Question

Mrs. Debbie Morgan is a 45-year-old female who works as a stocking clerk for a local home improvement store. While she was at work today a large box of metal rivets fell from a 20-ft.-high overhead shelf, striking her outstretched arm and knocking her to the ground. The ambulance personnel reported that she had lost quite a bit of blood at the accident scene and was “knocked out” when they arrived. To minimize further hemorrhage, the paramedics applied a pressure bandage to her arm.

You meet the paramedics as they bring Mrs. Morgan into the emergency room and begin to assess her for injuries. She is awake and alert, but complaining of severe left arm and back pain, plus she has a “killer headache.” To fully examine her injuries you remove four blood-soaked bandages from her arm. You notice a large open wound on her arm with what appears to be bone tissue sticking out of the skin. She also has bruises covering her left shoulder, left wrist, and lower back. To determine the extent of her injuries Mrs. Morgan undergoes several x-rays, which reveal the following:

1. One way bones are classified is by their shape. How would you classify the bones fractured by Mrs. Morgan (3 points)?

2. The body of Mrs. Morgan’s vertebra is fractured. What type of bone tissue makes up the majority of the vertebral body (1 point)? Describe the structure and function of this type of bone (2 points).

3. The diaphysis of Mrs. Morgan’s humerus is fractured. What type of bone tissue makes up the majority of the diaphysis of long bones like the humerus (1 point)? List and describe/define the layers (lamellae) of bone tissue found here (3 points)

Answer 1

1.Classification of bone based on shape:-

●Long bones

●short bones

●Flat bones

●Irregular bones

●Sesamoid bones

Long bones are cylindrical in shape. They are found in arms (humerus, radius, ulna ) ,legs (femur , tibia, fibula).

Short bones are cube shaped & are equal in length, width and thickness. Eg:-Carpals, tarsals.

Flat bones are thin and curved. Eg:-sternum, scapula, ribs.

Irregular bones donot have a specific shape. They have more complex structures. Eg:-Sphenoid bone, Mandible

Sesamoid bone is a small round bone.Eg :-patella.

3.The body of vertebra is formed of cancellous bone. It is surrounded by a layer of compact bone.

4.Structure and function of Cancellous bone :-

☆Cancellous bone is made of spongy bone with red bone marrow. It is present in vertebra, pelvis, skull etc .

☆It's main function is the production of RBC's.

5.Diaphysis of long bones are formed of cortical bone. It also contains bone marrow and adipocytes. Cortical bone is also called compact bone. It is the dense outer surface of bone and is able to bend under torsion.

6.Layers of bone

■Periosteum forms the outer layer of bone.It has fibrous and cellular layers .

■Endosteum is the inner layer and lines the medullary cavity.

-In a flat bone there is layer of spongy bone ( Diploe) between these two layers.