Lecture Notes - Axilla, Posterior Shoulder, & Arm

Boundaries of axilla

• anterior axillary fold - pectoralis major
• posterior axillary fold - teres major and latissimus dorsi
• medial - serratus anterior (chest wall)
• lateral - humerus
• superior - clavicle, scapula, & first rib
• floor - skin

Contents of axilla

• Fat and lymph nodes
• Axillary vein
• Axillary artery - continuation of subclavian a.
  • Subdivided into 3 parts by pectoralis minor
    • 1st part - 1 branch - highest or supreme thoracic
    • 2nd part - 2 branches
      • thoracoacromial
      • lateral thoracic
    • 3rd part - 3 branches
      • anterior circumflex humeral
      • posterior circumflex humeral
      • subscapular - divides into circumflex scapular & thoracodorsal
  • Relationship to brachial plexus and axillary sheath
• Brachial plexus
  • Formation - roots (5), trunks (3), divisions (6), cords (3), and branches
  • Nerves of plexus
    • From roots
      • dorsal scapular (C5)
      • long thoracic (C5,6,7)
    • From trunks
      • suprascapular (from superior trunk)
    • From divisions - none
    • From cords
      • lateral cord - 3 branches
        • lateral pectoral
        • lateral contribution to median n.
        • musculocutaneous
      • medial cord - 5 branches
        • medial pectoral
        • medial brachial cutaneous
        • medial antebrachial cutaneous
        • medial contribution to median n.
        • ulnar
      • posterior cord - 5 branches
        • upper subscapular
        • thoracodorsal (middle subscapular)
        • lower subscapular
        • axillary
        • radial

Brachial plexus injuries

• Erb-Duchenne palsy - upper plexus
• Klumpke's palsy - lower plexus
• Nerve compression & lesion

Fascial compartments of arm

• Anterior compartment
  • Muscles
    • coracobrachialis
    • biceps brachii (long & short heads)
    • brachialis
  • Nerve
    • musculocutaneous
• Posterior compartment
  • Muscles
    • triceps brachii (long, lateral & medial heads)
    • anconeus
  • Nerve & vessel
    • radial n.
    • deep brachial a.
    • (ulnar n. - travels distally within)
• Neurovascular compartment
  • Nerves of passage
    • median
    • medial antebrachial cutaneous
  • Artery
    • brachial

Contents of cubial fossa