Beyond the EU: DORA and NIS 2 Directive's Global Impact
ANATOMY OF THE UPPER LIMBSSAxilla 2.pdf
1. AXILLA
G. O. Omotoso B.Sc., MB;BS, Ph.D.
Deparment of Anatomy
University of Ilorin
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Dr Omotoso/Axilla 2021
2. Description
• The axilla (armpit) is a pyramid-
shaped space between the
upper part of the arm and the
side of the chest
• passage for brachial plexus and
other neurovascular
bundles .from the root of the
neck to the upper limb
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Dr Omotoso/Axilla 2021
3. Boundaries
• The axilla has
• an apex,
• base and
• anterior wall,
• posterior wall,
• medial wall and
• lateral wall
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Dr Omotoso/Axilla 2021
4. Apex of the Axilla
• It is the upper end of the axilla
• It continues into posterior
triangle of the neck through the
cervico-axillary canal
• The apex is also referred to as
the axillary inlet.
• Boundaries of the cervico-
axillary canal
• Ant: clavicle,
• Post: upper border of scapula
• Medially: outer border of the
first rib
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Dr Omotoso/Axilla 2021
5. Base of the Axilla
• It is the lower end of the axilla
• It is formed by the skin stretching
between the anterior and posterior
walls
• Boundaries
• Ant: anterior axillary fold (formed by
the lower border of pectoralis mj),
• Post: posterior axillary fold (formed
by the tendon of latissimus dorsi &
teres mj)
• Medially: the chest wall
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Dr Omotoso/Axilla 2021
6. Medial Wall
• The medial border is formed by
• the serratus anterior,
• the thoracic wall
• intercostal spaces (including the
neurovascular structures and
muscles) (upper 4 ICS)
• ribs (R1-4/5)
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7. Lateral Wall
• By the coracobrachialis
• biceps muscles in the bicipital
groove of the humerus
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Dr Omotoso/Axilla 2021
8. Anterior Wall
• pectoralis major
• subclavius
• pectoralis minor
muscles
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12. Axillary artery
• Begins at the lateral border of
the first rib as a continuation of
the subclavian artery and
terminates at the lower border
of the teres major to continue as
the brachial artery.
• 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
(which is continuous with the
prevertebral fascia)
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Dr Omotoso/Axilla 2021
13. Parts of the Axillary Artery
• The pectoralis minor muscle
crosses in front of the axillary
artery and divides it into
three parts:
• First part above the
pectoralis minor muscle
• Second part behind the
pectoralis minor muscle
• Third part below the
pectoralis minor muscle
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Dr Omotoso/Axilla 2021
14. First Part of the Axillary Artery
• This extends from the lateral border of
the first rib to the upper border of the
pectoralis minor.
• Relations
• Anteriorly: The pectoralis major and the
skin.
• Posteriorly: The long thoracic nerve
(nerve to the serratus anterior)
• Laterally: The three cords of the brachial
plexus
• Medially: The axillary vein
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Dr Omotoso/Axilla 2021
15. Second Part of the Axillary Artery
• This lies behind the pectoralis minor
muscle.
• Relations
• Anteriorly: Pectoralis minor, the
pectoralis major, and the skin
• Posteriorly: Posterior cord of BP;
subscapularis muscle, and the
shoulder joint
• Laterally: Lateral cord of BP
• Medially: Medial cord of BP; Axillary
vein
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16. Third Part of the Axillary Artery
• This extends from the lower border of the pectoralis minor to the lower
border of the teres major.
• Relations
• Anteriorly: Pectoralis major; crossed by medial root of median nerve inferiorly
• Posteriorly: Subscapularis, latissimus dorsi, teres major, axillary nv, radial nv
• Laterally: Coracobrachialis, biceps, humerus, lateral root of the median nv,
musculocutaneous nv
• Medially: Ulnar nv, Axillary vn, medial cutaneous nerve of the arm
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Dr Omotoso/Axilla 2021
18. Branches of the Axillary Artery
• From the first part:
• Superior thoracic artery is small and runs along the upper border of the P minor.
• From the second part:
• (i) Thoracoacromial artery immediately divides into terminal branches.
• (ii) Lateral thoracic artery runs along the lower border of the pectoralis minor
• From the third part:
• (i) Subscapular artery runs along the lower border of the subscapularis muscle
• (ii) Anterior circumflex humeral artery winds around the front of the surgical neck
of the humerus.
• (iii) Posterior circumflex humeral artery winds around the back of the surgical neck
of the humerus
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21. Axillary lymph nodes
• Anterior group
• The anterior group (pectoral group) drains the
lymph from the anterolateral aspect of the
abdominal wall, superior to the level of the
umbilicus and the lateral quadrants of the
breast.
• Posterior group
• The posterior group (subscapular group) drain
the superficial lymphatic vessels from the back,
as far back as the superior border of the iliac
crests.
• Lateral group
• The lateral group drains the majority of
lymphatic fluid from its upper limb.
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