Download 05 - pectoral region

BREASTS
They are modified 
sweat glands which
are capable to secrete
milk.
They are present in 
both sexes.
(A) Males and 
Immature Females:
The nipples are 
small.
BREASTS
They are surrounded 
by a small colored area
(areola).
The breast tissue is 
formed of little duct
system embedded in
connective tissue that
is restricted to the
margin of the areola.
BREASTS
(B) At puberty in 
(Females):
The mammary glands 
increase in size mainly
by the deposition of fat
and by the influence of
the ovarian hormones.
It protrudes forward 
from a circular base.
POSITION
Most of the gland lies
in the superficial
fascia.
Its base extends 
from :
A. 2nd -6th ribs. 
B. Lateral margin of
the sternum to the
midaxillary line.


BREASTS
Axillary Tail: 
It is the part of the 
gland in the deep
fascia.
It extends upward and
laterally to enter the
axilla.

STRUCTURE
(1) lobes :
It is formed of (15-20) lobes 
radiating from the nipple.
The lobes are separated by 
fibrous septa.
In the upper part, they are 
well developed (suspensory
ligaments) binding the skin
to the deep fascia.
STRUCTURE
2. Ducts : 
A main duct arises 
from each lobe.
It opens separately 
on the summit of the
nipple.
Each duct has a 
dilatation (ampulla)
prior to its
termination.
STRUCTURE
Areolar glands: 
They produce tiny 
tubercles on the areola.
Retromammary 
space:
It is a loose connective
tissue separating the
breasts from the
underlying deep fascia.

BLOOD SUPPLY
Arteries : 
1. Internal thoracic & 
intercostal : perforating
branches.
2. Axillary : lateral 
thoracic &
thoracoacromial.
BLOOD SUPPLY
Veins : 
Correspond to the
arteries.

LYMPH DRAINAGE
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.
BREAST QUADRANTS
Regarding the 
lymph drainage,
the breast 
(mammary gland)
is divided into four
quadrants:
Upper medial. 
Lower medial. 
Upper lateral. 
Lower lateral. 
LYMPH DRAINAGE
1.Lateral quadrants: 
To anterior axillary 
(pectoral) group of
lymph nodes.
2.Medial quadrants: 
To internal thoracic 
lymph nodes along the
internal thoracic artery
within the thoracic
cavity.
LYMPH DRAINAGE
3. To the opposite 
breast.
4. To the anterior 
abdominal wall.
5. To the posterior 
intercostal nodes
along the posterior
intercostal arteries.
CANCER BREAST
Cancer occurring in 
the lateral quadrants
of the breast spreads
to the axillary lymph
nodes which can be
removed surgically.
60% of carcinomas of
the breast occur in the
upper lateral
quadrant.

CANCER BREAST
Thoracic 
metastases (from
carcinomas) of the
medial quadrants
are difficult to
treat.
PECTORAL MUSCLES
They are four 
muscles that move
the shoulder girdle
and attach it to the
thoracic wall.
(1) PECTORALIS MAJOR
It triangular in shape. 
It covers the upper chest. 
Its lower border forms the 
anterior wall of the axilla.
Superiorly it is separated 
from deltoid muscle along
the clavicle by the
deltopectoral triangle.
(1) PECTORALIS MAJOR
Origin 
It has two heads : 
Clavicular : 
from the medial half of the
clavicle.
Sternocostal: 
Anterior sternum. 
Upper six costal cartilages.
External oblique 
aponeurosis.


(1) PECTORALIS MAJOR
Insertion : 
Lateral lip of the bicipital
groove of the humerus.
Nerve supply : 
Medial and lateral 
pectoral nerves.
Action : 
Adduction and medial 
rotation of humerus.
Flexion of arm (clavicular
head).


(2) PECTORALIS MINOR
It is a thin triangular 
muscle that is
covered by pectoralis
major.
Origin : 
Anterior surfaces of 
3rd -5th ribs.
Insertion : 
Coracoid process. 
(2) PECTORALIS MINOR
Nerve supply : 
Medial pectoral nerve. 
Action : 
Pulls the shoulder 
downwards and
forwards.
It elevates the ribs 
(acessory muscle of
respiration) when the
scapula is fixed.
(3) SUBCLAVIUS
Origin : 
1st costal cartilage. 
Insertion : 
Inferior surface of the 
clavicle.
Nerve supply : 
A branch from the upper 
trunk of the brachial plexus.
Action : Depresses the 
clavicle.
CLAVIPECTORAL FASCIA
It is a strong sheet of 
fascia.
Attachment : 
Superiorly : 
It is attached to the clavicle
and splits to enclose the
subclavius muscle.
Inferiorly : It encloses the
pectoralis minor and
continues as the
suspensory ligament of
the axilla and joins the


CLAVIPECTORAL FASCIA
Contents : 
1.Nerve : lateral 
pectoral.
2.Artery : 
thoracoacromial.
3. Vein : cephalic. 
4. Lymph nodes. 
CLAVICLE
It is a long bone 
that lies
horizontally across
the root of the
neck.
It is subcutaneous
throughout its
length.

CLAVICLE
Articulations : 
Medially : 
Sternum. 
1st costal cartilage.
Laterally : 
Scapula 
(acromion).

CLAVICLE
Functions : 
1.Holds the arm away
from the trunk.
2. Transmits forces 
from the upper limb to
the axial skeleton.
3. Gives attachment 
to muscles.

CLAVICLE
Shape : 
Its medial 2/3 are
convex forward.
Its lateral 1/3 is 
concave forward.
