Boundaries & Walls of Axilla

Question 1

Upper end of the axilla, or apex

Answer 1

✓ Front by the clavicle
✓ Behind by the upper border of the scapula
✓ Medially by the outer border of the first rib

Question 2

Lower end, or base

Answer 2

✓ Front by the anterior axillary fold (the lower border of the pectoralis major muscle).
✓ Behind by the posterior axillary fold (formed by the tendon of latissimus dorsi and the teres major muscle).
✓ Medially by the chest wall.

Question 3

Anterior wall

Answer 3

By the pectoralis major, subclavius, and pectoralis minor muscles

Question 4

Posterior wall

Answer 4

By the subscapularis, latissimusdorsi, and teres major muscles from above down

Question 5

Medial wall

Answer 5

By the upper four or five ribs and the intercostal spaces covered by the serratus anterior muscle

Question 6

Lateral wall

Answer 6

By the coracobrachialis and biceps muscles in the bicipital groove of the humerus

Question 7

The base

Answer 7

Formed by the skin stretching between the anterior and posterior walls