Download structure of the thoracic wall

human anatomy 2016
lecture eleven
Dr meethak ali ahmed
neurosurgeon
opening of the thorax
The thoracic cavity communicates with the root of the neck through an
opening called the thoracic inlet ; is bounded post. by first thoracic
vertebra, laterally by the medial border of the first ribs & their costal
cartilage , & ant. by the superior border of the manubrium sterni.
the opening is obliquely placed facing upward & forward . Through this
small opening pass the esophagus &trachea and many vessels & nerve .
because of the obliquely of the opening ,the apices of the lung and
pleurae project upward into the neck.
The thoracic cavity communicates with abdomen through a large
opening called the thoracic outlet . The opening is bounded post. by the
twelfth thoracic vertebrae , laterally by the curving costal margin ,& ant.
by xiphisternal joint . Through this large opening , which is closed by the
diaphragm ,pass the esophagus & many large vessels & nerve ,all which
pierce the diaphragm.
structure of the thoracic wall
The thoracic wall is coverd on the outside by skin & by muscles attaching
the shoulder girdle to the trunk. lined with parietal pleura .
thoracic part of the vertebral column
is concave forward & is made up of twelve vertebrae , together with their
intervertebral disc.
sternum
the sternum is flat bone that may be divided into three parts
reference, snell clinical anatomy
human anatomy 2016
lecture eleven
Dr meethak ali ahmed
neurosurgeon
manubrium; is the upper part of the sternum ,& it articulates with the
clavical & the first & upper part of the second costal cartilages on each
side . it opposite the third and fourth thoracic vertebrae.
body of the sternum articulates above with manubrium by
fibrocartilaginus joint , below it articulate with the xiphoid process. on
each side are noches for articulation with lower part of the second costal
cartilage & third to seventh costal cartilage articulate with the sternum
at synovial joint.
xiphoid process is the lowest & smallest part of the sternum it is thin
plate of hyaline cartilage that becomes ossified at its proximal end in
adult life .
sterna angle (angle of Louis) ,formed by the articulation of the
manubrium with the body of the sternum , can be recognized by the
presence of transverse ridge on the anterior aspect of the sternum , the
sternum angle lies opposite the intervertebral disc between the fourth
and fifth thoracic vertebrae.
xiphisternal joint lies opposite the body of the ninth thoracic vertebrae.
costal cartilage
are barsof hyaline cartilage connecting the upper seven ribs to the lateral
edge of the sternum , & eighth , ninth & tenth ribs to the cartilage
immediately above . the cartilage of the eleventh & twelfth ribs end in
the abdominal musculature.
ribs
there are twelve pairs of the ribs , all of which are attached posteriorly to
the thoracic vertebrae .the upper seventh pairs are attached anteriorly to
the sternum by their costal cartilage . the eighth , ninth & tenth pairs of
the ribs are attached anteriorly to each other & to the seventh synovial
reference, snell clinical anatomy
human anatomy 2016
lecture eleven
Dr meethak ali ahmed
neurosurgeon
joints . the eleventh & twelfth pairs have no anterior attachment & are
referred to as floating ribs.
typical ribs is a long ,twisted ,flat bone having thin inferior border
overhangs & forms the costal groove , which accommodates the
intercostal vessels & nerve .
A rib has a head , neck tubercle, shaft , angle . the head has two facets
for articulation with the numerically corresponding vertebral body & that
of the vertebra immediately above . the neck is a constricted portion
situated between the head & the tubercle. the tubercle is a prominence
on the outer surface of the rib at the junction of the neck with the shaft .
it has a facet for articulation with the transverse process of the
numerically corresponding vertebra . the shaft or body is thin and
flattened and twisted on its long axis . its inferior border has the costal
groove . the angle is where the shaft of the rib bends sharply forward .
the anterior end of each rib is attach to the corresponding costal
cartilage. The first rib is atypical . its important because of its close
relation ship to the nerve of the brachial plexus and main vessels to the
arm ,namely the subclavian vessels .this rib is flattened from above down
ward . it has tubercle on the inner border , known as the scalene
tubercle , for the insertion of the scalenus anterior muscle . anterior to
the tubercle the subclavian vein crosses the rib , posterior to the tubercle
is subclavian groove , where the subclavian artery & the lower trunk of
the brachial plexus cross the rib & lie in contact with the bone.
intercostals spaces
the space between the rib are called intercostals space , each space
contains three muscles of respiration :the external intercostals , the
internal intercostals & transverses thoracic muscle . the transverses
thoracis muscle is lined internally by the endothoracic fascia & parietal
pleura . the intercostals nerve & blood vessel run between the
intermediate & deepest layer of the muscle , they are arrange in the
reference, snell clinical anatomy
human anatomy 2016
lecture eleven
Dr meethak ali ahmed
neurosurgeon
following order from above downward : intercostals vein ,intercostals
artery , intercostals nerve.
intercostals muscle
the external intercostals muscle form superfaicial layer its fiber are
directed downward & forward from the inferior border of the rib above
to the superior border of the rib below . the extend forward from the rib
tubercle behind to the costochondral junction in front where the muscle
replaced by an aponeurosis the anterior ( external) intercostals
membrane.
the internal intercostals muscle froms the intermediate layer . its fiber
directed downward backward from the subcostal groove of the rib above
to the upper border of the rib below the muscle extends back ward from
the sternum in front to the angle of the rib behind where the muscle is
replaced by the an aponeurosis , the posterior (internal ) intercstal
membrane .
the transversus thorcis muscle ,from the deepest layer and corresponds
to the transversus abdominis muscle in the anterior abdominal wall .
divided into three portions which are more or less separated from one
another (1) the subcastalis (2) intercostalis intimus (3) sternocostalis.
reference, snell clinical anatomy
human anatomy 2016
lecture eleven
Dr meethak ali ahmed
neurosurgeon
blood and nerve supply from intercostals nerve and vessels
reference, snell clinical anatomy
human anatomy 2016
lecture eleven
Dr meethak ali ahmed
neurosurgeon
reference, snell clinical anatomy