Regional Gross Anatomy
“Pectoral Region”
By
Vijittra Leardkamolkarn, Ph.D.
Associate Professor
Department of Anatomy
Pectoral region
1. Bony landmark :
Sternum:
Jugular notch (body of T2)
Sternal angle of Louise (T4-5)
Xiphosternal joint (T9)
Ribs & costal cartilage
Scapular: acromian,
coracoid process
Clavicle:
Humerus:
head
•supraclavicular fossa
•infraclavicular fossa
2. Superficial structure
- skin & derivative of
skin (breast)
Breast : nipple, areolar,
mammary gland (F)
1. Surface Anatomy
(position) :
Nipple – 4-5” from the
midline, intercostal space
4
Breast – between rib 2-7
2. Components :
- subcutaneous fat,
mammary gland
- Lactiferous duct
- Cooper’s ligament
(suspensory ligament)
- Retinaculum cutis
fascia
The majority of the breast is in the superficial
fascia, except the tail part (Tail of Spence) extends
upward laterally into deep fascia at the lower border
of pectoralis major.
2/3 of the gland lies on pectoralis major
1/3 of the gland lies on serratus anterior
Deltopectoral Triangle
-deep fascia separating deltoid and pectoralis
muscles
- Platysma = superficial muscle, thin plate, extends
from the mandible to the clavicle
3. Muscles of
pectoral region
a. Pectoralis Major
b. Pectoralis Minor
c. Serratus Anterior
d. Subclavious
a. Pectoralis Major
O. middle ½ clavicle,
sternum, rib 1-5
I. lateral lip of bicipital
groove of humerous
A. adduction, medial
rotation of arm
b. Pectoralis Minor
O. rib 3-5
I. coracoid process of
scapular
A. draw the scapular
down / lift up the ribs
c. Serratus Anterior
O. half way of the anterior part
of rib 1-8
I. medial border (anterior
surface) of the scapular
A. pull scapular to chest wall /
lift up the ribs
d. Subclavious
O. 1st costal cartilage
I. inferior surface of clavicle
A. protecting structures
underneath the clavicle
PectoralGirdle :
clavicle, scapular,
ribs
Clavipectoral fascia /
Costocoracoid
membrane
- deep fascia separating
the pectoralis and the
subclavious
-Blood supply to the pectoral region
1. Axillary artery
2. Perforating branches of the internal thoracic a.
1. Axillary artery :
divided into 3 parts
First part :
Supreme thoracic a.
Second part :
1.Thoraco-acromial trunk
Acromial branch
Pectoral branch
Clavicular branch
Deltoid branch
2. Lateral thoracic a.
Third part :
give branches to supply head of
humerus and scapular regions
Venous drainage at the pectoral region
1. Deep veins - axillary v. <= from the muscles
2. Superficial veins
- cephalic v. (from upper
limb) at the deltopectoral
triangle, it pierces the
clavipectoral fascia (or
infraclavicular fossa) into the
axillary v.
-from mammary gland, it
drains into deep veins =>
internal thoracic v. and
lateral thoracic v.
Lymphatic drainage of the breast
1. Superficial
- around the mammary gland, lymphatic network is
highly anastomosed / drainage is parallel the venous
drainage.
2. Deep
- lymph nodes are
formed along the
lymphatic vessels.
A. from lateral side of the
breast, drains into the
anterior group of the
axillary lymph node (the
pectoral node).
B. from medial side of the
breast, drains into the
parasternal node (the
internal thoracic node)
Nerve Supply of the pectoral
region
1. - medial & lateral pectoral
nerve (terminal branches from the
cords of the Brachial plexus
(C5-8 & T1)
- nerve to subclavius (a branch
from upper trunk of the Brachial
plexus)
- long thoracic nerve (nerve roots
from C5-6-7 of the Brachial
plexus)
Brachial plexus (C5-8 & T1)
2.Spinal n. / Sensory (cutaneous) n
- Supraclavicular nerve (C3-4, medial, intermediate
& lateral branches)
- Intercostal nerve T3-7 (anterior & lateral cutaneous
branches)
*Dermatome at the pectoral region: C3-4, T3-7
Clinical Relevance
1. Chest wall – heart /lung sound
2.Clavipectoral fascia
- protection of the vessels and nerves underneath
-limit spreading of the abscess from upper limb to
the neck
3. Fracture of clavicle
- common site is at 1/3 from the lateral
4. Breast cancer
- structural abnormality
- lymphatic drainage & metastasis
- mastectomy
Accessory nipples may appear on the milk line
Regional Gross Anatomy
“Axilla”
By
Vijittra Leardkamolkarn, Ph.D.
