Rash at the costal arch
There are several possible reasons for swelling of the costal arch. If the swelling is superficial in the skin, a hair root or sebaceous gland may be inflamed or clothing may have rubbed too much against the skin. The swelling usually disappears within a few days.
If it does not or if pain occurs, you should always consult a doctor. Swelling of the costal arch can also have serious causes. A rib could have been bruised or broken by a fall. If the swelling is more under the costal arch on the right or left, organs such as the liver or spleen may be affected. However, an inflammation of the cartilage on the breastbone can also lead to swelling, this is known as costochondritis, an inflammation of the rib cartilage, although this is rather rare.
Bruise on the ribcage
If, unfortunately, you fall on your chest in a fall, you need to pay attention, because the lung is located directly below the chest. A bruise of the ribs will result in swelling of the area, possible pain, possibly resulting in slight breathing restrictions and later bruising. The symptoms usually subside on their own. If breathing difficulties suddenly occur or the pain becomes more severe, a doctor should be consulted urgently. The rib could be broken and have damaged the lung.
Torn muscle fiber at the ribcage
At the costal arch both the abdominal muscles have their origin and the respiratory auxiliary muscles, which can support breathing. The respiratory support muscles are the chest muscles (major and minor pectoralis muscles) and the intercostal muscles that connect the ribs to each other. If the forearms are supported when breathing in, the chest muscles help to lift the chest.
If a torn muscle fibre is torn in the pectoral muscles, e.g. during sport, motion-dependent stabbing pain in the chest area can occur. Torn muscle fibers in the intercostal muscles are rather rare and often a consequence of rib fractures, e.g. due to a fall. Abdominal muscles overstrained by frequent abdominal training can lead to a torn muscle fiber there. The pain can occur at the costal arch or in deeper areas of the abdomen, depending on where the muscle is damaged.
