The Female Parts

Ovaries

The ovaries are the location of the female gametes (oocytes) and where they develop.  They are located beneath the external iliac artery and in front of the internal iliac artery and ureter.  These oocytes also produce reproductive hormones as apart of the endocrine gland.  The ovaries are suspended by a short peritoneal fold known as the mesovarium, and not by the fallopian tubes as some believe.  The ovaries lie within the peritoneal cavity on either side of the uterus and attached to it via the ovarian ligament.  With its location, the ovary is the only organ in the human body that is invaginated into the peritoneum.  The hormones FSH and LH stimulate the growth of 15-20 eggs in the ovaries each in its own shell.  After which, estrogen levels rise and turn off the FSH to stop the number of follicles that mature, and in each of these ovaries there will be several follicles but one will dominate which suppresses all others.  The LH will then increase in production causing the follicle to release the egg.  The fimbriae of the fallopian tubes capture the egg after its release and hold it in the fallopian tube.  The follicle develops into the corpus luteum, and secretes progesterone, which preps the uterus for fertilization.  If the egg is not fertilized it will be shedded and if it is fertilized it will travel through the fallopian tube into the uterus.    

Vagina

The vagina is the gate to the uterus.  It is a fibromuscular tubular tract where sexual intercourse occurs, and is the connection of the vulva to the cervix.  The vagina is 2.5-3in across and about 3.5 inches long.  During sex, the vagina expands in size as well as during childbirth.  Rugae are contained on the outer third of the vagina.  These rugae allow for the expansion of the vagina, and are transverse epithelial ridges.  The vagina also produces its own lubrication from the Bartholin’s glands.  In addition to producing lubrication for intercourse, the moisture also provides a housing environment for sperm.  The alkaline environment houses the sperm until implantation occurs in the egg.  At the opening of the vagina, is a membrane of tissue known as the hymen.  It is often thought to be a determinate of whether or not a female has had sexual relations; however, this membrane can break during pelvic examinations, injury or sports. 

Pap smears are a common examination of the cells of the vagina.  A spatula is inserted into the vagina up to the external os of the uterus.  The spatula is rotated to scape the cellular material of the vagina from the mucosa level.  Then a cytobrush is inserted into the cervical canal and rotated to gather cellular material of the supravaginal cervical mucosa.  They are placed on glass slides and examined.  This process is important in the detection of cervical cancer. 

Fallopian tubes

The purpose of the fallopian tubes is too discharge the oocyte during childbearing years.  In addition to this, the fallopian tubes are the site of fertilization.  The tubes extend laterally and open into the peritoneal cavity near the ovaries.  The tubes are approximately 10 cm long and lie in the mesoalpinx forming the free anterosuperior edges of the broad ligaments.  In illustrations, the tubes are extended symmetrically posterolaterally to the later pelvic walls.  In reality, the tubes are commonly asymmetrically arranged with one or the other lying posterior or superior to the uterus.  The fallopian tubes divide into the following four parts:  the infundibulum, the ampulla, the isthmus and the uterine part.  The infundibulum is where the fimbriae are located that hold onto the egg. In the ampulla, fertilization usually occurs here.  The isthmus has a very thick wall and is where the tube enters the uterine horn.  Finally, you have the uterine part where that enters the uterus. 

Ectopic tubal pregnancy

Some woman may have a collection of pus in there uterine tubes and the tubes may be partly occluded by adhesions.  In this condition, the blastocyst may not be able to move down the tube even though the sperm have.  When this occurs, the blastocyst may implant in the mucosa of the uterine tubes.  If not caught early, the tube can rupture and cause severe hemorrhaging.  

Does anyone need to make?

