Anatomy of Upper Limb and Thorax by Vishram Singh PDF 13: A Comprehensive and Updated Textbook for Medical Students
The axilla is a small anatomical space located between the upper thoracic wall and the arm. The main contents include the brachial plexus, axillary artery and vein, and axillary lymph nodes. Lymph nodes contain a range of immune cells, including lymphocytes and macrophages. These remove damaged cells, foreign material, and microorganisms from the lymphatic fluid before returning it to the venous circulation. The axillary lymph nodes arrange into five groups based on their anatomical relations. Collectively, they drain the wall of the thorax, breast, arm, and upper abdominal wall above the umbilicus. The axillary lymph nodes are of particular clinical significance as they are often the first site of breast cancer metastasis. Axillary node involvement is the single most significant prognostic variable for breast cancer patients. Axillary lymphadenopathy is also associated with hematological malignancies, infection, and various autoimmune etiologies. It is, therefore, crucial to have a thorough understanding of this region.
anatomy of upper limb and thorax by vishram singh pdf 13
Lymph nodes do not contain their nervous supply; however, they are often near many different nerves. For example, the axillary lymph nodes are situated near the cords and branches of the brachial plexus, which innervate the muscles of the upper limb. Anatomically, the brachial plexus divisions become cords at the mid-clavicle, while the branches typically originate at the level of the pectoralis minor muscle. The long thoracic nerve, which originates from C5-7 nerve roots, is also located within the axilla. It is important to be aware of these structures as they are vulnerable to injury during axillary lymph node surgery.
There are many possible complications of an ALND for carcinoma of the breast. These usually affect the ipsilateral upper limb and may include numbness (39%), pain (39%), arm swelling (25%), and limitation of arm movement (16%). Arm swelling due to interruption of the lymphatic drainage of the upper limb is also known as lymphedema. In this condition, lymph accumulates in the subcutaneous tissue leading to symptoms such as pain and altered sensation, limb heaviness, and difficulty fitting into clothing. A winged scapula may also be observed postoperatively due to injury to the long thoracic nerve, especially in patients with a low body mass index. This nerve innervates the serratus anterior, which acts to pull the scapula forward.