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Surface Anatomy and Surface Landmarks for Thoracic Surgery
Article in Thoracic Surgery Clinics · December 2007
DOI: 10.1016/j.thorsurg.2006.12.002 · Source: PubMed
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Thorac Surg Clin 17 (2007) 449–461
Surface Anatomy and Surface Landmarks
for Thoracic Surgery
Rana A. Sayeed, MA, PhD, MRCP, FRCS(C-Th)a,b,
Gail E. Darling, MD, FACS, FRCSCa,*
a
University of Toronto, Division of Thoracic Surgery, Toronto General Hospital, 200 Elizabeth Street,
Toronto, Ontario M5G 2C4, Canada
b
Department of Cardiothoracic Surgery, John Radcliffe Hospital, Oxord OX3 9DU, UK
A thorough knowledge of thoracic anatomy is of
fundamental importance to the thoracic surgeon.
Surface anatomy is an often-neglected component
of traditional topographic anatomic teaching, but
a proper understanding of the relationship of
surface features to deeper structures is invaluable
in the clinical assessment of a patient and in the
interpretation of radiologic imaging. Familiarity
with thoracic surgical landmarks is a prerequisite
for the successful placing of a thoracic incision.
The surface anatomy that is most relevant is
those landmarks that define location of the pulmonary fissures and hila, the trachea and tracheal
carina, aortic arch, and the level of the diaphragm.
Thoracic incisions are placed to provide the best
access to the pulmonary hila, trachea, or great
vessels based on knowledge of the surface anatomy.
Similarly, knowledge of the intrathoracic anatomy
and level of the diaphragm based on surface
landmarks is useful for interventional procedures,
such as tube thoracostomy. Furthermore, knowledge of the chest wall musculature is essential in the
use of muscle flaps for reconstruction.
Surface anatomy of the chest and neck
Muscular landmarks
The sternocleidomastoid arises by two heads,
from the upper part and anterior surface of the
* Corresponding author.
E-mail address: [email protected]
(G.E. Darling).
manubrium and from the medial third of the
clavicle. The muscle extends diagonally upward to
insert onto the mastoid process of the skull base.
The medial border of the muscle is an important
landmark for oblique cervical incisions used in
approaches to the cervical esophagus and for
cannulation of the internal jugular vein.
Pectoralis major arises from the second to sixth
costal cartilages and ribs, sternum, and medial
half of the clavicle and passes as a fan-shaped
muscle to insert into the lateral lip of the
intertubercular groove of the humerus. The lower
margin of the muscle forms the anterior fold of
the axilla. In men, the lower border may be seen as
a curved line leading out to the axilla that
corresponds to the fifth rib (Fig. 1).
Below pectoralis major lies serratus anterior on
the anterolateral aspect of the chest wall. Serratus
anterior arises from muscular slips from the upper
eight ribs and attaches to the anterior surface and
vertebral border of the scapula. The muscular
slips on the lower ribs may be seen on thin,
muscular patients: the highest visible digitation
indicates the sixth rib (see Fig. 1).
The posterior thoracic cage is covered by large
muscles related to the upper limb, neck, and spine.
Latissimus dorsi is of most importance to the
thoracic surgeon. This muscle has an extensive
origin through a broad aponeurosis from the
spines of the lower six thoracic vertebrae, the
lumbodorsal fascia, and the iliac crest. The muscle
tapers into a narrow tendon that inserts into the
intertubercular groove: this tendon forms the
posterior fold of the axilla as it runs below teres
minor.
1547-4127/07/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved.
doi:10.1016/j.thorsurg.2006.12.002
thoracic.theclinics.com
450
SAYEED & DARLING
Sternocleidomastoid
muscle
Manubrium
Jugular
(suprasternal)
notch
Manubrosternal
angle (of Louis)
T2
Pectoralis
major muscle
T4
Body of
sternum
Xiphisternal
angle
Serratus
anterior
muscle
T9
Xiphoid
process
Mid-clavicular line (C)
Lateral sternal line (B)
Mid-sternal line (A)
Fig. 1. Bony surface landmarks on the anterior chest. Note the commonly used reference lines. (A) Midsternal line. (B)
Lateral sternal line. (C) Midclavicular line.
The muscular borders of the axilla define the
axillary lines, imaginary vertical lines that are
useful for description of thoracic anatomy. The
anterior axillary line passes through the anterior
axillary fold produced by the pectoralis major and
extends downward to pass through the anterior
superior iliac spine. The posterior axillary line
passes through the posterior axillary fold that is
formed by latissimus dorsi and teres major. The
midaxillary line runs vertically between these
anterior and posterior lines.
