Abdomen | Definition, Anatomy, & Functions

Abdomen | Definition, Anatomy, & Functions

Abdomen Definition

Where is your abdomen? It is the area of the human body between the thorax and pelvis. It houses several important organs, including the stomach, intestines, pancreas, liver, spleen, and kidneys. Trillions of bacteria that aid in digestion also inhabited the abdominal cavity.

Pain in the lower abdomen is called painful abdomen that involved many factors. From constipation to appendicitis to ulcers – may cause abdominal pain but it can often be difficult for doctors to pinpoint an exact cause without performing other tests such as blood work or imaging scans. This article will help to understand a brief understanding of the Abdomen.

Abdomen Anatomy

The abdominal cavity has two separate parts: the upper abdominal part and the lower abdominal part. It is the area between the chest and pelvis region. The abdominal cavity proper contains some important organs including:

1. Spleen
2. Stomach
3. Pancreas
4. Liver

The abdominal part contains the digestive tract, which is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. The first section of the digestive tract begins through the esophagus and stomach; next comes the small intestine (which includes three parts: duodenum, jejunum, and ileum); then the large intestine (which includes the ascending, transverse, and descending colon, rectum and anal canal); and finally ends at the anus. The digestive tract breaks down food into nutrients that your body can absorb. The large intestine absorbs water from indigestible food residue (fiber), which helps to form stool or feces.


Abdominal Muscles

The abdomen properly contains three layers of muscles.

1. Transverse Abdominal Muscle

The innermost layer is the transverse abdominal muscle, which lies underneath the internal oblique and forms a corset-like structure around your abdomen. Transversus abdominis compresses the abdomen inward by pulling up on its lower attachments, while it helps stabilize the pelvis at the hip level.

2. Internal OIblique Muscle

The Internal oblique muscle is the middle abdomen muscle. It originates from ribs and the vertebral column, it runs down to the pelvis where it forms an inverted “V” shape that inserts into a horizontal band called inguinal ligament connecting at pubis crest of the hip bone. They involved the internal obliques in forced exhalation when they work with other muscles during heavy exercise or coughing by pulling up on their lower attachments to put tension on the abdomen cavity so the air/is exhaled forcibly out of the lungs.

3. External Oblique Muscle

The external oblique is the outermost abdominal muscle running horizontally around your abdomen just below your chest; its fibers run diagonally upward toward the centerline (stomach). This abdominal muscle pulls down on the front part of the rib cage, which tightens the abdomen and also helps to rotate the trunk.


Abdomen function

The abdomen contains many organs, including the stomach, small intestine, and colon, along with other digestive organs. It also houses two kidneys and an adrenal gland, and muscles in between layers. The abdominal cavity has many nerve endings, which make it very sensitive to pain and pressure changes, such as those associated with injury or illness. Functions of the Abdomen are included below:

1. Protecting internal abdominal contents
2. Providing space for pelvic region structures that support reproductive system (organs)
3. Allows movement of leg during walking/running by creating more flexibility around the hip joint area because of oblique muscle attachments running horizontally across the abdominal cavity
4. Helps to stretch to accommodate your growing uterus/baby bump; ligaments hold abdominal contents in place.


Abdomen Types

There are three different abdomens based on where the belly button is located:

1. Upper Abdomen:

It is only seen in infants and children, where the belly button is on the abdominal upper part.

2. Middle abdomen:

This is the typical part seen in adults with a belly button in the middle of the abdominal part. It is a “potbelly” or spare tire in which the belly button is located centrally in the abdominal cavity. This type of abdominal part often has a higher risk factor for heart disease because of increased body fat around the waistline and high blood pressure risks.

3. Lower abdomen:

The most common type is where the abdominal lower section forms a V shape between hips and pubic bone. It is called a distended abdomen. The belly button is always in this area when it appears on an adult abdominal part. Although there are different abdominal cavities, they all have similar structures because the same organs/structures are present in each one (i.e., stomach, intestines). As stated before, abdominal cavities can stretch to accommodate enormous meals or growing baby bumps but eventually return to their original size after we have digested eating or pregnancy ended.

Ways for abdominal Examination

Abdomen Examination

An abdominal examination is done through abdominal palpation to determine if there are any abnormalities. Palpating the abdomen involves gently touching the abdominal cavity with hands in order to feel for abnormal tissues that might not be visible by sight or touch alone, especially when the patient is experiencing pain. Abnormalities like:
Tenderness: This is often associated with inflammation and/or infection (i.e., appendicitis)
Hard Areas: tumors which could also mean cancer; masses of fluid too because it causes swelling and pockets filled up inside the abdominal cavity where they do not belong.

Abdominal ultrasound

To find out the solution to the painful lower abdomen, abdominal ultrasound is used. In an abdominal ultrasound, a transducer is placed on the abdominal’s surface to emit high-frequency sound waves that create echoes. These echoes bounce back to the same transducer and are processed into black-and-white pictures by a machine, which creates images of different layers of your abdominal cavity based on their densities (i.e., fat vs muscle).

Abdominal ultrasound can help diagnose many conditions, including:
1. Abnormal pregnancy
2. Tumors
3. Gallstones
4. Kidney stones,
5. Pancreas issues such as pancreatitis or cysts