Monthly Archives: August 2011

Lecture 25 – Humerus, Radius, and Ulna


Thank you all for reading the last lecture.  The numbers were dropping, and by simply asking everyone to remain with us, the numbers on the site rose even higher than before the drop off last week.  I know that time is valuable and I appreciate you for sharing a portion of your time with me.  In today’s world, everybody is bombarding us with messages.  I would not insist if you did not have a ‘body’.  So, since we all have bodies, none of us are exempt from knowing the basics and some advanced information.

As we delve further in the survey of our bodies, I will list guides to assist you in locating information as you need it.  In an effort to save time, I will recapitulate the topics we have studied so far.  Whenever you need to know a certain piece of information, you can refer to this guide.  If you like, I can provide a test for you to determine how much you have retained about your own anatomy.  Send a note to dr.danna.mckellar@gmail.com if you would like a copy of an anatomy test.

Index of Lectures and Labs

Lecture 1 Body Basics

Lecture 2 Common Anatomic Derivatives

Lecture 3 More Common Anatomic Derivatives

Lecture 4 Anatomic Derivatives

Lecture 5 Anatomic Derivatives

Lecture 6 Anatomic Derivatives

Lecture 7 Anatomic Derivatives

Lecture 8 Anatomic Derivatives

Lecture 9 Anatomic Derivatives

Lecture 10 Final Set of Anatomic Derivatives

Lecture 11 Bone Cells

Human Dissection Techniques – Advanced Anatomy Lab               

Lecture 12 Part 1 – The Power of Review

Bones – Axial and Appendicular Skeletons

Lecture 12 Part 2 – The Power of Review

Lecture 13 Skeletal System – Facial Bones

Lecture 14 Skeletal System – Nasal Bones, Hard Palate (Continued)

Human Dissection Techniques – Advanced Anatomy Lab #2

Lecture 15 Random Historical Facts in Medicine

Lecture 16 Survey of Bones (Continued)

Lecture 17 Review of Scientific Notation

Lecture 18 More Tips on Significant Digits

Lecture 19 Review of Conversion Factors

Lecture 20 Temperature Conversions

Lecture 21 Bone Density

Lecture 22 The Vertebral Column – Atlas and Adontoid Process

Lecture 23 The Thoracic Cavity

Lecture 24 The Vertebral Column

Lecture 25 Contains the index of the first 25 lectures; Details about humerus, radius, and ulna

On the anterior portion of the scapula, the corocoid process protrudes superiorly.  The short head of the biceps originate here.

Upper Extremity – Humerus

It has a head, which is divided by the anatomic neck.  The anatomic neck divides the head into the greater and lesser tubercles.  Immediately inferior to the head is the surgical neck of this bone, followed by the shaft.

On the distal end of the humerus, we have the lateral and medial epicondyles.  Tennis elbow is common at this site, and is simply inflammation of muscle on the lateral epicondyle.

Forearm – Radius is lateral

It also has a head.  The radial tuberosity is just below it.  The biceps insert here.

The ulna is medial.  Anteriorly, you can see the semi-lunar notch.  (Half-moon notch)  Proximally, we have the olecranon process.  (Bend your elbow and feel the point.

Distally, we have the styloid process for the wrist bones, or carpal bones.  (Silly Hint: Carpals can carry things!)  There are two rows, with each having four bones.  We have five metacarpals.  (Carpus)  The heads of the metacarpals are commonly called “knuckles”.  We have three phalanges in the fingers and two phalanges in the thumbs.  Do well with this information.

 

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Lecture 24 – The Vertebral Column


We have discussed the hyoid bone before.  It is unique in that is has no bony attachments and is only connected by muscles and ligaments.  It is a u-shaped bone in the anterior portion of the neck.  It is inferior to the mandible and superior to the larynx.  Some people may casually call it the Adam’s apple.

The vertebral column has 33 bones:

7          cervical (neck)

12        thoracic

5          lumbar

5          sacral – immovable

4          coccygeal – immovable  (The sacrum and coccyx are fused.)

From the posterior angle, the spine looks like a column, while laterally it looks like a curve.  From superior to inferior, the curves are as follows:

Cervical curve

Thoracic curve

Lumbar curve

Sacral curve (also called the pelvic curve)

Coccygeal curve

Thoracic vertebrae have processes called ribs.  Thoracic vertebrae also have large spines, which are longer than the adjacent vertebra.  The lumbar vertebrae have the largest bodies because they are weight-bearing.