In men, the nipple overlies the fourth intercostal space, near the lower border of pectoralis
major, just lateral to the midclavicular line (approximately 10 cm from the midline). In women,
nipple position is inconsistent but the circular base
of the breast arises over the second to sixth ribs
and extends from the lateral border of the sternum
to the midaxillary line; the upper outer quadrant
extends into the axilla along the lower border of
pectoralis major.
Bony landmarks
The sternum is easily palpable and is comprised of the manubrium, body, and xiphisternum. The manubrium lies superiorly with the
suprasternal or jugular notch marking its upper
border, which is easily palpable between the
clavicular heads. The upper border of the manubrium is used as a landmark when making
a mediastinoscopy or collar incision. It also
corresponds to the level of the lower border of
the second thoracic vertebra and first thoracic
SURFACE ANATOMY AND LANDMARKS FOR THORACIC SURGERY
spinous process (see Fig. 1). The manubrium is 4
cm long and overlies the aortic arch. The manubrium articulates with the sternal body at the
(sternal) angle of Louis: this manubriosternal
junction is palpable as a transverse ridge in most
patients. The second costal cartilages articulate
with the lateral border of the sternum at the angle
of Louis: counting the ribs anteriorly is most
easily started at this level because the first rib is
impalpable beneath the clavicle. The angle of
Louis lies at the level of the lower border of the
fourth thoracic vertebra. The sternal body is
10 cm long and lies opposite the fifth to eighth
vertebrae in front of the heart. Below the body
is the cartilaginous xiphisternum, which may be
palpable, and lies at the level of the ninth thoracic
vertebra.
The plane passing through the angle of Louis
and the lower border of the fourth thoracic
vertebra is an important landmark for deeper
thoracic structures. The plane arbitrarily divides
the superior mediastinum from the rest of the
mediastinum. The tracheal carina lies at this
level. The concavity of the aortic arch lies just
above and the bifurcation of the pulmonary
trunk just below this plane. The ligamentum
arteriosum between the origin of the left pulmonary artery and the concavity of the aortic arch
runs almost horizontally at this level, which
marks the lowest descent of the left recurrent
laryngeal nerve. The azygos vein arches forward
over the right hilum to enter the back of the
superior vena cava in this plane, and the thoracic
duct, ascending from the abdomen to the right of
the midline, crosses over to reach the left side of
the chest by this level.
The costal cartilages connect the anterior ends
of the ribs to the sternum, increase in length from
the first to seventh cartilage, and then shorten.
The costochondral junctions lie in a line from
a point 5 cm from the midline at the angle of
Louis to a point 2.5 cm behind the lowest part of
the tenth costal cartilage. The fifth rib lies just
under the lower border of pectoralis major at the
level of the xiphisternal joint. The seventh costal
cartilage is usually the lowest that articulates
directly with the sternum. Below this, the costal
margin forms the easily palpable lower boundary
of the bony thorax with contributions from the
seventh to tenth costal cartilages. The tenth
costal cartilage marks the lowest point of the
costal margin, at the level of the third lumbar
vertebra in the midaxillary line. The tips of the
eleventh and twelfth ribs may be palpable in the
451
body wall behind the lowest part of the costal
margin.
Counting of the ribs may be accomplished by
counting from the second rib as identified by the
angle of Louis, or less commonly by counting up
from the seventh rib anteriorly or tenth rib
posteriorly.
On the back, the scapula overlies the first to
seventh ribs. It is covered with muscle and may
be difficult to palpate, but nonetheless bears
important landmarks. The superior angle lies
opposite the spinous process of the second
thoracic vertebra, the scapula spine opposite the
spinous process of the third vertebra, and the
inferior angle covers the eighth rib and marks
the level of body of T9 (Fig. 2). With the arm in
full abduction, the vertebral border of the scapula
marks the line of the oblique fissure of the lung
(Fig. 3).
In the posterior midline, the most prominent
spinous process arises from the seventh cervical
vertebra (vertebra prominens [see Fig. 2]); the
spine of the first thoracic vertebra may be equally
prominent in some cases. Below this, the spines of
the remaining thoracic vertebrae run downward,
so that the tip of each lies posterior to the subjacent vertebral body.
Trachea
The trachea is easily palpable above the suprasternal notch. It runs down almost vertically from
the cricoid cartilage at the level of the sixth
cervical vertebra to enter the thoracic cavity
behind the manubrium. The trachea is 15 cm
long: just 5 cm is palpable above the notch with
the head in a neutral position, but this length
increases up to 8 cm when the neck is extended
(eg, in the position for tracheostomy). Within the
chest the trachea lies slightly to the right of the
midline and ends at its bifurcation at the carina at
the level of the lower border of the fourth thoracic
vertebra. This is the level described in the cadaver:
the carina may travel up to 2 to 3 cm with each
breath and may lie at the level of the fifth or sixth
thoracic vertebra at full inspiration.
