thorax 2
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Thorax
Anhui Medical University Depart of Human Anatomy, Jiao Yi
The Intercostal Spaces, the Pleura, the Pleural Cavity and the lung
Boundaries and DivisionsBoundaries Superior - jugular notch, st
ernoclavicular joint, superior border of clavicle, acromion, spinous processes of C7
Inferior - xiphoid process, costal arch, 12th and 11th ribs, vertebra T12
Regions Thoracic wall Thoracic cavity
Landmarks Sternal angle connects 2nd costal
cartilage laterally , corresponds with The lower border of 4th thoraci
c vertebra The bifurcation of trachea in th
e adult The beginning of aortic arch w
hich ends posteriorly at the same level
The esophagus is crossed by the left main bronchus
Reference lines of thorax
Anterior median line Sternal line Midclavicular line Parasternal line Anterior axillary line Posterior axillary line Midaxillary line Scapular line Posterior median line
Thoracic wall Skin Superficial fascia
Thoracoepigastric v.( 胸腹壁静脉) Supraclavicular n. Anterior and lateral cutan
eous branches of intercostal n.
Deep fascia
The lymphatic drainage of thorax
The lymphatic drainage of thoracic wall
To axillary lymph nodes To parasternal lymph nodes
(along internal thoracic vessels)
To intercostals lymph nodes from deeper structures
Intercostal space
Posterior intercostal v.
Posterior intercostal a.
Intercostal n.
The muscles of thoraxExtrinsic muscles Pectoralis major Pectoralis minor Serratus anterior(锯状肌)
The muscles of thorax
Intrinsic muscles Intercostales externi Intercostales interni
Intercostales externi Origin: lower border of ri
b Insertion: upper border o
f rib below origin Action: elevate ribs addin
g in forced inspiration Replaced anteriorly by ex
ternal intercostals membrane.
Intercostales interni Origin: upper border of ri
b Insertion: lower border of
rib above origin Action: depress ribs for fo
rced expiration Replaced posteriorly by in
ternal intercostals membrane.
The Pleura 胸膜General features Serous membranes formi
ng closed sacs Two layers
Visceral pleura - adheres to lung, continuous with parietal pleura at root of lung
Parietal pleura - lines the thoracic cavity
Two pleural layers continue with each other at root of lung forming closed potential space - pleural cavity 胸膜腔 Contains a small amount
of pleural fluid Subatmospheric pressur
e in it
Named parts of parietal pleura Cupula of pleura 胸膜顶 - extends up into the n
eck, over the apex of lung, 2 ~ 3cm above the medial third of clavicle
Costal pleura 肋胸膜 - lines the inner surface of the wall of the chest
Mediastinal pleura 纵隔胸膜 - Lines mediastinum Diaphragmatic pleura 膈胸膜- Lines diaphragm
Pleura recesses 胸膜隐窝- potential spaces of pleural cavity which lungs are not occupied in quiet respiration
Costodiaphragmatic recess肋膈隐窝- are the slit-like intervals between costal and diaphragmatic pleurae on each side, the lowest point of pleural cavity
Costomediastinal recess 肋纵隔隐窝- on the left side between the mediastinal pleural and costal pleura
The surface projection of lower border of lung and pleurae
Lower border
Midclavicular lines
Midaxillary lines
Sides of the vertebral column
Lungs 6th rib 8th rib 10th rib
Pleura 8th rib 10th rib 12th rib
Internal thoracic artery 胸廓内动脉- descends into thorax 1.2cm lateral to edge of sternum, and ends at the sixth costal cartilage by dividing musculophrenic and superior epigastric arteries
Thoracic aorta 胸主动脉 Main branches
Parietal branches Nine pairs posterior interc
ostals arteries One pair subcostal artery For lower nine intercostals
spaces and upper part of abdominal wall; superior phrenic arteries supply the superior surface of the diaphragm.
The Lungs 肺Position: located in the tho
racic cavity by both sides of mediastinum
General features Cone-shaped, the right l
ung is shorter and broader, the left one is longer and narrower
The Lungs 肺 Apex of lung - rises 2
~ 3 cm above the medial third of clavicle into neck
Base - concave, related to diaphragm, also called diaphragmatic surface
Costal surface - large, convex, related to thoracic wall
Medial surface - concave, related to mediastinum and vertebrae Hilum of lung 肺门: area on
medial surface where structures in root enter or leave lung
Root of lung 肺根 Contents
Principal bronchus Pulmonary artery and vein Nerves and lymphatics
Surrounded by connective tissue
Order of structures in the root of lung From before backward: 1.The superficial pulmonary
vein, 2.The pulmonary artery, 3.The principal bronchus, 4.The inferior pulmonary vein.