During a laminectomy, a surgeon will cut through the lamina to perform a tumor.  The thoracic area is a common site for spinal tumors.

C1 – 1st cervical vertebra – also called the atlas.  (The globe holds the world, which is round.  Keep it light-hearted with a silly hint!)  Likewise, the altas holds the skull.  Atlas articulates with the occipital bone and C2.  The occipital bone is immediately superior to the atlas.  The 1st cervical vertebra is a just a ring with no body.  C2 looks slightly different because it has a tooth-like process.  (Adontoid process)  The body of the first is fused to the body of the second, and fits like a puzzle.  C1 and C2’s fusion allows us to turn our heads laterally.

Intervertebral discs or just ‘discs’, as commonly called, are between the vertebrae to cushion them.  The shape of a disc is similar to a donut.  They are composed of rings of fibrocartilage.  The exterior is called annulus fibrosis, and the interior is called nucleus pulposis.  The nucleus pulposis is a soft, gelatinous center.  As a kid, I used to think that a slipped disc actually slipped out of place, creating a bone on bone situation.  In reality, the nucleus of the disc is leaking.  It involves a lot more than the implication that the whole disc slipped out of place.  This condition is exceedingly painful because many nerves are involved.  With degenerative disc disease, the discs take turns slipping.

Now, brace yourself for some really silly business!  I insist on drawing and writing pieces of information the old-fashioned way.  Over the next few lectures, I will upload some crude drawings from my many years of notes.  Believe it or not, these drawings still help me to remember the most minute details.  I look forward to providing you with a great laugh.  Do well with this information.  njoy

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Lecture 23 – Thoracic Cavity


Do remember my earlier lecture about anatomy being for everyone?  Do not ignore these lectures because you are not a nursing student or a medical student.  If you are a breathing being you need to know about your chest cavity.  Remember, an informed patient is a better patient.  One of my goals is to educate the public about our bodies.  You anatomy will be with you, so do not ignore these great lessons.  We all like to get something for free, and these lessons are free.  I love to make complex medical topics simpler.  I see many people in the hospital who do not know simple medical terms and are totally confused when family members have medical problems.  Let’s break the cycle of ignorance by learning our bodies.  Now that we are into the 23rd lecture, the numbers are dropping.  NOW is when you need to read the information.  I know that we are all very busy, but this is important.  I read the prayer requests on Facebook and they are full of stories about people with illnesses.  Read these lectures in more than one session if needed.  Too many times we fill up on unnecessary information and skip the wholesome stuff!  If there is something that you would like to have clarified, just say so.  Just like the telephone banking voice, you can say, “Repeat that!” or “That does not make sense to me.”  I will gladly find another way to make the point.

The sternum is the proper name for the breast bone.  It is a flat bone.  (I previously gave you a way to categorize all bones by the type of bone.  The sternum has costal cartilages which attach the ribs.

Thoracic Cavity –

Sternum – Major parts – manubrium, body, and xiphoid process

Costal cartilages

Ribs

Thoracic vertebrae

The sterna angle is the articular point between the manubrium and the body.  It is the most commonly fractured area of the sternum.  Beware parents of little league football players!

There are 12 ribs –

7 true ribs – Numbers 1 through 7, costal cartilages attach directly to the sternum.

5 False ribs – Do not attach directly to the sternum.  (3 attach directly to the superior costal cartilage and 2 floating do not attach anteriorly at all.)  Review anatomic directions if necessary.

11 and 12 are floating ribs-

10 attaches to 9

9 attaches to 8

8 attaches to 7

All ribs have posterior attachments to the thoracic vertebrae.  Do you remember the appendicular skeleton?  The whole upper extremity only articulates (meets) with the axial skeleton at the sternoclavicular joint.  It is all held up by muscles.  The clavicle articulates with the sternum at the manubrium.  (Clavicle – anterior; scapula – posterior)

The scapula is thin and lies over ribs 2 through 7 posteriorly.  It is triangular shaped.  The acromion process divides the scapula into the supraspinous fossa and the infraspinous fossa.  The ‘spine’ comes across and expands into the acromion process.  You cannot see this process because it lies underneath the scapula and clavicle.  It is medial to the head of the humerus.  The glenoid cavity lies just inferior to it.  This is where the head of the humerus articulates.

