Thoracic Wall: Osteology & Muscles Flashcards
what is thorax?
the part of the body between the neck and the abdomen, including the cavity enclosed by the ribs, sternum, and dorsal vertebrae, and containing the chief organs of circulation and respiration; the chest
mediastinum
central compartment
L/R pleural compartments are separated by the
mediastinum
what shape does the thoracic skeleton take the shape of? (3)
a dome, birdcage or truncated cone
where is the thoracic cavity narrowest?
superiorly, with the circumference increasing inferiorly
the floor of the respiratory diaphragm is — superiorly
convex
are the walls of the thoracic wall thick or thin?
relatively thin
what are the four functions of the thoracic cavity?
protect vital thoracic/abdominal organs from external forces
resist the negative internal pressure created by the elastic recoil of the lungs
provide attachments for and support the weight of the upper limbs
provide the origin for some upper limb muscles and attachments for muscles of the abdomen, neck, back, and respiration
true ribs
1-7
attach vertebrae to the sternum
(costal cartilage) from the sternal end to the sternum/breastbone
false ribs
8-10 have cartilages attached to the cartilages of ribs superior
(don’t have a cartilage of their own, join the intrasternal angle)
floating ribs
11-12 have cartilages ending in the posterior abdominal wall musculature
what are cartilages of 7-10 are joined to form the
infrasternal angle
ribs and costal cartilages are separated by an
intercostal space
what is the superior thoracic aperture (thoracic outlet and inlet) bounded by?
1st thoracic vertebra, 1st pair of ribs, and superior border of the manubrium
inferior thoracic aperture is closed by the
diaphragm
structures must pass through the inferior thoracic aperture – it
behind
what do the facets of the head of the ribs articulate with?
inferior and superior costal facets of the adjacent thoracic vertebrae
where does the tubercle of the ribs articulate with?
the costal facet of the transverse process of vertebrae of the same number
what is the number of ribs increased by? what is it decreased by?
increased by the presence of cervical and/or lumbar ribs
decreased by failure of the 12th pair to form
how common are cervical ribs?
fairly common
.5-2%
what do cervical ribs interfere with?
neuromuscular structures exiting the superior thoracic aperture
what is the clinical significance of supernumerary (extra) ribs
confusion in radiological diagnosis
thoracic outlet syndrome (TOS)
a group of disorders that occur when there is compression, injury, or irritation of the brachial plexus and/or subclavian vessels in the lower neck and upper chest
the manubriosternal and xiphisternal joints can fuse and become a
synostosis in older persons