2. Pectoral Region
ο The pectoral region lies on the front of
the chest.
ο Consists of structures which connect
the upper limb to the anterolateral chest
wall
ο Under the skin lies the superficial fascia
of the pectoral region
5. (1) PECTORALIS MAJOR
ο Origin
ο It has two heads :
ο Clavicular :
ο Anterior surface the
medial half of the
clavicle.
ο Sternocostal:
ο Anterior surface of
sternum.
ο Upper six costal
cartilages.
ο External oblique
aponeurosis.
6. (1) PECTORALIS MAJOR
Insertion :
ο Lateral lip of the
bicipital groove of the
humerus.
Nerve supply :
ο Medial and lateral
pectoral nerves.
Action :
ο Adduction and medial
rotation of humerus.
ο Flexion of arm
(clavicular head).
7. (2) PECTORALIS MINOR
ο It is a thin triangular
muscle that is covered
by pectoralis major.
Origin :
ο Anterior surfaces of 3rd
-5th ribs.
Insertion :
ο Medial border and
superior surface of
coracoid process of
scapula.
8. (2) PECTORALIS MINOR
Nerve supply :
ο Medial pectoral nerve.
Action :
ο Pulls the shoulder
downwards and
forwards.
ο It elevates the ribs
when the scapula is
fixed.
9. (3) SUBCLAVIUS
Origin :
ο Junction of the 1st rib and
its costal cartilage.
Insertion :
ο Subclavian groove in the
middle one-third of the
clavicle.
Nerve supply :
ο Nerve to subclavius (C5,
C6)
Action :
Anchors and depresses the
10. Serratus Anterior
Origin:
ο External surfaces of
lateral parts of 1st β 8th
ribs
Insertion
ο Anterior surface of medial
border of scapula
Nerve supply
ο Long thoracic nerve
(C5, C6, C7)
Action
ο The main action of the
serratus anterior is to
rotate the scapula
ο Protract the scapula and
holds it against thoracic
wall
11. Winging of
scapula
ο If damage to the long
thoracic nerve occurs,
the serratus anterior
muscle will become
paralysed.
ο The inferior angle and
medial border of the
scapula become
unduly prominent
ο When pushing with the
affected limb, the
scapula is no longer
held against the rib
cage, and protrudes
out of the back.
12. Winging of
scapula
ο It is said to have a
βwingedβ appearance
due to unopposed
action of the
rhomboidius and
levator scapulae.
ο The long thoracic nerve
can become damaged
by trauma to the
shoulder, repetitive
movements involving
the shoulder or by
structures becoming
inflamed and pressing
14. BREASTS
ο Are modified apocrine
sweat glands present
in both males and
females
ο It is rudimentary in
males but well
developed in female
after puberty
ο In females at puberty,
the mammary glands
increase in size mainly
by the deposition of fat
and by the influence of
15. Shape of Breast
ο In postpubertal nulliparous female β is
conical or hemispherical in shape
ο In old life - penduulous
16. Position
ο It lies on the
front and
sides of the
chest in the
superficial
fascia which
split to
enclose it.
17. Axillary tail ο Small upper lateral part of
the gland may extend
towards the axilla β the
axillary tail of Spence
ο It pierces the axillary (deep)
fascia through a small
foramen known foramen of
langer and lies in the axilla
18. Extent
Vertically:
ο The base of the breast
extends from 2nd -6th
ribs.
Horizontally:
ο Lateral margin of the
sternum (medially) to
the midaxillary line
(laterally).
19. Relations
ο About 2/3rd of
the base lies on
the deep fascia
covering the
pectoralis major
ο Inferolateral 1/3
lies on serratus
anterior and
external oblique
muscle
20. Retromammary space
ο Is a potential
space filled with
loose connective
tissue lying
between the deep
aspect of the
breast and fascia
covering
pectoralis major
ο It allow the breast
some degree of
movement on
pectoral fascia.
