The belly button, or navel, is a common anatomical landmark, yet its origins and connections often remain a mystery. This indentation signifies a profound link to our earliest development, hinting at internal pathways central to our existence before birth. Understanding these connections offers insight into the human body’s design and potential health considerations.
The Umbilical Cord
The umbilical cord facilitated our initial connection to the maternal environment during development. This structure linked the fetus to the placenta, exchanging vital substances by supplying oxygen and nutrients from the mother and removing waste products.
The umbilical cord contains three blood vessels: two umbilical arteries and one umbilical vein. The arteries carry deoxygenated blood and waste from the fetus to the placenta, while the vein transports oxygen-rich blood and nutrients back to the fetus. These vessels are encased in Wharton’s jelly, which cushions and protects them. After birth, the cord is clamped and cut, leaving a stump that dries and detaches, forming the navel.
Internal Structures
After birth, the external umbilical cord is severed, but its internal components transform into fibrous remnants. The umbilical vein, which carried oxygenated blood, obliterates to form the round ligament of the liver (ligamentum teres hepatis). This fibrous cord is located within the falciform ligament, extending from the liver to the umbilicus, serving as an anatomical landmark.
The two umbilical arteries, which carried deoxygenated blood from the fetus, also change. Their distal portions obliterate to become the paired medial umbilical ligaments on the inner anterior abdominal wall. Conversely, their proximal segments remain open, functioning as the superior vesical arteries that supply blood to the urinary bladder.
The urachus, a remnant of the allantois, also transforms internally. During fetal development, it formed a tubular connection between the fetal bladder and the umbilicus, aiding in waste removal. After birth, this duct typically involutes into a solid fibrous cord known as the median umbilical ligament. This unpaired structure extends from the urinary bladder to the umbilicus, providing some bladder support but losing its original fetal function.
Related Health Matters
The remnants of these fetal connections can be associated with health conditions. An umbilical hernia occurs when the abdominal muscle opening around the navel doesn’t completely close after birth. This allows intestine or fatty tissue to protrude, creating a soft bulge. Umbilical hernias are common in infants and often resolve as muscles strengthen, though they can also affect adults due to increased abdominal pressure.
Urachal anomalies can arise from its incomplete closure during development. These conditions include cysts, sinuses, or fistulas. For example, a urachal cyst is a fluid-filled sac if a segment remains patent, while a urachal fistula is a continuous open channel between the bladder and navel, potentially leading to discharge. These conditions may present with umbilical discharge or abdominal pain.
The navel area is susceptible to infection, particularly in newborns. Omphalitis is a bacterial infection of the umbilical cord stump and surrounding tissues. It is caused by bacteria like Staphylococcus aureus entering the site before the stump dries and falls off. If untreated, omphalitis can spread, potentially leading to widespread infection.