Lobes and Fissure Right lung
Two fissures : horizontal an oblique
Three lobes : superior, middle, inferior
Left lung One fissure : oblique Two lobes : superior
and inferior
Arteries of thorax
Pulmonary trunk Arises from right ventricle Runs up, back ,and to the
left Bifurcates inferior to
aortic arch into right and left pulmonary arteries, one for each lung
Arteries of thorax
Pulmonary arteries Right pulmonary artery -
passes posterior to ascending aorta and superior vena cava to hilum of right lung
Left pulmonary artery - passes anterior to descending aorta and left main bronchus to hilum of left lung
Arterial ligament 动脉韧带- remnant of ductus arteriosus, connects bifurcation of pulmonary trunk to inferior border of aortic arch
Ascending aorta 升主动脉 Runs upward, forward
and to the right, Extends to level of seco
nd right sternocostal joint
Branches: right and left coronary arteries
Thoracic aorta 胸主动脉 Main branches
Visceral branches Bronchial branches: one or
two for each lung Esophageal branches Pericardial branches
Veins of thoraxBrachiocephalic veins Formed by union of internal
jugular and subclavian veins posterior to the sternoclavicular joint
Angle of union is termed venous angle
Veins of thoraxSuperior vena cava Formed by union of right a
nd left brachiocephalic veins behind the right sternocostal synchorndrosis of first rib
Runs vertically down on right of ascending aorta
Veins of thoraxSuperior vena cava
Joined by azygos vein at level of sternal angle
Enters right atrium at level of lower border of third right sternocostal joint
Collects blood from veins of upper half of body
Azygos vein 奇静脉 Begins as continuation of ri
ght ascending lumbar vein Ascending along the right si
de of vertebral column
Azygos vein 奇静脉 Joins superior vena cava by
arching above right lung root at level of T4 to T5
Receives right posterior intercostals and subcostal veins plus some of bronchial, esophageal and pericardial veins, and hemiazygos vein
Tributaries - hemi-azygos v. 半奇静脉 and accessory hemi-azygos v. 副半奇静脉 , which receive most left posterior intercostals vein and left bronchial veins
Thoracic duct 胸导管 Begins in front of L1 as a dila
ted sac, the cisterna chyli 乳糜池 , which formed by joining of left and right lumbar trunks and intestinal trunk
Thoracic duct 胸导管 Enter thoracic cavity by passi
ng through the aortic hiatus of the diaphragm and ascends along on the front of the vertebral column, between thoracic aorta and azygos vein
Thoracic duct 胸导管 Travels upward, veering to
the left at the level of T5 At the root of the neck, it tu
rns laterally and arches forwards and descends to enter the left venous angle
Just before termination, it receives the left jugular, subclavian and bronchomediastinal trunks
Drains lymph from lower limbs, pelvic cavity, abdominal cavity, left side of thorax, and left side of the head, neck and left upper limb
Right lymphatic duct 右淋巴导管 Formed by union of right j
ugular, subclavian, and bronchomediastinal trunks
Ends by entering the right venous angle
Receives lymph from right half of head, neck, thorax and right upper limb
Anterior branches of thoracic nerves
1.Intercostal nerves (anterior rami of T1- T11
Anterior branches of thoracic nerves
2.Subcostal nerve (anterior ramus of T12): follows inferior border of T12 rib and passes into abdominal wall
Phrenic nerve 膈神经 Descends over scalenus an
terior to enter thorax Accompanied by pericard
iophrenic vessels and passes anterior to lung roots between mediastinal pleura and pericardium to supply motor and sensory innervation to diaphragm
Phrenic nerve 膈神经 Sensory fibers supply to
pleurae, pericardium and peritoneum of diaphragm; usually right phrenic nerve may be distributed on liver, gallbladder and biliary system.