21. Applied Anatomy of Retromammary
Space
ο Invasion of the carcinoma of breast may
cause fixity of the breast to the pectoral
fascia and the muscle
22. Structure of the Breast
ο The structure of the breast may be
divided into the:
1. Skin
2. Parenchyma
3. Stroma
23. Skin
ο Covers the gland
and the following
features are seen:
ο Nipple & areola
Nipple:
ο Is a conical or
cylindrical
projection in the
centre of areola
24. ο The nipple lies just
below the center of
the breast at the
level of 4th
intercostal space.
ο Is perforated by 15-
20 lactiferous
ducts.
Skin
25. ο Contains circular
and longitudinal
smooth muscle
fibers
ο Circularly arranged
smooth muscles :
make the nipple stiff
ο Longitudinally
arranged smooth
muscles : make the
nipple flatten
Skin
26. ο Has few modified
sweat & sebaceous
glands
ο Rich in nerve supply
& many sensory end
organs at the
termination of nerve
fibers
Skin
27. οΆ Is a dark pink /
brownish circular area
of skin that surrounds
the nipple.
ο Dark brown or black
during pregnancy and
lactation
ο Rich in sebaceous glands
(areola) and are devoid of
fat & hair
ο Become large during
pregnancy & lactation and
form raised tubercles
Areola
28. βMontgomery,s tubercles
ο Produce oily secretions
i. Lubricate nipple &
areola & prevent them
from cracking during
lactation
ii. Add firmness of
adhesion to the lips
of the new born baby
while suckling the
breast
iii. Create great sensitivity
so that sympathetic
stimulation leads to
Areola
29. Paranchyma
ο Is made up of glandular tissue
ο The glandular tissue consists of
15-20 lobes
ο Each lobe consists of several
lobules
ο each lobule consists of clusters
of alveoli which opens into the
smallest branch of lactiferous
duct
ο These branches unite to form
larger branches of the duct
ο Each lobe is drained by a
lactiferous duct
30. ο Lactiferous duct
converge towards the
nipple and opens on it
ο Each duct has a
dilatation called
ampulla or
lactiferous sinus
prior to its
termination.
31. Stroma
ο The stroma forms
supporting
framework for the
gland
ο It is partly fibrous and
partly fatty
ο Fibrous stroma forms
numerous septa known as
the Suspensory ligament of
Cooper which anchors the
gland to the overlying skin
and to the underlying deep
fascia (pectoral fascia)
ο And divides the gland into 15
β 20 lobes
32. Stroma ο The fatty stroma
ο Forms the main bulk of the
gland
ο Is distributes all over the
breast except beneath
areola and nipple
33. BLOOD SUPPLY
ο Breast is supply
by :
1. Internal thoracic
: through its
perforating
branches
(subclavian
artery).
2. Some branches
of Axillary artery
:
β’ Superior thoracic
ο lateral thoracic
ο thoracoacromial
3. Lateral branches
of posterior
intercostal
34. VENOUS SUPPLY
β’ Veins follow the
corresponding
arteries.
β’ Circular venous
plexus are found
at the base of
nipple.
Finally, veins of
this plexus drain
into axillary ,
internal thoracic
veins & posterior
intercostal veins.
35. Venous Drainage
ο Carcinoma can spread through veins as veins
indicate lymphatic pathway
ο The posterior intercostals veins drain into the
azygous /hemiazygous system of veins along
side the bodies of vertebrae, which empties in
the superior vena cava.
ο Through this route cancer cells can spreads
from breast to the vertebrae and from there to
the skull and the brain.
36. Nerve supply
ο The breast is supplied by the anterior and
lateral cutaneous branches of the 4th to 6th
intercostals nerves.
