Grays Anatomy Ch. 1 The Body

Why is image interpretation important?

diagnose pathological changes to tissues.

systemic approach

each system of the body is studied and followed throughout the entire body. For example, a study of the cardiovascular system looks at the heart and all of the blood vessels in the body

Do fascia have blood vessels

yes

Most common radiograph=

Chest taken posterioranteriorly

What are the two types of bone?

, compact and spongy (trabecular or cancellous). Compact bone is dense bone that forms the outer shell of all bones and surrounds spongy bone. Spongy bone consists of spicules of bone enclosing cavities containing blood-forming cells (marrow).

Wilhelm Roentgen

1895 inventor of xray

In western cultures skeletal maturity occurs when?

20-25 years

How does a CT work

A CT scanner obtains a series of images of the body (slices) in the axial plane. The patient lies on a bed, an X-ray tube passes around the body ( Fig. 1.7 ), and a series of images are obtained. A computer carries out a complex mathematical transformation on the multitude of images to produce the final

Whats a fascia

A fascia is a thin band of tissue that surrounds muscles, bones, organs, nerves, and blood vessels and often remains uninterrupted as a three-dimensional structure between tissues. It provides important support for tissues and can provide a boundary between structures

X-rays are attracted to..?

Areas of high atomic mass or elements lower on the periodic table ie: calcium in bones

What is Arthroscopy

Arthroscopy is a technique of visualizing the inside of a joint using a small telescope placed through a tiny incision in the skin. Arthroscopy can be performed in most joints. However, it is most commonly performed in the knee, shoulder, ankle, and hip joints. The elbow joint and wrist joint can also be viewed through the arthroscope. Arthroscopy allows the surgeon to view the inside of the joint and its contents. Notably, in the knee, the menisci and the ligaments are easily seen, and it is possible using separate puncture sites and specific instruments to remove the menisci and replace the cruciate ligaments. The advantages of arthroscopy are that it is performed through small incisions, it enables patients to quickly recover and return to normal activity, and it only requires either a light anesthetic or regional anesthesia during the procedure

What is an Epiphyseal fracture

As the skeleton develops, there are stages of intense growth typically around the ages of 7 to 10 years and later in puberty. These growth spurts are associated with increased cellular activity around the growth plate and the metaphyseal region. This increase in activity renders the growth plates and metaphyseal regions more vulnerable to injuries, which may occur from dislocation across a growth plate or fracture through a growth plate. Occasionally an injury may result in growth plate compression, destroying that region of the growth plate, which may result in asymmetrical growth across that joint region. All fractures across the growth plate must be treated with care and expediency, requiring fracture reduction.

Atherosclerosis

Atherosclerosis is a disease that affects arteries. There is a chronic inflammatory reaction in the walls of the arteries, with deposition of cholesterol and fatty proteins. This may in turn lead to secondary calcification, with reduction in the diameter of the vessels impeding distal flow. The plaque itself may be a site for attraction of platelets that may "fall off" (embolize) distally. Plaque fissuring may occur, which allows fresh clots to form and occlude the vessel.

What is avascular necrosis

Avascular necrosis is cellular death of bone resulting from a temporary or permanent loss of blood supply to that bone. Avascular necrosis may occur in a variety of medical conditions, some of which have an etiology that is less than clear. A typical site for avascular necrosis is a fracture across the femoral neck in an elderly patient. In these patients there is loss of continuity of the cortical medullary blood flow with loss of blood flow deep to the retinacular fibers. This essentially renders the femoral head bloodless; it subsequently undergoes necrosis and collapses. In these patients it is necessary to replace the femoral head with a prosthesis

How does a fracture heal?

Between the fracture margins a blood clot is formed into which new vessels grow. A jelly-like matrix is formed, and further migration of collagen-producing cells occurs. On this soft tissue framework, calcium hydroxyapatite is produced by osteoblasts and forms insoluble crystals, and then bone matrix is laid down. As more bone is produced, a callus can be demonstrated forming across the fracture site.

Cardiac muscle

Cardiac muscle is striated muscle found only in the walls of the heart (myocardium) and in some of the large vessels close to where they join the heart. It consists of a branching network of individual cells linked electrically and mechanically to work as a unit. Its contractions are less powerful than those of skeletal muscle and it is resistant to fatigue. Cardiac muscle is innervated by visceral motor nerves.

