Bone case study - Grade: B PDF

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Case study on bones...

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Mrs. Maxine Sweetwater 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. Sweetwater 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. Sweetwater undergoes several x-rays, which reveal the following: 1) fracture of the left humerus at the proximal diaphysis,

2) depressed fracture of the occipital bone,

3) fracture of the 3rd lumbar vertebral body.

Short Answer Questions 1. Define the following terms, used in the case and also in associated questions: Hemorrhage, according to our book, is Blood loss; to bleed can be from the left humerus or depressed occipital bone. Pg 21 Fracture is a break or cracks in the bone, in this case, humerus, occipital, or lumbar vertebral body. 6 Proximal is a direction towards the point of attachment or origin; for a limb towards its attachment to the truck, in this case, the injury was left humerus at the proximal diaphysis. 1,8 The diaphysis is the shaft of the long bone left humerus at the proximal diaphysis. 6

One way bones are classified is by their shape. How would you classify the bones fractured by Mrs. Sweetwater? The shapes of the bones are found on pg 182 of our book. The occipital bone is classified as a flat bone that has thin surfaces, and parallel. The humerus is classified as a long bone, slender in shape, and long. The 3rd lumbar vertebral body is classified as an irregular bone; the definition is a complex shape that is short, flat, notched, or ridged on the surface.

The body of Mrs. Sweetwater’s vertebra is fractured. What type of bone tissue makes up the majority of the vertebral body? Describe the structure and function of this type of bone. Pg 188 The type of bone tissue makes up the majority of the vertebral body is a matrix of spongy bone. Spongy bone is a mesh network of trabeculae, small and can be found in bone along the stress lines or cross-brace. Areas that do not require a lot of stress or movement in multiple directions you will not find spongy bone. Another function is to add less weight to the bone, so that our bodies can move. The diaphysis of Mrs. Sweetwater’s humerus is fractured. What type of bone makes up the majority of the diaphysis of long bones like the humerus? Describe the layers of bone tissue found here. Pg185, pg 187 The diaphysis or the shaft of the long bone is made up almost entirely by compact bone and medullary cavity. The medullary cavity contains a marrow for blood supply. Compact bone layers are similar to rings of a tree trunk cut, made up of a more extensive system called osteons or Haversian system. Osteons middle contains a central canal and is the home to our blood vessels. The next layer of osteon bony layer are rings around the canal called circumferential lamellae it can be found at the outer/inner surfaces of compact bone, within these rings are small spaces called lacunae that are home to mature bone cells called osteocyte. Interstitial lamellae are located between the osteons with connections are made between the lacunae with little tunnels called canaliculi.

Most connective tissue, including bone, is highly vascular. Which anatomical structures in Mrs. Sweetwater's compact bone house blood vessels? What sign or symptom in Mrs. Sweetwater's case is directly related to the disruption of these structures by her bone fractures? How is the sign or symptom related to these anatomical structures? Pg 187, 189, 190

The anatomical structures in the compact bone of the humerus that house blood vessels and veins would be the Volkmann’s canals to the Haversian canal (perforating) and central canal; this is the pathway for the blood vessels to pass into the periosteum. Hemorrhaging is uncontrolled bleeding either caused when the humerus diaphysis broke, causing damage to the blood vessels and veins also the tearing of the soft tissue surrounding the bone. Hemorrhaging also can be caused by the depressed fracture of the occipital bone.

Within days after a fracture, a “soft callus” of fibrocartilage forms. What fibers are found in this type of cartilage? Identify the cells required for fibrocartilaginous callus formation and list their functions. Pg 201-202, 203

When fibrocartilaginous callus starts, the soft callus of fibrocartilage forms from Collagen fibers starts; information calls that are present would be fibroblast, chondroblasts. Fibroblasts produce collagen fibers helping in the healing process bridge the fracture ends together. Chondroblast function in the healing process is aiding in the secreting of the cartilage matrix.

As a fracture is repaired, new bone is added to the injury site. What term is used to describe the addition of new bone tissue? Identify which bone cell is responsible for this process and explain how it occurs. Pg 186,190,205

The term that best describes the addition of new bone is a process is called ossification or osteogenesis. The bone cell responsible for the process is osteoblast when the secretion of the organic matrix is made from collagen or osteoid ground substances. Osteoid will become the sight of the new bone formation when calcium and phosphorous are present. In the final stage of bone repair, some of the osseous tissue must be broken down and removed. What term is used to define the breaking down of osseous tissue? Which bone cell would be best suited for this task? Pg 187, 194

Osseous tissue in the final stage of bone repair is breaking down and removal of bone the process is called bone remodeling; it is best to describe dissolving away osseous tissue. Osteoclast bone destroying cells are needed to reabsorb the bone matrix.

The extracellular matrix (ECM) of bone is considered a composite material made up of organic and inorganic matter. What makes up the organic and inorganic portions of the matrix? Describe the cellular mechanism involved in breaking down this matrix; include the bone cell required for the process. Slide 14, pg 183 187

The inorganic matrix that makes up extracellular matrix is calcium salts, as well as two-thirds phosphorus. Most of the calcium and phosphorus salts exist as a large molecule of a mineral called hydroxyapatite crystals, making the bone one of the hardest substances in the body and gives bone its strength as well as the ability to resist compression. Function of support and protection is given from the bone. The organic matrix of bone is known as osteoids made from protein fibers, proteoglycans, glycosaminoglycans, glycoproteins. Collagen fibers are one of the most important components of the bone in terms of strength. The function of collagen fibers in bone is to help bone to resist forces; aligning with hydroxyapatite crystals, reinforcing the hardness of the bone. Extracellular matrix aids in re-growth and healing. Osteoregenic is cellular mechanism involved in breaking down matrix. Osteoregnic process involves osteoclasts (is responsible for the process of bone rebuilding, during which they break down the bone ECM)pg 186 and osteoblasts, pg 186 both are organic (cells) that use inorganic material to break down and reconstruct the extracellular matrix on a regular basis....