Kidneys

One of the major functions of the kidneys is filtration.  The kidneys filter and remove excess water, salts, wastes and restore nutrients into the body.  The portal into the kidney is known as renal sinus, which is located within the cleft portion of the kidney known as the renal hilum.  The blood supply for the kidneys is the renal vein and artery that lie anterior to the renal pelvis. The perinephric fat is a fat that encapsulates the kidneys to protect them from injury.  Internally, the major structural unit of the kidney is the nephron.  The nephrons regulate the filtration and removal of the materials listed above.  There are two types of nephrons, the cortical nephrons and the juxtamedullary nephrons.  These two types are named based on there location.  Cortical nephrons are located in the superficial renal cortex and the juxtamedullary nephrons are located in the renal medulla.  Each nephron contains the internal filtering component, the renal corpuscle, which filters out the large solutes from the blood.  The renal tubule is responsible for reabsorption of the water.  The renal corpuscle is contains the glomerulus and the Bowman’s capsule, and is the starting point of the nephron.  The glomerulus is an intricate part of the kidney filtration system because it is a tuft of capillaries that receives the blood supply needing to be filtered.  The glomerulus also provides the pressure to push water and solutes out and into a space where they enter the Bowman’s capsule.  Podocytes, located in the visceral inner layer of the Bowman’s capsule, receives the fluids that have been filtered by the glomerulus, and this fluid is further processed to form urine.  After passing through the renal tubule, the filtrate flows into the collecting duct system.  The following are components of the renal tubule:  Proximal convoluted tubule, Loop of Henle (Descending and Ascending), Thin ascending limb of loop of Henle, Thick ascending limb of loop of Henle, Distal convoluted tubule.  The collecting duct is generally impermeable to water unless ADH (antidiuretic hormone) is present and as much as three-fourths of the water in the fluid can be reabsorbed as it leaves the collecting ducts.  Urine leaves the medullary collecting ducts in the following order: renal papillae, renal calyces, renal pelvis, and then arrives into the urinary bladder. 

FSGS

Focal Segmented Glomerulosclerosis is an uncommon nephrotic disease occurring in adolescents.  It is a complete failure of the kidneys.  It occurs when scarring occurs on some of the glomeruli in the kidney.  The appearance of the glomeruli is more of crystallization.  This causes kidney failure within the patient, and the patient must receive dialysis or a kidney transplant to avoid death.  The causes of FSGS can be genetic, HIV, and the use of heroin to name a few.  There is still much to learn about this disease, as there is no cure for it.  Some individuals can receive a kidney transplant and be free of it, however, some individuals, like my brother, have recurrent FSGS, where even after a kidney transplant the disease returns.  We are hoping the continued studies that a cure can be found for recurrent FSGS.  My brother is awaiting a kidney transplant, and they do have certain medications that can inhibit the return of the disease, but there is always a possibility of it returning. 

FSGS Kidney

Normal Kidney

Suprarenal glands

The suprarenal glands are located on the superior portion of the kidney and connected to the diaphragm through connective tissue.  Like the kidneys, each gland of the suprarenal glands contain a hilum where the veins and lymphatic’s exit.  Each gland contains two major parts: the suprarenal medulla and suprarenal cortex.  The function of the cortex is to secrete corticosteroids and androgens.  The adrenal glands act as a warning system to the kidneys by releasing these hormones in response to body stress.  The hormones released will cause the kidney to retain sodium and water in response to whatever the body is experiencing.  The medulla is portion of the adrenal gland is important for our flight or fight response.  The cells in the medulla known as chromaffin cells) secrete a substance known as catecholamine’s (which is mostly epinephrine) into the bloodstream from the presynaptic neuron signals.  This secretion activates our adrenaline and noradrenaline. 

Cushing’s Syndrome

Cushing’s Syndrome is a disease in the adrenal glands where too much of the corticosteroids are produced.  When over production of corticotrophin occurs, the adrenal gland is stimulated to continue to produce corticosteroids.  This production of corticotrophin occurs in the pituitary gland.  This is just one possible cause of Cushing’s syndrome.  Another cause could be excessive cortisol levels in the blood due to a tumor in the pituitary gland, adrenal gland, or elsewhere in the body.  If the patient has a pituitary adenoma causing the Cushing’s, then one option is transphenoidal adenomectomy, where the surgeon goes into the pituitary gland.  Other treatment options such as radiotherapy are used as well.  Common symptoms of Cushing’s Syndrome are weight gain in the back, face, and collar bone, easy bruising, and loss of muscles to name a few.