Surface projections of the pleura and lungs
Knowledge of the surface anatomy of the lobes
and fissures of the lungs is necessary for the
localization of abnormalities detected by clinical
examination or chest radiology.
452
SAYEED & DARLING
Spinous process of C7
(vertebra prominens)
Superior angle
of scapula
at T2 level
Spinous process
of T1
1
2
3
Scapular
spine
4
5
6
Triangle of
auscultation
7
8
9
Inferior
angle
10
11
12
Fig. 2. Bony surface landmarks on the back. Note the area of the triangle of auscultation formed by the lateral border of
trapezius muscle, medial border of scapula, and upper border of latissimus dorsi. Because this area is free of intervening
muscle masses, respiratory sounds can be easily detected.
Major airways and pulmonary hila
Pleura
The trachea ends at its bifurcation at the level
of the angle of Louis. The right main bronchus
runs more vertical than the left, arising at 25
degrees from the vertical, and running for 2.5 cm
before entering the right lung hilum at the level of
the fifth thoracic vertebral body. The left main
bronchus runs at 45 degrees for 5 cm before
entering the left hilum at the level of the sixth
thoracic vertebra (Fig. 4).
The hilum lies behind the second to fourth
costal cartilages parallel and 2.5 cm lateral to the
sternal edge. Posteriorly, this corresponds to
a vertical line 5 cm from the midline alongside
the fourth to sixth thoracic spinous processes.
The parietal pleura lines the chest wall and
mediastinum and bounds the pleural cavity; the
surface projection of the pleura is of clinical
importance in the prevention of inadvertent pneumothorax during central venous cannulation or
abdominal surgery. The thoracic inlet is bounded
by the oblique first rib: from the lateral aspect, the
upper border of the pleura follows the line of the
rib, but from the front, the apex of the pleura lies 2.5
cm above the medial third of the clavicle and behind
the sternocleidomastoid muscle (Fig. 5). From the
apex, the pleura follows a curved line, convex upward, toward the sternoclavicular joint. On both
sides of the chest, the pleura runs toward the
453
SURFACE ANATOMY AND LANDMARKS FOR THORACIC SURGERY
Level of
horizontal
fissure
Spinous
process
of T4, T5
and T6
Anterior
axillary line
Projection of
oblique fissure
Tip of
scapula
Level of 6th or 7th
costochondral
junction
Latissimus
dorsi muscle
Posterior
axillary line
Iliac
crest
Fig. 3. Surface anatomy of the back. Note that the origin of the right oblique fissure is normally at a lower level than
that of the left, and that it runs downward and forward to end in the region of the sixth or seventh costochondral
junction.
454
SAYEED & DARLING
Angle of
Louis (T4)
Carina
Right
hilum (T5)
Left
hilum (T6)
Fig. 4. Surface anatomy and projections of the tracheobronchial tree.
midline behind the angle of Louis at the level of the
second costal cartilage and continues downward in
the midline to the fourth costal cartilage. Here the
right and left pleura diverge. The right pleura continues downward to the right side of the xiphisternal joint. The left pleura is deflected laterally to
the sternal edge at the lower border of the left sixth
costochondral joint. The lower limit of the costal
pleura continues laterally on both sides to cross
the eighth rib in the midclavicular line, the tenth
rib in the midaxillary line, and the twelfth rib at
the lateral border of erector spinae.
Lungs
The surface markings of the lungs closely
follow those of the pleurae because only a thin
film of fluid separates these structures in health
(see Fig. 5). In quiet respiration, however, the
lower edge of the lung is usually 5 cm or two
rib-spaces above the limit of the pleura; the excursion of the lung may be up to 7.5 cm in deep respiration. Although the projection of the lung
apices matches the pleural projection, the inferior
border of the lung crosses the sixth rib in the midclavicular line, the eighth rib in the midaxillary
line, and the tenth rib at erector spinae. On the
left side, the lung displays the cardiac notch and
lies 2.5 cm from the edge of the pleura and sternum at the level of the fifth costal cartilage and
4 cm from the midline at the level of the sixth cartilage. The posterior borders of the lungs follow
a line down either side of the vertebral column
from the level of the spine of the seventh cervical
455
SURFACE ANATOMY AND LANDMARKS FOR THORACIC SURGERY
A
Cupula
Cardiac
notch
Oblique
fissure
Inferior
margin
of lung
10
6
8
Inferior
margin
of pleura
B
Costadiaphragmatic
recess
Upper
lobe
Upper lobe
T4
T4
4th costochondral
junction
Oblique
fissure
Oblique
fissure
Middle
lobe
Horizontal
fissure
Lower
lobe
6th costochondral
junction
Costodiaphragmatic
recess
LATERAL VIEW OF THE RIGHT LUNG
LATERAL VIEW OF THE LEFT LUNG
Fig. 5. (A, B) Surface projections of the pleurae and lungs.
vertebra down to the spine of the tenth thoracic
vertebra.
