Final answer:
The femur is the long bone that is the second most common site for lytic Paget's disease. This condition creates porous, abnormally shaped bones that are typically straight but become curved. Diagnosis involves imaging tests and measuring blood levels of alkaline phosphatase.
Step-by-step explanation:
The femur is the long bone where the second most common site of lytic Paget's disease is found, following the pelvis which is the most common site.
Paget's disease affects the normal remodeling process of bone, causing the affected bones to become porous and abnormally shaped, and can lead to bone pain, deformities, and fractures. Normal long bones, as noted in Figure 6.14, are straight, but in Paget's disease, they become porous and curved.
Diagnostic methods for Paget's disease include imaging studies, such as X-rays and bone scans, and laboratory tests measuring the blood levels of an enzyme called alkaline phosphatase, which tends to be elevated in affected individuals.