By Y. Dargoth. Southwest Baptist University.
There are eight pairs of cervical nerves designated C1 to C8 purchase urispas 200 mg on line spasms to right side of abdomen, twelve thoracic nerves designated T1 to T12 order urispas 200mg on-line muscle relaxant valium, five pairs of lumbar nerves designated L1 to L5 generic urispas 200mg visa muscle relaxant definition, five pairs of sacral nerves designated S1 to S5 urispas 200mg with visa spasms in throat, and one pair of coccygeal nerves. The nerves are numbered from the superior to inferior positions, and each emerges from the vertebral column through the intervertebral foramen at its level. The same occurs for C3 to C7, but C8 emerges between the seventh cervical vertebra and the first thoracic vertebra. For the thoracic and lumbar nerves, each one emerges between the vertebra that has the same designation and the next vertebra in the column. The nerves in the periphery are not straight continuations of the spinal nerves, but rather the reorganization of the axons in those nerves to follow different courses. This occurs at four places along the length of the vertebral column, each identified as a nerve plexus, whereas the other spinal nerves directly correspond to nerves at their respective levels. In this instance, the word plexus is used to describe networks of nerve fibers with no associated cell bodies. Of the four nerve plexuses, two are found at the cervical level, one at the lumbar level, and one at the sacral level (Figure This OpenStax book is available for free at http://cnx. The cervical plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head, as well as the phrenic nerve, which connects to the diaphragm at the base of the thoracic cavity. Spinal nerves C4 through T1 reorganize through this plexus to give rise to the nerves of the arms, as the name brachial suggests. A large nerve from this plexus is the radial nerve from which the axillary nerve branches to go to the armpit region. The lumbar plexus arises from all the lumbar spinal nerves and gives rise to nerves enervating the pelvic region and the anterior leg. The femoral nerve is one of the major nerves from this plexus, which gives rise to the saphenous nerve as a branch that extends through the anterior lower leg. The most significant systemic nerve to come from this plexus is the sciatic nerve, which is a combination of the tibial nerve and the fibular nerve. The sciatic nerve extends across the hip joint and is most commonly associated with the condition sciatica, which is the result of compression or irritation of the nerve or any of the spinal nerves giving rise to it. These plexuses are described as arising from spinal nerves and giving rise to certain systemic nerves, but they contain fibers that serve sensory functions or fibers that serve motor functions. Those are axons of sensory neurons in the dorsal root ganglia that enter the spinal cord through the dorsal nerve root. Other fibers are the axons of motor neurons of the anterior horn of the spinal cord, which emerge in the ventral nerve root and send action potentials to cause skeletal muscles to contract in their target regions. For example, the radial nerve contains fibers of cutaneous sensation in the arm, as well as motor fibers that move muscles in the arm. Spinal nerves of the thoracic region, T2 through T11, are not part of the plexuses but rather emerge and give rise to the intercostal nerves found between the ribs, which articulate with the vertebrae surrounding the spinal nerve. It is often the result of the olfactory nerve being severed, usually because of blunt force trauma to the head. The sensory neurons of the olfactory epithelium have a limited lifespan of approximately one to four months, and new ones are made on a regular basis. Age-related anosmia is not the result of impact trauma to the head, but rather a slow loss of the sensory neurons with no new neurons born to replace them. There are only five tastes sensed by the tongue, and two of them are generally thought of as unpleasant tastes (sour and bitter). The rich sensory experience of food is the result of odor molecules associated with the food, both as food is moved into the mouth, and therefore passes under the nose, and when it is chewed and molecules are released to move up the pharynx into the posterior nasal cavity. Often, the only way to enjoy food is to add seasoning that can be sensed on the tongue, which usually means adding table salt. The problem with this solution, however, is that this increases sodium intake, which can lead to cardiovascular problems through water retention and the associated increase in blood pressure. A specialized region of this layer, the neuroectoderm, becomes a groove that folds in and becomes the neural tube beneath the dorsal surface of the embryo. The brain develops from this early tube structure and gives rise to specific regions of the adult brain. As the neural tube grows and differentiates, it enlarges into three vesicles that correspond to the forebrain, midbrain, and hindbrain regions of the adult brain. The spinal cord develops out of the rest of the neural tube and retains the tube structure, with the nervous tissue thickening and the hollow center becoming a very small central canal through the cord. The rest of the hollow center of the neural tube corresponds to open spaces within the brain called the ventricles, where cerebrospinal fluid is found. The frontal lobe is responsible for motor functions, from planning movements through executing commands to be sent to the spinal cord and periphery. The most anterior portion of the frontal lobe is the prefrontal cortex, which is associated with aspects of personality through its influence on motor responses in decision-making. The occipital lobe is where visual processing begins, although the other parts of the brain can contribute to visual function. The temporal lobe contains the cortical area for auditory processing, but also has regions crucial for memory formation. Nuclei beneath the cerebral cortex, known as the subcortical nuclei, are responsible for augmenting cortical functions. The basal nuclei receive input from cortical areas and compare it with the general state of the individual through the activity of a dopamine-releasing nucleus. The output influences the activity of part of the thalamus that can then increase or decrease cortical activity that often results in changes to motor commands. The cerebellum is