Cartilage is defined as...

Cartilage is an avascular form of connective tissue consisting of extracellular fibers embedded in a matrix that contains cells localized in small cavities.

Pia matter

Closest to brain lines the cerebral cortex

3 different planes

Coronal planes are oriented vertically and divide the body into anterior and posterior parts. ▪ Sagittal planes also are oriented vertically but are at right angles to the coronal planes and divide the body into right and left parts. The plane that passes through the center of the body dividing it into equal right and left halves is termed the median sagittal plane . ▪ Transverse, horizontal , or axial planes divide the body into superior and inferior parts.

Degenerative Joint disease

Degenerative joint disease is commonly known as osteoarthritis or osteoarthrosis. The disorder is related to aging but not caused by aging. Typically there are decreases in water and proteoglycan content within the cartilage. The cartilage becomes more fragile and more susceptible to mechanical disruption ( Fig. 1.23 ). As the cartilage wears, the underlying bone becomes fissured and also thickens. Synovial fluid may be forced into small cracks that appear in the bone's surface, which produces large cysts. Furthermore, reactive juxta-articular bony nodules are formed (osteophytes) ( Fig. 1.24 ). As these processes occur, there is slight deformation, which alters the biomechanical forces through the joint. This in turn creates abnormal stresses, which further disrupt the joint.

How do bones develop?

Developmentally, all bones come from mesenchyme by either intramembranous ossification, in which mesenchymal models of bones undergo ossification, or endochondral ossification, in which cartilaginous models of bones form from mesenchyme and undergo ossification.

How does a doppler ultrasound work?

Doppler ultrasound enables determination of flow, its direction, and its velocity within a vessel using simple ultrasound techniques. Sound waves bounce off moving structures and are returned. The degree of frequency shift determines whether the object is moving away from or toward the probe and the speed at which it is traveling. Precise measurements of blood flow and blood velocity can therefore be obtained, which in turn can indicate sites of blockage in blood vessels.

Explain subtraction angiography

During angiography it is often difficult to appreciate the contrast agent in the vessels through the overlying bony structures. To circumvent this, the technique of subtraction angiography has been developed. Simply, one or two images are obtained before the injection of contrast media. These images are inverted (such that a negative is created from the positive image). After injection of the contrast media into the vessels, a further series of images are obtained, demonstrating the passage of the contrast through the arteries into the veins and around the circulation. By adding the "negative precontrast image" to the positive postcontrast images, the bones and soft tissues are subtracted to produce a solitary image of contrast only. Before the advent of digital imaging this was a challenge, but now the use of computers has made this technique relatively straightforward and instantaneous

regional approach

Each region of the body is studied separately and all aspects of that region are studied at the same time. For example, if the thorax is to be studied, all of its structures are examined. This includes the vasculature, the nerves, the bones, the muscles, and all other structures and organs located in the region of the body defined as the thorax

A synovial joint is characteristic of

First, a layer of cartilage, usually hyaline cartilage , covers the articulating surfaces of the skeletal elements. In other words, bony surfaces do not normally contact one another directly. As a consequence, when these joints are viewed in normal radiographs, a wide gap seems to separate the adjacent bones because the cartilage that covers the articulating surfaces is more transparent to X-rays than bone. A second characteristic feature of synovial joints is the presence of a joint capsule consisting of an inner synovial membrane and an outer fibrous membrane .

What are fractures

Fractures occur in normal bone because of abnormal load or stress, in which the bone gives way. Fractures may also occur in bone that is of poor quality (osteoporosis); in such cases a normal stress is placed upon a bone that is not of sufficient quality to withstand this force and subsequently fractures. In children whose bones are still developing, fractures may occur across the growth plate or across the shaft. These shaft fractures typically involve partial cortical disruption, similar to breaking a branch of a young tree; hence they are termed "greenstick" fractures

What happens to bone marrow during the aging process?

From birth most of the body's marrow is red; however, as the subject ages, more red marrow is converted into yellow marrow within the medulla of the long and flat bones.

An MRI needs what biological molecule in order to work propperly

H20

What are the two types of bone marrow cells?

