Clinical Anatomy Of The Axilla & Brachial Plexus

Question 1

What is the axilla?

Answer 1

A pyramid-shaped space between. Between upper arm and thorax

Axillary inlet (apex, cervicoaxillary canal)
  -clavicle, coracoid process and superior margin of scapula, 1st rib

Question 2

What are the 4 walls of the axilla?

Answer 2

Anterior

Posterior

Medial

Lateral

Also has floor

Question 3

What constitutes the walls and floor of the axilla?

Answer 3

• Anterior (anterior fold)= pectoralis major and minor
• Posterior (posterior fold)= teres major, latissimus dorsi subscapularis
• Medial= serratus anterior, ribs, etc.
• Lateral= Intertubercular (bicipital) groove of humerus

Floor= axillary fascia

Question 4

What is the function abs innervation of the serratus anterior?

Answer 4

Long thoracic nerve (C5,6,7)

Rotates scapula upward to allow lifting arm above 90 degrees

-protracted the scapula to keep the medial border against the thoracic wall

Clinical correlate: winged scapula

Question 5

What are the muscles of the anterior wall? What are the functions of the muscles?

Answer 5

Pectoralis major-medial and lateral pectoral nerves

Flexion, adduction and medial rotation of the arm

Pectoralis minor- medial pectoral nerve, pulls tip of shoulder down

Question 6

What are the muscles of the posterior wall? W(at are there functions?

Answer 6

Subscapularis- upper and lower subscapular nerves. Medial rotation of the arm

Teres major- lower subscapular nerve. Medial rotation, adduction, extension of the arm

Latissimus dorsi- thoracodorsal nerve. Medial rotation, adduction, extension of the arm

Question 7

What are the brachial plexus chords?

Answer 7

Lateral, posterior, medial

Question 8

What are the components of the posterior scapular spaces?

Answer 8

Triangular space:
-circumflex scapular artery

Quadrangular space:
-axillary nerve

-Posterior humeral circumflex artery

Triangular interval
-radial nerve

-deep brachial artery

Question 9

What is the Subclavian artery?

Answer 9

Divided into three parts by the anterior scalene muscle. Most branches from the first division:

1st part (medial to scalene )

• Vertebral
• Internal thoracic
• Thyrocervical trunk
  
  • transverse cervical
    
    • deep
    • superficial
• suprascapular
• inferior thyroid

2nd part (behind the scalene)
-costocervical

3rd part (lateral to scalene)
 -dorsal scapular if present

Question 10

Which blood vessel curves over the 1st rib?

Answer 10

Distal part of the Subclavian artery as it curves over 1st rib to become the axillary artery

Question 11

What is the axillary artery?

Answer 11

Continuation of Subclavian artery

Begins at lateral border 1st rib

Ends at inferior margin of teres major

Divided into 3 parts by pectoralis minor:

• proximal
• posterior
• distal

Question 12

What are the parts of the axilllary artery?

Answer 12

1st part -proximal: superior thoracic

2nd part- posterior

• thoraco-acromial
  
  • acromial(A)
  • pectoral(P)
  • clavicular(C)
  • deltoid(D)
• lateral thoracic

3rd part-distal

• subscapular
  
  • Thoracodorsal
  • circumflex scapular
• Posterior circumflex humeral
• Anterior circumflex humeral

Question 13

What are the parts of the scapular anastomosis?

Answer 13

Dorsal scapular or deep branch of transverse cervical artery

Suprascapular artery

Circumflex scapular artery

Question 14

What is the dorsal scapular/ deep branch of transverse cervical artery ?

Answer 14

Which is a branch of thyrocervical trunk from Subclavian

Question 15

What is the suprascapular artery?

Answer 15

A branch of thyrocervical trunk from Subclavian

Question 16

What is the circumflex artery?

Answer 16

Branch of subscapular artery which is from 3rd Parathion of axillary

Question 17

What is the axillary vein formed by?

Answer 17

• basilic vein and paired brachial veins
• begins at inferior margin of teres major
• ends at lateral border 1st rib
• receives the cephalic

Question 18

What is the axillary sheath?

Answer 18

• surrounds arteries, veins, nerves and lymphatic

- can be used for brachial plexus blocks

Question 19

What are the axillary vein purpose ?

Answer 19

The axillary vein is used as an entrance to the Subclavian vein for the insertion of “Subclavian” venous catheter

Question 20

What is the somatic plexus?

Answer 20

Thoracic ventral rami. Innervating the trunk remain separate from each other

Ventral rami innervating the limbs merge with adjacent rami to form somatic plexuses: nerve fibers from adjacent rami intermingle

Named nerves arise from plexus and contain fibers from two or more rami

Question 21

What are Apical nodes?

Answer 21

Most superior nodes

Receive lymph from all other axillary nodes and superficial lymphatics from lateral upper limb accompanying cephalic vein

Question 22

What are central nodes?

Answer 22

Receive lymph from anterior, lateral and posterior groups

Question 23

What are the lateral nodes(humeral)?

Answer 23

Receive lymph from the medial aspect of the upper limb accompanying the basilic vein

Question 24

What are posterior nodes(scapular)

Answer 24

Receive lymph from posterior thoracic wall, back and posterior shoulder

Question 25

What are anterior nodes (pectoral)?

Answer 25

Receive lymph from anterior and lateral thoracic wall and breast