The separation of visceral and parietal pleura
below the base of the lung gives rise to the slit-like
costodiaphragmatic recess behind the dome of
the diaphragm. There is a similarly formed
costomediastinal recess behind the left lower
costal cartilages because of the cardiac notch of
the left lung.
Pulmonary fissures
The left lung is separated into upper lobe and
lower lobe by the oblique or major fissure. An
additional transverse or minor fissure produces
the middle lobe of the right lung. The right
oblique fissure starts opposite the fourth thoracic
spinous process and follows the line of the fifth
rib, or a line just below, to end near the right sixth
456
SAYEED & DARLING
costochondral junction or just above in the fifth
intercostal space (see Fig. 5B). The transverse fissure leaves the oblique fissure in the fifth intercostal space in the midaxillary line and runs forward
to end behind the right fourth costal cartilage at
the anterior border of the lung. The left oblique
fissure is more variable in position than the right:
it starts opposite the third of fourth spinous process and runs forward and downward through
the fifth intercostal space in the midaxillary line
to end near the left sixth costochondral junction
or just above in the fifth intercostal space.
Surface projections of the heart and great vessels
Heart
The heart and pericardium fill the middle
mediastinum, lying behind the body of the
sternum and the third to sixth costal cartilages
B
A
D
C
A
B
C
D
Upper border of right 3rd costal cartilage.
Lower border of left 2nd costal cartilage.
Apex beat at left 5th intercostal space, lateral to mid-clavicular line.
Middle of right 6th costal cartilage
Fig. 6. Surface projection of the heart.
457
SURFACE ANATOMY AND LANDMARKS FOR THORACIC SURGERY
on both sides. The superficial surface projection
corresponds to the area of cardiac dullness that
is of only historical interest. The deep projection
defines the anatomic boundaries of the heart
(Fig. 6). It is bounded by gently convex lines
that join the following four points: (1) the upper
border of the right third costal cartilage 1.25 cm
Right common
carotid
artery
from the sternal edge, (2) the middle of the right
sixth chondrosternal joint 1.25 cm from the
midline, (3) the left fifth intercostal space 9 cm
from the midline, and (4) the lower border of
the left second costal cartilage 1.25 cm from
the sternal edge. The point at the left fifth intercostal space 9 cm from the midline represents
Left common
carotid
artery
Left subclavian
artery
Right subclavian
artery
Aortic
arch
Brachiocephalic
artery
Right
pulmonary
artery
Left
pulmonary
artery
Pulmonary
trunk
Fig. 7. Surface projections of the great arteries.
458
SAYEED & DARLING
Right
brachiocephalic
vein
Left
brachiocephalic
vein
Superior
vena cava
Inferior
vena cava
Fig. 8. Surface projections of the great veins.
459
SURFACE ANATOMY AND LANDMARKS FOR THORACIC SURGERY
the position of the apex beat, the outermost and
lowest point for the palpation of the cardiac impulse. This position may vary by 6 to 10 cm and
may lie in the fourth to sixth space with respiration.
The surface markings of the pericardium
closely follow those for the heart with the exception that the pericardium extends more superiorly
around the great vessels, so that it reaches the
Left
phrenic
nerve
4
5
8
Xiphoid
10
12
Fig. 9. Lateral view of the left diaphragm.
Esophagae
hiatus at
level T10
Aortic
hiatus at
level 12
460
SAYEED & DARLING
level of the right second costal cartilage where it
invests the superior vena cava.
Pulmonary artery, aorta, and important arterial
branches
The pulmonary trunk is approximately 5 cm
long and 2.5 cm wide. The vessel begins at the
pulmonary orifice behind the left third costal
cartilage and runs upward to the left to reach
the left second costal cartilage 1.25 cm from the
sternal edge where the vessel bifurcates. The left
pulmonary artery passes to the left for 2.5 cm to
enter the hilum. The right pulmonary artery runs
to the right at the level of the second costal
cartilage (Fig. 7).
