Grays Anatomy - Chapter 1

Regional approach

each region of the body is studied separately and all aspects of that region are studied at the same time

Systemic approach

each system of the body is studied and followed throughout the entire body

Sagittal plane

divides body into left and right

Coronal plane

divides body into anterior and posterior parts

Median sagittal plane

passes vertically through the midline of the body, dividing it into left and right halves

Transverse plane

horizontal division of the body into superior and inferior portions

Cranial

towards the head

Caudal

towards the tail

Rostral

used to describe the position of a structure in reference to the nose

Superficial

near the surface

Levels of interaction of X rays in the body

bone > water > fat > air

Bone on an x ray appear white

due to the lack of exposure to X rays

Air appears black in X rays

due to the abundance of exposure to X rays

Images acquired via CT scans

in the axial plane and viewed such that the observer looks from below and upward towards the head

-the right side of the patient is the left side of the image

-the uppermost border of the image is anterior

Axial skeleton

consists of bones of the skull, vertebral column, ribs, and sternum

Appendicular skeleton

bones of the upper and lower limbs

Cartilage

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

-nourished by diffusion and has no blood vessels, lymphatics, or nerves

The amount and kind of extracellular fibers is based on

the type of cartilage

In heavy weightbearing areas or areas prone to pulling forces, the amount of collagen

greatly increases and cartilage is almost inextensible

Cartilage contains elastic fibers and fewer collagen fibers in areas

lighter weightbearing demands and stresses are placed

Functions of cartilage

-support soft tissues

-provide a smooth, gliding surface for bone articulations at joints

-enable the development and growth of long bones

Types of cartilage

Hyaline

Elastic

Fibrocartilage

Hyaline cartilage

matrix contains a moderate amount of collagen fibers (articular surfaces of bones)

-most common

Elastic cartilage

matrix contains collagen fibers along with a large number of elastic fibers (external ear)

Fibrocartilage

matrix contains a limited number of cells and ground substance amidst a substantial amount of collagen fibers (intervertebral discs)

Bone functions

-supportive structures of the body

-protects vital organs

-reservoirs of calcium and phosphorous

-levers for muscles to act to produce movement

-contains blood producing cells

Compact bone (trabecular)

dense bone that forms the outer shell of all bones and surrounds the spongy layer

Spongy bone (cancellous)

consists of spicules of bone enclosing cavities containing blood forming cells

Classification of bones

-long

-short

-flat

-irregular

-sesamoid

Long bones

tubular

-humerus and femur

Short bones

cuboidal

-bones of the wrist and ankle

Flat bones

consist of two compact bone plates separated by spongy bone

-skull

Irregular bones

bones of various shapes

-face

Sesamoid bones

round or oval bones that develop in tendons

Artery adjacent to bone

gives off nutrient artery that directly enters the internal cavity of the bone and supplies the marrow, spongy bone, and inner layers of compact bone

All bones are covered externally by

periosteum (fibrous connective tissue membrane)

In the area of a joint where articular cartilage is present

periosteum is not present

Periosteum

fibrous membrane covering bone that has the ability of forming new bone

-receives blood vessels

Nerves that pass into the internal cavity of bone alongside the nutrient artery

vasomotor fibers

Vasomotor fibers

nerves that regulate blood flow inside the bone

All bones come from

mesenchyme by either intramembranous ossification or endochodral ossification

Intramembranous ossification

mesenchymal models of bone undergo ossification

Endochondral ossification

cartilaginous models of bones form from mesenchyme and undergo ossification

Determination of skeletal age

the nondominant hand is radiographed and compared to a series of standard radiographs

Red bone marrow (myeloid tissue)

produces blood cells, platelets, and most white blood cells

Yellow bone marrow

dominanted by fat globules with some white blood cells produced

As a person ages red bone marrow

is converted to yellow bone marrow in the medulla of long and flat bones

Hemopoietic stem cell

produce white blood cells, red blood cells, and platelets

Mesenchymal stem cell

differentiates into structures that form bone, cartilage, and muscle

Bone fracture

bone gives way after abnormal load or stress

Bone fractures in children

occur across growth plate or across the shaft

-partial cortical disruption

After a fracture occurs

-blood clot forms between the fracture margins

-jelly like matrix is formed and further migration of collagen producing cells occur

-calcium hydroxyapatite is produced by osteoblasts and forms insoluble crystals and bone matrix is laid down

-callus forms across the fracture site

Fracture line reduction

used in the treatment of a fracture

Avascular necrosis

cellular death of bone resulting from a temporary or permanent loss of blood supply to the bone