Let’s digest these principles before moving on.  Do well with this information.  You just get one body.  Take care of it by first getting to know it.

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Lecture 22 – The Vertebral Column (Atlas and Adontoid Process)


We have discussed the hyoid bone before.  It is unique in that is has no bony attachments and is only connected by muscles and ligaments.  It is a u-shaped bone in the anterior portion of the neck.  It is inferior to the mandible and superior to the larynx.  Some people may casually call it the Adam’s apple.

The vertebral column has 33 bones:

7          cervical (neck)

12        thoracic

5          lumbar

5          sacral – immovable

4          coccygeal – immovable  (The sacrum and coccyx are fused.)

From the posterior angle, the spine looks like a column, while laterally it looks like a curve.  From superior to inferior, the curves are as follows:

Cervical curve

Thoracic curve

Lumbar curve

Sacral curve (also called the pelvic curve)

Coccygeal curve

Thoracic vertebrae have processes called ribs.  Thoracic vertebrae also have large spines, which are longer than the adjacent vertebra.  The lumbar vertebrae have the largest bodies because they are weight-bearing.

During a laminectomy, a surgeon will cut through the lamina to perform a tumor.  The thoracic area is a common site for spinal tumors.

C1 – 1st cervical vertebra – also called the atlas.  (The globe holds the world, which is round.  Keep it light-hearted with a silly hint!)  Likewise, the altas holds the skull.  Atlas articulates with the occipital bone and C2.  The occipital bone is immediately superior to the atlas.  The 1st cervical vertebra is a just a ring with no body.  C2 looks slightly different because it has a tooth-like process.  (Adontoid process)  The body of the first is fused to the body of the second, and fits like a puzzle.  C1 and C2’s fusion allows us to turn our heads laterally.

Intervertebral discs or just ‘discs’, as commonly called, are between the vertebrae to cushion them.  The shape of a disc is similar to a donut.  They are composed of rings of fibrocartilage.  The exterior is called annulus fibrosis, and the interior is called nucleus pulposis.  The nucleus pulposis is a soft, gelatinous center.  As a kid, I used to think that a slipped disc actually slipped out of place, creating a bone on bone situation.  In reality, the nucleus of the disc is leaking.  It involves a lot more than the implication that the whole disc slipped out of place.  This condition is exceedingly painful because many nerves are involved.  With degenerative disc disease, the discs take turns slipping.

Now, brace yourself for some really silly business!  I insist on drawing and writing pieces of information the old-fashioned way.  In the next few lectures, I will upload some crude drawings from my many years of notes.  Believe it or not, these drawings still help me to remember the most minute details.  I am excited about providing you with a great laugh!

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Lecture 21 – Bone Density


What is a Bone Density Test?  What do the numbers mean?

A bone mineral density test (BMD) is the best way to determine your bone health.  The test can identify osteoporosis, measure your response to osteoporosis treatment, and determine your risk for broken bones.  The most widely used BMD test is a dual-energy x-ray absorptiometry, or DXA test.  It is painless and is similar to having an x-ray.  The test measures bone density at your hip and spine.

A DXA test measures your bone mineral density and compares it to that of your established norm to give you a score.  Although no bone density is 100 % accurate, the DXA test is the single most important predictor of whether a person will have a fracture in the future.

Your DXA test results are compared to the ideal or peak mineral density of a 30-year-old adult, and you are given a T-score.  A score of 0 means your BMD is equal to the norm for a healthy young adult.  Differences between your BMD and that of the healthy young adult norm are measured in units called standard deviations.  (SD’s)  The more standard deviations below zero, indicated as negative numbers, the lower the BMD and the higher the risk of fracture.

A T-score between +1 and -1 is considered normal or healthy.  A T-score between -1 and -2.5 indicates that you have low bone mass, although not low enough to be diagnosed with osteoporosis.  A T-score of -2.5 or lower indicates that you have osteoporosis.  In conclusion, the greater the number the more severe the osteoporosis.

World Health Organization Standards

Normal

Bone density is within 1 SD (+1 or −1) of the young adult mean.

Low bone mass

Bone density is between 1 and 2.5 SD below the young adult mean
(−1 to −2.5 SD).