Hemopoietic stem cells give rise to the white blood cells, red blood cells, and platelets. Mesenchymal stem cells differentiate into structures that form bone, cartilage, and muscle.

How is the hand supplied with blood

In certain circumstances, organs have more than one vessel perfusing them, such as the hand, which is supplied by the radial and ulnar arteries. Loss of either the radial or the ulnar artery may not produce any symptoms of reduced perfusion to the hand

Arthritis=

In the United States, osteoarthritis accounts for up to one-quarter of primary health care visits and is regarded as a significant problem....Various treatments are available, including weight reduction, proper exercise, anti-inflammatory drug treatment, and joint replacement

Why is it said the lymphatic system also carries around fats

In the small intestine, certain fats absorbed and processed by the intestinal epithelium are packaged into protein-coated lipid droplets ( chylomicrons ), which are released from the epithelial cells and enter the interstitial compartment. Together with other components of the interstitial fluid, the chylomicrons drain into lymphatic capillaries (known as lacteals in the small intestine) and are ultimately delivered to the venous system in the neck. The lymphatic system is therefore also a major route of transport for fat absorbed by the gut.

Why is Iodine used intravenously in x-rays?

Iodine is chosen because it has a relatively high atomic mass and so markedly attenuates X-rays, but also, importantly, it is naturally excreted via the urinary system. Intra-arterial and intravenous contrast agents are extremely safe and are well tolerated by most patients. Rarely, some patients have an anaphylactic reaction to intra-arterial or intravenous injections, so the necessary precautions must be taken. Intra-arterial and intravenous contrast agents not only help in visualizing the arteries and veins but because they are excreted by the urinary system, can also be used to visualize the kidneys, ureter, and bladder in a process known as intravenous urography.

Air is dark on film because....?

It was exposed to the greatest number of x-rays

Bone appears white on film because...?

It was exposed to the least amount of xrays

What happens if a bone is stripped of its periosteum?

It will not surrvive

Bones are classified by shape

Long bones are tubular (e.g., humerus in upper limb; femur in lower limb). ▪ Short bones are cuboidal (e.g., bones of the wrist and ankle). ▪ Flat bones consist of two compact bone plates separated by spongy bone (e.g., skull). ▪ Irregular bones are bones with various shapes (e.g., bones of the face). ▪ Sesamoid bones are round or oval bones that develop in tendons.

Chyle

Lymph carried by lymphatic vessels from the small intestine is opaque and milky because of the presence of chylomicrons and is termed

define lymph node

Lymph nodes are small (0.1-2.5 cm long) encapsulated structures that interrupt the course of lymphatic vessels and contain elements of the body's defense system, such as clusters of lymphocytes and macrophages. They act as elaborate filters that trap and phagocytose particulate matter in the lymph that percolates through them. In addition, they detect and defend against foreign antigens that are also carried in the lymph

Medial Vs. Latteral

Medial and lateral describe the position of structures relative to the median sagittal plane and the sides of the body. For example, the thumb is lateral to the little finger. The nose is in the median sagittal plane and is medial to the eyes, which are in turn medial to the external ears.

Movements and where they are in the body

Muscles that move the shoulder joint are innervated mainly by spinal nerves from spinal cord levels C5 and C6. ▪ Muscles that move the elbow are innervated mainly by spinal nerves from spinal cord levels C6 and C7. ▪ Muscles in the hand are innervated mainly by spinal nerves from spinal cord levels C8 and T1.

primary techniques a student should use to learn anatomy

Observation and visualization

What is Osteoprosis

Osteoporosis is a disease in which the bone mineral density is significantly reduced. This renders the bone significantly more at risk of fracture. Typically, osteoporotic fractures occur in the femoral necks, the vertebrae, and the wrist. Although osteoporosis may occur in men, especially elderly men, the typical patients are postmenopausal women. There are a number of risk factors that predispose bones to develop osteoporosis. These factors include poor diet, steroid usage, smoking, and premature ovarian failure. Treatment involves removing underlying potentiating factors, such as improving diet and preventing further bone loss with drug treatment (e.g., vitamin D and calcium supplements; newer treatments include drugs that increase bone mineral density) (

Positron Emission Tomography

Positron emission tomography (PET) is an imaging modality for detecting positron-emitting radionuclides. A positron is an anti-electron, which is a positively charged particle of antimatter. Positrons are emitted from the decay of proton-rich radionuclides. Most of these radionuclides are made in a cyclotron and have extremely short half-lives. The most commonly used PET radionuclide is fluorodeoxyglucose (FDG) labeled with fluorine-18 (a positron emitter). Tissues that are actively metabolizing glucose take up this compound, and the resulting localized high concentration of this molecule compared to background emission is detected as a "hot spot." PET has become an important imaging modality in the detection of cancer and the assessment of its treatment and recurrence.

