Axilla

Axilla

1. What?

   • Space between the upper arm and the side of the upper chest(thorax) that is important acess ofr arteries, nerves and lumphatics getting from axial skeleton to the upper limb

2. Borders

   • Apex
     • Apex formed by the outer border of the first rib medially, the clavicle anteriorly and the superior border of the scapula posterioly
     • Also known as
       • cervicoaxillary canal
   • Base
     • (Armpit) has a posterior border formed by the lattimus dorsi (posterioly axillary fold), an anterior border by the pectoralis major (anteriorl axillary fold), medial border by the serratus anterior, and lateral border by the medial aspect of the humerus

3. Walls

   • Posterior
     • Subscapularis, teres major and latissimus dorsi
       • Subscapularis is a big muscle that sits anterior to the scapula in the subscapula fossa. Below that there is a muscle called the teres major (teres = round) then the latissimus dorsi is most posterior)
   • Anterior
     • Subclavious, costacoracoid ligament and membrane, pectoralis major, pectoralis minor and the suspensory ligament of the axilla
       • Inner layer = pectoralis minor muscle, quite small. Has fascia going around it. This fascia is continuous with the fascia called the suspensory ligament inferiorly (the ligament that shapes the axilla ie gives the armpit the indented shape) that connects with the axillary fascia. The fascia surrounding the pectoralis minor is also continuous with another superoprly fascia called the costacoracoid ligament and membrane ( a fascia that covers the underside of the pectoralis major at the clavicular part. It occupies the interval between the pectoralis minor and the subclavius and protects the axillary arteries and nerves) which blends with the fascia of the subclavius (muscle from first rib to clavicle)- this forms a muscular membrane. Infront of that we have the superficial layer which is the pectoral major (covers all of this)
   • Floor
     • Axillary fascia- fascia below the skin, wall of the armpit

4. Contents

   • Cords and branches of the brachial plexus, axillary artery and vein, lymph nodes and lymphatics and fat
     • 5 groups of lymph nodes (+ what do they drain)
       • Lateral
         • Drains the arm
       • Pectoral
         • Drains much of the breast and hence is important in spread of....
           • ....carcinoma in that organ
       • Posterior or subscapular
         • which drains the upper part of the trunk posteriorly and the axillary tail of the breast
       • Central
         • Recieve from the other groups
       • Apical
         • Recieve from all other gruops and eventually drains into the thoracic duct or right lymphatic duct
     • Where are each located relative to the scalene muscles

Images and files in the map