Osteoporosis

Bone density is 2.5 SD or more below the young adult mean
(−2.5 SD or lower).

Severe (established) osteoporosis

Bone density is more than 2.5 SD below the young adult mean, and there have been one or more osteoporotic fractures.

 

Bone mineral density is sometimes to that of a typical individual whose age is matched to yours.  The comparison gives you a Z-score.  Because a low BMD level is common among older adults, comparisons with the BMD of a typical individual whose age is matched to yours can be misleading.  The diagnosis of osteoporosis or low bone mass is based on your T-score.  However, a Z-score can be useful for determining whether an underlying disease or condition is causing bone loss.

Low Bone Mass Versus Osteoporosis

The information provided by a BMD can help your doctor decide which prevention or treatment options are right for you.  If you have low bone mass that is not low enough to be diagnosed as osteoporosis, this is referred as osteopenia.  Low bone mass can be caused by many factors such as:

heredity,

the development of less-than-optimal peak bone mass in your youth,

a medical condition or medication to treat such a condition that negatively affects bone, or

abnormally accelerated bone loss.

Everyone who has low bone mass will not develop osteoporosis, but everyone with low bone mass is at a higher risk for the disease and the resulting fractures.

A person with low bone mass can take steps to slow down bone loss and prevent osteoporosis in the future.  Physicians will encourage healthy habits, such as eating foods that are rich in calcium and vitamin D.  Weight-bearing exercises, such as walking, jogging, or dancing will help increase strength.  In some cases doctors may recommend medication to prevent osteoporosis.  These medications may slow or reverse bone loss.  Future BMD tests will be necessary to check the progress.

The U.S. Preventative Services Task recommends that women age 65 and older should be screened routinely for osteoporosis.  This task force also recommends that routine screening begin at age 60 for women who are at increased risk for osteoporotic fractures.  A panel convened by the National Institutes of Health in 2000 recommended that bone density testing be considered in people taking glucocorticoids medications for two months or more.  This also holds for people with other conditions that place them at high risk for an osteoporosis-related fracture.

The panel did not find enough scientific evidence upon which to base universal recommendations about when all men and women should receive a BMD test.  Each person is analyzed on a case by case basis.

For more information you may contact the Centers for Disease Control and Prevention’s National Center for Health Statistics

3311 Toledo Road

Hyattsville, MD 20782

800-232-4636

 

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Lecture 20 – Temperature Conversions


The measure of intensity of heat of a substance is called temperature.  A thermometer measures temperature.  Temperature is measured in three different units: Fahrenheit (degrees F) in the United States, Celsius (degrees C in science and everywhere else on the planet), and Kelvin to measure absolute temperature.  Below you can see how the temperature systems compare.

Fahrenheit                                Celsius                                     Kelvin

212                                          100                                          373

176                                          80                                            353

140                                          60                                            333

104                                          40                                            313

68                                            20                                            293

32                                            0                                              273

-4                                             -20                                           253

-40                                           -40                                           233

A comparison of the three temperature scales shows their differences clearly.

 

The conversion factor for Celsius to Fahrenheit is:

t(F) = [t(C)  x 1.8 F/1 degree C] + 32 = [t(C) x 1.8] + 32

The conversion factor for Fahrenheit to Celsius is (hint: subtract 32 so that both numbers start at the same temperature!  This is so easy!

t(C) = [t(F) – 32 degrees F] x 1 degree C/1.8 degrees F = [t(F) – 32]/1.8

or a simpler way to say it is:

degrees C = 5/9 (degrees F – 32)

Tip:  If you believe in buying stock, buy stock in 3×5 cards.  I have very nice files for my 3 x 5 cards.  The cards are neatly indexed by subject matter and banded together.  I am quite patient when need to wait in a line because I always have subject matter in my handbag to review.  If you are the ‘brightest bulb on the Christmas tree’, that is great.  If not, just be the most disciplined and hardest working.

Let’s work a few examples before we part company.

Example 1:

A summer day in Hawaii might be 21 degrees Celsius.  What is that in Fahrenheit?

21 degrees C = 5/9 (degrees F -32)

21+ 32 = 5/9 degrees F

53 x 9 = 5 degrees F

477/5 = 70 degrees F

To obtain absolute zero (the lowest temperature possible), the Kelvin scale is used, where the lowest temperature is zero.  A Kelvin is an SI temperature unit.    The heat energy is zero.