Neural tube

Precursor to brain and spinal chord

myeloid tissue=

Red bone marrow

smooth muscle

Smooth muscle (absence of stripes) consists of elongated or spindle-shaped fibers capable of slow and sustained contractions. It is found in the walls of blood vessels (tunica media), associated with hair follicles in the skin, located in the eyeball, and found in the walls of various structures associated with the gastrointestinal, respiratory, genitourinary, and urogenital systems. Smooth muscle is innervated by visceral motor nerves.

What is Superfiscial Fascia

Superficial (subcutaneous) fascia lies just deep to and is attached to the dermis of the skin. It is made up of loose connective tissue usually containing a large amount of fat. The thickness of the superficial fascia (subcutaneous tissue) varies considerably, both from one area of the body to another and from one individual to another. The superficial fascia allows movement of the skin over deeper areas of the body, acts as a conduit for vessels and nerves coursing to and from the skin, and serves as an energy (fat) reservoir.

superior vs inferior

Superior and inferior describe structures in reference to the vertical axis of the body. For example, the head is superior to the shoulders and the knee joint is inferior to the hip joint

Different Fibrous joints

Sutures occur only in the skull where adjacent bones are linked by a thin layer of connective tissue termed a sutural ligament . ▪ Gomphoses occur only between the teeth and adjacent bone. In these joints, short collagen tissue fibers in the periodontal ligament run between the root of the tooth and the bony socket. ▪ Syndesmoses are joints in which two adjacent bones are linked by a ligament. Examples are the ligamentum flavum, which connects adjacent vertebral laminae, and an interosseous membrane, which links, for example, the radius and ulna in the forearm

Central nervous system

The CNS is composed of the brain and spinal cord, both of which develop from the neural tube in the embryo

The anatomical position

The body is in the anatomical position when standing upright with feet together, hands by the side and face looking forward. The mouth is closed and the facial expression is neutral. The rim of bone under the eyes is in the same horizontal plane as the top of the opening to the ear, and the eyes are open and focused on something in the distance. The palms of the hands face forward with the fingers straight and together and with the pad of the thumb turned 90° to the pads of the fingers. The toes point forward.

Define Epidermis and Dermis

The epidermis is the outer cellular layer of stratified squamous epithelium, which is avascular and varies in thickness. The dermis is a dense bed of vascular connective tissue.

A good chest radiograph shows...

The lungs, cardiomediastinal contour, diaphragm, ribs, and peripheral soft tissues.

How Nuclear Medicine imaging worksP

The most commonly used radionuclide (radioisotope) is technetium-99m. This may be injected as a technetium salt or combined with other complex molecules. For example, by combining technetium-99m with methylene diphosphonate (MDP), a radiopharmaceutical is produced. When injected into the body this radiopharmaceutical specifically binds to bone, allowing assessment of the skeleton. Similarly, combining technetium-99m with other compounds permits assessment of other parts of the body, for example the urinary tract and cerebral blood flow. Depending on how the radiopharmaceutical is absorbed, distributed, metabolized, and excreted by the body after injection, images are obtained using a gamma camera

Give an overview of the brain

The parts of the brain are the cerebral hemispheres, the cerebellum, and the brainstem. The cerebral hemispheres consist of an outer portion, or the gray matter , containing cell bodies; an inner portion, or the white matter , made up of axons forming tracts or pathways; and the ventricles , which are spaces filled with cerebrospinal fluid (CSF). The cerebellum has two lateral lobes and a midline portion. The components of the brainstem are classically defined as the diencephalon, midbrain, pons, and medulla. However, in common usage today, the term "brainstem" usually refers to the midbrain, pons, and medulla.