connected to the brain stem, primarily at the pons, where it receives a copy of the descending input from the cerebrum to the spinal cord. It can compare this with sensory feedback input through the medulla and send output through the midbrain that can correct motor commands for coordination. The arterial blood to the brain comes from the internal carotid and vertebral arteries, which both contribute to the unique circle of Willis that provides constant perfusion of the brain even if one of the blood vessels is blocked or narrowed. The blood that nourishes the brain and spinal cord is behind the glial-cell–enforced blood-brain barrier, which limits the exchange of material from blood vessels with the interstitial fluid of the nervous tissue. This fluid is produced by filtering blood at the choroid plexuses in the four ventricles of the brain. It then circulates through the ventricles and into the subarachnoid space, between the pia mater and the arachnoid mater. It surrounds the venous space known as the dural sinuses, which connect to the jugular veins, where blood drains from the head and neck. Sensory ganglia contain unipolar sensory neurons and are found on the dorsal root of all spinal nerves as well as associated with many of the cranial nerves. Autonomic ganglia are in the sympathetic chain, the associated paravertebral or prevertebral ganglia, or in terminal ganglia near or within the organs controlled by the autonomic nervous system. Nerves are classified as cranial nerves or spinal nerves on the basis of their connection to the brain or spinal cord, respectively. The twelve cranial nerves can be strictly sensory in function, strictly motor in function, or a combination of the two functions. Sensory fibers are axons of sensory ganglia that carry sensory information into the brain and target sensory nuclei. Motor fibers are axons of motor neurons in motor nuclei of the brain stem and target skeletal muscles of the head and neck. Spinal nerves emerge from the spinal cord and reorganize through plexuses, which then give rise to systemic nerves.
Management: - It usually gets absorbed spontaneously and should be left - Local compress to alleviate pain - Aseptic evacuation or aspiration only if very large (expanding) or over a cosmetic area or leading to compression of vital structures generic 200 mg urispas overnight delivery spasms vs seizures. Management: - Cleanse using scrubbing brushes - Use antiseptic or lean tap water and soap - Analgesic Punctures These may be compound wounds which involve deeper structures buy urispas 200 mg spasms 14 year old beagle. Management: - Careful inspection - Adequate cleansing - Closure generic urispas 200 mg mastercard spasms at night, if feasible trusted urispas 200mg muscle relaxant 751, under appropriate anesthesia - Proper wound debridement if needed - Appropriate antibiotic prophylaxis - Tetanus Prophylaxis - Analgesics as needed Crush and avulsion wounds These are compound complicated wounds. They are usually associated with systemic involvement and have more extensive damage than may appear. Management: - Correct associated life threatening conditions - Proper wound debridement - Early skin cover if possible or late graft, wound left open if contaminated - Appropriate antibiotics - Tetanus Prophylaxis - Analgesics as needed Missile injuries These are type of wounds which are compound and complicated. They usually present with severe life threatening conditions and should be carefully managed. Human bites These are relatively rare but more heavily contaminated than those of most animalss due to polymicrobial nature including anaerobic organisms as a normal oral flora. To avoid this complication the animal must be kept for observation for at least 10 days. Management should include: First aid measures: - Local wound irrigation - Apply pressure bandage proximally to avoid or reduce venom spread with caution on the blood supply - Immobilize the limb to minimize venom absorption - Transport patient immediately to nearby hospital Hospital Measures: - Identify the species - Conduct necessary laboratory investigations like hemoglobin, renal function. Local: Local complications may manifest as one or more of the following conditions- - Hematoma - Seroma 55 - Infection - Dehiscence - Granuloma formation - Scar formation - Contracture leading to loss of joint function etc Systemic: - Death may occur if un controlled sepsis or hemorrhage - Systemic manifestations of hemorrhagic shock due to massive bleeding - Bacteremia and sepsis from a source of locally infected wound 56 Review Questions 1. A) Duration of injury B) The circumstance of wounding C) The mechanism of injury D) Local appearance of the wound E) All of the above 2. A) Bullet wound of one hour duration B) Human bite of 30 minutes duration C) Glass laceration of five hours duration D) Crush injury of the leg following car accident E) None of the above 3. A proper wound care includes all measures except A) Removing all devitalized tissue B) Removing foreign bodies impregnated to the wound C) Wound inspection following primary management D) Inadequate hemostasis of a bleeding artery E) Decision to close a wound primarily 4. A) Forearm laceration from a knife B) Dog bite to the calf of one hour duration C) Blast wound to the thigh of two hours duration D) Stick wound to the scalp of four hours E) B and C are correct 5. In a contaminated wound left open to heal without closure, healing is effected by A) First intention B) Second intention C) Third intention D) Purely by epithelialization E) All of the above 7. A) Presence of foreign body B) Systemic illness C) Sex of the patient D) Poor patient nutritional state E) Presence of infection 58 Key to the Review Questions 1. It can be defined broadly as an infection related to or complicating a surgical therapy and requiring surgical management. Many infections occupy a non-vascularized space of tissue, thus are likely to respond to non-surgical treatments. These types of infection therefore definitely require surgery as a primary or definitive therapeutic approach. Examples of such infections, which definitely need surgery, can be: - Gas gangrene - Abscess - Appendicitis. On the other hand, any infection that is related to surgical therapy but that may not definitely require surgery is also categorized as a surgical infection. Examples: - Urinary tract infections after catheterization for surgical purpose - Pulmonary complications following