Example 2:

To see how temperature conversion works, let’s convert normal body temperature, 98/6 degrees F, to Celsius.

Degrees C = 5/9 (degrees F – 32)

Degrees C = 5/9 (98.6 degrees F – 32)

=5/9 (66.6) = 37.0 degrees C

Degrees C can be converted to K by adding 273 to the Celsius temperature.

Example 3:

K = degrees C + 273

K = 37 degrees C + 273 = 310 K

There are reactions where heat can play an important role in determining the character of the final compound.  Do well with this information.  Next lecture we get back to bone density and bone structure.

 

 

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Lecture 19 Review of Conversion Factors


Conversion factors make use of the relationship between two units or quantities expressed in the fractional form.  The factor-label method , also called dimensional analysis, changes one unit to another by using conversion factors.

Conversion factors are helpful when you need to compare two measurements that are not in the same units.  If given a measurement in meters and the map only reads in kilometers, you have a small problem.  You could guess or use the conversion factor of 1 km/10m3.  Look at the conversion below.

0.392m x 1 km/10m3 = 0.392 x 103 km

= 3.92 x 10-4

If you have centimeters and need to know the answer in inches, then use the conversion factor 1 inch/2.54 cm.  (Once again, I need to reiterate that certain scientific data just needs to be committed to memory.)  This particular conversion factor has been as available to me as my name, since my sophomore year of college.  Do you remember the article I wrote about how silly the measuring system is in America?  I just buckled down with flashcards and memorized several conversion factors.  I needed to make my life easier.  Face the facts; If you plan a career in the health sciences, there is no escaping just knowing the information.  Forget learning what you need to know for the test.  If you know all of the information about your subject matter, the test becomes irrelevant.  You will conquer the test!

Your flashcards should look like this.

1 inch = 2.54 cm

You will be amazed at how simply looking at this data will plant it into your memory.  Remember the songs that we hate, but know all of the words because the radio station plays them so much.  I have teenagers.  Need I say more?  There are many songs that I wish I could forget the lyrics.  Repetition works.  I know we are in the day of high technology.  I create marvelous Power Point presentations, but still receive greater command of any information that I physically write.

914 cm x 1 inch/2.54 cm = 360 inches (since 914 has 3 significant digits)

Converting measurements can also be a two-step process.

mg à g–à kg

liters-àquarts-à gallons

miles per hour -à liters per minute

Look at the two step conversions below.

 

Example 1

2461 mg-à ? kg

mg à g–à kg

1mg = 10-3 g; 1 kg = 103 g (conversion factors) You must have these to begin.

Even if a professor allows you to have this information available during a test, it would look foolish for a young intern to need to peek at a conversion factor to determine a medication dosage.  You will administer many doses of medications in your career.  Make it easy and re-learn this information if you are rusty.  Professionals are not born, but rather created.  These days we have to continue to reinvent ourselves.

2461 mg x 10-3 g/mg x 1 kg/103 g

= 2461 x 10-6 kg = 2.461 x 10-3 kg

 

Example 2

8.47 liters à ? gallons

liters-àquarts-à gallons

1.06 qt/liters; 1 gal.4 qt (conversion factors)

(I still chuckle about running away from home in the third grade because I thought feet, cups, drops, and pinches were ridiculous!  Learn to enjoy the more organized way to measure, by units of ten.)

8.47 liters x 1.06 qt/liter x 1 gal/4 qt = 2.24 gallons

Example 3

70 miles per hour àmeters/minute

Miles/hour à km/hour; à m/hrà m/min

1.61 km/mi; 103 m/km x 1 hr/60 min (conversion factors)

70 mi/hr x 1.61 km/mi x 103 m.km x 1 hr/60 min

=1878.33 m/min = 1.9 x 103 m/min

SI derived units are obtained by combining SI base units.

Habits can be difficult to break.  If you travel internationally you will see just how rusty you can be when every distance is measure in meters and kilometers instead of miles.  We will review temperatures during the next lecture, quickly complete our survey of bones, and spend an immense amount of time on blood.  You will do well with this highly technical information after this hefty review.  I hope have not been too bored!  Have a great day.

 

 

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