Urinary Bladder

The urinary bladder is an organ that collects urine after it has been filtered from the kidneys.  The urinary bladder resides on the pelvic floor and the urinary bladder is composed of transitional epithelium.  Urine enters the bladder via ureters and exits via the urethra.  For urine to exit the bladder, there is an involuntary and voluntary controlled sphincter to regulate exiting.  The detrusor muscle is a layer of smooth muscle located in the wall of the urinary bladder.  As the bladder fills with urine, the rugae begin to stretch and the wall begins to thin.  The detrusor muscle senses this and through parasympathetic signaling alerts the need to urinate.  The adult bladder usually holds 300-350 mL of urine but can hold up to 500-700 mL, however, this large amount can cause injury to the bladder.  At 25% fullness, the bladder alerts the need to void.  If the bladder ever reached 100% fullness, the voluntary sphincter in the bladder would deactivate, and voiding would automatically begin.

Bladder Rupture

If injuries occur to the anterior abdominal wall, rupturing can occur to the bladder.  An injury example would be the fracture of the pelvis, which would take away the support to the urinary bladder that the pelvic floor provides.  When a rupture occurs, the urine can escape either extraperitoneally or intraperitoneally.  The determination of this is whether the tear occurs superior part of the bladder or the posterior part of the bladder.   

Stomach Knowledge

Parts of the Stomach

The stomach is made up of four parts, the cardial orifice, the Fundus, Body, and pyloric part.  The cardial orifice is on the superior portion of the stomach.  It is the connection point to the esophagus.  The fundus lies also on the superior part of the stomach, and is a dilated portion that also lies to the left of the dome of the diaphragm.  The cardial notch lies in between the esophagus and the fundus.  The body of the stomach is the major portion of the stomach where contents within the stomach reside.  Finally the pyloric part of the stomach has several different divisions.  The pyloric antrum (wider portion of the pyloric part), leads into the pyloric canal.  Leading from the pyloric canal, is the pylorus, which is the sphincter region of smooth muscle within the stomach.  From here the contents of the stomach (known as chyme), discharge out through the pyloric orifice. 

Congenital Hypertrophic Pyloric Stenosis

This particular disease effects 1 of every 750 female infants and 1 of every 150 male infants every year.  It is a thickening of the smooth muscle in the pylorus.  The cause is not yet known as to why this happens, but genetics play a big role in it.  Monozygotic twins are at a high risk for it.  The disease causes the pyloric canal and orifice to become narrow thus not allowing chyme to move out of the stomach. 

Blood Vessels of the Stomach

The stomach is very rich in blood vessels.  The arterial supply of the stomach comes from the celiac trunk.  The right and left gastric arteries run along the lesser curvature, and the right and left gastro-omental arteries run along the greater curvature.  The fundus and upper body of the stomach receives its blood from the short and posterior gastric arteries.  These groups of arteries supply blood to the stomach through anastomoses.  The veins of the stomach are more jumbled up in their organization.  Unlike the arteries, where everything is right and left with the same fitting name, the veins of the stomach are mixed up in how they drain blood from the stomach.  The short gastric, and left gastro-omental veins will drain into the splenic vein that flows into the superior mesenteric and then into the hepatic portal vein.  The right gastro-omental vein empties just into the superior mesenteric vein.  The right and left gastric veins do follow each other into the hepatic portal vein. 

Gastrorectomy

A partial gastrorectomy is a procedure generally performed to remove a carcinoma from a region of the stomach.  Due to anastomoses of the arteries surrounding the stomach, it is possible to remove a part of the stomach without effecting the circulation.  An example is when the pyloric antrum is removed.  The omental branches of the gastro-omental artery are ligated.  However, anastomoses to other arteries allow blood supply to continue.

Lymph Vessels of the stomach

The gastric lymph vessels flow along the greater and lesser curvatures along with the gastric arteries.  The lymph is drained from the anterior and posterior surfaces of the stomach towards the curvatures of the stomach where the gastric and gastro-omental lymph nodes reside.  The pathway of the superior two thirds of the stomach flow through the right and left gastric vessels into the gastric lymph nodes.  The pancreaticosplenic lymph nodes receive lymph drainage from the fundus and superior part of the body of the stomach.  The pyloric lymph nodes handle the right 2/3 of the inferior portion of the stomach and the right gastro-omental vessel does the draining.  The remaining 1/3 of the inferior portion of the stomach drains into the pancreaticoduodenal lymph nodes via the short gastric and splenic vessels. 