The aorta arises from the aortic orifice behind
the medial end of the left third costal cartilage and
runs up to the right second chondrosternal joint.
The arch passes up to the right side of the angle of
Louis and arches over and to the left behind the
left second costal cartilage. The descending aorta
continues downward, moving toward the midline,
to enter the abdomen through the aortic hiatus of
the diaphragm, approximately 9 cm below the
xiphisternal junction (see Fig. 7).
The brachiocephalic artery arises from the
aortic arch deep to the center of the manubrium
and runs up toward the right sternoclavicular
joint. The left common carotid artery arises just to
the left of the center of the manubrium and runs
up to the left sternoclavicular joint. The left
subclavian artery originates from the aortic arch
behind the left border of the manubrium and
passes up to lie behind the left sternoclavicular
joint (see Fig. 7).
The internal thoracic artery originates 2 cm
above the clavicle between the sternal and clavicular heads of sternocleidomastoid. Each vessel
passes down toward the second costal cartilage
3 cm from the midline and then runs vertically
downward 1.25 cm or a fingerbreadth from the
sternal edge behind the costal cartilages to the
sixth cartilage where the vessel bifurcates into its
terminal branches.
Brachiocephalic, caval, and azygos veins
The brachiocephalic vein arises from the junction of the internal jugular and subclavian vein
behind the sternoclavicular joint (Fig. 8). The left
brachiocephalic vein runs obliquely behind the
manubrium to join its vertically descending right
counterpart behind the lower border of the right
first costochondral junction to give origin to the
superior vena cava. The superior vena cava runs
downward, receiving the azygos vein at the level
of the second costal cartilage, to drain into the
right atrium behind the right third costochondral
junction, 1.5 cm from the midline.
The inferior vena cava has a short intrathoracic course: it gains the chest through the caval
opening in the central tendon of the diaphragm
(see below) and runs upward to enter the right
atrium behind the right sixth costal cartilage 2 cm
from the midline (see Fig. 8).
The azygos vein enters the thoracic cavity
alongside the aorta at the aortic hiatus or separately through the right crus. It runs to the right of
the midline, ascending vertically to the level of the
fourth vertebra, where it arches forward to enter
the superior vena cava behind the right second
costal cartilage, at the level of the angle of Louis.
Surface projection of the diaphragm
The diaphragm has an extensive origin from its
crura on the upper lumbar vertebra, muscular
slips arising from the lower ribs, and the sternum.
The diaphragm is dome-shaped and its apex lies at
a variable position according to respiration. The
right hemidiaphragm descends to the level of the
tenth thoracic vertebra, opposite the anterior end
of the fifth rib, with deep inspiration. The left
hemidiaphragm usually lies 1 cm lower (Fig. 9).
The diaphragm transmits several important
structures between thorax and abdomen. The inferior vena cava and right phrenic nerve pass through
the central tendon of the diaphragm 2.5 cm to the
right of the midline at the level of the eighth
thoracic vertebra, behind the right sixth costal
cartilage. The esophageal hiatus, though which
passes the esophagus, the anterior and posterior
vagal trunks, and the esophageal branches of the
left gastric artery, passes through a sling of fibers
from the right crus. This hiatus lies 2.5 cm to the
left of the midline at the level of the tenth thoracic
vertebra, behind the left seventh costal cartilage.
The aortic hiatus lies just to the left of the midline
behind the median arcuate ligament of the diaphragm and passes the descending aorta, thoracic duct, and azygos vein (although this may
pierce the right crus separately).
Further readings
Agur AMR, Dalley AF, Grant JCB. Grant’s atlas of
anatomy. 11th edition. Philadelphia: Lippincott
Williams & Wilkins; 2005.
SURFACE ANATOMY AND LANDMARKS FOR THORACIC SURGERY
Deslauriers J, Mehran R. Handbook of perioperative
care in general thoracic surgery. Philadelphia: Elsevier Mosby; 2005.
Gray H, Standring S. Gray’s anatomy: the anatomical
basis of clinical practice. 39th edition. Edinburgh
(UK): Elsevier Churchill Livingstone; 2005.
Kaiser LR. Atlas of general thoracic surgery. St. Louis
(MO): Mosby; 1997.
View publication stats
461
Keogh B, Ebbs S. Normal surface anatomy. London:
Heinemann Medical; 1984.
Pearson FG. Thoracic surgery. 2nd edition. New York:
Churchill Livingstone; 2002.
Sinnatamby CS, Last RJ. Last’s anatomy: regional and
applied. 10th edition. Edinburgh (UK): Churchill
Livingstone; 1999.