Bony Thorax, Sternum, and Ribs Anatomy

bony thorax purposes

• support the walls of pleural cavity and diaphragm

• allow thoracic cavity volume to vary

• protect heart and lungs

bony thorax

formed by sternum, 12 pairs of ribs, and 12 thoracic vertebrae

widest part of thorax

at level of 8th and 9th ribs

jugular notch

T2-3

Sternal Angle

T4-5

Xiphoid Tip

T9-10

Sternum location

midline anteriorly

sternum

narrow flat bone 6 inches long, divided into 3 parts

parts of the sternum

• manubrium

• body

• xiphoid process

sternum function

support the clavicles and provide attachment to the costal cartilages of ribs 1-7 laterally

manubrium

• forms the superior border of the sternum

• 4 sides

• widest part of the sternum

palpable concavity of manubrium

jugular notch

jugular notch also called

suprasternal notch

sternoclavicular joint is formed by

clavicular notch articulating with sternal end of clavicle

SC Joint

attachment for the 1st pair of ribs

body of sternum

longest part, 4’’ long

joins the manubrium at the sternal angle (T4-5)

sternal body

where do the 2nd pair of ribs attach

the junction of the manubrium and body

where do rib pairs 3-7 attach

to the lateral border of the sternal body

ribs 3-7 attachments form the

sternocostal joints

xiphoid process

• distal and smallest part

• cartilage that ossifies

• T10

Ribs

12 pairs

ribs

long, narrow curved bone with anterior piece of costal cartilage (hyaline)

true ribs

ribs 1-7, attached to sternum by costal cartilage

false ribs

8-10, attach to costal cartilage of rib 7

floating ribs

11-12, no anterior articulation

number of ribs may be increased by the presence of

cervical or lumbar ribs

cervical ribs articulate with C7 but not

sternum

lumbar ribs

rare and can look like a fracture of the transverse process of L1

head of rib

posterior, attaches to vertebra at the costal facet (forms costovertebral joint)

the tubercle

also has a facet for articulation with transverse process of vertebra

costotransverse joint

joint formed by the tubercular facet and the transverse process of the spine

rib body

anteriorly attaches to costal cartilage forming costochondral joints

ribs 11-12 do not have

a neck or tubercular facets

anterior end of the rib

sternal end

posterior end of the rib

costal end

the costal groove is located on

inferior and internal border of each rib

costal groove cotains

costal arteries, veins, and nerves

trauma to costal neurovascular structures

causes pain and hemorrhage

rib parts

• head

• flattened neck

• tubercle

• costotransverse joint

• costochondral joint

• costal groove

sternoclavicular joint

costovertebral joint

costotransverse joint

costochondral joint

sternocostal joint

interchondral joint

manubriosternal joint

xiphisternal joint