Lymph node resectioning

Lymph node removal is also important during a carcinoma situation.  As cancer spreads if any cells are left behind, it is important to remove those nodes that are infected.  The pyloric lymph nodes are most common as far as being removed.  In addition to them are the gastro-omental lymph nodes.  In more advanced cases, dismantling the celiac lymph nodes becomes necessary.  This is the location for which all lymph vessels drain into from the stomach.  

The Male Anatomy

Ductus Deferens

The ductus deferens are apart of the male genitals.  They are a continuation of the duct of epididymis.  The ductus deferens is the primary components of the spermatic cord and its cordlike structure is due to its thick walls.  The ductus deferens goes through the anterior wall of the abdominal cavity via the inguinal canal.  In addition it runs along the lateral wall of the pelvis and finally retires when it joins the seminal gland and forms the ejaculatory duct.  The ductus deferens are the only structure to come into contact with the peritoneum.  The ductus deferens also cross superior to the ureters where it runs in between the ureter and the peritoneum of the ureteric fold to gain access to the bladder.  The ductus deferens begin by running posterior to the bladder and superior to the seminal gland but then descend to the medial border of the seminal gland and ureter.  This is where the ductus deferentia enlarge and form the ampulla of the ductus deferens.

Male sterilization is a common procedure performed on males to inhibit pregnancy from occurring.  It is a simple out patient procedure, and involves the ligation of the ductus deferens through an incision in the superior portion of the scrotum.  The fluid formulated by the seminal gland, bulbourethral gland, and the prostate will now contain no semen.  Since sperm are no longer ejaculated, they are destroyed in the epididymis and the proximal part of the ductus deferens.

Prostate

The prostate is a walnut shaped gland in the male reproductive organ system.  The matrix of the prostate is 2/3 glandular and 1/3 fibromuscular.  The fibrous capsule of the prostate contains the vascularization part of the gland.  The blood supply of the prostate is the prostatic arteries and these branch off of the internal iliac artery especially the inferior vesicle arteries and the middle rectal arteries.  The venous drainage of the prostate all form together to make the prostatic venous plexus.  Which lies between the fibrous capsule and the prostatic sheath.  The prostate also can be divided into right and left lobes with the separation of these lobes being the isthmus of the prostate.  Each lobe has the following four lobules:  inferoposterior lobule, inferolateral lobule, superomedial lobule, and anteromedial lobule.  The third and fourth lobule actually arises from an embryonic middle lobe.  Some clinicians refer to this section as the central zone.  The prostate also contains prostatic ducts (20-30) and these ducts flow into the prostatic sinuses that reside on each side of the seminal colliculus.  The fluid produced by the prostate accounts for 20% of the milky fluid in semen.  This fluid also has a role in the activation of sperm. 

Prostate cancer is a major cancer that has been at the forefront of research.  It occurs when cancer cells begin to reproduce uncontrollably.  Prostate cancer is generally slow moving but can metastasize to other parts of the body in aggressive cases.  It has been found that genetics and the diets of males can play a part in the formation of prostate cancer.  I have first hand witnessed an aggressive case of prostate cancer in my own cadaver.  His prostate had metastasized into his abdominopelvic cavity, and in his thoracic cavity with large tumors. 

3-D photo of prostate cancer

Innervation of the Male Genital organs

The male genitals are highly innervated throughout the seminal glands, ejaculatory ducts, and prostate.  Presynaptic sympathetic fibers begin at T12-L2 and fibers travel to become part of the lumbar splanchnic nerves, hypogastric plexus and pelvic plexus.  The presynaptic parasympathetic fibers that originate at S2-S3 follow to the pelvic splanchnic nerves, which join the inferior hypogastric and pelvic plexus as well.  The parasympathetic and postsynaptic sympathetic fibers synapse within these plexuses in their journey to the pelvic viscera.  During an orgasm, sympathetic system plays an important role in stimulating the urethral sphincter to inhibit retrograde ejaculation.  In addition, it also causes peristaltic contractions of the ductus deferens, seminal glands, and prostate that provide the vehicle for moving semen out during ejaculation.  The parasympathetic function in the internal male organs is still unclear.  However, it is known that the parasympathetic fibers ultimately form the cavernous nerves that pass to the erectile bodies of the penis are the known component of an erection. 

