AFOM Chapter 9

sternum

breastbone

manubrium

the superior portion of the sternum

suprasternal (jugular) notch

superior surface of manubrium; u shaped notch

body of the sternum

middle portion of the sternum

xiphoid process

pointed tip at the bottom of the sternum

head of the ribs

connects to thoracic vertebrae

body of the ribs

shaft, flat, main part of rib

sternal end of the ribs

attaches to sternum, flat end

true ribs

first 7 pairs of ribs; attach directly to sternum

false ribs

last 5 pairs of ribs (8-12); attach indirectly to sternum by cartilage connecting to another rib

floating ribs

last two pairs of ribs; do not attach to sternum

thoracic vertebrae

second set of 12 vertebrae; they articulate with the 12 pairs of ribs to form the outward curve of the spine

sternocostal joint

articulation between the costal cartilage of the first 7 ribs and the sternum

costochondral joint

articulation between the ribs and the cartilage attaching the ribs to the sternum

costal cartilage

the cartilages that connect the sternum and the ends of the ribs

costovertebral joints

attach the ribs to the thoracic vertebrae; articulation between the head of the rib and thoracic vertebrae

diaphragm

dome-shaped, muscular partition separating the thorax from the abdomen

what happens to the diaphragm during inhalation

it contracts and flattens downward, increasing chest volume to draw air in

what happens to the diaphragm during exhalation

it relaxes, returns back to its dome shape, and pushes air out

internal intercostal muscles

contract to depress the ribs and pull them closer together (squeezing)

action of internal intercostal muscles

forced expiration

external intercostal muscles

work alongside the diaphragm (forced inspiration)

action of external intercostal muscles

quiet inspiration

transversus thoracis

coughing, sneezing, heavy breathing

action of transversus thoracis

accessory muscle during forced expiration

quiet inspiration

contraction of diaphragm and external intercostals

quiet expiration

relaxation of diaphragm and external intercostals with contraction of abdominal muscles

forced inspiration

deep inspiration that involves both diaphragm and accessory muscles of inspiration

forced expiration

contraction of abdominal muscles and internal intercostals to push air out