MICROANATOMY

Detailed explanation-1: -Long bones have a long longitudinal axis (Figure 1). Short bones have a short longitudinal axis and are more cube-like. Flat bones are thin and curved such as some of the bones of the skull. Irregular bones are often found in groups and have a variety of shapes and sizes.

Detailed explanation-2: -The wider section at each end of the bone is called the epiphysis (plural = epiphyses), which is filled with spongy bone.

Detailed explanation-3: -The long axis was defined as a line from the center of the femoral head to the anterolateral attachment of the posterior cruciate ligament. The transverse axis was defined as a line through the posterior cruciate ligament parallel to the line connecting each epicondyle.

Detailed explanation-4: -The epiphyseal growth plate is the main site of longitudinal growth of the long bones. At this site, cartilage is formed by the proliferation and hypertrophy of cells and synthesis of the typical extracellular matrix. The formed cartilage is then calcified, degraded, and replaced by osseous tissue.

Detailed explanation-5: -Long bones function to support the weight of the body and facilitate movement. Long bones are mostly located in the appendicular skeleton and include bones in the lower limbs (the tibia, fibula, femur, metatarsals, and phalanges) and bones in the upper limbs (the humerus, radius, ulna, metacarpals, and phalanges).