Pudendal Nerve Entrapment

Pudendal nerve entrapment is not common but occurs when the pudendal nerve has been compressed.  The chronic pain associated with PNE causes urinary incontinence, genital numbness, and fecal incontinence.  It is common in cyclists who sit for long periods of time.  Standing, changing positions, or sitting on a toilet seat, can relieve it.  If pain continues, MRI’s can be useful at diagnosing the issue.  If it is a positional issue when lying or standing, then it can be attributed to a tunneling syndrome.  

Fistulas and lobectomies and splenectomies! OH MY!

Hepatic Portal vein

            The liver has a dual blood supply like that of the lungs.  The hepatic portal vein is like the workhorse of the liver, supplying 70-80 percent of the blood.  The blood that enters the liver contains about 40 percent more oxygen then those in the systemic system.  This is due to the oxygen need of the parenchyma cells in the liver.  20-25 percent of the blood to the liver comes from the hepatic artery, and is first given to non-parenchymal structures first.  The hepatic portal vein is made from the superior mesenteric and splenic veins.  It ascends from the IVC in part of the hepatic portal triad in the heptoduodenal ligament.  The hepatic vein is divided into divisions throughout the lobes of the liver, and is called the right, intermediate and left hepatic veins. 

An interesting fact about the hepatic system is that the right and left hepatic portal veins do not communicate.  This discovery allowed for doctors to perform hepatic lobectomies with little bleeding.  Now using laser surgery, doctors perform hepatic segmentectomies now when a portion of the liver is injured.  The hepatic veins provide guidance to the fissures where the doctors will cut. 

Importance of the Spleen

Before birth, the spleen is a vital organ for making blood.  After birth, the spleen is used to identify red blood cells, and determine whether they need to be destroyed or not.  The spleen also serves as a blood reservoir for the body, and stores red blood cells and platelets.  The spleen contains red pulp and white pulp.  The red pulp is involved in the recognition of the red blood cells and there destruction once they reach the proper age.  The white pulp is responsible for filtering antigens and producing lymphocytes. 

            When blunt trauma occurs to the spleen, it is an emergency situation and must be surgically repaired due to excessive bleeding out.  Either a total or partial splenectomy will be performed.  If a partial is performed, regeneration can occur like that of the liver.  However, if total removal must occur, then other reticuloendothelial organs, like the liver, carry out the functions that the spleen provides.  One major drawback of loosing your spleen is that you are more susceptible to certain bacterial infections. 

Gallbladder

The gallbladder lies on the visceral surface of the liver and is in very intimate contact with the duodenum.  The gall bladder can hold up too 50 ml of bile at one time.  The cystic duct is connected to the neck of the gallbladder and empties into the hepatic duct.  An important part of the gallbladder is the spiral folds at the neck.  These folds allow the cystic duct to remain open.  This allows movement of bile out of the gallbladder into the duodenum when the gallbladder contracts or allows for bile to be moved back into the gallbladder when the sphincter of the bile duct is closed at the distal end.  These spirals fold also aides in sudden dumping of bile when major pressure occurs in the abodominopelvic cavity, like when you sneeze or cough. 

When a gallbladder has been inflamed due to a trapped gallstone, the walls of the gallbladder can begin to break down.  A possible complication that can occur in addition to this problem is the formation of a fistula.  A fistula is a passageway between two endothelial-lined organs that usually are not connected.  In the case of the gallbladder and the duodenum, This newly created passageway would allow the gallstone to move into the duodenum causing a bowel obstruction or impaction in the digestive tract.  Another problem would be the movement of gas from the duodenum into the gallbladder. 

Sources 

of Information:

Clinically Oriented Anatomy Book

http://en.wikipedia.org/wiki/Fistula

A Few More Tasty Tid Bits of Information on the Upper Limbs!