Osteoporosis

disease in which the bone mineral density is significantly reduced

Osteoporotic fractures

typically occur in the femoral necks, vertebra, and the wrist

Epiphyseal fractures

fractures that occur in growth plate and metaphyseal regions

-these regions are more vulnerable between the ages of 7-10 and puberty due to rapid growth

Synovial joints

skeletal elements are separated by an articular cavity

Features of synovial joints

-layer of cartilage covers the articulating surfaces of the skeletal elements (usually hyaline cartilage)

-joint capsule

-contain additional structures such as articular discs, fat pads, and tendons

Joint capsule

consists of an inner synovial joint and an outer fibrous membrane

Solid joints

no cavity separating the skeletal elements and the components are held together by connective tissue

Types of solid joints

fibrous and cartilaginous

The synovial membrane attaches to

margins of the joint surfaces at the interface between the cartilage and bone

Synovial membrane

membrane lining the capsule of a joint

-highly vascular and produces synovial fluid

Closed sacs of synovial membranes

can occur outside of joints and form synovial bursae or tendon sheaths

Synovial bursae

intervene between structures such as tendons and bones, tendons and joints, and skin and bones

Purpose of synovial bursae

reduce friction of one structure when it moves over the other

Tendon sheaths

surround tendons and reduce friction

Articular discs

absorb compression forces, adjust to changes in the contours of the joint surfaces, and increase the range of movements

-composed of primarily fibrocartilage

Fat pads

occur between synovial membranes and the capsule

-these move into and out of the region as the joint contours

Synovial joints are based upon

shape and movement

Synovial joints based on shape

based on their articular surfaces

-described as plane (flat), hinge, pivot, bicondylar (two sets of contact points), condylar (ellipsoid), saddle, and ball and socket

Plane synovial joint

allow sliding or gliding movements when one bone moves across the surface of another

ex: acromioclavicular joint

Hinge synovial joint

allow movement around one axis that passes transversely through the joint

-permits extension and flexion

ex: elbow joint

Pivot synovial joint

allow movement around one axis that passes longitudinally along the shaft of the bone

-permits rotation

ex:atlanto-axial joint

Bicondylar synovial joint

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

ex: knee joint

Condylar synovial joint

allow movement around two axes that are at right angles to each other

-permits flexion, extension, abduction, adduction, and circumduction

ex: wrist joint

Saddle synovial joint

allow movement around two axes that are at right angles to each other

-articular surfaces are saddle shaped permitting flexion, extension, abduction, adduction, and circumduction

ex: carpometacarpal joint of the thumb

Ball and socket synovial joint

allow movement around multiple axes

-permits extension, flexion, abduction, adduction, circumduction, and rotation

ex: hip joint

Synovial joints based on movement

described as uniaxial (movement in one plane), biaxial (movement in two planes), multiaxial (movement in three planes)

A hinge joint has what type of movement

uniaxial

A ball and socket joint has what type of movement

multiaxial

Subtraction angiography

imaging technique where images are taken before the injection of the contrast media

Abduction

Movement away from the midline of the body

Adduction

Movement toward the midline of the body

Circumduction

circular movement of a limb at the far end

Types of fibrous joints

-suture

-gomphoses

-syndesmoses

Fibrous joints

consists of inflexible layers of dense connective tissue, holds the bones tightly together

-solid joints

Sutures

occurs only in the skull where adjacent bones are linked by a thin layer of connective tissue

Sutural ligament

thin layer of dense connective tissue that joins flat bones of the skull together

Types of cartilaginous joints

-synchondroses

-symphyses

Synchodroses

occur when two ossification centers in a developing bone remain separated by a layer of cartilage

-allows for bone growth

The type of joint at the growth plate between the head and shaft of a long bone

synchodroses

Symphyses

occur where two separate bones are interconnected by cartilage

Type of joint that occurs at the midline, including the pubic symphysis and intervertebral discs

symphyses

Degenerative joint disease

osteoarthritis

-decreases in water and proteoglycan content with the cartilage

Osteophytes

juxta-articular bony nodules that are formed as a result of osteoarthritis

As a result of osteophytes

this leads to deformations which alter the biomechanics of the joint

Etiology of osteoarthritis

not clear however this can occur after other joint diseases such as rheumatoid arthritis and infection

Arthtoscopy

technique used to visualize the inside of a joint. using a small telescope

-most commonly used on the knee, shoulder, ankle, and hip