Associate Professor
Department of Anatomy
Axilla
(Arm pit – Pyramid)
Walls / Folds:
.Anterior : pectoralis maj. & min.,
subclavious, clavipectoral fascia
.Posterior : latissimus dorsi, teres
major, subscapularis
.Lateral : humerus, tendon of long
head of biceps brachii, tendon of
coracobrachialis
.Medial : rib 1-3 & intercostal
muscles, serratus anterior (superior
part)
Muscles of Scapular region
Muscles of Scapular
region
1. Deltoideus
O.lateral 1/3 of clavicle,
acromion, spine of scapula
I. deltoid tuberosity of
humerus
A. abduct arm to 90 c,
medial & lateral rotate arm
N. axillary n.
2. Subscapularis
O. subscapular fossa
I. lesser tubercle of humerus
A. medially rotate arm
N. upper & lower subscapular
nerves (C5,6)
3. Teres Major
O. inferior 1/3 lateral border of
scapular
I. medial lip of bicipital groove
A. adduction & medial rotation
of arm
N. lower subscapular nerve
(branch of posterior cord)
4. Supraspinatus
O.supraspinus fossa
I. superior facet of
greater tubercle of
humerus
A. abduction of arm
N. suprascapular nerve
5. Infraspinatus
O. infraspinus fossa
I. middle facet of greater
tubercle of humerus
A. abduct & lateral rotate
arm
N. suprascapular nerve
3. Teres Minor
O. superior 2/3 lateral
border, dorsal surface
of scapular
I. inferior facet of
greater tubercle of
humerus
A. lateral rotation of
arm
N. axillary nerve
Quadrangular Space:
Triangular Space:
Contents of the Axilla
1. Axillary a. & branches
2. Axillary v. &
tributaries
3. Brachial plexus
Axillary sheath – deep fascia that wrap around the
axillary vessels and the brachial plexus
-formed by part of cervical fascia
1. Axillary a. & branches
Third part :
- anterior humeral circumflex a.
- posterior humeral circumflex a.
- subscapularis a.
2. Axillary v. & tributaries
Superficial branch : cephalic v.
Deep branch : venae comitant of brachial v.
In the axilla vein lies medial to the atery. It is the most
expandable structure in the axillary sheath (enlarge
when the blood flow is high)
3. Brachial plexus
- formed by anterior
primary rami of spinal
nerves level C5-8 & T1
- formed into trunk,
division, cord and
branches
Upper trunk = C5 + C6
Middle trunk = C7
Lower trunk = C8 + T1
Most of the the
brachial plexus in
the axilla are cords
& branches -
1. Lateral cord & branches :
- musculocutaneous n.
- lateral head of median n.
- lateral pectoral n.
2. Medial cord & branches :
- medial head of median n.
- ulnar n.
- medial pectoral n.
- medial cutaneous nerve of arm
- medial cutaneous nerve of forearm
3. Posterior cord & branches :
- axillary n.
- radial n.
- thoracodorsal n.
- upper subscapular n.
- lower subscapular n.
Axillary lymph
nodes
- received vessels
drainage from the
upper limb, lateral
part of the breast,
superficial of
thorax and
abdomen (above
the umbilicus) and
the back.
Axillary lymph nodes
- divided into 6 groups:
1. Anterior group
2. Posterior group
3. Lateral group
4. Central group
5. Apical group
6. Subclavian lymph trunk
Node & Vessel Locations:
1. Anterior group
– at the lower border of pectoralis minor
- drinage parallel the lateral thoracic v.
2. Posterior group
– anterior to subscapularis m.
- drainage parallel the subscapular v.
3. Lateral group
- at the lower border of teres major
- drainage parallel medial side of axillary v.
4. Central group
- the outer border of 1st rib
5. Apical group
– at the apex of the axilla
6. Subclavian lymph trunk