Explain an MRI (magnetic Resonance Imaging)

The process of magnetic resonance imaging (MRI) is dependent on the free protons in the hydrogen nuclei in molecules of water (H 2 O). Because water is present in almost all biological tissues, the hydrogen proton is ideal. The protons within a patient's hydrogen nuclei can be regarded as small bar magnets, which are randomly oriented in space. The patient is placed in a strong magnetic field, which aligns the bar magnets. When a pulse of radio waves is passed through the patient the magnets are deflected, and as they return to their aligned position they emit small radio pulses. The strength and frequency of the emitted pulses and the time it takes for the protons to return to their pre-excited state produce a signal. These signals are analyzed by a powerful computer, and an image is created

Pros and Cons of regional and systemic approach

The regional approach works very well if the anatomy course involves cadaver dissection but falls short when it comes to understanding the continuity of an entire system throughout the body. Similarly, the systemic approach fosters an understanding of an entire system throughout the body, but it is very difficult to coordinate this directly with a cadaver dissection or to acquire sufficient detail.

superficial vs deep

Two other terms used to describe the position of structures in the body are superficial and deep . These terms are used to describe the relative positions of two structures with respect to the surface of the body. For example, the sternum is superficial to the heart, and the stomach is deep to the abdominal wall.

Explain an ultrasound

Ultrasound is a very high frequency sound wave (not electromagnetic radiation) generated by piezoelectric materials, such that a series of sound waves is produced. Importantly, the piezoelectric material can also receive the sound waves that bounce back from the internal organs. The sound waves are then interpreted by a powerful computer, and a real-time image is produced on the display panel.

Nuclear Medicine Imaging

Uses Gamma Rays

Varicose veins

Varicose veins are tortuous dilated veins that typically occur in the legs, although they may occur in the superficial veins of the arm and in other organs. In normal individuals the movement of adjacent leg muscles pumps the blood in the veins to the heart. Blood is also pumped from the superficial veins through the investing layer of fascia of the leg into the deep veins. Valves in these perforating veins may become damaged, allowing blood to pass in the opposite direction. This increased volume and pressure produces dilatation and tortuosity of the superficial veins ( Fig. 1.28 ). Apart from the unsightliness of larger veins, the skin may become pigmented and atrophic with a poor response to tissue damage. In some patients even small trauma may produce skin ulceration, which requires elevation of the limb and application of pressure bandages to heal.

Safety in imaging

Whenever a patient undergoes an X-ray or nuclear medicine investigation, a dose of radiation is given ( Table 1.1 ). As a general principle it is expected that the dose given is as low as reasonably possible for a diagnostic image to be obtained. Numerous laws govern the amount of radiation exposure that a patient can undergo for a variety of procedures, and these are monitored to prevent any excess or additional dosage. Whenever a radiograph is booked, the clinician ordering the procedure must appreciate its necessity and understand the dose given to the patient to ensure that the benefits significantly outweigh the risks.

Gross Anatomy

Without the aide of microsocope

Barium sulfate

Works as a contrast agent....an insoluble salt, is a nontoxic, relatively high-density agent that is extremely useful in the examination of the gastrointestinal tract. When barium sulfate suspension is ingested it attenuates X-rays and can therefore be used to demonstrate the bowel lumen ( Fig. 1.4 ). It is common to add air to the barium sulfate suspension, by either ingesting "fizzy" granules or directly instilling air into the body cavity, as in a barium enema. This is known as a double-contrast (air/barium) study.

How X-rays work

X-rays are photons (a type of electromagnetic radiation) and are generated from a complex X-ray tube, which is a type of cathode ray tube ( Fig. 1.2 ). The X-rays are then collimated (i.e., directed through lead-lined shutters to stop them from fanning out) to the appropriate area, as determined by the radiographic technician. As the X-rays pass through the body they are attenuated (reduced in energy) by the tissues. Those X-rays that pass through the tissues interact with the photographic film.

Bone is defined as

a calcified, living, connective tissue that forms the majority of the skeleton. It consists of an intercellular calcified matrix, which also contains collagen fibers, and several types of cells within the matrix.

The bodys compnents reduce x-ray energy(attenuate) in different ways

air attenuates X-rays a little; fat attenuates X-rays more than air but less than water; and bone attenuates X-rays the most.

