1. The axilla

2. The axilla Walls Axillary sheath Axillary artery Axillary vein
Scapular anastomosis

3. The axilla
Is the space between the medial part of the arm and the side of the chest

4. The axilla
forms an important passage for nerves and vessels from the neck to the upper limb

5. The axilla
It has the shape of a truncated 3-sided pyramid

6. Apex of the axilla The apex is directed towards the root of the neck
it is a narrow triangular gap which is bounded by the clavicle anteriorly, scapula posteriorly, and the first rib medially.

7. Apex of the axilla
The apex is also called the inlet since it allows the entrance to the axilla of nerves and vessels

8. Base of the axilla
The base faces inferiorly and is formed by fascia and skin, the fascia is supported by the suspensory ligament of the axilla which renders the base hollow

9. Base of the axilla
The base faces inferiorly and is formed by fascia and skin, the fascia is supported by the suspensory ligament of the axilla which renders the base hollow

10. Anterior wall of the axilla
This is formed by the clavicle, pectoralis major, pectoralis minor, subclavius, and the clavipectoral fascia
Pectoralis
minor
Pectoralis major

11. Posterior wall of the axilla
scapula
subscapularis
Teres major
Latissimus dorsi

12. Axillary folds
The anterior and posterior walls of the axilla can be palpated by fingers and thumb thus forming the anterior and posterior axillary folds.
The anterior axillary fold is formed by the lateral border of pectoralis major

13. Axillary folds
The posterior axillary fold is formed by teres major and latissimus dorsi
teres
major
latissimus
dorsi

14. Medial wall of axilla
The medial wall is formed by the upper ribs and intercostal muscles covered by serratus anterior muscle

15. Lateral wall of axilla
The lateral wall is narrow and is formed by the floor of the intertubercular groove of the humerus to which is attached the tendon of latissimus dorsi and in which runs the tendon of the long head of biceps

16. Contents of the axilla Fat axillary artery axillary vein
brachial plexus
axillary lymph nodes
brachial
plexus
fat
axillary
lymph
nodes

17. Axillary sheath
The vessels and the brachial plexus are enclosed in a fascial sleeve (axillary sheeth) which is a downward prolongation of the pre-vertebral fascia in the neck

18. Axillary sheath
In the neck, the cervical vertebrae and the muscles attached to them are bound together by a dense fascial layer called prevertebral fascia

19. Axillary sheath
Among the muscles of the neck are scalenus anterior and scalenus medius, these are attached to the anterior and posterior tubercles of the transverse process of cervical vertebrae respectively

20. Axillary sheath
The roots of the brachial plexus lie between these muscles
The subclavian artery passes behind scalenus anterior at the root of the neck

21. Axillary sheath
the brachial plexus and the axillary artery (the continuation of the subclavian artery), during their passage from the neck to the axilla have to pierce the prevertebral fascia and while doing so they take a prolongation of the fascia down with them in the form of a sleeve called the "axillary sheath"

22. Axillary artery
Begins at the outer border of the first rib as the continuation of the subclavian artery

23. Axillary artery
Ends by becoming the brachial artery at the lower border of teres major

24. Axillary artery
For descriptive purposes it is divided into three parts by pectoralis minor muscle

25. Axillary artery
The second part is located behind the muscle

26. Axillary artery
the axillary vein is medial to the artery

27. Axillary artery
the cords of the brachial plexus are arranged according to their names around the second part of the axillary artery
Axillary v.
Axillary a.
Medial
cord
lateral
cord
posterior
cord

28. Axillary artery
the medial cord is thus between the artery and vein

29. Branches of the axillary artery
1 from the 1st part
2 from the 2nd part
3 from the 3rd part

30. Branches of the 1st part of the axillary artery
Superior thoracic artery

31. Branches of the 2nd part of the axillary artery
Thoraco-acromial artery

32. Thoraco-acromial artery
This artery is short and wide, it pierces the clavipectoral fascia and is divided then into four branches (acromial, deltoid, pectoral, and clavicular)

33. Branches of the 2nd part of the axillary artery
Thoraco-acromial artery
lateral thoracic artery

34. Lateral thoracic artery
The lateral thoracic artery follows the lower border of pectoralis minor muscle and is important for the blood supply of the female breast.

35. Branches of the 3rd part of the axillary artery
Anterior circumflex humeral artery
posterior circumflex humeral artery

36. Branches of the 3rd part of the axillary artery
Anterior circumflex humeral artery
posterior circumflex humeral artery
subscapular artery

37. Subscapular artery
descends along the lateral border of the scapula and ends as the circumflex scapular and thoracodorsal arteries
Circumflex scapular
Thoraco-dorsal

38. Subscapular artery
the circumflex scapular artery passes around the lateral border of the scapula to supply muscles on the dorsal aspect of the scapula.
The thoracodorsal artery is the continuation of the subscapular artery along the lateral border of the scapula

39. Circumflex humeral arteries
the posterior is the larger
the circumflex humeral arteries pass around the surgical neck of the humerus to anastomose with each other

40. Palpation of the axillary artery
The third part of the axillary artery can be palpated in the lateral wall of the inferior part of the axilla and can be compressed against the humerus

41. Axillary vein
begins at the lower border of teres major as the continuation of the basilic vein
It receives the venae comitantes of the brachial artery and tributaries that correspond to the branches of the axillary artery in addition to the cephalic vein.

42. Axillary vein
It becomes the subclavian vein at the outer border of the first rib

43. Axillary vein
It is located medial to the axillary artery but when the arm is abducted it lies anterior to the artery hiding it from vision
Owing to the large size of the axillary vein and its exposed position, it is liable to be injured in wounds of the axilla

44. Axillary vein
Injury is dangerous not only because of severe hemorrhage but also because of the risk of air entering the vessel since the wall tends to be held apart by the fibrous expansions over the vessel from the clavipectoral fascia

45. Axillary vein
for this reason, the axillary vein is cleared away to avoid injuring it in subsequent dissection

46. Scapular anastomosis
Several vessels around the scapula form a network that provides collateral circulation for the upper limb during ligation of an injured axillary or subclavian artery

47. Subclavian artery
The subclavian artery is divided (for descriptive purposes) into three parts by scalenus anterior muscle

48. Subclavian artery The first part lies medial to scalenus anterior
one of its branches is the thyrocervical trunk

49. Thyrocervical trunk
From the thyrocervical trunk arises the transverse cervical and suprascapular arteries.

50. Transverse cervical artery
The transverse cervical has a descending branch that runs along the vertebral border of the scapula

51. Suprascapular artery
crosses over the transverse ligament of the scapular notch
passes through supraspinous fossa then around the lateral border of the scapular spine (spino-glenoid notch) to supply the infraspinous fossa.

52. Scapular anastomosis
The subscapular artery from the third part of the axillary artery descends along the lateral border of the scapula and provides the circumflex scapular artery which enters the infraspinous fossa.

53. Scapular anastomosis
The subscapular, suprascapular, and descending branch of the circumflex scapular arteries anastomose, thus connecting the first part of the subclavian with the third part of the axillary artery

54. Scapular anastomosis
Thus the axillary artery may be ligated between the thyrocervical trunk and the subscapular artery i.e. between the first part of the subclavian artery and the third part of the axillary artery

55. Scapular anastomosis
in this case the circulation of blood in the subscapular artery is reversed