08 Pectoral region & axilla.ppt111111111

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1. PECTORAL REGION
AND AXILLA
by
Dr. Francis Abu Bayor
CHO, MBChB

2. OBJECTIVES
•By the end of the lecture the students should be
able to :
•Identify and describe the muscles of the pectoral region.
Pectoralis major.
Pectoralis minor.
Subclavius.
Serratus anterior.
•Describe and demonstrate the boundariesand contents
of the axilla.
•Describe the formationof the brachial plexus and its
branches.

3. Pectoralis Major
•Origin :2 heads;
•Clavicular head: From;
•Medial ½ of the front of
the clavicle.
•Sternocostal head: From;
•Sternum.
•Upper 6 costal cartilages.
•Aponeurosis of the
external oblique muscle.
•Insertion :
•Lateral lip of bicipital groove.
•Nerve supply :
•Medial & lateral pectoral
nerves.
•Action :
•Adduction and medial
rotationof the arm.
•Clavicular head helps in
flexion of arm (shoulder).

4. Pectoralis Minor
•Origin:
•From 3
rd
,4
th
, & 5
th
ribs close to their
costal cartilages.
•Insertion:
•Coracoid process.
•Nerve supply:
•Medial pectoral
nerve.
•Action:
•Depression of the
shoulder.
•Draw the ribs
upward and
outwards during
deep inspiration.
3
4
5

5. Subclavius
•Origin:
•From 1
st
rib at its
costal cartilage.
•Insertion:
•Subclavian groove
in the middle 1/3 of
the inferior surface
of clavicle.
•Nerve supply:
•Nerve to subclavius
from upper trunk of
brachial plexus.
•Action:
•Fixes the clavicle
during movement of
shoulder joint.

6. Clavipectoral Fascia
•It is a thickened
membrane of deep
fasciabetween the
subclaviusand
pectoralis minor.
•It is pierced by :
Lateral pectoral nerve.
Thoraco-acromial artery
Cephalic vein.
Few lymph vessels.

7. Origin:
•Upper eight ribs.
•Insertion:
•anterior aspect of
the medial border
and inferior angle of
scapula.
•Nerve supply:
•Long thoracic nerve.
•Action:
•Draws the scapula
forward in boxing,
(protrusion).
•Rotates scapula
outwards in raising
the arm above 90
degree.
Serratus anterior

8. AXILLA
•A pyramid-shaped
space between the
upper part of the
armand the side
of thechest
through which
major
neurovascular
structures pass
between neck&
thoraxand upper
limbs.
•Axilla has an apex,
a baseand four
walls.

9. Boundaries of the
Axilla
Apex:
Is directed upwards &
medially to the root of
the neck.
It is called
•Cervicoaxillary
canal.
It is bounded, by 3
bones:
•Clavicle anteriorly.
•Upper border of the
scapula posteriorly.
•Outer border of
the first rib
medially.
C
L
A
V
I
C
L
E
1
R
I
B

10. Base:
Formed by skinstretching
between the anterior and
posterior walls.
is bounded:
•In frontby the anterior
axillary fold (formed by
the lower border of
Pectoralis major).
•Behindby the posterior
axillary fold (formed by
tendons of latissimus
dorsi and teres major).
•Mediallyby upper 4 to 5
ribs & the chest wall.

11. Anterior wall:
Is formed by :
•Pectoralis
major
•Pectoralis
minor
•Subclavius
•Clavipectoral
fascia:
Pectoralis
major
Pectoralis
minor
Clavipectoral fascia

12. •Posterior wall:
•Is formed by:
•Subscapularis.
•Latissimus dorsi.
•Teres major
muscles.

13. The medial wall:
It is wide and formed
by:
•Serratus anterior.
•Upper 4-5 ribs &
Intercostal muscles .
The lateral wall:
It is narrow and
formed by:
•Coracobrachi-alis.
•Biceps brachii.
•Bicepital groove of
the humerus.

14. Contents of The
Axilla
•Cords and braches of
the brachial plexus
•Axillaryartery and its
branches.
•Axillaryvein and its
tributaries.
•Axillarylymph nodes.
•Axillaryfat.
•Looseconnective
tissue.
The neurovascular bundle is enclosed in connective tissue
sheath, called ‘axillary sheath’
Axillary a. & v.
Brachial
plexus

15. Location & Formation
Brachial Plexus is present in the posterior triangle
of the neck& axilla.
It is formed by union of the anterior Rami of the
C 5
th
, 6
th
, 7
th
& 8
th
and 1
st
thoracic spinal nerve.
What is a Brachial Plexus ?
Brachial Plexus is a network of nerves thatpresent at
the root of the neck to enter the upper limb.
Roots of C5 & C6 unite to form----Upper trunk
Root of C7 continuous as the--------Middle trunk
Roots of C8 & T1 unite to form----Lower trunk
15

