Chapter 10- Musculoskeletal System: Anatomy & Physiology

temporal bones

-2 of these, 1 on each side of the skull, form part of the lower cranium -each has a complicated shape that contains various cavities and recesses associated with the internal ear -projects downward to form the mastoid process

lacrimal bones

-2 thin, paired bones -located at the corner of each eye -unite to form the groove for the lacrimal sac and canals through which the tear ducts pass into the nasal cavity

cranium (skull)

-8 bones that enclose and protect the brain and the organs of hearing and equilibrium -its bony structure consists of cranial bones and facial bones, almost all of which are joined together by sutures -connected to muscles to provide head movements, chewing motions, and facial expressions

periosteum

-a dense, white, fibrous membrane that covers the remaining surface of the long bones -contains numerous blood and lymph vessels and nerves, as well as osteoblasts in its inner layer -provides a means for bone repair and general bone nutrition -serves as a point of attachment for muscles, ligaments, and tendons

trochanter

-a non-articulating surface -very large, irregularly shaped process found only on the femur -example: greater ___ of the femur

tubercle

-a site of muscle and ligament attachment -small, rounded process -example: ___ of the femur

articular cartilage

-a type of elastic connective tissue that provides a smooth surface for movement of joints -covers the epiphyses -reduces friction and absorbs shock at the freely movable joints

fontanel (soft spot)

-an unossified membrane in an infant's skull (incomplete bone formation) -lies between the cranial bones -allows the bones to move as the fetus passes through the birth canal during the delivery process -with age, they begin to fuse together and become immobile in early childhood

appendage

-any body part attached to a main structure -examples include the arms and legs

aponeurosis

-attachment when the fibrous attachment spans a large area of a bone -found in the lumbar region of the back -sometimes it penetrates the bone itself -these are flattened

flat bones

-bones that provide broad surfaces for muscular attachment -provide protection for internal organs -examples: bones of the skull, shoulder blades, and sternum

irregular bones

-bones with complex shapes -includes bones that cannot be classified as short or long -examples: vertebrae and bones of the middle ear

pectoral (shoulder) girdle

-consists of 2 bones: the anterior clavicle and posterior scapula -attaches the bones of the upper limbs to the axial skeleton -provides attachments for muscles that aid upper limb movements

muscles

-contribute to posture, produce body heat, and act as a protective covering for internal organs -make up the bulk of the body -have the ability to be excited by a stimulus, contract, relax, and return to their original shape and size -primary responsibility is movement

axial skeleton

-divided into 3 major regions: skull, rib cage, and vertebral column -contributes to the formation of body cavities -provides protection for internal organs -provides central support for the body

ligaments

-flexible bands of fibrous tissue that are highly adapted for resisting strains -one of the principal mechanical factors that hold bones close together in a synovial joint -connect bone to bone

fleshy attachments

-in these, muscle fibers arise directly from bone -distribute force over wide areas -weaker than the other attachment -it is contractile

fibrous attachments

-in these, the connective tissue converges at the end of the muscle to become continuous and indistinguishable from the periosteum -non-contractile and inelastic

cruciate ligaments

-ligaments that cross each other, forming an X within the notch between the femoral condyles -along with other structures, they help secure and stabilize the knee -prevent anterior-posterior displacement of the articular surfaces

cardiac muscle

-muscle found only in the heart and makes up most of the heart's wall -unique for its branched interconnections -it is striated, but produces rhythmic involuntary contractions

smooth (involuntary or visceral) muscles

-muscles whose actions are involuntary -found principally in the visceral organs, walls of arteries and respiratory passages, and urinary and reproductive ducts -their contraction is controlled by the autonomic nervous system

head

-projection that forms joints -prominent, rounded, articulating end of a bone -example: ___ of the femur

condyle

-projection that forms joints -rounded, articulating knob -example: ___ of the humerus

bones

-provide the framework of the body -storehouse for minerals -produce blood cells in marrow -protect and support organs -provide points of attachment for muscles, tendons, and ligaments -assist in body movement

sinus

-site for blood vessel, nerve, and duct passage -cavity or hollow space in a bone -example: ___ of the frontal sinus containing a duct

fissure

-site for blood vessel, nerve, and duct passage -narrow, slit-like opening -example: ___ of the sphenoid bone

meatus

-site for blood vessel, nerve, and duct passage -opening or passage into a bone -example: external auditory ___ of the temporal bone

foramen

-site for blood vessel, nerve, and duct passage -rounded opening through a bone -example: ___ of the skull through which cranial nerves pass

tuberosity

-site of muscle and ligament attachment -large, rounded process -example: ___ of the humerus

short bones

-somewhat cube-shaped bones -consist of cancellous bone -examples: bones of ankles, wrists, and toes

mandible

-the lower jaw bone -its movement is needed for speaking and chewing -contains sockets for the roots of the teeth

maxillae

-the paired upper jawbones that are fused in the midline by a suture -form the upper jaw and hard palate -contain sockets for the roots of the teeth

epiphyses

-the two ends of long bones -have a somewhat bulbous shape to provide space for muscle and ligament attachments near the joints -covered with articular cartilage -made up largely of spongy bone surrounded by a layer of compact bone

surface features

-these are rarely smooth -may be rounded, sharp, narrow, or contain ridges -consist of projections, depressions, and openings that provide sites for muscle and ligament attachment -provide pathways and openings for blood vessels, nerves, and ducts

