Why are my legs bruised and my head swollen even though they were both caused by collisions? (Attached is a guide to reduce swelling →)

Bumping, hitting, falling, and bumping into something will not only cause pain, but also bring with it the side effects of pain: bruises and swellings. Why do limbs usually have bruises, while the head has swellings? How do these bruises come about? And how can we reduce the swelling quickly and painlessly?

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01 Why is there a swelling here?

When our blood vessels are injured, bruised or otherwise damaged, the blood vessel walls may rupture. After the blood vessels rupture, blood will leak into the surrounding tissue spaces, which is what we often call congestion.

As the congestion progresses, the broken red blood cells release hemoglobin, and the metabolites of hemoglobin undergo a series of reactions to form a blue-black pigment, which appears to be blue to the naked eye, and thus becomes a "bruise". This is especially true of the surface of the knee joint, which will turn blue and purple with just a slight bump.

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But the scalp, which is also made of skin and bones, is slightly different. When the head is accidentally hit, swelling often appears. Why is this?

In fact, swelling can also occur when the limbs are injured by blunt force trauma, especially when blood vessels are ruptured. However, compared with the head, the limbs usually have more subcutaneous fat and connective tissue, which can buffer the impact of external forces to a certain extent.

Therefore, even if a collision occurs, the limbs may not be as likely to form obvious lumps as the head. In other words, the more subcutaneous fat there is, the less likely it is to swell.

The scalp is mainly composed of three layers: epidermis, dermis and subcutaneous tissue. Among them, the subcutaneous tissue contains some fat, but compared with the trunk, buttocks and other parts, the subcutaneous fat layer of the scalp is thinner, but the blood vessels under the scalp are rich, and when hit by external force, the blood vessels rupture and form a hematoma, which is commonly known as a big swelling.

In general, the differences in the physiological structure of the skin on the head and limbs make it easy for swelling and bruises to form when exposed to external forces.

02 Don’t take bruises and blood loss lightly

Hematoma and bruises are all caused by damaged blood vessels. Although it seems that they are all superficial blood vessel damage in our body, it does not mean that we can take it lightly and just observe it for a few days.

Injuries to different physiological parts may lead to different symptoms and manifestations, which are related to factors such as the physiological structure, blood supply and nerve distribution of that part.

For example, bruises on the limbs do not only appear after bumps and collisions. When there is a fracture or joint injury, there may also be obvious swelling, accompanied by limited movement, severe pain and other symptoms. Therefore, when there is a possibility of a fracture, you must not move the affected limb without authorization. You should fix it and seek medical attention in time.

For example, the typical physical sign of patients with acute hemorrhagic necrotizing pancreatitis is the Grey-Tuner sign, which is the blood seeping into the subcutaneous tissue of the abdominal wall through the retroperitoneal space, manifesting as large purple bruises on the waist, hypochondrium and abdomen.

So the swelling and bruising that appears may not actually be a small problem. Injuries to different parts of the body need to be evaluated and treated according to the specific situation. Severe injuries may require professional medical intervention. When dealing with injuries, it is crucial to seek medical attention in a timely manner and receive professional advice.

03 Quick guide to reducing swelling

Sometimes, we only have swelling caused by a bump, and we can confirm that it is not a fracture. So how can we deal with the hematoma and reduce the swelling as soon as possible? After a bump causes a swelling, cold compress and hot compress are commonly used methods to reduce swelling and relieve pain. Here are some suggestions:

Initial stage (approximately within the first 24-48 hours)

Cold compress. In the early stage of hematoma or bruise (within 24 hours), it is not recommended to use hot compress! It is easy to aggravate bleeding, increase the risk of swelling, and promote the continuation of inflammatory response.

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Method: Use ice packs, cold compresses or towels wrapped in ice cubes to apply cold compresses, and avoid direct contact of ice cubes with the skin to cause frostbite. It is recommended to apply cold compresses every 2 hours or so, for 15-20 minutes each time.

48 hours after injury

Consider applying heat.

Method: Use a hot water bottle, hot compress patch or warm wet towel to avoid overheating and burns. The frequency is the same as cold compress, apply hot compress every 2 hours or so, for 15-20 minutes each time.

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As for why cold compress is used first and then hot compress, it is based on the physiological process of injury and treatment principles at different stages. The use of this sequence helps to minimize swelling, pain and promote recovery.

When cold compress is applied, blood vessels contract, slowing blood flow to the injured area, thereby reducing local swelling. Cold compress can also have a certain degree of paralysis, reduce the metabolic rate of tissues, slow down inflammatory reactions, and relieve pain. When hot compress is applied, blood vessels dilate, blood flow increases, bringing more oxygen and nutrients, and promoting healing. At the same time, hot compress can relax muscles, relieve tension and spasms, and reduce pain. In a certain period after injury, hot compress can promote the flexibility of soft tissues to help better recovery.

However, this is only a general treatment method, and the specific situation depends on the nature and extent of the injury and individual differences. If the symptoms persist or worsen, it is best to consult a professional doctor for advice.

In addition to reducing swelling through physical means such as cold or hot compresses, are there any related medicines that can have a better effect in reducing swelling?

Of course there are. For epidermal swelling and congestion caused by trauma like this, drugs such as Yunnan Baiyao and safflower oil can reduce swelling, promote blood circulation and remove blood stasis. However, you should be sure to read the instructions carefully before use. Patients with open wounds or those who are allergic to related ingredients need to use it with caution.

04 Choose carefully when using folk remedies to reduce swelling!

Sometimes, when the above medicines are not available, the older generation in the family may use the folk remedy of applying lard to reduce swelling. However, it should be pointed out here that there is no sufficient scientific support and research to prove that lard can effectively reduce swelling.

Lard has a certain moisturizing property and may help to moisturize the skin to a certain extent, relieving dry skin and discomfort. And when lard is applied, due to its body temperature, it may produce a certain local warming effect, which is sometimes believed to have a certain effect on relieving some swelling and pain.

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Due to individual differences, the effectiveness of this type of traditional remedy varies from person to person, so although some people may feel relief from applying lard, it has not been scientifically proven to have a significant effect in reducing swelling.

In the early stages of an injury, it is wise to avoid rubbing the hematoma too vigorously. This is because in the early stages of an injury, the tissue may be sensitive and fragile, and excessive rubbing may cause further damage and inflammation, increasing pain and swelling. So the action of "rubbing lard" is not correct.

Folk remedies should not replace modern medical treatments. We should adopt a dialectical attitude towards so-called folk remedies. We can flexibly use those with scientific basis, but it is best not to easily try folk remedies that have no scientific basis.

Finally, I would like to emphasize: if pain, swelling or other symptoms persist or worsen after treatment such as cold compresses, remember to seek medical attention in a timely manner and obtain professional diagnosis and treatment advice!

Source: Chongqing Science and Technology Museum

Source: Yingjiang, medical major.

Review experts: Huang He, Li Chunli, Xu Xiaoping

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