intubation for surgery - Tracheotomy site infection All wounds that follow operative procedure or incision are also grouped as surgical infections. According to temporal relation to surgery, surgical infections are grouped into three types. Ante/pre operative infections: These infections happen before a surgical procedure. Example: - Accidents - Appendicitis - Boils - Carbuncle - Pyomyositis… Operative infections: These are types of surgical infections that happen during a surgical procedure. It can occur either due to contamination of the site or poor tissue handling technique. These include: - An infectious agent - A susceptible host - Favorable external factors or local condition with closed, less or non-per fused space. An infection becomes overt only when the equilibrium between the bacterial and host factors becomes disturbed. The common organisms in decreasing order are:- 1- Aerobic bacteria - Staphylococcus aureus - Streptococci - Klebsiella - E. Host Susceptibility: Reduced immune host defense predisposes to surgical infections. Local and external factors: Closed spaces, usually with poor vascularization, are areas susceptible to infection. Favorable situations under such condition contributing to infection include:- - Poor perfusion of blood and oxygen - Presence of dead tissue 63 - Presence of foreign bodies - Closure under tension etc. External factors like a break in the sterility technique also contribute to the development of surgical infection. Post-Operative Wound Infection This is contamination of a surgical wound during or after a surgical procedure. Source of infection: The source of contamination in more than 80% cases is the patient (endogenous). In about 20% of cases, the source is from the environment, operating staff or unsterile surgical equipment (exogenous). It contains necrotic tissue and suppuration from damage by the bacteria, and white blood cells. It is surrounded by area of inflamed tissue due to the body’s response to limit the infection. Clinical features: Patients with an abscess anywhere in the body may present with the following findings. It usually involves the extremities and identifiable portal of entry is detectable. Etiology: The most common etiologic organisms are - Beta hemolytic streptococci - Staphylococci - Clostridium perfringens Clinical Features: There is usually an identifiable portal of entry which can be a surgical wound, puncture site, skin ulcer or dermatitis. Clinical Pictures: - Series of small intra epithelial abscesses , multiple - Bullous lesions - Skin erosion and - Crust formation. Poor hygiene, immune suppressive diseases and irritation are known contributing factors. Clinical feature: - There is an intense local irritation of acute onset - Painful firm, reddish, round swelling initially, which later becomes fluctuant - Suppuration and central necrosis occurs later - The condition subsides and is self-limited to recur in multiple lesions (chronicity) Treatment: • It may subside spontaneously without suppuration (Blind boil) • Incision /Excision if complicated • Antibiotics Carbuncle Carbuncle is an infective gangrene of subcutaneous tissue which commonly occurs in patients with diabetes and other immune suppressive conditions. Clinical Feature: • Formed by multiple furuncles • Pain • Erythema • Induration • Progressive suppuration of thick pus • Tissue loss with shallow and deep ulcer surrounded by smaller areas of necrosis 67 Treatment: • Adequate systemic antibiotics in early stages • Aggressive debridement • Local wound care • Detect and treat predisposing factors like diabetes mellitus Pyomyositis Pyomyositis is an acute bacterial infection of skeletal muscles with accumulation of pus in the intra-muscular area. It usually occurs in the lower limbs and trunk spontaneously or following penetrating wounds, vascular insufficiency, trauma or injection. Poor nutrition, immune deficiency, hot climate and intense muscle activity are highly associated factors. Clinical Features: It usually has sub-acute onset and can present with • Localized muscle pain and swelling, late tenderness • Induration, erythema and heat • Muscle necrosis due to pressure • Fever and other systemic manifestations later after some days Treatment: • Immediate intravenous antibiotics before surgery • Surgical drainage of all abscess • Excision of all necrotic muscles • Supportive care Madura Foot This is a chronic granulomatous disease commonly affecting the foot with extensive granulation tissue formation and bone destruction. The disease is common in the tropics and occurs through a prick in barefoot walkers in 90% of cases. Etiology: The causative microorganisms for this infection are various fungi or actinomycetes found in road dust. Treatment: • Sulphonamides and Dapson (prolonged course) • Broad spectrum antibiotics for secondary infection • Amputation if severe and disfiguring infection Necrotizing fasciitis This is an acute invasive infection of the subcutaneous tissue and fascia characterized by vascular thrombosis, which leads to tissue necrosis. It is idiopathic in origin but minor wounds, ulcers and surgical wounds are believed to be initiating factors. The condition is described as "Meleney’s synergistic gangrene" if it occurs over the abdominal wall and “Fournier’s gangrene “if in the scrotum and perineal area. Bacteriology: Mixed pathogens of the following microorganisms are usually cultured. The following surgical procedures may be required: - Debridement and excision of all dead tissue - Multiple incisions for drainage - Repeated wound inspection - Skin graft may be needed later if extensive skin involved. It can practically be eliminated by tetanus vaccine immunization if properly initiated and maintained.
It is located on the floor of the pelvic cavity and 346 Human Anatomy and Physiology like the kidneys and ureters order 200mg urispas with mastercard muscle relaxant wpi 3968. The opening of ureters and urethra in the cavity of the bladder outline triangular area called the trigone buy cheap urispas 200mg line spasms hands fingers. At the site where the urethra leaves the bladder generic urispas 200 mg without prescription muscle relaxant brands, the smooth muscle in the wall of the bladder forms spiral generic 200mg urispas mastercard muscle relaxer z, longitudinal and circular bundles which contract to prevent the bladder from emptying prematurely. Far there along the urethra in the middle membranous portion a circular sphincter of voluntary skeletal muscle form the external urethral sphincter. In male it pass through prostate, membranous portion (pelvic diaphragm muscle), spongy portion (that pass through corpus spongosus) and open at the tip of penis. However, it is composed of mainly water, urea, chloride, potassium, sodium, cretinin, phosphate, sulfates and uric acid. Proteins, glucose, casts (decomposed blood) and calculi from minerals are abnormal if present in urine. To maintain the proper osmotic concentration of the extra cellular fluid to excrete wastes and to maintain proper kidney function the body must excrete at least 450ml of urine per day. The volume and concentration of urine is controlled by: - Antidiuretic hormone - Aldestrone - The Renin – angiotensin mechanism 349 Human Anatomy and Physiology 12. Steps of urination are: Conscious desire to urinate Pelvic diaphram muscle relax Smooth muscle of Urinary bladder neck Moves Urinary bladder down, outlet Opens, wall Contracts & urine stretch, and wall stretch ejects Receptors are stimulated 350 Human Anatomy and Physiology Study Questions 1. The apex of each renal pyramid end in the a) Cortical region b) Papilla c) Juxta medullary region d) Capsule e) Tubule 2. The inner most layer of the ureters is the a) Mucosa b) Muscularis c) Adventitia d) Longitudinal layer e) Circular layer 3. The kidney function in all of the following except a) Acid – base balance b) An endocrine organ c) By removing metabolic waste d) By removing excess carbon dioxide e) By maintaining osmotic concentration 4. An increased volume of urine formation would follow:- a) Inhibition of tubular sodium re-absorption b) A fall in plasma osmolarity c) A fall in plasma volume d) a and b e) a, b and c 5. The volume or chemical makeup of these fluids whenever deviates even slightly from normal, disease results. The correct proportion of water and electrolytes in the water and proper acid base balance are necessary for life to exist. Loss of 10% of total body water usually produce lethargy, fever and dryness on mucous membrane and a 20% loss is fatal. Extra cellular fluids found as interstitial fluid (the immediate environment of body cells), blood plasma and lymph, cerebrospinal, synovial, fluids of the eye & ear, pleural, pericardial, peritoneal, gastrointestinal and glomerular filtrate of the kidney. The concentration of water in the interstitial fluid is slightly higher than the concentration of water in plasma. The plasma proteins are responsible for this difference 354 Human Anatomy and Physiology A B Figure: 13. Hydrostatic pressure: it is the force exerted by a fluid against the surface of the compartment containing fluid. Osmotic pressure: Is the pressure that must be applied to a solution on one side of a selectively permeable membrane to prevent the Osmotic flow of water across the membrane from a compartment of pure water. When there is shift in the pressure of water to wards the interstitial space, accumulation of fluid in the space occur. Such accumulation of water produces distention of the tissue which appears as puffiness on the surface of the body. Causes of edema may be plasma protean leakage decreased protein synthesis, increased capillary or venous hydrostatic pressure, obstructed lymphatic vessels and inflammatory reaction. Under normal condition water is taken in to and excreted from the body, so it matches to maintain homeostasis. Drinking of water is regulated by nervous mechanism (thirst center in the brain) together with hormonal mechanism (Antidiuretic hormone). Kidneys are the organs regulated by homeostatic feed back response they are responsible for excreting most of the water from the body. These three electrolytes are particularly important in maintaining body function and normal water distribution among the fluid compartment. Enzymes, hormones and the distribution 360 Human Anatomy and Physiology of ions can all be affected by the concentration of hydrogen H ion. H Homeostatic maintenance of an acceptable P range in the extra cellular fluid is accomplished by three mechanisms: 1. This task is accomplished in renal tubules, where + hydrogen & ammonium ions are secreted in to urine, when H is excreted sodium is exchanged. Movement of water from one body compartment to another is controlled by a) Atmospheric pressure b) Hydrostatic pressure c) Osmotic pressure d) a & c only e) b & c only 364 Human Anatomy and Physiology 4. The function of electrolytes in the body include a) Contributing to body structure b) Facilitating the movement of water between body compartments c) Maintaining acid – base balance d) a and b only e) a, b, & c 5. Reproduction by means of sexual intercourse produces new human beings and hereditary traits to be passed from both parents to their children’s. The sex hormones play an important role both in the development and function of the reproductive organ and in sexual behavior & drives. By third fetal month it stats is to descend and by the seventh month of fetal life it passes through the inguinal canal. Because the tests hang in scrotum out side the body their temperature is of cooler than the body temperature by 3 Degree Fahrenheit. Next to tunica albuginea is Tunica Vaginals, which is a continuation of membrane of abdomino-pelvic cavity. Each test contain 800 lightly coiled Semniferous Tubules which produce thousands of sperm each second. The germinal tissue contains two types of cells: spermatogenetic cell producing or developing the sperm cell and the sustentacular cell, which provide nourishment for the germinal sperm. Between the semniferous tubules clusters of endocrine cells called interstitial endocrinocytes (Leydig cell) secret male sex hormone (Androgens) where testosterone is the most important. Epididymis: - The semniferous tubules merge in the central posterior portion of the testes as epydidimis. It is located easily over the spermatic cord; hence male permanent (surgical) contraceptive method (vasectomy) is usually performed over it. As it passes from tail of epididymis it is covered by spermatic cord containing testicular artery, vein, autonomic nerves, lymphatic and connective tissue. After the ducts deferens pass through the inguinal canal it free from spermatic cord and pass behind the urinary bladder, where it 372 Human Anatomy and Physiology travels along side an accessory gland, the seminal vesicle and becomes ejaculatory duct. They receive secretion from the seminal vesicles and pass through the prostate