thorax Flashcards
what is thorax?
superior part of trunk
label superior thoracic aperture and inferior thoracic aperture
what does thoracic wall consist of?
skin, fascia, muscles, nerves, vessels and bones
how is skeletal framework formed in thoracic wall?
anteriorly - sternum
laterally - ribs
posteriorly - thoracic vertebrae
what is sternum?
flat elongated bone that forms middle of anterior part of thoracic cage
what are the three parts of sternum?
-manubrium
- body
- xiphoid process
what is Manubrium of sternum?
- widest and thickest of three parts of sternum
- concave center and superior border of manubrium is jugular notch
what is Body of sternum?
- lateral margins of body of sternum have articular facets for costal cartilages
- at junction of body and manubrium = sternal angle
- landmark for counting ribs
what is Xiphoid process of sternum?
cartilaginous in young ppl but may ossify in adults older than 40
what are Ribs?
- curved, flat bones that form most of thoracic cage
- twelve pairs of ribs
what are True ribs?
upper seven ribs, articulate directly with sternum through their own costal cartilages
what are False ribs?
- remaining 5 pairs
- costal cartilages of ribs 8th-10th articular anteriorly with costal cartilages of ribs immediately above
- 11th-12th ribs have no anterior connection with sternum or with other ribs, FLOATING RIBS
What are the features of ribs
- head
- neck
- tubercle
- body
- costal groove
What type of costovertebral joints are there
- joints of heads of ribs
- costotransverse joints
what is joints of heads of ribs?
- head of rib articulates with bodies of 2 adjacent vertebrae
what is Costotransverse joints?
- joint between tubercles of ribs and transverse process of vertebrae
what are sternocostal joints?
joints between upper seven costal cartilages and sternum
what are intercostal spaces?
- seperate adjacent ribs and their costal cartilages
- occupied by intercostal muscles, intercostal blood vessels and nerves
what are the 3 intercostal muscles?
- external intercostal
- internal intercostal
- innermost intercostal
Explain External intercostal muscles
- 11 pairs
- occupy intercostal spaces from tubercles of ribs to costochrondral junctions
- muscles run inferoanteriorly from inferior border of rib above superior border of rib below
Explain internal intercostal muscles
- 11 pairs
- run deep to and at right angles to external intercostals
- fibers run inferoposteriorly from inferior border of rib above to superior border of rib inferior to them
Explain Innermost intercostal muscles
- similar to internal intercostals
- seperated from internal intercostals by intercostal nerves and vessels
What is transversus thoracis origin, insertion, function?
- four or five slips
origin - xiphoid process and inferior part of the body of sternum
insertion - 3rd-6th ribs
function - have a weak expiratory function, pull ribs inferiorly
What are subcostal muscles?
- extend from internal surfaces of one rib to internal surface of second or third rib below
