thoracic wall Flashcards
how many thoracic vertebrae are there
12
how many pairs of ribs and costal cartilages are there
12 attached to respective thoracic vertebrae
define sternum
breastbone in centre of chest that connects to the ribs via cartilage
what are the true ribs and what do they reach
1-7; reach sternum
what are the false ribs and what do they reach
8-10; reach costal carilage above
what are the floating ribs and why are they called this
11-12; lack anterior attachment
what are articulations
joints
where are articulations located
with vertebral column via head and tubercle (sticks out of bony structure to provide attachment; facets are where bones join to other bones), and with costal cartilages
what is the costal margin
attachment of ribs to diaphragm
what is the name of the space between each rib
intercostal space
what are the 3 parts of the sternum
manubrium, body, xiphoid
where do the 1st costal cartilages attach to on the sternum
manubrium
where do the 2nd costal cartilages attach to on the sternum
sternal angle (manubriosternal joint)
where do the 3rd-7th costal cartilages attach to on the sternum
sternum
where do the 8th-10th costal cartilages attach to on the sternum
cartilage above
where do the 11th-12th costal cartilages attach to on the sternum
nothing - they are floating
what is the thoracic inlet (superior thoracic aperture) formed of
1st thoracic vertebra (T1), 1st ribs, manubrium
what are the contents of the thoracic inlet
great vessels heading for neck and upper limb, oesophagus, trachea, nerves and lymphatics
where are most lung tissue and most capacity for lung expansion
lower parts of the thorax
what muscles aid in expanding chest and lung volume
diaphragm, intercostal muscles
what does the diaphragm consist of
flat central tendon with muscle radiating to costal margin (anteriorly) and crus (posteriorly) and vertebrae
diaphragm: first stage of insipiration
dome flattens to inrease vertical diameter of chest
diaphragm: second stage of insipiration
pulls costal margin up to increase transverse and antero-posterior diameters
what is the secondary role of intercostal muscle
stiffen chest wall to improve efficiency of breathing movements
movement of ribs to increase chest volume
ribs move out and up to increase thoracic volume anteroposteriorly and mediolaterally, assisting in changing pressure
how many layers of muscles are present in the intercostal muscles, and how are they organised
3, like plywood
what are the 3 layers of the intercostal muscles (superficial to deep) and direction
external intercostals (infromedially), internal intercostals (supromedially), innermost intercostals (superior-inferior)
external intercostals movement
downward and laterally from lower border of rib above to rib below
what are external intercostals replaced by when they move, and where does this happen
anterior intercostal membrane at costo-chondral (rib-cartilage) junction
where do internal intercostals attachments begin
anteriorly at sternum
internal intercostals movement
from lower border of rib above to rib below
how are the fibres directed in internal intercostals
at right angles to external intercostals (hence plywood organisation)
what are internal intercostals replaced by
membrane posteriorly
what passes close together through internal intercostal near bottom of each rib (superior to inferior)
neurovascular bundle of intercostal vein (run posteriorly and anteriorly), intercostal artery (run posteriorly and anteriorly), intercostal nerve (runs from posterior to anterior)
how many pairs of intercostal nerves are there and what are they
11; T1-T11 (+ 1 subcostal T12)
what type of nerve are the intercostal nerves
mixed, so motor (efferent at front of roots) and sensory (afferent at back of roots); anterior ramus supplies front, posterior ramus supplies errector spinal muscles and skin
where do the intercostal nerves originate from and what do they supply
originate from spinal cord (posterior) and pass through intercostal spaces as they travel towards the anterior, where they innovate muscle and skin
what axis does the lateral cutaneous branch innovate
anterior and posterior
what axis does the anterior cutaneous branch innovate
medial and lateral
border area for inserting a chest drain safely to avoid intercostal vessels and nerve, and avoid important structures
anterior border of latissimus dorsi, lateral border of pectoralis major muscle, line superior to horizontal level of nipple, apex below axilla (armpit); 5th intercostal space anterior to mid axillary line
what does each intercostal artery join (anastomose) with
major artery at each end of the intercostal space
what are the major internal thoracic arteries
subclavian, which then branch to form internal thoracic, anterior intercostal, maculophrenic, superior epigastric, inferior epigastric and external iliac arteries and veins on anterior chest wall
how is the thoracic cavity filled
laterally by lungs
where do the lungs lie
own pleural cavity; pair of membranes folded back on itself with fluid between creates surface tension so both layers move out when insipiring; if puncture will move but lung won’t inflate
what is the space between the pleural cavities called
mediastinum
what is present in the mediastinum
heart, great vessels, oesophagus, trachea, thymus, thoracic duct and major lymph trunks, lymph nodes, phrenic and vagus nerves
what doe the heart lie in
pericardial sac
diagram of the parts of the vertebra
diagram from slide 11 of living anatomy
