Chapter 26: Bones and Joints

Chapter 26: Bones and Joints

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

MULTIPLE CHOICE

1. The autosomal dominant bone disorder caused by a mutation of fibroblast growth factor receptor 3 (FGFR3) is characterized by short stature, rhizomelic shortening of limbs, frontal bossing of the skull, and midface abnormalities. Which of the following disorders is described by these characteristics?
2. Achondrogenesis
3. Achondroplasia
4. Multiple epiphyseal dysplasia
5. Synpolydactyly
6. Holt-Oram syndrome

ANS: B,  Dwarfism, characterized by short limbs and relatively large head with midfacial changes involving the nose, is related to the mutation of the fibroblast growth factor receptor 3 (FGFR3) and is called achondroplasia.

2. Compression fractures of vertebral bodies seen in elderly women are causally related to reduced recruitment of osteoclasts. This process is associated with an increased concentration of which chemical mediators in the bone?

1. Prostaglandins
2. Leukotrienes
3. Cytokines such as interleukin (IL)-1 and IL-6
4. Oncogenes such as c-MYC and K-RAS
5. Fibroblast growth factors

ANS: C, Compression fractures of vertebral bones in postmenopausal women are related to reduced levels of estrogens. Reduced levels of estrogen lead to an increase of cytokines, such as interleukin (IL)-1 and IL-6, which retard the recruitment of  monocytes to the bones and inhibit their transformation into osteoclasts (a process known as osteoclast recruitment).

3. Osteoid osteoma is a small benign bone tumor associated with pain that is disproportionate to the size of the lesion. This pain is caused by an excess of which of the following substances?
4. Interleukin (IL)-1 and IL-6
5. Leukotrienes
6. Prostaglandin E₂
7. Complement C3
8. Bradykinin

ANS: C, It has been known for many years that the severe pain caused by osteoid osteoma can be treated with aspirin. It has been shown that the pain is caused by prostaglandin E₂, which is produced by the proliferating osteoblasts in the tumor.

4. Loss of heterozygosity, structural rearrangements, or point mutations of the retinoblastoma tumor suppressor gene (RB) are found in 60%–70% of all sporadic bone tumors. Which of the following is the best classification for this tumor?
5. Osteosarcoma
6. Osteoblastoma
7. Osteoid osteoma
8. Chondrosarcoma
9. Ewing sarcoma

ANS: A, Changes involving the retinoblastoma tumor suppressor gene RB are found in 60%–70% of all sporadic osteosarcomas.