The dissection of the axilla:
The axilla is rich in fat and lymph nodes appear as small grey structures. During dissection of the axilla, special precautions should be taken to protect the many important and tiny structures that lie there. After reflecting the skin and cleaning the fascia, attempt to identify the walls of the axilla. The brachial plexus and axillary vessls branches will appear in a fascial sheath called the axillary sheath. They pass in the space between the clavicle and the first rib. Open the axillary sheath and start to identify the structures, beginning with the axillary vessels. The first part of the axillary artery lies proximal to the upper border of pectoralis minor, one branch is directed to the chest wall and is the highest thoracic artery. Notice the second part passing behind pectoralis minor and its two branches, the first being the thoracoacromial artery and the second the lateral thoracic artery. The third part is identified distal to the lower border of pectoralis minor and has three branches: the subscapular artery, and the anterior and posterior circumflex humeral arteries which pass around the surgical neck of the humerus. Regarding the brachial plexus, the terminal part of the medial cord passes anterior to the lower part of the axillary artery before joining the terminal part of the lateral cord and forming a Y-shape, its lower end forming the median nerve. Attempt to find the branches of the medial cord by following the course proximally before formation of the median nerve; the first branch will be the ulnar nerve which runs on the medial side of the axillary artery. The next branch is the medial cutaneous nerve of the forearm and proximal to it is the medial cutaneous nerve of the arm. The medial pectoral nerve appears further up in the same direction. The ulnar nerve usually lies between the axillary artery and vein. Repeat the same procedure with the lateral cord find the musculocutaneous nerve leaving the lateral cord by piercing coracobrachialis in order to reach biceps brachii. Further up, in the same direction is the lateral pectoral nerve. Identify the posterior cord under the axillary artery before it continues as the radial nerve. Attempt to identify the branches, firstly the cutaneous branch to the posterior part of the arm. Further up, the axillary nerve leaves the posterior cord passing to the quadriangular space to the deep surface of deltoid. Higher up in the same direction the subscapular and thoracodorsal nerves can be found.
The axilla is rich in fat and lymph nodes appear as small grey structures. During dissection of the axilla, special precautions should be taken to protect the many important and tiny structures that lie there. After reflecting the skin and cleaning the fascia, attempt to identify the walls of the axilla. The brachial plexus and axillary vessls branches will appear in a fascial sheath called the axillary sheath. They pass in the space between the clavicle and the first rib. Open the axillary sheath and start to identify the structures, beginning with the axillary vessels. The first part of the axillary artery lies proximal to the upper border of pectoralis minor, one branch is directed to the chest wall and is the highest thoracic artery. Notice the second part passing behind pectoralis minor and its two branches, the first being the thoracoacromial artery and the second the lateral thoracic artery. The third part is identified distal to the lower border of pectoralis minor and has three branches: the subscapular artery, and the anterior and posterior circumflex humeral arteries which pass around the surgical neck of the humerus. Regarding the brachial plexus, the terminal part of the medial cord passes anterior to the lower part of the axillary artery before joining the terminal part of the lateral cord and forming a Y-shape, its lower end forming the median nerve. Attempt to find the branches of the medial cord by following the course proximally before formation of the median nerve; the first branch will be the ulnar nerve which runs on the medial side of the axillary artery. The next branch is the medial cutaneous nerve of the forearm and proximal to it is the medial cutaneous nerve of the arm. The medial pectoral nerve appears further up in the same direction. The ulnar nerve usually lies between the axillary artery and vein. Repeat the same procedure with the lateral cord find the musculocutaneous nerve leaving the lateral cord by piercing coracobrachialis in order to reach biceps brachii. Further up, in the same direction is the lateral pectoral nerve. Identify the posterior cord under the axillary artery before it continues as the radial nerve. Attempt to identify the branches, firstly the cutaneous branch to the posterior part of the arm. Further up, the axillary nerve leaves the posterior cord passing to the quadriangular space to the deep surface of deltoid. Higher up in the same direction the subscapular and thoracodorsal nerves can be found.