Extensors of the Forearm

The extensor carpi radialis brevis is a short, wide, flattened muscle.  It arises from the humerus and narrows into a long, flat tendon about two-thirds of the way down the arm.  It lies between the extensor carpi radialis longus and the extensor digitorum along the outer surface of the radius.  This muscle extends and radially deviates the hand at the wrist joint.  The extensor carpi radialis longus is a short, flat muscle that arises from the humerus and extends down the arm.  This muscle helps to extend and radially deviate hand at the wrist.  It also helps flex the elbow joint.  The extensor carpi ulnaris is a superficial muscle on the forearm.  It is a narrow, elongated, flattened muscle that extends from the humerus to the dorsal aspect of the fifth metacarpal.   This muscle helps extend the wrist.  The extensor digiti minimi is a small, slender muscle that originates from the humerus and lies between the extensor digitorum and the extensor carpi ulnaris.  At the wrist, the muscle develops a double tendon, which inserts at the extensor expansion of the fifth digit.  The extensor digitorum is a wide, lateral muscle group that extends from the humerus and towards the lower half of the forearm and develops into four tendons that insert into the middle and distal phalanges of the fingers.  It does not insert into the thumb.  This muscle works to extend all the joints of the fingers.  It also extends the wrist.  The extensor indicis is located deep in the forearm, where it originates from the back of the ulna.  At the wrist it develops into a tendon that extends along the back of the hand with the extensor digitorum and inserts in the index finger.  It extends and adducts the index finger.

            A common injury to this muscle group is Elbow Tendinitis (also known as tennis elbow).  This injury occurs from repetitive use of the superficial extensor muscles.  The pain associated with this injury is felt along the lateral epicondyle down the posterior surface of the arm.  With this injury, simple tasks such as opening a door or lifting a book can be painful. 

Proximal end of the humerus

The humerus is the largest bone in the upper limb.  It contains several protrusions and processes.  The anatomical neck of the humerus provides the attachment of the gleno- humeral capsule.  The greater and lesser tubercles are the junction of the head and neck and are the attachment point to several scapulo-humeral muscles.  The interterbicular groove is the separation point of the greater and lesser tubercles and is the protective passageway of the tendon of the biceps brachii. 

Fractures to the proximal end of the humerus are common.  These fractures occur at the neck of the humerus and are common in elderly patients, especially those with osteoporosis.  It is common that the fracture becomes impacted due to a piece of the fractured bone being stuck into the spongy bone.  Due to the fractured area being impacted, the individual can still have stable movement and little pain. 

 

Clavicle

The clavicle is an important connection site between the upper limb and the trunk of the body.  It has two ends, the sternal end and the acromial end.  These ends allow attachment to the sternum and acromion of the scapula, respectively.  The clavicle gives the upper limb the ability to have a free range of motion by keeping it as far away from the trunk as possible.  In addition, it also provides more range of movement for the scapula via the scapulothoracic joint.  It also assists in the elevation of the ribs for inspiration, and provides a protective boundary for nerves that run to the upper limbs. 

            Fracturing the clavicle is one of the most common bone injuries in the body.  In fracturing the clavicle, a domino effect occurs in this region.  With the clavicle fractured, the trapezius can no longer hold up the lateral fragment, causing the upper limb to drop.  However, luckily the strong corococlavicular ligament usually keeps the AC joint from dislocating. 

Information Source:

Clinically Oriented Anatomy

Upper Limb Veins, Nerves, and Lymphatics

Lymphatic Drainage of Upper Limb

The superficial lymphatic vessels exist in the skin, fingers, palm of the hands, and flow up the arm in close proximity with the basillic and cephalic veins.   Some of these vessels enter into the cubital lymph nodes while some continue and terminate at the humeral axillary lymph nodes.  Other nodal locations for superficial vessels are the deltopectoral lymph nodes and the apical axillary lymph nodes.  For deeper lymphatic vessels, they flow in cross proximity with the basilic and cephalic veins and terminate at the humeral axillary lymph nodes.  These nodes drain the lymph from the following locations:  joint capsules, periosteum, tendons, nerves and muscles. 

            Lymphatic drainage is important for the filtration of harmful toxins to our body.  One important clinical notation about the lymph nodes is their relationship to cancer.  For my cadaver dissection, the lymph nodes of my cadaver were severely swollen, which lead to our discovery that he died due to prostate cancer.  These nodes are usually very small, about the size of a pea but flat, however, his were severely enlarged in the apical axillary lymph nodes for example. 

Venous Drainage of Upper Limbs

The two major superficial veins of the upper limbs are the basilic and cephalic.  The median cubital vein provides a connection between these two superficial veins.  The cephalic vein is located on the lateral side of the upper limb and runs up the arm along the deltopectoral groove into the clavipectoral triangle.  It continues on its path toward the costocoracoid membrane and finally terminates at the axillary vein.  The basilica vein, in contrast, follows along the medial side of the forearm and ascends up the arm.  The basilic runs parallel with the brachial artery and medial cutaneous nerve until it terminates at the axillary vein.  A smaller network of veins known as the perforating veins, serve as a connection between the superficial veins and the deep veins of the upper limbs.  Common deep veins of the upper limbs are the radial, ulnar and deep brachial to name a few. 