16. The Plexus can be divided into5 stages:
Roots:in the posterior∆
Trunks: in the posterior∆
Divisions: behind the clavicle (in cervico-axillary canal)
Cords:in the axilla
Branches:in the axilla
•The first 2 stages liein the posterior triangle, whilethe last 2 sages liein the axilla.16

17. The anterior divisions of the upper and middle trunks
unite to form the Lateral cord.
The anterior division of the lower trunk continues as the
Medial cord.
All the posterior divisions of three trunks join to form the
Posterior cord.
17

18. B
R
N
C
H
E
S
Lateral cord-3 Medial cord-5 Posterior cord-5
Lateral pectoral nerve. Medial pectoral nerve. Axillary nerve.
Musculocutaneous nerve. Ulnar nerve. Radial nerve.
Median nerve (lateral root).Median nerve (medial root).Upper & lower
subscapular nerves.
Medial cutaneous nerve of
arm & forearm.
Thoracodorsal or N. to
latissimus dorsi.

19. SUMMARY
Muscles of the pectoral region are connecting the upper
limb with anterior and lateral thoracic wall:
Pectoralis major.
Pectoralis minor.
Subclavius.
Serratus anterior.
The axilla is a pyramidal space situated between the upper part of
arm and the side of the chest, it has 4 walls (anterior, posterior, medial
and lateral), base, and apex.
The axilla is an important space as it transmits the neurovascular
bundle from the neck and thorax to the upper limb.
It contains:
Axillary vessels.
Cordsand branchesof the brachial plexus.
Axillary lymph nodes.

20. Paralysis of Serratus anterior
muscle……Winging of
scapula
Dislocation of shoulder
joint…….Winging of Scapula.

21. THANK YOU

22. 1. Which one of the following muscles performs adduction of the arm ?
a. Pectoralis minor.
b. Pectoralis major.
c. Subclavius.
d. Serratus anterior.
2. Serratus anterior is innervated by :
a.Thoracodorsal nerve.
b.Long thoracic nerve.
c.Axillary nerve.
d.Radial nerve.
3. Which one of the following muscles contributes in rotation of the scapula above the head?
a. Pectoralis major.
b. Pectoralis minor.
c. Serratus anterior.
d. Teres major.
4. Which one of the following muscles forms the lateral wall of axilla ?
a. Pectoralis major.
b. Pectoralis minor.
c. Serratus anterior.
d. Biceps brachii.
5. Which stage of the brachial plexus lies in the axilla ?
a. Roots.
b. Divisions.
c. Trunks.
d. Cords.

23. Arteries Of The Upper Limb
Axillary artery
Right subclavian
artery
Left subclavian
artery
Brachial artery
Radial
artery
Ulnar
artery
Palmar
arches

24. The Subclavian Artery
The right
artery
originates from
the
brachiocephalic
artery.
The left
artery
originates from
the arch of the
aorta
Cotinues as
Axillary artery at
the lateral border
of the 1
st
rib

25. Begins at the lateral border of
the 1
st
rib as continuation of the
subclavian artery.
Continues as brachial arteryat
lower border of teres major
muscle.
Is closely related to the cords of
brachial plexusand their
branches
Is enclosed within the axillary
sheath.
Is crossed anteriorly by the
pectoralis minor muscle, and is
divided into three parts; 1
st
, 2
nd
& 3
rd
.
The Axillary Artery
Subclavian artery
Axillary arteryBrachial artery

26. 1
st
part
Pectoralis
minor
Teres
major
2nd part
3
rd
part
Extends from the lateral
border of 1
st
ribto upper
border of the pectoralis
minor muscle.
Related:
•Anterioly: to the
pectoralis major
muscle
•Laterally:to the cords
of the brachial plexus.
ONE branch: Highest
thoracic artery
The 1
st
part of the axillary artery
Highest thoracic
artery a.

27. 1
st
part
Pec. minor
Teres
major
2nd part
3
rd
part
The 2
nd
part of the axillary artery
Thoraco-
acromial a.
Lateral
Thoracic a.
Lies behind the pectoralis
minor muscle.
It is related medially,
laterally, and posterioly to
the corresponding cordof
the brachial plexus.
TWO branches:
•Thoracoacromial .
•Lateral thoracic.

28. 1
st
part
Pec. minor
Teres
major
2nd part
3
rd
part
The 3rd part of the axillary artery
Anterior & posterior
circumflex humeral aa.
Subscapular a.
•Extends from the lower border
of pectoralis minor muscle to
the lower border teres major
muscle.
•Related medially, laterally, and
posterioly, to thebranches of the
cords of the brachial plexus
•Gives THREE Branches:
•Subscabular,
•Anterior circumflex
humeral
•Posterior circumflex
humeral.