Most observers view a radio graph via the...?

anatomical position

A common characteristic of synovial joints

articular discs (usually composed of fibrocartilage), fat pads , and tendons . Articular discs absorb compression forces, adjust to changes in the contours of joint surfaces during movements, and increase the range of movements that can occur at joints. Fat pads usually occur between the synovial membrane and the capsule and move into and out of regions as joint contours change during movement. Redundant regions of the synovial membrane and fibrous membrane allow for large movements at joints.

axial skeleton

bones of the skull (cranium), vertebral column, ribs, and sternum

appendicular skeleton

bones of the upper and lower limbs

CT stands for ...?

computed tomography

What are solid joints

connections between skeletal elements where the adjacent surfaces are linked together either by fibrous connective tissue or by cartilage, usually fibrocartilage ( Fig. 1.22 ). Movements at these joints are more restricted than at synovial joints

Difference between Gamma and X-rays

gamma rays are produced from within the nucleus of an atom when an unstable nucleus decays, whereas X-rays are produced by bombarding an atom with electrons

myocardial infraction

heart attack

Microscopic anatomy

histology, is the study of cells and tissues using a microscope.

Three types of cartilage

hyaline—most common; matrix contains a moderate amount of collagen fibers (e.g., articular surfaces of bones); ▪ elastic—matrix contains collagen fibers along with a large number of elastic fibers (e.g., external ear); ▪ fibrocartilage—matrix contains a limited number of cells and ground substance amidst a substantial amount of collagen fibers (e.g., intervertebral discs).

example of bone marrow malignancy

luekemia

skeletal muscle

skeletal muscle forms the majority of the muscle tissue in the body. It consists of parallel bundles of long, multinucleated fibers with transverse stripes, is capable of powerful contractions, and is innervated by somatic and branchial motor nerves. This muscle is used to move bones and other structures, and provides support and gives form to the body. Individual skeletal muscles are often named on the basis of shape (e.g., rhomboid major muscle), attachments (e.g., sternohyoid muscle), function (e.g., flexor pollicis longus muscle), position (e.g., palmar interosseous muscle), or fiber orientation (e.g., external oblique muscle).

3 types of muscle

skeletal muscular smooth

malnutrition and hypothyroidism lead to..?

slower bone maturity

Functions of Cartilage

support soft tissues, provide a smooth, gliding surface for bone articulations at joints, and enable the development and growth of long bones.

anatomy is derived from the Greek word temnein , meaning

to cut

Anterior vs posterior

▪ Anterior (or ventral ) and posterior (or dorsal ) describe the position of structures relative to the "front" and "back" of the body. For example, the nose is an anterior (ventral) structure, whereas the vertebral column is a posterior (dorsal) structure. Also, the nose is anterior to the ears and the vertebral column is posterior to the sternum.

Deep Fascia

▪ Deep fascia usually consists of dense, organized connective tissue. The outer layer of deep fascia is attached to the deep surface of the superficial fascia and forms a thin fibrous covering over most of the deeper region of the body. Inward extensions of this fascial layer form intermuscular septa that compartmentalize groups of muscles with similar functions and innervations. Other extensions surround individual muscles and groups of vessels and nerves, forming an investing fascia. Near some joints the deep fascia thickens, forming retinacula. These fascial retinacula hold tendons in place and prevent them from bowing during movements at the joints.

Arteries are divided into

▪ Large elastic arteries contain substantial amounts of elastic fibers in the tunica media, allowing expansion and recoil during the normal cardiac cycle. This helps maintain a constant flow of blood during diastole. Examples of large elastic arteries are the aorta, the brachiocephalic trunk, the left common carotid artery, the left subclavian artery, and the pulmonary trunk. ▪ Medium muscular arteries are composed of a tunica media that contains mostly smooth muscle fibers. This characteristic allows these vessels to regulate their diameter and control the flow of blood to different parts of the body. Examples of medium muscular arteries are most of the named arteries, including the femoral, axillary, and radial arteries. ▪ Small arteries and arterioles control the filling of the capillaries and directly contribute to the arterial pressure in the vascular system

Veins overview

▪ Large veins contain some smooth muscle in the tunica media, but the thickest layer is the tunica externa. Examples of large veins are the superior vena cava, the inferior vena cava, and the portal vein. ▪ Small and medium veins contain small amounts of smooth muscle, and the thickest layer is the tunica externa. Examples of small and medium veins are superficial veins in the upper and lower limbs and deeper veins of the leg and forearm. ▪ Venules are the smallest veins and drain the capillaries.

