The Human Body Skeletal System Anterior View And Posterior View
The Human Body Skeletal System Anterior View And Posterior View

The skeletal system may be divided into two functional parts. The axial skeleton consists of the bones of the head ( cranium or skull), neck ( hyoid bone and cervical vertebrae ), and trunk ( ribs, sternum, vertebrae , and sacrum ). The appendicular skeleton consists of the bones of the limbs, including those forming the pectoral (shoulder) and pelvic girdles. Cartilage and Bones The skeleton is composed of […]

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Transverse Sections Of The Humerus
Transverse Sections Of The Humerus

Cartilage and Bones The skeleton is composed of cartilages and bones. Cartilage is a resilient, semirigid form of connective tissue that forms parts of the skeleton where more flexibility is required—for example, where the costal cartilages attach the ribs to the sternum. Also, the articulating surfaces (bearing surfaces) of bones participating in a synovial joint are capped with articular cartilage that provides smooth, […]

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Bone Markings And Formations
Bone Markings And Formations

Classification of Bones Bones are classified according to their shape. Long bones are tubular (e.g., the humerus in the arm). Short bones are cuboidal and are found only in the tarsus (ankle) and carpus (wrist). Flat bones usually serve protective functions (e.g., the flat bones of the cranium protect the brain). Irregular bones have various shapes other than long, […]

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Development And Growth Of A Long Bone
Development And Growth Of A Long Bone

Bone Development Most bones take many years to grow and mature. The humerus (arm bone), for example, begins to ossify at the end of the embryonic period (8 weeks); however, ossification is not complete until age 20. All bones derive from mesenchyme (embryonic connective tissue) by two different processes: intramembranous ossification (directly from mesenchyme) and endochondral ossification […]

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Vasculature And Innervation Of A Long Bone
Vasculature And Innervation Of A Long Bone

Most secondary ossification centers appear in other parts of the developing bone after birth; the parts of a bone ossified from these centers are epiphyses . The chondrocytes in the middle of the epiphysis hypertrophy, and the bone matrix (extracellular substance) between them calcifies. Epiphysial arteries grow into the developing cavities with associated osteogenic cells. The flared part of the diaphysis nearest the […]

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Fractured Bone Healing Process
Fractured Bone Healing Process

Trauma to Bone and Bone Changes Bones are living organs that cause pain when injured, bleed when fractured, remodel in relationship to stresses placed on them, and change with age. Like other organs, bones have blood vessels, lymphatic vessels, and nerves, and they may become diseased. Unused bones, such as in a paralyzed limb, atrophy (decrease in […]

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Osteoporotic Bone View
Osteoporotic Bone View

Osteoporosis During the aging process, the organic and inorganic components of bone both decrease, often resulting in osteoporosis, a reduction in the quantity of bone, or atrophy of skeletal tissue. Hence, the bones become brittle, lose their elasticity, and fracture easily. Bone scanningis an imaging method used to assess normal and diminished bone mass (see section “Medical […]

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