Running Head:

Abnormal Psychology

[Name of the writer]

[Name of the institution]

Peripheral Nerve Injuries

Introduction

“Your peripheral nerves link your brain and spinal cord to the other parts of your body, such as your muscles and skin. Peripheral nerves are fragile and easily damaged. A nerve injury can interfere with your brain's ability to communicate with your muscles and organs. If you feel tingling or numbness in your leg, arm or hand, you may have injured one or more nerves when you had an accident or broke a bone (Olsen, 43). Weakness in one of those places can also mean that you have injured your sciatic or radial nerve. It is important to get medical care for such an injury as soon as possible because nerve injuries can be repaired. Evidence suggests that you can heal better when you have a severe nerve injury repaired soon after your injury. Peripheral nerve injury is a general term used to describe damage of the nerves outside the brain or spinal cord. Peripheral nerve injuries are often caused by trauma (Powell, 213). Common symptoms of a peripheral nerve injury are weakness, altered sensation, pain, and loss of function below the level of the injury. Surgical repair of the damaged nerve is sometimes required. Whether surgery is required or not, physiotherapy has a very important role in your rehabilitation enabling you to reach your maximum possible recovery. The physiotherapists at Manchester Neuro Physio understand the impact that a peripheral nerve injury can have on your everyday life. We provide home and clinic based appointments (Cross, 249).

Anatomy of Peripheral Nerves

Peripheral nerves consist of fascicles that contain myelinated and unmyelinated axons. Endoneurium is the small amount of matrix that is present between individual axons. The perineurium is a sheath of special, fiber-like cells that ties the axons of each fascicle together ((Hoeller, 650). Epineurium is the connective tissue that surrounds the entire nerve trunk and gives off vascular connective tissue septa that traverse the nerve and separate fascicles from one another.

Single myelinated axon

Normal nerve

Axons thicker than one micron in the CNS and peripheral nervous system (PNS) are myelinated. Myelin is a spiral sheet of cell membrane wrapped around the axon. In the CNS, myelin is produced by oligodendroglial cells and in the PNS by Schwann cells. Each oligodendrocyte makes multiple segments of myelin that wrap around many axons. Each Schwann cell makes one segment of myelin. This is one reason why peripheral myelin regenerates more efficiently (Cross, 249). Nodes of Ranvier are points of discontinuity between adjacent myelin sheaths in which the axon is not covered by myelin. Unmyelinated axons are covered by Schwann cell cytoplasm, but there is no spiraling of Schwann cell membrane around them.

The structure of central and peripheral myelin is essentially the same. Myelin is composed of 70% lipids and 30% protein. There are some important differences in myelin proteins between CNS and PNS. These differences explain why an allergic reaction against PNS myelin does not cause central demyelination and vice versa; ...