The axillary vein dumps into the subclavian vein and at the end of the axillary vein is the point of entry for subclavian vein puncture.  This occurs during catheterization, but it is referred to subclavian due to the needle being pushed medially to the start point of the subclavian vein.  This central line is necessary to administer parenteral (venous nutrients) fluids and medications. 

Nerves of the Upper Limbs

Most nerves of the upper limbs all have a correlating origin at the brachial plexus.  The brachial plexus consists of nerves from the anterior rami of C5-T1.  The nerves are grouped into lateral, medial, and posterior in the brachial plexus.  Surprisingly, the shoulder actually obtains its nerve source from the cervical plexus.  This particular network of nerves originates from the first four cranial nerves.  Important nerves to notate in the arm are the radial, median, and ulnar nerves. 

Several different injuries can occur to the brachial plexus and cause temporary or permanent paralysis of the arm depending on the severity of the injury.  When avulses (tears) occur to the brachial plexus it causes this paralysis.  If there is no movement it is referred to complete paralysis while some movement is referred to incomplete paralysis.  In infants, delivery by pulling excessively on the arms or making sharp angles with the head can cause avulses in the brachial plexus. 

 

Thought this was interesting.  This guy has tattoos of his upper limb veins in their exact location.

Source:

Clinically Oriented Anatomy Book

Spinal Cord, IV discs, and Zygapophysial Joints

Spinal Cord

The spinal cord is one of the major components of the vertebral canal.  It begins at the foramen magnum as a continuation of the medulla oblongata and continues down to vertebrae T12-L3, depending on the person.  The inferior end of the spinal cord is known as the conus medullaris.  The spinal cord runs through the vertebral canal and is protected by the spinal vertebrae.  The spinal cord is the major communication channel between the brain and the body.  It contains numerous spinal nerves that connect from it to the parts of the body.  When an impulse is sent from a specific part of the body, it travels from the nerve to the spinal cord, and then to the brain. 

The spinal cord has been at the forefront of research due to its complexity.  Researchers are working hard to find a way to reproduce the spinal cord in order to cure injuries that have occurred to the spinal cord.  When the spinal cord is severed, the nerves inferior to the lesion are no longer able to send out impulses.  This is a great devastation to the body. 

IV discs

The intervertebral discs (IV) are joints that connect the vertebral bodies of the spinal vertebrae.  IV discs are symphyses joints that allow the vertebral column to flex and permit gliding movements between the articular processes.  The intervertebral discs are composed of an outer fibrous part called the annulus fibrous, and an inner part known as the nucleus pulpous.  The nucleus pulpous has a semi-fluid nature that permits the flexibility of the spinal cord.  The CI-C2 vertebra does not contain an IV disc and L5-S1 is the most inferior IV disc location.  The thicknesses of the discs are relative to their location and the thickness is most uniform in the thoracic region.  Their relative thickness is greatest in the cervical and lumbar region. 

 Herniated discs are a common IV disc injury.  In young individuals, the vertebrae are very strong, and a lot of times the vertebrae will fracture in a fall before the discs actually rupture.  However, if there is extreme flexion of the vertebral column the disc can rupture due to an increase in turgid pressure of the nucleus pulpous.  If the nucleus pulpous is pushed to posteriorly into the annulus fibrous region then it can herniate into the vertebral canal and compress the spinal cord. 

Zygapophysial Joints            

The zygapophysial joints are synovial joints between the superior and inferior articular processes of the adjacent vertebrae.  The zygapophysial joints in the cervical region are much more loose and flexible which allows for the vast movement of the head.  The medial branches of the posterior rami of spinal nerves innervate the zygapophysial joints and each zygapophysial joint contains two nerves. 

 Zygapophysial joints can be injured and when this occurs the spinal nerves are also affected.  This causes pain along the appropriate dermatome of the spinal nerves affected and it also causes spasms in the associated myotomes (muscles that are innervated by this particular effected nerve).  Doctors rectify this situation by denervating the zygapophysical joint through sectioning or radiofrequency dissolution.