases in metastasis. A grade will also be assigned, including G1 through G4, with lower numbers indicating low-grade tumors, and higher numbers indicating high-grade tumors ("Detailed Guide").

Incidence and Prevalence: According to the American Cancer Society, an estimated 3,010 new cases of malignant bone tumors were diagnosed in 2013 in the US, with an estimated 1,440 deaths ("Detailed Guide").

Multiple myeloma (MM) affects approximately 5 to 7 individuals per 100,000 each year. According to the Multiple Myeloma Research Foundation, more than 56,000 Americans are living with the disease. MM is usually diagnosed between the ages of 50 and 70 and can involve any bone (Lonial).

Chondrosarcoma and osteosarcoma account for about 40% and 28% of primary bone cancers in adults, respectively ("Detailed Guide"). In the US each year, 400 new cases of osteosarcoma are diagnosed, or 4.8 cases per 1 million individuals younger than age 20; the incidence among blacks is 5.2 cases per 1 million each year, and among whites it is 4.6 cases per 1 million each year (Mehlman).

Fibrosarcoma and malignant fibrous histiocytoma account for 4% of primary bone cancers, and chordoma accounts for 10%. Ewing's sarcoma of the bone accounts for 8% of cases of primary bone cancer ("Detailed Guide"); about 2.9 cases are diagnosed per 1 million individuals, with the incidence in whites about 9 times that in blacks (Toretsky). Rare tumors, such as giant cell tumors, make up the remainder of primary bone cancers.

Source: Medical Disability Advisor