Clinical imaging difference between T1 and T2 of an MRI

▪ Most T1-weighted images show dark fluid and bright fat—for example, within the brain the cerebrospinal fluid (CSF) is dark; ▪ T2-weighted images demonstrate a bright signal from fluid and an intermediate signal from fat—for example, in the brain the CSF appears white.

What are the different types of synovial joints

▪ Plane joints—allow sliding or gliding movements when one bone moves across the surface of another (e.g., acromioclavicular joint) ▪ Hinge joints—allow movement around one axis that passes transversely through the joint; permit flexion and extension (e.g., elbow [humero-ulnar] joint) ▪ Pivot joints—allow movement around one axis that passes longitudinally along the shaft of the bone; permit rotation (e.g., atlanto-axial joint) ▪ Bicondylar joints—allow movement mostly in one axis with limited rotation around a second axis; formed by two convex condyles that articulate with concave or flat surfaces (e.g., knee joint) ▪ Condylar (ellipsoid) joints—allow movement around two axes that are at right angles to each other; permit flexion, extension, abduction, adduction, and circumduction (limited) (e.g., wrist joint) ▪ Saddle joints—allow movement around two axes that are at right angles to each other; the articular surfaces are saddle shaped; permit flexion, extension, abduction, adduction, and circumduction (e.g., carpometacarpal joint of the thumb) ▪ Ball and socket joints—allow movement around multiple axes; permit flexion, extension, abduction, adduction, circumduction, and rotation (e.g., hip joint)

proximal vs distal

▪ Proximal and distal are used with reference to being closer to or farther from a structure's origin, particularly in the limbs. For example, the hand is distal to the elbow joint. The glenohumeral joint is proximal to the elbow joint. These terms are also used to describe the relative positions of branches along the course of linear structures, such as airways, vessels, and nerves. For example, distal branches occur farther away toward the ends of the system, whereas proximal branches occur closer to and toward the origin of the system

Different Cartilaginous joints

▪ Synchondroses occur where two ossification centers in a developing bone remain separated by a layer of cartilage, for example, the growth plate that occurs between the head and shaft of developing long bones. These joints allow bone growth and eventually become completely ossified. ▪ Symphyses occur where two separate bones are interconnected by cartilage. Most of these types of joints occur in the midline and include the pubic symphysis between the two pelvic bones, and intervertebral discs between adjacent vertebrae.

What are the meninges of the brain

▪ The dura mater is the thickest and most external of the coverings. ▪ The arachnoid mater is against the internal surface of the dura mater. ▪ The pia mater is adherent to the brain and spinal cord

Veins distinguishable features

▪ The walls of veins, specifically the tunica media, are thin. ▪ The luminal diameters of veins are large. ▪ There often are multiple veins (venae comitantes) closely associated with arteries in peripheral regions. ▪ Valves often are present in veins, particularly in peripheral vessels inferior to the level of the heart. These are usually paired cusps that facilitate blood flow toward the heart.

Cardiovascular system overview

▪ arteries, which transport blood away from the heart; ▪ veins, which transport blood toward the heart; ▪ capillaries, which connect the arteries and veins, are the smallest of the blood vessels and are where oxygen, nutrients, and wastes are exchanged within the tissue

Bones main functions are

▪ supportive structures for the body, ▪ protectors of vital organs, ▪ reservoirs of calcium and phosphorus, ▪ levers on which muscles act to produce movement, and ▪ containers for blood-producing cells

Two different types of joints

▪ the skeletal elements are separated by a cavity (i.e., synovial joints ), and ▪ there is no cavity and the components are held together by connective tissue (i.e., solid joints

Walls of blood vessels contain

▪ tunica externa (adventitia)—the outer connective tissue layer, ▪ tunica media—the middle smooth muscle layer (may also contain varying amounts of elastic fibers in medium and large arteries), and ▪ tunica intima—the inner endothelial lining of the blood vessels