Download Axilla Is a pyramidal region between :

Axilla
Is a pyramidal region between :
• upper thoracic wall
• arm
Boundaries of axilla
 Medial wall:
upper ribs and their intercostal muscles and serratus anterior muscle.
 Lateral wall:
humerus.
 Posterior wall:
subscapularis, teres major, and latissimus dorsi muscles.
 Anterior wall:
pectoralis major and pectoralis minor muscles.
 Base:
axillary fascia.
 Apex:
interval between clavicle, scapula, and first rib.
B. Contents of the axilla
Include :
1.
2.
3.
4.
axillary vasculature,
branches of brachial plexus,
lymph nodes,
areolar tissue.
•
B. Contents of the Axilla
1. Brachial plexus and its branches
2. Axillary artery
has many branches, including :
1.
2.
3.
4.
5.
superior thoracic,
thoracoacromial,
Lateral thoracic,
thoracodorsal,
circumfl ex humeral (anterior and posterior) arteries.
3. Axillary vein
is formed by union of :
A. brachial veins (venae comitantes of brachial artery) &
B. basilic vein,
receives cephalic vein and veins that correspond to branches of axillary artery,
drains into subclavian vein.
4. Lymph nodes and areolar tissue are present.
5. Axillary tail (tail of Spence)
–is a superolateral extension of mammary gland.
Structures of the Shoulder Region
A. Quadrangular space
Is bounded :
superiorly by :
teres minor &subscapularis muscles,
inferiorly by :
teres major muscle,
medially by :
long head of triceps,
laterally by :
surgical neck of humerus.
Transmits the axillary nerve and the posterior humeral circumflex
vessels.
B. Triangular space (upper)
Is bounded :
superiorly by :
teres minor muscle,
inferiorly by :
teres major muscle,
laterally by :
long head of the triceps.
Contains :
circumflex scapular vessels.
C. Triangular space (lower)
Is formed
superiorly by :
teres major muscle,
medially by:
long head of triceps,
laterally by:
medial head of the triceps.
Contains :
radial nerve & profunda brachii (deep brachial) artery.
D. Triangle of auscultation
Is bounded by
upper border of latissimus dorsi muscle,
lateral border of trapezius muscle,
medial border of scapula;
its floor is formed by rhomboid major muscle.
Is the site at which breathing sounds are heard most clearly.
II. Axillary Artery
Is considered to be central structure of axilla.
Extends from :
outer border of first rib
to inferior border of teres major muscle,
where it becomes brachial artery.
is bordered on its medial side by axillary vein.
Is divided into three parts by pectoralis minor muscle.
A. Superior or supreme thoracic artery
Supplies intercostal muscles in first & second anterior intercostal
spaces and adjacent muscles.
B. Thoracoacromial artery
Is a short trunk from first or second part of axillary artery
has :
1. pectoral, branch
2. clavicular, branch
3. acromial, branch
4. deltoid branch.
Pierces costocoracoid membrane (or clavipectoral fascia).
C. Lateral thoracic artery
Runs along lateral border of pectoralis minor muscle.
Supplies:
pectoralis major,
pectoralis minor,
serratus anterior muscles
axillary lymph nodes,
gives rise to lateral mammary branches.
D. Subscapular artery
• Is largest branch of axillary artery,
• arises at lower border of subscapularis muscle,
• descends along axillary border of scapula.
Divides into:
1. Thoracodorsal artery
2. circumflex scapular artery.
1. Thoracodorsal artery
Accompanies thoracodorsal nerve
supplies
1. latissimus dorsi muscle
2. lateral thoracic wall.
2. Circumflex scapular artery
Passes posteriorly into triangular space bounded by:
•
subscapularis muscle & teres minor muscle above,
•
teres major muscle below,
•
long head of triceps brachii laterally.
Ramifies in infraspinous fossa and
anastomoses with branches of dorsal scapular and suprascapular
arteries.
E. Anterior humeral circumflex artery
Passes anteriorly around the surgical neck of the humerus.
Anastomoses with the posterior humeral circumflex artery.
F. Posterior humeral circumflex artery
Runs posteriorly with the axillary nerve through the
quadrangular space bounded by the teres minor and teres
major muscles, the long head of the triceps brachii, and the
humerus.
Anastomoses with the anterior humeral circumflex artery and
an ascending branch of the profunda brachii artery and also
sends a branch to the acromial rete.
If axillary artery is ligated
between thyrocervical trunk & subscapular artery, then the blood from
anastomoses in the scapular region arrives at the subscapular artery in
which the blood flow is reversed to reach the axillary artery distal to the
ligature.
axillary artery may be compressed or felt for the pulse in front of the teres
major or against the humerus in the lateral wall of the axilla
C. Axillary Lymph Nodes
1. Central Nodes
2. Brachial (Lateral) Nodes
3. Subscapular (Posterior) Nodes
4. Pectoral (Anterior) Nodes
5. Apical (Medial or Subclavicular) Nodes
C. Axillary Lymph Nodes
1. Central Nodes
• Lie near base of axilla
• between lateral thoracic and subscapular veins;
• receive lymph from :
1. lateral, groups of nodes
2. anterior, groups of nodes
3. posterior groups of nodes;
• drain into apical nodes.
2. Brachial (Lateral) Nodes
• Lie posteromedial to axillary veins,
• receive lymph from upper limb,
• drain into central nodes.
3. Subscapular (Posterior) Nodes
• Lie along subscapular vein,
• receive lymph from posterior thoracic wall &posterior aspect of shoulder,
• drain into the central nodes.
4. Pectoral (Anterior) Nodes
• Lie along inferolateral border of pectoralis minor muscle;
• receive lymph from anterior and lateral thoracic walls, including breast;
• drain into central nodes.
5. Apical (Medial or Subclavicular) Nodes
Lie at :
apex of axilla medial to axillary vein &
above upper border of pectoralis minor muscle,
receive lymph from all of other axillary nodes (from breast),
drain into subclavian trunks.
C. Axillary Lymph Nodes
1. Central Nodes
■ Lie near the base of the axilla between the lateral thoracic and subscapular veins;
receive lymph from the lateral, anterior, and posterior groups of nodes; and drain into
the apical nodes.
2. Brachial (Lateral) Nodes
■ Lie posteromedial to the axillary veins, receive lymph from the upper limb, and drain
into the central nodes.
3. Subscapular (Posterior) Nodes
■ Lie along the subscapular vein, receive lymph from the posterior thoracic wall and the
posterior aspect of the shoulder, and drain into the central nodes.
4. Pectoral (Anterior) Nodes
■ Lie along the inferolateral border of the pectoralis minor muscle; receive lymph from
the anterior and lateral thoracic walls, including the breast; and drain into the central
nodes.
5. Apical (Medial or Subclavicular) Nodes
■ Lie at the apex of the axilla medial to the axillary vein and above the upper border of the
pectoralis minor muscle, receive lymph from all of the other axillary nodes (and occasionally
from the breast), and drain into the subclavian trunks.