What is sinus brachia? Understanding Branchial Cleft Anomalies

September 21, 2025 •

3 min read

Approximately 20% of all congenital neck masses are branchial cleft anomalies. This guide addresses the query, What is sinus brachia?, by explaining the likely reference to a branchial sinus, a condition present from birth due to improper embryonic development.

Quick Summary

A branchial sinus is a congenital neck abnormality, a small tract or opening on the skin leftover from embryonic development. This occurs when tissues forming the neck and throat don't fully close, creating a channel that may drain fluid and can become infected.

Key Points

Correction of Term: "Sinus brachia" is a common misspelling of "branchial sinus," a congenital neck anomaly, and should not be confused with the heart condition sinus bradycardia.
Congenital Origin: A branchial sinus is a birth defect resulting from the incomplete closure of tissues in the neck during embryonic development.
Main Symptom: The condition typically presents as a small opening or pit on the skin of the neck that may drain fluid or mucus.
Infection Risk: Branchial sinuses are prone to infection, which can cause pain, swelling, and redness.
Surgical Cure: The definitive treatment is surgical excision of the entire sinus tract to prevent future infections.
Associated Conditions: Branchial sinuses can occur along with cysts and fistulas and, rarely, as part of a genetic syndrome.

Clarifying the Term: Sinus Brachia vs. Branchial Sinus

The term "sinus brachia" is commonly used interchangeably with "branchial sinus." In medical terms, a branchial sinus is related to the embryonic development of the neck and face, not the arm (brachium). It's also distinct from "sinus bradycardia," a heart condition. This article focuses on the congenital neck anomaly properly known as a branchial sinus or branchial cleft sinus.

What is a Branchial Sinus?

A branchial sinus is a type of branchial cleft anomaly, a birth defect resulting from the incomplete formation of neck tissues during early fetal development. During this process, structures called branchial arches and clefts typically disappear. If they don't fully resorb, remnants can form, including:

Branchial sinus: A blind-ending tract with an opening on the neck skin or into the pharynx.
Branchial fistula: A complete channel connecting the skin to the pharynx.
Branchial cyst: A closed, fluid-filled sac.

These anomalies most frequently arise from the second branchial arch, leading to an opening near the front of the sternocleidomastoid muscle.

Causes of Branchial Anomalies

These anomalies are congenital, meaning they are present at birth due to abnormal embryonic tissue development. While usually isolated, bilateral cases can sometimes be linked to genetic syndromes like branchio-oto-renal (BOR) syndrome, which can also affect hearing and kidneys.

Symptoms and Diagnosis

Symptoms of a branchial sinus may be apparent at birth or appear later, often following an infection.

Common Symptoms

Symptoms can include a small pit or lump on the neck, typically near the collarbone or jawline, which may drain fluid. Infection can cause redness, swelling, pain, and warmth. Rarely, a large anomaly can lead to difficulty swallowing or noisy breathing.

Diagnostic Process

Diagnosis often begins with a physical examination. Imaging like ultrasound, CT, or MRI can help determine the extent of the anomaly for surgical planning. Endoscopy may be used to identify internal openings, especially if a pharyngeal connection is suspected.

Treatment for Branchial Sinus

Surgical removal is the definitive treatment to prevent recurrent infections and complications. Infections are typically treated with antibiotics before surgery.

Surgical Excision

Surgery involves removing the entire sinus tract and any associated cysts. The complexity depends on the anomaly's location and proximity to vital structures. A horizontal neck incision is often used to minimize visible scarring.

Potential Complications

Potential surgical complications include infection, bleeding (hematoma), fluid collection (seroma), nerve damage, and recurrence if the entire tract isn't removed.

Comparison of Branchial Cleft Anomalies


Feature	Branchial Sinus	Branchial Cyst	Branchial Fistula
Embryonic Remnant	Partial tract	Closed sac	Complete tract
Connection	Single opening to skin or pharynx	No openings	Connection between skin and pharynx
Symptoms	Draining pit, potential for infection	Non-draining lump, swelling when infected	Draining tract, more consistent drainage
Appearance at Birth	Small opening may be visible	May appear later if asymptomatic	Small opening with drainage

Conclusion

Although "sinus brachia" is a common misnomer for branchial sinus, understanding the condition is key to proper treatment. This congenital defect stems from developmental issues in the neck and can lead to recurrent infections if not addressed. Surgical removal provides a definitive cure. Early diagnosis and consulting a healthcare professional, such as a pediatric ENT specialist, are crucial for effective management. For more information on pediatric head and neck conditions, resources like Boston Children's Hospital offer valuable insights.

Frequently Asked Questions

A branchial sinus is a tract or pathway with an opening to either the skin or the pharynx, often draining fluid. In contrast, a branchial cyst is a closed, fluid-filled sac with no external opening. A cyst can still become infected and swell.

Not always. While the small skin opening of a branchial sinus may be noticed at birth, some can be asymptomatic for years and are only discovered later in life, often when they become infected for the first time.

Diagnosis is typically made through a physical examination. The doctor may also use imaging, such as an ultrasound, CT scan, or MRI, to confirm the location and full extent of the tract.

Antibiotics are used to treat any active infection within the tract. However, they do not cure the underlying congenital defect. Surgical removal is the only way to prevent recurrent infections and provide a definitive cure.

A branchial sinus tract is lined with epithelial tissue that can produce mucus-like material, which may drain from the small skin opening. If infected, the drainage can be pus-like.

If left untreated, a branchial sinus is likely to become repeatedly infected. Repeated infections can lead to abscess formation and scarring, which can make eventual surgical removal more difficult.

As with any surgery, there are risks, including infection, nerve injury (especially the facial nerve for some types), and recurrence. However, with an experienced pediatric ENT surgeon, the procedure is generally safe and successful.