Introduction to Bones and Joints

Os

a bone; pl. ossa; adj. osseous

Ossicles

a little bone

Ossify

To form bone

Calcification

a deposit of calcium, not the formation of bone

Ala

A wing

Condyle

A rounded knoblike projection of knuckle

Cornu

A horn

Crest

A narrow ridge of bone the crest of the ilium

Epicondyle

A bony projection on or above a condyle

Malleolus

A small hammer, a rounded bony prominence

Process

Any definite or marked bony prominence

Spine or spinous process

A sharp slender process

Styloid process

A sharp slender process

Trochanter

A very large rounded process

Tubercle

A small rounded process

Tuberosity

A large rounded process

Fovea

A small pit or depression

Facet

A smooth articular surface, an older

term for smooth articular surface of

vertebrae

- Protection

- Support and framework

- Levers

Functions of bones

Periosteum

A membrane that covers all bones

with the exception of the articular

surfaces

Compact bone

Cortical bone; dense closely knit bone

resembling ivory, made up of compact

Haversian system

Spongy or cancellous bone

Porous loosely-knit bone similar in

appearance to a sponge, or honeycomb,

or latticework

The medullary cavity

Or marrow cavity is a central cavity

extending longitudinally in the shafts of

long bones. It contains bone marrow.

Endosteum

Membrane that lines the

medullary cavities of a long

bone.

Bone marrow

Tissue occupying the medullary

cavities of long bones and the

spaces in spongy bone.

The nutrient foramen

Small opening in the

periosteum and opens

into a nutrient canal.

It carries a nerve and

artery into bone, and

provides a passage

for veins and

lymphatics.

Diploe

A layer of spongy bone called the ... lies

between the two compact layers.

Flat bones

consists of thin layers of

compact bone lie adjacent to the periosteum

covering the external and internal surfaces.

Intracartilaginous ossification

The cartilage in the shafts of long bones in the bodies

of some other bones is replaced by bone while in the

fetus is still within the uterus.

Primary center of ossification

Group of bone cells that make their appearance in

the center of the bodies of long and other bones.

Diaphysis

Part of bone formed from a primary center of

ossification and includes the body or shaft.

Secondary center of ossification

Group of bones that makes its appearance

in the end of a bone, or in a bony

prominence.

Epiphyseal cartilage

The part formed from one or more

secondary centers of ossification

Epiphyseal cartilage

Is a layer of cartilage between a diaphysis

and epiphysis of bone, that persists during

the growing period.

Metaphysis

The end of diaphysis adjacent to an

epiphyseal cartilage.

Intramembranous ossification

Occurs in the bones of the vault of the skull

that form first as membranes

Abduction

Movement away or across the median line of the body

Adduction

Movement towards or across the median line of the body

Flexion

The movement of bending

Extension

The movement of straightening or stretching out

Inversion

The movement of turning a part to face towards the

median line.

Eversion

The movement of turning a part away from the median

line.

Rotation

The movement of turning a part in one axis.

Circumduction

Movement in a circular direction about a cone shaped

axis.

Dorsiflexion

Bending backwards

Hyperextension

Extension beyond the normal limit

Hyperflexion

Flexion beyond normal

Circumflexion

Bending around

Forced inversion

forcibly inverting beyond normal

Internal rotation

Turning inwards in 1 axis

External rotation

Turning outwards in 1 axis

Fibrous joints

Joints with no movement

Cartilaginous joints

Joints with slight movement

Synovial joints

Joints with free movement

Fibrous joints

Have a layer of

fibrous tissue

between the bone

ends forming the

joint.

Cartilaginous joints

Have cartilage on

the adjacent bone

ends with a plate or

disc of fibrocartilage

uniting the two

together.

Synovial joints

Have a joint cavity

between the bone

ends and are held

together by a

capsule surrounding

the joint.

Articular surface

Are the ends of the bones forming a joint.

Articular cartilages

Cover the bone ends and adjacent bone

margins.

Articular capsule

A membrane that surrounds the joint

Inner synovial membrane

Forms the lining for the joint cavity. It does not

cover the articular cartilages. It secretes a fluid

that lubricates the joints

Fibrous Tissue Capsule

Lies outside of the synovial membrane, extending

from bone to bone, completely encircling the

joint. It gives support.

Joint cavity

The potential space within the capsule

Ligaments

Composed of fibrous tissue pass from

one bone across the joint to the other

bone, inside or outside the capsule

Muscles

Frequently cross the joint and tend to

give additional support

Bursa

Closed sac of synovial tissue that lies

between a muscle or tendon and an

adjacent bone or bony prominence

Hyaline Cartilage

Forms articular cartilages at joints, costal cartilages,

nasal and laryngeal cartilages, and the ringlike

cartilages of the trachea and bronchi.

Fibrocartilage

Forms articular discs at some joints such as the

intervertebral discs, semi-lunar cartilages at knee

joint, and discs at the wrist, symphysis pubis, TMJ,

acromioclavicular and sternoclavicular joints.

Elastic Cartilage

Forms epiglottis, cartilages of the

external ear and auditory tube

Gliding joints

Are those that have flat

or slightly curved articular

surfaces that slide over

each other during

movement.

Hinge joints

Have trochlea (pulley-

shaped surface) fitting a

concave surface to allow

an angular motion

similar to a hinge

Condylar joints

Have condyle (knuckle-like

process) fitting into a

concave surface, allowing

flexion, extension,

abduction, adduction and

circumduction.

Saddle joints

Adjacent bone ends are

shaped like a western saddle,

convex in one direction and

concave in the other.

Pivot joints

Are those in which a rounded

bone end is encircled by a

ring of cartilage or bone so

that there is rotation or

turning on one axis.

Ball and socket joints

Have a globelike end or

head fitting into a cup-

shaped cavity.