37. Lymph nodes
ο Lymph from the breast drains
into the following lymp nodes:
1. Axillary lymph nodes:
Anterior (pectoral),
Posterior (subscapular),
lateral (humeral), central
and apical (infraclavicular)
groups
2. Internal mammary
(parasternal) nodes which
lies along the internal
thoracic vessels
3. Supraclavicular nodes,
cephalic (deltopectoral)
node, posterior intercostal
nodes, subdiaphragmatic
and subperitoneal lymph
plexuses
38. LYMPH DRAINAGE
ο It is of considerable
clinical importance
because of the
frequent
development of
cancer of the gland
and the
dissemination of the
malignant cells along
the lymph vessels.
39. BREAST QUADRANTS
ο Regarding the lymph
drainage, the breast
(mammary gland) is
divided into four
quadrants:
ο Upper Inner / Superior
medial
ο Lower Inner / Inferior
medial
ο Upper Outer / Superior
lateral
ο Lower Outer / Inferior
40. ο Lymphatic vessels in
the skin of the
breast, except the
nipple and areola,
drain into the
anterior (pectoral)
group of axillary
lymph nodes
ο Also into the
parasternal nodes
medially
ο Some vessels from the
upper part of the skin
crosses the clavicle
and drains into
supraclavicular lymph
nodes
41. LYMPHATIC DRAINAGE
ο Lymph passes from
the nipple, areola
and parenchyma of
the gland to the
subareolar lymphatic
plexus (of Sappy)
which lies beneath
the areola.
ο From this plexus:
1. More than 75% of
the lymph,
especially from the
lateral quadrants of
the breast, drains to
the axillary or
pectoral group of
42. ο Some lymph may
drain directly to the
other axillary nodes
ο Lymph from the
axillary nodes drains
into infraclavicular
and supraclavicular
nodes and from them
into the subclavian
lymphatic trunk,
which also drains
lymph from upper
limb.
43. Lymph
Drainage
ο The medial quadrant
drains to the internal
thoracic (parasternal)
group of
nodes(situated within
the thoracic cavity
along the course of
the internal thoracic
artery) of the same
and opposite sides.
(about 20%)
ο Lymph from
parasternal nodes
enters the
bronchomediastinal
trunk, which drains
lymph from the
44. Lymph Drainage
ο The inferolateral part
of the breast drains
into the posterior
intercostal nodes
(situated along the
course of the
posterior intercostal
arteries);
ο Some vessels
communicate with
the lymph vessels of
the opposite breast
45. Lymph Drainage
ο 5.The
inferomedial part
of the breast may
communicate
with
subdiaphragmati
c and
subperitoneal
lymph plexuses
to nodes in
abdomen
ο Then to liver,
ovaries,
peritoneum
46. Development of the breast
ο Develops from an
ectodermal thickening,
called mammary ridge
or milk line
ο Extends from the axilla
to the groin
ο In humans, the milk
ridge persist only in the
pectoral region
ο Ingrowth from milk ridge
give rise to the
glandular tissue, the
duct and alveoli of the
breast
ο The surrounding
mesoderm gives rise to
the connective tissue
thatβs supports the
glandular tissues
47. Applied anatomy:
Changes in the breasts
οΆ Changes, such as branching of the lactiferous
ducts, occur in the breast tissues during the
menstrual cycles and pregnancy.
οΆ Although mammary glands are prepared for milk
secretion by mid pregnancy, they do not produce
milk until shortly after the baby is born.
οΆ Colostrum, a creamy white to yellowish premilk
fluid, may secrete from the nipples during the last
trimester of pregnancy and during initial episodes
of nursing.
οΆ Colostrums is believed to be especially rich in
protein, immune agents
48. Applied
Anatomy
Incisions:
β’ The lactiferous ducts
are radially arranged
from the nipple, so
incision of the gland
should be made in a
radial direction to
avoid cutting
through the ducts.
49. ο Infiltration of the
suspensory ligaments
by cancer cells causes
shortening contraction
of the suspensory
ligaments.
ο Dimpling of skin over
the breast
ο Infiltration of lactiferous
ducts and their
consequent fibrosis can
cause retraction of
nipple.