where they receive additional secretion. Seminal vesicles Seminal vesicles are paired; secretary sacs lie next to the Ampulla of the ducts deference. Bulbo urethral glands secrets clearly alkaline 374 Human Anatomy and Physiology fluid to neutralize the acidity of urine during the onset of sexual excitement and it also act as a lubricant. Has two main function, It caries urine through urethra to the out side during urination and it transports semen through the urethra during ejaculation. The loosely fitting skin of the penis is folded forward over the glans to form the prepuce or foreskin, which usually excised during circumcision. The rest is a fluid secretion from accessory glands, which provide fructose to nourish sperm and alkaline medium to neutralize urethral (acidity because of urine) & vaginal acidity. Each ovary is attached by a mesentery called 379 Human Anatomy and Physiology mesovarium to the backside of each broad ligament. The cortex contains round epithelial vesicle or follicles; follicles are actual center of ovum production or oogenesis. After ovulation the lining of the follicles grow in ward, forming corpus luteum (yellow body), which temporary function as endocrine tissue. It secret estrogen & progesterone which stops additional ovulation, thickening of uterine wall & stops additional mammary glands in anticipating prognoses.
The large expansion found on the medial side of the distal tibia is the medial malleolus (“little hammer”) trusted 200 mg urispas xanax muscle relaxant dosage. Both the smooth surface on the inside of the medial malleolus and the smooth area at the distal end of the tibia articulate with the talus bone of the foot as part of the ankle joint order urispas 200mg with mastercard muscle relaxant voltaren. It articulates with the inferior aspect of the lateral tibial condyle buy generic urispas 200 mg on line spasms right flank, forming the proximal tibiofibular joint best 200 mg urispas muscle relaxer 86 62. The thin shaft of the fibula has the interosseous border of the fibula, a narrow ridge running down its medial side for the attachment of the interosseous membrane that spans the fibula and tibia. The distal end of the fibula forms the lateral malleolus, which forms the easily palpated bony bump on the lateral side of the ankle. The deep (medial) side of the lateral malleolus articulates with the talus bone of the foot as part of the ankle joint. This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint. Three areas of articulation form the ankle joint: The superomedial surface of the talus bone articulates with the medial malleolus of the tibia, the top of the talus articulates with the distal end of the tibia, and the lateral side of the talus articulates with the lateral malleolus of the fibula. Inferiorly, the talus articulates with the calcaneus (heel bone), the largest bone of the foot, which forms the heel. The medial calcaneus has a prominent bony extension called the sustentaculum tali (“support for the talus”) that supports the medial side of the talus bone. The cuboid has a deep groove running across its inferior surface, which provides passage for a muscle tendon. The talus bone articulates anteriorly with the navicular bone, which in turn articulates anteriorly with the three cuneiform (“wedge-shaped”) bones. Each of these bones has a broad superior surface and This OpenStax book is available for free at http://cnx. Metatarsal Bones The anterior half of the foot is formed by the five metatarsal bones, which are located between the tarsal bones of the posterior foot and the phalanges of the toes (see Figure 8. This expanded base of the fifth metatarsal can be felt as a bony bump at the midpoint along the lateral border of the foot. Each metatarsal bone articulates with the proximal phalanx of a toe to form a metatarsophalangeal joint. The heads of the metatarsal bones also rest on the ground and form the ball (anterior end) of the foot. Phalanges The toes contain a total of 14 phalanx bones (phalanges), arranged in a similar manner as the phalanges of the fingers (see Figure 8. Arches of the Foot When the foot comes into contact with the ground during walking, running, or jumping activities, the impact of the body 336 Chapter 8 | The Appendicular Skeleton weight puts a tremendous amount of pressure and force on the foot. The bones, joints, ligaments, and muscles of the foot absorb this force, thus greatly reducing the amount of shock that is passed superiorly into the lower limb and body. The foot has a transverse arch, a medial longitudinal arch, and a lateral longitudinal arch (see Figure 8. It is formed by the wedge shapes of the cuneiform bones and bases (proximal ends) of the first to fourth metatarsal bones. This arch helps to distribute body weight from side to side within the foot, thus allowing the foot to accommodate uneven terrain. The lateral longitudinal arch is relatively flat, whereas the medial longitudinal arch is larger (taller). The longitudinal arches are formed by the tarsal bones posteriorly and the metatarsal bones anteriorly. Posteriorly, this support is provided by the calcaneus bone and anteriorly by the heads (distal ends) of the metatarsal bones. The talus bone, which receives the weight of the body, is located at the top of the longitudinal arches. Body weight is then conveyed from the talus to the ground by the anterior and posterior ends of these arches. Strong ligaments unite the adjacent foot bones to prevent disruption of the arches during weight bearing. On the bottom of the foot, additional ligaments tie together the anterior and posterior ends of the arches. These ligaments have elasticity, which allows them to stretch somewhat during weight bearing, thus allowing the longitudinal arches to spread. The stretching of these ligaments stores energy within the foot, rather than passing these forces into the leg. When the weight is removed, the elastic ligaments recoil and pull the ends of the arches closer together. This can occur in overweight individuals, with people who have jobs that involve standing for long periods of time (such as a waitress), or walking or running long distances. If stretching of the ligaments is prolonged, excessive, or repeated, it can result in a gradual lengthening of the supporting ligaments, with subsequent depression or collapse of the longitudinal arches, particularly on the medial side of the foot. Mesenchyme gives rise to the bones of the upper and lower limbs, as well as to the pectoral and pelvic girdles. Development of the limbs begins near the end of the fourth embryonic week, with the upper limbs appearing first. Thereafter, the development of the upper and lower limbs follows similar patterns, with the lower limbs lagging behind the upper limbs by a few days. Limb Growth Each upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after (Figure 8. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying mesenchyme to rapidly proliferate, producing the outgrowth of the developing limb. As the limb bud elongates, cells located farther from the apical ectodermal ridge slow their rates of cell division and begin to differentiate. During the sixth week of development, the distal ends of the upper and lower limb buds expand and flatten into a paddle shape. Shortly after this, a second constriction on the limb bud appears at the future site of the elbow or knee. Within the paddle, areas of tissue undergo cell death, producing separations between the growing fingers and toes. Also during the sixth week of development, mesenchyme within the limb buds begins to differentiate into hyaline cartilage that will form models of the future limb bones. The early outgrowth of the upper and lower limb buds initially has the limbs positioned so that the regions that will become the palm of the hand or the bottom of the foot are facing medially toward the body, with the future thumb or big toe both oriented toward the head. During the seventh week of development, the upper limb rotates laterally by 90 degrees, so that the palm of the hand faces anteriorly and the thumb points laterally. In contrast, the lower limb undergoes a 90-degree medial rotation, thus bringing the big toe to the medial side of the foot. On what days of embryonic development do these events occur: (a) first appearance of the upper limb bud (limb ridge); (b) the flattening of the distal limb to form the handplate or footplate; and (c) the beginning of limb rotation? Ossification of Appendicular Bones All of the girdle and limb bones, except for the clavicle, develop by the process of endochondral ossification. This process begins as the mesenchyme within the limb bud differentiates into hyaline cartilage to form cartilage models for future bones. By the twelfth week, a primary ossification center will have appeared in the diaphysis (shaft) region of the long bones, initiating the process that converts the cartilage model into bone. A secondary ossification center will appear in each epiphysis (expanded end) of these bones at a later time, usually after birth. The primary and secondary ossification centers are separated by the epiphyseal plate, a layer of growing hyaline cartilage.
However purchase urispas 200mg without a prescription muscle relaxant vs anti-inflammatory, small areas of notochord tissue persist between the adjacent vertebrae and this contributes to the formation of each intervertebral disc urispas 200 mg cheap spasms from catheter. The ribs initially develop as part of the cartilage model for each vertebra order urispas 200 mg with visa muscle relaxant mechanism, but in the thorax region urispas 200mg generic muscle relaxant yellow house, the rib portion separates from the vertebra by the eighth week. The cartilage model of the rib then ossifies, except for the anterior portion, which remains as the costal cartilage. The sternum initially forms as paired hyaline cartilage models on either side of the anterior midline, beginning during the fifth week of development. Eventually, the two halves of the cartilaginous sternum fuse together along the midline and then ossify into bone. The manubrium and body of the sternum are converted into bone first, with the xiphoid process remaining as cartilage until late in life. What are the two mechanisms by which the bones of the body are formed and which bones are formed by each mechanism? This error in the normal developmental process results in abnormal growth of the skull and deformity of the head. It is produced either by defects in the ossification process of the skull bones or failure of the brain to properly enlarge. It is a relatively common condition, occurring in approximately 1:2000 births, with males being more commonly affected. Primary craniosynostosis involves the early fusion of one cranial suture, whereas complex craniosynostosis results from the premature fusion of several sutures. The early fusion of a suture in primary craniosynostosis prevents any additional enlargement of the cranial bones and skull along this line. Continued growth of the brain and skull is therefore diverted to other areas of the head, causing an abnormal enlargement of these regions. For example, the early disappearance of the anterior fontanelle and premature closure of the sagittal suture prevents growth across the top of the head. This is compensated by upward growth by the bones of the lateral skull, resulting in a long, narrow, wedge-shaped head. This condition, known as scaphocephaly, accounts for approximately 50 percent of craniosynostosis abnormalities. Although the skull is misshapen, the brain still has adequate room to grow and thus there is no accompanying abnormal neurological development. The amount and degree of skull deformity is determined by the location and extent of the sutures involved. This results in more severe constraints on skull growth, which can alter or impede proper brain growth and development. A team of physicians will open the skull along the fused suture, which will then allow the skull bones to resume their growth in this area. After treatment, most children continue to grow and develop normally and do not exhibit any neurological problems. It serves to support the body, protect the brain and other internal organs, and provides a rigid structure upon which muscles can pull to generate body movements. The appendicular skeleton consists of 126 bones in the adult and includes all of the bones of the upper and lower limbs plus the bones that anchor each limb to the axial skeleton. The brain case is formed by eight bones, the paired parietal and temporal bones plus the unpaired frontal, occipital, sphenoid, and ethmoid bones. The narrow gap between the bones is filled with dense, fibrous connective tissue that unites the bones. The coronal suture joins the parietal bones to the frontal bone, the lamboid suture joins them to the occipital bone, and the squamous suture joins them to the temporal bone. These