tendon

-when connective tissue fibers form a cord or strap -localizes a great deal of force in a small area of bone -connects muscle to bone

nasal bones

2 thin, nearly rectangular bones that lie side-by-side and are fused medially, forming the shape and the bridge of the nose

vertebrae

26 bones that compose the vertebral column

coccyx

4 or 5 fragmented fused vertebrae that makes of the tail of the vertebral column

sacrum

5 sacral vertebrae that are fused into a single bone in the adult

lumbar vertebrae

5 vertebrae that are situated in the lower back area and carry most of the weight of the torso

cervical vertebrae

7 of these form the skeletal framework of the neck

medullary (marrow) cavity

a central canal in long bones that contains fatty yellow marrow in adults, consisting primarily of fat cells and a few scattered blood cells

cleft palate

a congenital defect that results if the maxillary bones do not fuse properly before birth

nucleus pulposus

a fibrocartilaginous substance with a gelatinous mass in the center that composes the intervertebral disks

vomer

a single, thin bone that forms the lower part of the nasal septum

ethmoid bone

a very light and spongy bone that forms most of the bony area between the nasal cavity and parts of the orbits of the eyes

clavicle

also known as the collar bone

scapula

also known as the triangular shoulder blade

sphenoid bone

bone located at the middle part of the base of the skull that forms a central wedge, which joints with all other cranial bones and holds them together

compact bone

bone that forms a cylinder and surrounds the medullary cavity in long bones, as well as encloses cancellous bone in short bones

osteoblasts

bone-forming cells contained in the inner layer of the periosteum in growing bones

zygomatic bones (cheekbones)

bones located on the side of the face below the eyes and form the higher portion of the cheeks below and to the sides of the eyes

long bones

bones that are found in the appendages of the body and consist of 3 main parts

girdles

bony rings that attach the limbs to the axial skeleton

paranasal sinuses

cavities located within the cranial and facial bones that open into the nasal cavities and are lined with ciliary epithelium

vertebral column

composed of vertebrae and supports the body, as well as provides a protective bony canal for the spinal cord

thoracic cage (rib cage)

consists of 12 pairs of ribs that are all attached to the spine and encloses and protects the internal organs of the thorax

appendicular skeleton

consists of bones of the upper and lower limbs and their girdles and enables the body to move

fibers

contractile cells that compose muscle tissue and provide movement of an organ or body part

flexion

decreases the angle of a joint

dorsiflexion

elevates the foot

intervertebral disks

flat, rounded structures that separate the vertebrae and are composed of nucleus pulposus

forehead

forms the anterior portion of the skull

frontal bone

forms the anterior portion of the skull and the roof of the bony cavities that contain the eyeballs

musculoskeletal system

includes muscles, bones, joints, and related structures, such as the tendons and connective tissue that function in support and movement of body parts and organs

extension

increases the angle of a joint

upper limb

its skeleton framework includes the arm, forearm, and hand and is adapted for mobility and flexibility

cancellous

latticelike arrangement of bony plates occurring at the ends of long bones

ciliary epithelium

lines the paranasal sinuses and is continuous with the mucosa of the nasal cavities

plantar flexion

lowers the foot (points the toes)

rotation

moves a bone around its own axis

abduction

moves away from the midline

adduction

moves closer to the midline

inversion

moves the sole of the foot inward

eversion

moves the sole of the foot outward

skeletal (voluntary or striated) muscles

muscles whose action is under voluntary control, such as those that moved the eyeballs, tongue, and bones

skeletal system

of a human adult, it consists of 206 individual bones

articulation, joint

place of union between two or more bones

hematopoiesis

production and development of blood cells, normally in the bone marrow

mastoid process

provides a point of attachment for several neck muscles

parietal bone

situated on each side of the skull just behind the frontal bone and meets the frontal bone along the coronal suture

cancellous bone

spongy bone that makes up the core of short bones, is enclosed in a thin surface layer of compact bone, and contains red bone marrow

mastication

term for chewing

sternum

term for the breastbone

atlas

the 1st cervical vertebrae that supports the skull

axis

the 2nd cervical vertebrae that makes possible the rotation of the skull on the neck

false ribs

the costal cartilage of these 5 pairs of ribs is not fastened directly to the sternum

internal ear

the essential part of the organ of hearing associated with the temporal bones

true ribs

the first 7 pairs of ribs that are attached directly to the sternum by a strip of costal cartilage

floating ribs

the last 2 pairs of false ribs that are not joined directly or indirectly to the sternum, but attach posteriorly to the thoracic vertebrae

sutures

the lines of junction between 2 bones, especially of the skull, and are usually immovable

hard palate

the roof of the mouth

diaphysis

the shaft, main portion of a bone that consists of compact bone surrounding the medullary cavity

coronal suture

the suture where the parietal bone meets the frontal bone

red bone marrow

this is contained in spongy bone, richly supplied with blood and consists of immature and mature blood cells in various stages of development

occipital bone

this single bone forms the back and base of the skull and contains an opening in its base through which the spinal cord passes

thorax

this term refers to the entire chest and includes the heart and lungs, which are enclosed and protected by the thoracic cage

pronation

turns the palm down

supination

turns the palm up

thoracic vertebrae

under the 7th cervical vertebra are these, which support the chest and serve as a point of articulation for the ribs