Left vagus nerve 左迷走神经 Enter thoracic inlet between l
eft common carotid and left subclavian arteries, posterior to left brachiocephalic vein
Crosses aortic arch where left recurrent laryngeal nerve branches off
Left vagus nerve 左迷走神经 Passes posterior to left lung ro
ot Forms anterior esophageal pl
exus Forms anterior vagal trunk at
esophageal hiatus where it leaves thorax and passes into abdominal cavity , then divides into anterior gastric and hepatic branches
Right vagus nerve 右迷走神经 Enter thoracic inlet on right
side of trachea Travels downward posterior
to right brachiocephalic vein and superior vena cava
Passes posterior to right lung root
Right vagus nerve 右迷走神经 Forms posterior esophageal ple
xus Forms posterior vagal trunk at
esophageal hiatus where it leaves thorax and passes into abdominal cavity, then divides into posterior gastric and celiac branches
Recurrent laryngeal nerves 喉返神经 Right one hooks around right s
ubclavian artery, left one hooks aortic arch
Both ascend in tracheo-esophageal groove
Nerves enter larynx posterior to cricothyroid joint, the nerve is now called inferior laryngeal nerve
Recurrent laryngeal nerves 喉返神经 Innervations: laryngeal mu
cosa below fissure of glottis , all laryngeal muscles except cricothyroid
Thoracic sympathetic trunk 胸交感干 Branches of sympathetic trunk
to thoracic plexuses Greater splanchnic nerve 内脏大神经 formed by preganglion
ic fibers from T5~T9 ganglia, and relay in celiac ganglion.
Thoracic sympathetic trunk 胸交感干 Lesser splanchnic nerve 内脏小神经 formed by preganglio
nic fibers from T10~T12 ganglia, and relay in aorticorenal ganglion.
The postganglionic fibers supply the liver, spleen, kidney and alimentary tract as far as the left colic flexure.
Experimental guide:
1. Cut through the clavicular attachment of the subclavius muscle and reflect the clavicle.
2. Dissect the intercostal spaces. 3. Open the thoracic cavity. 4. Observe the posterior aspect of the anterior t
horacic wall. 5. Observe the pleura. 6. Cut off the root of the lung. 7. Look for the intercostal vessels and nerve.
The Mediastinum
The Mediastinum 纵隔 Concept - all of organs b
etween the left and right mediastinal pleurae is called mediastinum. It extends from the sternum in front to the vertebral column behind, and from the thoracic inlet above to the diaphragm below.
Subdivisions of mediastinum Superior mediastinum 上纵隔 Inferior mediastinum 下纵隔
Anterior mediastinum Middle mediastinum Posterior mediastinum
Superior mediastinum 上纵隔Locating - from inlet of t
horax to plane extending from level of sternal angle anteriorly to lower border of T4 vertebra posterioly
Superior mediastinum 上纵隔Contents Superficial layer
Thymus Three veins
Left brachiocephelic v.
Right brachiocephelic v.
Superior vena cava
Middle layer Aortic arch and its t
hree branches Phrenic n. Vagus n.
Posterior layer Trachea Esophagus Thoracic duct
Triangule of ductus arteriosus 动脉导管三角 Bounded by phrenic n., left vag
us n. and left pulmonary a. Contents - arterial ligament ,
left recurrent n. and superficial cardiac plexuses
Inferior mediastinum 下纵隔Anterior mediastinum 前纵隔 Location - posterior to bo
dy of sternum and attached costal cartilages, anterior to heart and pericardium
Contents - fat, remnants of thymus gland, anterior mediastinal lymph nodes
Middle mediastinum 中纵隔 Location - between ante
rior mediastinum and posterior mediastinum
Contents: heart and pericardium, beginning or termination of great vessels, phrenic nerves, pericardiacophrenic vessels , lymph nodes,
Posterior mediastinum 后纵隔 Location - posterior to he
art and pericardium, anterior to vertebrae T5 - T12
Contents: esophagus, vagus n., thoracic aorta, azygos system of veins, thoracic duct, thoracic sympathetic trunk, posterior mediastinal lymph nodes
Right side of mediastnum
Root of lung
Pericardium
Superior vena cava
Phrenic n. & pericardiacophrenic a.
Left vagus n.
Azygos v.
Sympathetic trunk
Esophagus
Arch of azygos v.
Trachea
Inferior vena cava
Left side of mediastnum
Root of lung
Pericardium
Phrenic n. & pericardiacophrenic a.
Left vagus n.
Left recurrent n. Thoracic aorta
Sympathetic trunk
Greater splanchnic n
Aortic archThoracic duct
Left subclavian a.
Esophagus
Experimental guide:
1. On the right side of the mediastinum.
2. On the left side of the mediastinum. (Attention: Don’t cut off the heart.)