consist of 14 bones, with the paired maxillary, palatine, zygomatic, nasal, lacrimal, and inferior conchae bones and the unpaired vomer and mandible bones. The maxilla also forms the larger anterior portion of the hard palate, which is completed by the smaller palatine bones that form the posterior portion of the hard palate. The floor of the cranial cavity increases in depth from front to back and is divided into three cranial fossae. A small area of the ethmoid bone, consisting of the crista galli and cribriform plates, is located at the midline of this fossa. The middle cranial fossa extends from the lesser wing of the sphenoid bone to the petrous ridge (petrous portion of temporal bone). The right and left sides are separated at the midline by the sella turcica, which surrounds the shallow hypophyseal fossa. Openings through the skull in the floor of the middle fossa include the optic canal and superior orbital fissure, which open into the posterior orbit, the foramen rotundum, foramen ovale, and foramen spinosum, and the exit of the carotid canal with its underlying foramen lacerum. Openings here include the large foramen magnum, plus the internal acoustic meatus, jugular foramina, and hypoglossal canals. Additional openings located on the external base of the skull include the stylomastoid foramen and the entrance to the carotid canal. The walls of the orbit are formed by contributions from seven bones: the frontal, zygomatic, maxillary, palatine, ethmoid, lacrimal, and sphenoid. Located at the superior margin of the orbit is the supraorbital foramen, and below the orbit is the infraorbital foramen. The mandible has two openings, the mandibular foramen on its inner surface and the mental foramen on its external surface near the chin. The large inferior nasal concha is an independent bone, while the middle and superior conchae are parts of the ethmoid bone. The nasal septum is formed by the perpendicular plate of the ethmoid bone, the vomer bone, and the septal cartilage. The paranasal sinuses are air-filled spaces located within the frontal, maxillary, sphenoid, and ethmoid bones. On the lateral skull, the zygomatic arch consists of two parts, the temporal process of the zygomatic bone anteriorly and the zygomatic process of the temporal bone posteriorly. The temporal fossa is the shallow space located on the lateral skull above the level of the zygomatic arch. It is held in position by muscles and serves to support the tongue above, the larynx below, and the pharynx posteriorly. The vertebral column originally develops as 33 vertebrae, but is eventually reduced to 24 vertebrae, plus the sacrum and coccyx. The vertebrae are divided into the cervical region (C1–C7 vertebrae), the thoracic region (T1–T12 vertebrae), and the lumbar region (L1–L5 vertebrae). The sacrum arises from the fusion of five sacral vertebrae and the coccyx from the fusion of four small coccygeal vertebrae. The cervical curve develops as the infant begins to hold up the head, and the lumbar curve appears with standing and walking. A typical vertebra consists of an enlarged anterior portion called the body, which provides weight-bearing support. Attached posteriorly to the body is a vertebral arch, which surrounds and defines the vertebral foramen for passage of the spinal cord. The vertebral arch consists of the pedicles, which attach to the vertebral body, and the laminae, which come together to form the roof of the arch. Arising from the vertebral arch are the laterally projecting transverse processes and the posteriorly oriented spinous process. The superior articular processes project upward, where they articulate with the downward projecting inferior articular processes of the next higher vertebrae. A typical cervical vertebra has a small body, a bifid (Y-shaped) spinous process, and U-shaped transverse processes with a transverse foramen. In addition to these characteristics, the axis (C2 vertebra) also has the dens projecting upward from 302 Chapter 7 | Axial Skeleton the vertebral body.
Deferoxamine in iron poisoning color urine red or methylene blue given in treatment of nitrate poisoning may color urine blue) effective 200mg urispas muscle relaxant cream. Strong-smelling poisons such as methylsalicylate can sometimes recognized in urine since they are excreted in part unchanged order urispas 200mg without prescription spasms near anus. Turbidity may be due to underlying pathology (blood buy generic urispas 200 mg on-line spasms quadriceps, microorganisms generic 200 mg urispas visa muscle relaxant valium, casts, epithelial cells), or carbonates, phosphates or urates (in amorphous or microcrystalline forms). Such findings should not be ignored, even though they may not be related to the poisoning. Stomach contents and scene residues Some characteristic smells can be associated with particular poisons (e. Very low or very high pH may indicate ingestion of acid or alkali, while a green/blue color suggests the presence of iron or copper salts. Microscopic examination using a polarizing microscope may reveal the presence of tablet or capsule debris. Undegraded tablets or capsules and any plant remains or specimens of plants thought to have been ingested should be examined separately. Apparatus Analytical toxicology services can be provided in clinical biochemistry laboratories that serve a local hospital or accident and emergency unit. In addition to basic laboratory equipment, some specialized apparatus, such as that for thin-layer chromatography, ultraviolet and visible spectrophotometry and microdiffusion, is needed. No reference has been made to the use of more complex techniques, such as gas-liquid and high-performance liquid chromatography, atomic absorption spectrophotometry or immunoassays, even if simple methods are not available for particular compounds. Although such techniques are more selective and sensitive than many simple methods, there are a number of factors, in addition to operator expertise, that have to be considered before they can be used in individual laboratories. The standards of quality (purity or cleanliness) of laboratory reagents and glassware and of consumable items such as solvents and gases needs to be considerably higher than for the tests described in this manual if reliable results are to be obtained. Additional complications, which may not be apparent when instrument purchase is contemplated, include the need to ensure a regular supply of essential consumables (gas chromatographic septa, injection syringes, chromatography columns, solvent filters, chart or integrator paper, recorder ink or fibre-tip pens) and spare or additional parts (detector lamps, injection loops, column packing materials). Similarly, immunoassay kits are relatively simple to use, although problems can arise in practice, especially in the interpretation of results. Moreover, they are aimed primarily at the therapeutic drug monitoring and drug abuse testing markets and, as such, have limited direct application in clinical toxicology. Reference compounds and reagents A supply of relatively pure compounds for use as reference standards is essential if reliable results are to be obtained. However, expensive reference compounds of a very high degree of purity, such as those marketed for use as pharmaceutical quality control standards, are not normally needed. Some drugs, such as barbiturates, caffeine and salicylic acid, and many inorganic and organic chemicals and solvents are available as laboratory reagents with an adequate degree of purity through normal laboratory chemical suppliers. Such a reference collection is a valuable resource, and it should be stored under conditions that ensure safety, security and stability. Although the apparatus required to perform the tests described in this manual is relatively simple, several unusual laboratory reagents are needed in order to be able to perform all the tests described. At last, it is beyond the scope of the lecture note to cover all the reagents (See annex I). General laboratory tests in clinical toxicology 36 Toxicology Many clinical laboratory tests can be helpful in the diagnosis of acute poisoning and in assessing prognosis. More specialized tests may be appropriate depending on the clinical condition of the victim, the circumstantial evidence of poisoning and the past medical history. Biochemical tests Blood glucose: Determination of blood glucose is essential to know those toxic substances that affect blood glucose biotransformation. A toxicant that causes hypoglycemia includes insulin, iron, acetyl salicylic acid & so on. Hyperglycemia is a less common complication of poisoning than hypoglycemia, but has been reported after over dosage with acetylsalicylic acid, salbutamol and theophylline. Electrolytes, blood gases and pH Toxic substances or their metabolites, which inhibit key steps in intermediary biotransformation, are likely to cause metabolic acidosis owing to the accumulation of organic acids, notably lactate. Cholinesterase activity Plasma cholinesterase is a useful indicator of exposure to organophosphorus compounds or carbamates, and a normal plasma cholinesterase activity effectively excludes acute poisoning by these compounds. The diagnosis can sometimes be assisted by detection of a poison or metabolite in a body fluid, but the simplest method available is relatively insensitive. Measurement of serum osmolality The normal osmolality of plasma (280-295mOsm/Kg) is largely accounted by sodium, urea &glucose. However, large increases in plasma osmolality may follow the absorption of osmotically active poisons (especially methanol, ethanol, or propan-2-ol) in relatively large amounts. Together with the standard chemistry panel, serum osmolality allows identification of an osmolal gap, which may indicate intoxication with ethanol or other alcohols. Hematological tests Hematocrit (Erythrocyte volume fraction) Acute or acute-on-chronic over dosage with iron salts, acetylsalicylic acid, indomethacin, and other non-steroidal anti- inflammatory drugs may cause gastrointestinal bleeding leading to anemia. Anaemia may also result from chronic exposure to toxins that interfere with haem synthesis, such as lead. Leukocyte count Increases in the leukocyte (white blood cell) count often occur in acute poisoning, for example, in response to an acute metabolic acidosis, resulting from ingestion of ethylene glycol or methanol, or secondary to hypostatic pneumonia following prolonged coma. Blood clotting The prothrombin time and other measures of blood clotting are likely to be abnormal in acute poisoning with rodenticides such as Coumarin anticoagulants. Carboxyhemoglobin Measurement of blood carboxyhemoglobin can be used to assess the severity of acute carbon monoxide poisoning. However, carboxyhemoglobin is dissociated rapidly once the victim is removed from the contaminated atmosphere, especially if oxygen is administered, and the sample should therefore be 39 Toxicology obtained as soon as possible after admission. Even then, blood carboxyhemoglobin concentrations tend to correlate poorly with clinical features of toxicity. Mention the steps that are necessary to undertake analytic toxicological investigations. Describe specimen collection, transportation, storage, characteristics & physical examination used in clinical toxicology laboratory. Describe apparatus, reference compounds & reagents used in clinical toxicology laboratory. Understand the common toxicology laboratory techniques Introduction Methods for particular toxicologic tests or panels are a well established part of routine laboratory tests, and information about them is available on request. In order to interpret toxicology results properly, the laboratory technician should have a rudimentary familiarity with the analytic methods employed. The choice depends on the size and budget of the institution, the types of victims served the proximity to more elaborate toxicology facilities, and other factors. Selection of test methods Selection of test methods can be generally classified as either screening or confirmatory. Screening methods Screening is the testing or examining of a poisoned person for a chemical agent causing toxicity. Screening methods are generally qualitative, relatively simple and inexpensive, and designed to maximize sensitivity (possibly with some sacrifice of specificity). Screening methods, give the emphasis on maximizing sensitivity, may produce significant numbers of false-positive results. A “negative” screen can rule out only the finite number of compounds tested for at concentrations above the threshold of detection for the particular method used. Because of the inherent limitations of screening tests, definitive results must be based on a second method, a confirmatory procedure. It is important to note that inclusion of chemicals in a screening panel is generally governed by methodological as well as clinical considerations.