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The clinical procedure for obtaining CSF is known as a lumbar puncture

commonly referred to as a spinal tap

Recall that the adult spinal cord typically ends at the level of the L1 vertebra, so it is safe to insert the needle between the L3 and L4 vertebrae or between the L4 and L5 vertebrae

The needle must be inserted through the skin, the subcutaneous layer, back muscles, and ligamentum flavum. Then, the needle must pass through the epidural space, dura mater, arachnoid mater, and enter the subarachnoid space. Here, approximately 3 to 9 milliliters of CSF are taken and then analyzed



a reactivation of their childhood chickenpox infection, a condition termed shingles

During the initial infection, the chickenpox virus (varicella-zoster) sometimes leaves the skin and invades the posterior root ganglia of the spinal cord. There,the virus remains latent until adulthood, when it becomes reactivated and proliferates, traveling through the sensory axons to the dermatome


Brachial Plexus Injuries

Axillary Nerve Injury

The axillary nerve can be compressed within the axilla, or it can be damaged if the surgical neck of the humerus is broken

A patient whose axillary nerve is damaged has great difficulty abducting the arm due to paralysis of the deltoid muscle, as well as anesthesia (lack of sensation) along the superolateral skin of the arm.


Brachial Nerve Injuries

Radial Nerve Injury

The radial nerve is especially subject to injury during humeral shaft fractures or in injuries to the lateral elbow. Nerve damage results in paralysis of the extensor muscles of the forearm, wrist, and fingers. 

A common clinical sign of radial nerve injury is “wrist drop,” meaning that the patient is unable to extend his or her wrist


Brachial Plexus Injuries

Posterior Cord Injury

The posterior cord of the brachial plexus (which includes the axillary and radial nerves) is commonly injured in the axilla.

One cause is improper use of crutches, a condition called crutch palsy.

Similarly, the posterior cord can be compressed if a person drapes the upper limb over the back of a chair for an extended period of time


Brachial Plexus Injuries

Median Nerve Injury

The median nerve may be impinged on or compressed as a result of carpal tunnel syndrome because of the close confines of this narrow passage.

Additionally, the nerve may be injured by any deep laceration of the wrist.

Median nerve injury often results in paralysis of the thenar group of muscles.

The classic sign of median nerve injury is the “ape hand” deformity, which develops over time as the thenareminence wastes away until the hand eventually resembles that of an ape


Brachial Plexus Injuries

Ulnar Nerve Injury

The ulnar nerve may be injured by fractures or dislocations of the elbow because of this nerve’s close proximity to the medial epicondyle of the humerus.

When you “hit your funny bone,” you have actually hit your ulnar nerve.

Most of the intrinsic hand muscles are paralyzed (including the interossei muscles, the hypothenar muscles, the adductor pollicis, and the medial two lumbricals), so the person is unable to adduct or abduct the fingers


Brachial Plexus Injuries

Superior Trunk Injury

The superior trunk of the brachial plexus can be injured by excessive separation of the neck and shoulder, as when a person riding a motorcycle is flipped from the bike and lands on the side of the head.

A superior trunk injury affects the C5 and C6 anterior rami, so any brachial plexus branch that has these nerves is also affected to some degree.


Brachial Plexus Injuries

Inferior Trunk Injury

inferior trunk of the brachial plexus can be injured if the arm is excessively abducted, as when a neonate’s arm is pulled too hard during delivery.

Inferior trunk injuries also may happen when grasping something above the head to break a fall—for example, grabbing a branch to keep from falling out of a tree.

An inferior trunk injury involves the C8 and T1 anterior rami, so any brachial plexus branch that is formed from these nerves (such as the ulnar nerve) also is affected to some degree.


Sarcral Plexus Nerve Injuries

Some branches of the sacral plexus are readily subject to injury.

For example,a poorly placed gluteal intramuscular injection can injure the superior or inferior gluteal nerves, and in some cases even the sciatic nerve

Additionally, a herniated intervertebral disc may impinge on the nerve branches that form the sciatic nerve

Injury to the sciatic nerve produces a condition known as sciatica which is characterized by extreme pain down the posterior thigh and leg

The common fibular nerve is especially prone to injury due to fracture of the neck of the fibula or compression from a leg cast that is too tight. Compression of the nerve compromises it and its branches (superficial fibular, deep fibular), paralyzing the anterior and lateral leg muscles and leaving the person unable to dorsiflex and evert

the foot.



inflammation of the pericardium typically caused by viruses, bacteria, or fungi.

Whatever the cause, the pericardium is inflamed, which causes an increase in capillary permeability. Thus the capillaries become leaky resulting in fluid accumulation in the pericardial cavity

At this point, the potential space of the pericardial cavity becomes real space as it fills with fluid and pus


Heart Sounds 

By using a stethoscope, a physician can sidcern four normal heart sounds with each contractions

The two familiar sounds referred to as "lubb-dupp" and two minor sounds

the lubb signifies the closing of the AV valves, while the dupp signifies the closing of the semilunar valves

the minor songs are caused by contraction of the atria and flow of blood into the ventricles



Heart Murmur

abnormal heart sounds, first indication of heart problems

may be heard before, during, or after normal heart sounds

usually the result of turbulence of the blood as it passes through the heart and may be caused by vulvar leakage, decreased valve flexibility or misshapen valve


Teenage athletes and sudden cardiac death

deaths were apparently caused by underlying, previously undetected cardiovascular disease. 

Autopsies revealed that most deaths were due to congenital heart defects and coronary artery anomalies, which lead to sudden death

'Cardiomegaly" an increase in the thickness of the heart muscle wall or an obvious increase or enlargement in heart size due to stress applied to the heart


Cardiac Arrhythmia


any abnormaility in the rate, regularity, or sequence of the cardiac cylce

also called dysrhythmia


Cardiac Arrhythmia

Atrial flutter

occurs when the atria attemt to beat at a rate of 200-400 times per minute

as a consequence, literally bombard the AV node with muschle impulses

this condition may persist for years and frequently degenerates into atrial fibrillation


Cardiac Arrhythmia

Atrial fibrillation

differs from atrial flutter in that the muscle impulses are significantly more chaotic leading to irregular heart rate

the ventricles respond by increasing and decreasing contraction activities, which may lead to serious disturbances in the cardiac rythm


Cardiac Arrhythmia

Premature ventricular contractions

often result from stress, stimulants such as caffeine or sleep deprivation

occur either singly or in rapid bursts due to abnormal impulses initiated within the AV node or the ventricular conduction system

all of us experience occasional PVC, most go unnoticed

skipping a beat and then jumping in the chest


Cardiac Arrhythmia

Ventricular fibrillation

a rapid repetitious movement of the ventricualr muscle that replaces normal contraction

life threatening condition caused by scattered impulses originating at different times and places throughout the entire myocardium


Cardiac arrest

the cessation of cardiac activity

fibrillation almost certainly results in death unless the normal rhythmic contractions of the heart are promptly restored