Definition
Pain under the armpit can have many causes. Anatomically, the armpit is the hollow space under the shoulder joint, which is formed by various muscle groups. Since many important structures and pathways for the chest and arms run through the anatomically narrow area around the shoulder joint, pain, diseases and injuries in the armpit should be taken seriously.
Causes for pain under the armpit
The causes of pain under the armpit can be serious and harmless. In this area, in addition to the joint structures, tendons and muscles of the shoulder girdle, numerous nerves, blood vessels and lymph channels run along both sides. The armpit is also a collection point for many lymph nodes that collect lymph from the arms, chest and neck structures.
Since the causes are numerous, the exact type of pain, duration of pain and concomitant circumstances must be inquired about at the beginning of the diagnosis, since they limit the potential causes many times over. Possible, often harmless causes of pain under the armpit are injuries and diseases of the musculoskeletal system in the shoulder area. The humerus, shoulder joint, shoulder blade or collarbone can be affected.
Often there are also strains, tears or tensions of the muscles that form the armpit. These include in particular the chest and upper back muscles, as well as the so-called “rotator cuff” of the shoulder. Pain under the armpit can also be caused by inflammation.
In most cases, inflammation is caused by invading pathogens that attack the skin or lymph nodes and cause painful redness with swelling. The skin is a common entry point for bacteria, viruses or fungi. Especially after minor injuries, for example after shaving, the probability of infection is increased.
Since the lymph nodes of the armpit are a central collection point, pathogens can also enter the armpit this way. Painfully swollen lymph nodes of the armpit are often found after a viral infection, for example after measles or whistling glandular fever. In rare cases, the lymph nodes can swell even without inflammation.
This can result in an unpleasant, painful feeling of pressure. Such a swelling can appear for no reason or as a result of a malignant disease in the drainage area of the axillary lymph nodes. Pain under the armpit can also be caused by inflammation.
In most cases, inflammation is caused by invading pathogens that attack the skin or lymph nodes and cause painful redness with swelling. The skin is a common entry point for bacteria, viruses or fungi. Especially after minor injuries, for example after shaving, the probability of infection is increased.
Since the lymph nodes of the armpit are a central collection point, pathogens can also enter the armpit this way. Painfully swollen lymph nodes of the armpit are often found after a viral infection, for example after measles or whistling glandular fever. In rare cases, the lymph nodes can swell even without inflammation.
This can result in an unpleasant, painful feeling of pressure. Such a swelling can appear for no reason or as a result of a malignant disease in the drainage area of the axillary lymph nodes. Tension or strains of muscles located near the armpit can lead to pain under the armpit.
These include the muscles of the rotator cuff, the pectoralis muscles of the chest and the large back muscle, the “latissimus dorsi”. Especially in the case of jerky and incorrect movements (as in throwing sports), the shoulder muscles in the throwing arm can be painfully damaged by jerky movements, which can also lead to tension. Pain under the armpit is only in very rare cases caused by the thyroid gland.
Nowadays, operations on the thyroid gland in the context of hyperactivity, nodules or cancer can be performed through an access route in the armpit. This avoids a scar on the neck, but post-operative pain and inflammation in the armpit can occur. Pain in the armpit can also occur in the context of thyroid cancer.
The cancer can infiltrate into the surrounding lymph nodes and cause them to swell. The pressure on surrounding structures can cause slight pain in the armpit. Pain under the armpit occurs unilaterally in almost all cases.Since these are mostly local events, a bilateral infestation is unlikely.
In athletes, pain in the right armpit may indicate load-related complaints. In most people, the right arm is dominant and thus more frequently affected by injuries. Also lymph node swelling and local inflammatory processes occur in most cases unilaterally, for example on the right side.
Breast cancer and its treatment also always involve the armpit and its lymph nodes. Complaints that originate from muscles are generally less frequent on the left side. On the left side, inflammation and complaints of the soft tissues in the armpit are the main focus. In rare cases, internal organs can also project pain onto the body surface. This can often be observed in heart attacks, which can lead to stabbing pain in the left arm, armpit or lower jaw.
All articles in this series:
