Download The Axilla

Pectoral region
In the male, the contour of pectoral region is formed by
the large pectoralis major muscle, while in females by the
breast.
It is covered by superficial and deep fascia (pectoral
fascia).
superficial fascia: of the pectoral region tends to be
thickest in male in the region deep to the nipple and
areola. In female it forms large masses between and
around the breast glandular tissue of the breast. It contains
the superficial vessels and nerves and continuous with the
superficial fascia of lateral thoracic wall, the abdomen, the
arm, and the neck.
Pectoral region
Pectoral fascia: The deep pectoral fascia is a thin lamina,
covering the surface of the pectoralis major, and sending
numerous prolongations between its fasciculi. It is
attached to the front of the sternum, to the clavicle
superiorly. Laterally and below it is continuous with the
fascia of the shoulder, axilla, and thorax. Posteriorly, it is
attached to the spinous processes of the thoracic vertebræ
Pectoral region
Muscle of the pectoral region
1. Pectoralis major muscle: it is
enclosed by the pectoral fascia, it is
large fan-shaped muscle arises from
clavicle, sternum, and upper six
costal cartilages. It is inserted into
the lateral lip of bicipital groove of
humerus. Nerve supply: Medial and
lateral pectoral nerves from brachial
plexus ( nerve roots:C5, 6, 7, 8; T1).
Function: Adducts arm and rotates it
medially; clavicular fibers also flex
arm.
Pectoral region
1. Pectoralis major muscle
Pectoral region
Muscle of the pectoral region
2. Pectoralis Minor muscle: it is
a thin triangular muscle that lies
beneath the pectoralis major. It
arises from the 3rd, 4th, and 5th
ribs and runs upward and laterally
to be inserted by its apex into the
coracoid process of the scapula.
Nerve supply: Medial pectoral
nerve from brachial plexus
(roots:C6, 7, 8).
Function: Depresses point of
shoulder; if the scapula is fixed, it
elevates the ribs of origin.
Pectoral region
Muscle of the pectoral region
3.Subclavius muscle: it is small
rounded muscle, it arises from
the 1st costal cartilage and it is
inserted in the clavicle. Nerve
supply: Nerve to subclavius
from upper trunk of brachial
plexus (roots:C5,6).
Function:
Depresses
the
clavicle and steadies this bone
during movements of the
shoulder girdle.
Pectoral region
Nerves:
Are mainly the nerves to the
pectoral muscles: the medial
and lateral pectoral nerves
(anterior thoracic nerves),
they are arise from medial
and lateral cords of the
brachial plexus.
Pectoral region
Blood vessels:
The two chief arteries of the pectoral
region are the thoracoacromial artery
and lateral thoracic artery: branches
of axillary artery. The thoracoacromial
artery pierces the clavipectoral fascia
and give rise to four branches:
clavicular, pectoral, deltoid, and
acromial.
The lateral thoracic artery runs
downward along the anterolateral
aspect of the chest wall.
The arteries are all accompanied by
veins.
The Axilla
The Axilla
The axilla, or armpit, is a pyramid-shaped space
between the upper part of the arm and the side of
the chest.
It forms an important passage for nerves, blood,
and lymph vessels as they travel from the root of the
neck to the upper limb.
The Axilla
The upper end of the axilla, or
apex, is directed into the root
of the neck and is bounded in
front by the clavicle, behind
by the upper border of the
scapula, and medially by the
outer border of the first rib.
The Axilla
The lower end, or base,
is bounded in front by
the anterior axillary fold
(formed by the lower
border of the pectoralis
major muscle), behind
by the posterior axillary
fold (formed by the
tendon of latissimus
dorsi and the teres major
muscle), and medially
by the chest wall.
The Axilla
Walls of the Axilla
The Axilla
Walls of the Axilla:
■ Anterior wall: By the pectoralis major, subclavius, and
pectoralis minor muscles.
The Axilla
Walls of the Axilla:
■ Posterior wall: By the subscapularis, latissimus dorsi,
and teres major muscles from above down.
The Axilla
Walls of the Axilla:
■ Medial wall: By the upper four or five ribs and the
intercostal spaces covered by the serratus anterior muscle.
The Axilla
Walls of the Axilla:
■ Lateral wall: By the coracobrachialis and biceps
muscles in the bicipital groove of the humerus.
The Axilla
Walls of the Axilla:
The base is formed by the skin stretching between the
anterior and posterior walls.
Key Muscle in the Axilla
(Pectoralis Minor):
It crosses the axillary artery and the
brachial plexus of nerves. It is used
when describing the axillary artery
to divide it into three parts.
The Axilla
Clavipectoral Fascia
It is a strong sheet of connective
that is attached above to the
clavicle. Below, it splits to
enclose the pectoralis minor
muscle and then continues
downward as the suspensory
ligament of the axilla and joins
the fascial floor of the armpit.
The Axilla
Contents of the Axilla
The axilla contains the principal vessels and nerves to
the upper limb and many lymph nodes. These
structures are embedded in fat.
Contents of the Axilla:
1. The axillary artery and its branches, which supply blood to
the upper limb.
2. The axillary vein and its tributaries, which drain blood
from the upper limb.
3. The lymph vessels and lymph nodes, which drain lymph
from the upper limb and the breast and from the skin of
the trunk, down as far as the level of the umbilicus.
4. The brachial plexus, is an important nerve plexus, which
innervates the upper limb.
Axillary Artery
It begins at the lateral border
of the 1st rib as a continuation
of the subclavian artery and
ends at the lower border of the
teres major muscle, where it
continues as the brachial artery.
The pectoralis minor muscle
crosses in front of the axillary
artery and divides it into three
parts (first, second, and third
part).
Axillary Artery
Throughout its course, it
is closely related to the
cords of the brachial
plexus and their branches
and is enclosed with them
in a connective tissue
sheath called the axillary
sheath. If this sheath is
traced upward into the
root of the neck, it is seen
to be continuous with the
prevertebral fascia.
Axillary Artery
 First Part: it extends from the lateral border of the 1st
rib to the upper border of the pectoralis minor.
 Second Part: it lies behind the pectoralis minor muscle.
 Third Part: This extends from the lower border of the
pectoralis minor to the lower border of the teres major
muscle.
Branches of the Axillary Artery:
From the first part:
The highest thoracic artery is small and runs along the
upper border of the pectoralis minor.
Branches of the Axillary Artery:
From the second part:
1. The thoracoacromial artery immediately divides into
terminal branches.
2. The lateral thoracic artery runs along the lower
border of the pectoralis minor.
Branches of the Axillary Artery:
From the third part:
1. The subscapular artery runs along the lower border of the
subscapularis muscle.
2. The anterior and posterior circumflex humeral arteries
wind around the front and the back of the surgical neck of
the humerus, respectively.
Axillary Vein
It is formed at the lower border of the teres major muscle by
the union of the venae comitantes of the brachial artery and the
basilic vein. It runs upward on the medial side of the axillary
artery and ends at the lateral border of the 1st rib by becoming
the subclavian vein. The vein receives tributaries, which
correspond to the branches of the axillary artery, and the
cephalic vein.
Axillary vessels