50. β’ Interference with the
lymphatic drainage of the
breast by cancer cells may
cause deviation of the
nipple and produce a
leatherlike, thickened
appearance of the skin.
β’ The skin is thickened or
βpuffyβwith prominent pores
that give it an orange peel
appearance (peau dβorange
sign), because of the
edema (excess fluid in the
subcutaneous tissue)
resulting from the blocked
lymphatic drainage.
51. ο Due to communications of the superficial
lymphatics of the breast across the midline,
cancer may spread from one breast to
another
ο Because of the communications of lymph
vessels with those in the abdomen, cancer
of the breast may spread to the liver and
cancer cells may drop into the pelvis
52. ο Mastectomy:
ο Excision of the breast is called
mastectomy. It is not as common as it once
was as a treatment for breast cancer.
ο In simple mastectomy, the breast is removed
down to the retromammary space.
ο Radical mastectomy, a more extensive
surgical procedure, involves removal of the
breast, pectoral muscles, fat, fascia, and all
lymph nodes in the axilla and pectoral
region.
53. ο Mammography:
It is the radiographic excision of the
breasts. It is one of the techniques to
detect breast masses.
ο The carcinoma appears as a large,
jagged density in the mammogram.
ο Mammography is also used by the
surgeons to guide them when removing
breast tumors, cysts, and abscesses.
54. ο Polymastia
ο Is a congenital anomaly in
humans in which there are
more than one breast on
one or both sides due to
the persistence of the milk
ridge
ο Polythelia
ο Presence of
supernumerary nipples
which may occur superior or
inferior to the normal breasts,
occasionally developing in
the axilla or anterior
abdominal wall.
55. ο Gynecomastia:
Enlargement of the breast in
males.
ο It commonly occurs at puberty
but may also accompany
ageing or be drug related
56. ο Amastia :
ο In either sex, there may be no breast
development or there may be a nipple
but no granulation tissue.
ο Athelia
ο The nipple may be absent
58. Muscles connecting the upper
limb to the vertebral column
ο They are:
1. Trapezius
2. Latissimus dorsi
3. Levator scapulae
4. Rhomboideus minor
5. Rhomboideus major
59. Trapezius
Origin
ο external occiptal
protuberunce of
occipital bone,
ο superior nuchal line,
of occipital bone
ο ligamentum nuchae,
ο spine of seventh
cervical vertebra
ο spines of all thoracic
vertebrae and their
supraspinous
ligament
60. Trapezius
Insertion
ο Upper fibers into
posterior
surface of lateral
third of clavicle;
ο middle fibers
into acromion
process of the
scapula
ο lower fibers into
the spine of
scapula
61. Nerve Supply / Action
Nerve Supply
ο Spinal part of accessory nerve (motor)
and C3 and C4 (sensory)
Action
ο Upper fibers: Elevate the scapula
ο Middle fibers: Retracts the scapula
ο Lower fibers: Depresses the scapula
62. Latissimus dorsi
Origin
ο Spines of lower six
thoracic vertebrae(T7-
T12)
ο Lower three or four
ribs
ο Posterior part of iliac
crest and lumbar
fascia
ο Inferior angle of
scapula
Insertion
ο Floor of bicipital
63. Nerve Supply / Action
Nerve Supply
ο Thoracodorsal nerve
Action
ο Extends, adducts, and medially
rotates the arm
ο Its called the climbing muscle
ο Raising of the trunk above the arm
64. Levator
scapulae
Origin
β’ Transverse processes of first
fourth cervical vertebrae
Insertion
β’ Dorsal lip of the medial
border of scapula above the
level of its spine
Nerve supply
β’ Ventral rami of 3rd and 4th
cervical nerve
β’ Dorsal scapular nerve
Action
β’ Raises medial border
of scapula
65. Rhomboid
minor
Origin
β’ Lower part of
Ligamentum nuchae
β’ Spines of C7 and T1
Insertion
β’ Medial border of
scapula opposite the
root of its spine
Nerve supply
β’ Dorsal scapular nerve
Action
β’ Raises medial border of
scapula upward and
medially
66. Rhomboid
major
Origin
β’ Spines of T2 β T5 and
their supraspinous
ligaments
Insertion
β’ Dorsal lip of the medial
border of scapula
below the level of the
spine
Nerve supply
β’ Dorsal scapular nerve
Action
67. Muscles connecting the scapula
to the humerus
1. Deltoid
2. Supraspinatus
3. Infraspinatus
4. Teres minor
5. Teres major
6. Subscapularis
68. Deltoid
ο Deltoid is a thick
powerful muscle,
covering the
shoulder and
forming its rounded
contour.
