The Axilla

A pyramidal space at the junction between the neck and the upper limb

ApexInterval between middle third of clavicle and 1st rib

Anterior Wall

• Pectoralis Major

•Pectoralis Minor

Anterior Wall

• Pectoralis Major

•Pectoralis Minor

Anterior Wall

• Pectoralis Major

•Pectoralis Minor

Anterior Wall

• Pectoralis Major

• Pectoralis Minor

Medial Wall

• Serratus Anterior

• Ribs

Medial Wall

• Serratus Anterior

• Ribs

Posterior Wall

• Subscapularis

• Teres Major

• Latissimus Dorsi

Posterior Wall

• Subscapularis

• Teres Major

• Latissimus Dorsi

Posterior Wall

• Subscapularis

• Teres Major

• Latissimus Dorsi

Posterior Wall

• Subscapularis

• Teres Major

• Latissimus Dorsi

Lateral Wall

Intertubercular Sulcus of the Humerus

Contents of Axilla

• Cords and branches of brachial plexus

• Axillary Artery

• Axillary Vein

Contents of Axilla

• Cords and branches of brachial plexus

• Axillary Artery

• Axillary Vein

Contents of Axilla

• Cords and branches of brachial plexus

• Axillary Artery

• Axillary Vein

Contents of Axilla

• Cords and branches of brachial plexus

• Axillary Artery

• Axillary Vein

Contents of Axilla

• Cords and branches of brachial plexus

• Axillary Artery

• Axillary Vein

(also lymph nodes and fat)

Summary of Muscles

Anterior WallPectoralis Major

Origin Clavicular head: anterior surface of medial half of clavicle; Sternocostal head: anterior surface of sternum, superior six costal cartilages, and aponeurosis of external oblique muscle

Insertion Lateral lip of intertubercular groove of humerus

Action Adducts and internally rotates humerus

Nerve Supply Lateral and medial pectoral nerves (C5, C6, C7, C8, and T1)

Blood Supply pectoral branch of thoracoacromial trunk

Anterior Wall

Pectoralis MinorOrigin 3rd to 5th ribs near their costal

cartilagesInsertion Medial border and superior

surface of coracoid process of scapula

Action Stabilises scapula, pulls it inferiorly and anteriorly against thoracic wall

Nerve Supply Medial and lateral pectoral nerves; (C8 and T1)

Blood Supply Pectoral branch of the thoracoacromial trunk

Medial Wall

Serratus AnteriorOrigin Lateral surfaces of upper 8 or 9

ribs at the side of chestInsertion Medial border of scapulaAction Pulls scapula forward and

upward; stabilises medial border of scapula

Nerve Supply Long thoracic nerve (C5, C6, C7)

Blood Supply Circumflex scapular artery

SubscapularisOrigin Subscapular fossa of scapulaInsertion Lesser tuberosity of humerus

Action Internal rotation and adduction of the arm

Nerve Supply Upper and lower subscapular nerves (C5, C6 and C7)

Blood Supply Subscapular artery

Posterior Wall

Posterior Wall

Teres MajorOrigin Dorsal surface of inferior angle

of scapulaInsertion Medial lip of intertubercular

groove of humerusAction Adducts and medially rotates

armNerve Supply Lower subscapular nerve (C6

and C7)Blood Supply Subscapular and circumflex

scapular arteries

Posterior WallLatissimus Dorsi

Origin Spinous processes of inferior 6 thoracic vertebrae, all lumbar vertebrae and dorsal crest of sacrum, thoracolumbar fascia, iliac crest, and inferior 3 or 4 ribs

Insertion Floor of intertubercular groove of humerus

Action Extends, adducts, and internally rotates humerus; pulls body up toward arms during climbing

Nerve Supply Thoracodorsal nerve (C6, C7, and C8)

Blood Supply Thoracodorsal artery