ο It has three parts:
anterior, posterior
and middle part
Origin
β’ Lateral one-third of
clavicle, acromion,
spine of scapula
Insertion
ο Deltoid tuberosity of
humerus
69. Deltoid
Nerve supply
ο Axillary nerve (C5, 6)
Action
ο Anterior fibers: flex
and medially rotate
arm;
ο Middle fibers:
Abducts arm
ο Posterior fibers:
extend and laterally
rotate arm
70. ο Deltoid is a common site for the
intramuscular injections of drugs.
ο They should be given in the lower half
of the muscle to avoid injury to the
axillary nerve
ο Injury to the axillary nerve leads to
atrophy of the deltiod muscle
ο As the deltoid atrophies, the rounded
contour of the shoulder disappears.
71. Supraspinatus
Origin
ο Supraspinous
fossa of scapula
Insertion
ο Greater tubercle of
humerus; capsule
of shoulder joint
Nerve supply
ο Suprascapular
nerve (C4, 5, 6)
Action
ο Abducts arm and
stabilizes shoulder
joint
72. Infraspinatus
Origin
ο Infraspinous fossa of
scapula
Insertion
ο Greater tubercle of
humerus; capsule of
shoulder joint
Nerve supply
ο Suprascapular nerve
(C4, 5, 6)
Action
ο Laterally rotates arm
and stabilizes
shoulder joint
73. Teres major
Origin
β’ Lower one-third of
lateral border of scapula
Insertion
β’ Medial lip of bicipital
groove of humerus
Nerve supply
β’ Lower subscapular
nerve (C6, 7)
Action
β’ Medially rotates and
adducts arm and
stabilizes shoulder joint
74. Teres minor
Origin
β’ Upper two thirds of
lateral border of
scapula
Insertion
β’ Greater tubercle of
humerus; capsule of
shoulder joint
Nerve supply
β’ Axillary nerve (C4), C5,
6
Action
β’ Laterally rotates arm
76. Rotator Cuff
β’ The rotator cuff is the
name given to the
tendons of the
subscapularis,
supraspinatus,
infraspinatus, and teres
minor muscles
β’ Which covers all except
the inferior aspect of the
shoulder joint
β’ The cuff plays a very
important role in
stabilizing the shoulder
joint & prevents upward
dislocation of the joint
β’ .
77. Quadrangular
Space
β’ The
quadrangular
space is an
intermuscular
space, located
immediately
below the
shoulder joint
Boundaries:
β’ Superiorly:
Subscapularis,
capsule of the
shoulder joint
and teres minor
β’ Inferiorly: teres
78. Quadrangular
Space
β’ Medially:
β’ long head of the
triceps
β’ Laterally:
β’ surgical neck of
the humerus.
Content
β’ axillary nerve
β’ posterior
circumflex
humeral artery
and vein
79. Triangular space
β’ The triangular space
is an area of
communication
between the axilla
and the posterior
scapular region
β’ Upper triangular
space
Boundaries
β’ Medial: teres minor
β’ Lateral: long head of
triceps
β’ Inferior: teres major
Content
β’ The circumflex
scapular artery and
vein pass through
this gap to the
infraspinous fossa
