Triangles in Thyroid Surgery

🔺 Important Triangles in Thyroid Surgery

🐻 Beahr’s Triangle

📐 Boundaries:

• Base: Common carotid artery

• Superior: Inferior thyroid artery

• Inferomedial: Recurrent laryngeal nerve

🎯 Clinical Importance:

• Found posterior to the thyroid gland after retracting it medially.

• Helps locate the recurrent laryngeal nerve (RLN) and avoid injury during surgery.

What is Beahr's triangle also known as?

🧊 Simon’s Triangle

📐 Boundaries:

• Superior: Inferior thyroid artery

• Lateral: Common carotid artery

• Medial: Esophagus or trachea

📦 Content:

• Recurrent laryngeal nerve passes through this triangle.

🎯 Clinical Importance:

• Unlike Beahr’s triangle, recurrent laryngeal nerve is a content here.

• Important zone for recurrent laryngeal nerve identification intraoperatively.

📐 Joll’s Triangle

📐 Boundaries:

• Superior: Superior attachment of strap muscles

• Medial: Midline of the neck

• Lateral: Superior pole of thyroid & superior thyroid vessels

• Floor: Cricothyroid muscle

📦 Content:

• External branch of the superior laryngeal nerve (EBSLN)

🎯 Clinical Importance:

• Identify and preserve EBSLN to avoid voice pitch issues post-thyroidectomy.

What is Joll's triangle also known as?

📏 Lore’s Triangle

📐 Boundaries:

• Medial: Trachea

• Lateral: Common carotid artery

• Superior: Inferior pole of thyroid gland

📦 Content:

• Recurrent laryngeal nerve

🎯 Clinical Importance:

• Key zone to locate and protect the recurrent laryngeal nerve during surgery.

🔻 Recurrent Laryngeal Nerve Triangle

📐 Boundaries (Inverted Triangle):

• Apex: Thoracic inlet

• Medial: Trachea

• Lateral: Medial edge of retracted strap muscles

• Superior: Lower edge of inferior thyroid pole

📦 Content:

• Recurrent laryngeal nerve as a single trunk

🎯 Clinical Importance:

• Identifying the recurrent laryngeal nerve trunk near thoracic inlet helps avoid nerve damage during lower pole dissection.

⚠️ Triangle of Concern

📐 Boundaries:

• Medial: Trachea

• Lateral: Recurrent laryngeal nerve

• Base: Thyrothymic ligament & loose fat over sternum

• Apex: Berry’s ligament

📦 Content:

• Small arterial branches of the inferior thyroid artery

🎯 Clinical Importance:

• Commonest site of bleeding during thyroidectomy.

• Lies close to recurrent laryngeal nerve → requires careful hemostasis to prevent nerve injury.

🧵 Cricothyroid Space of Reeves

• Avascular space between upper thyroid pole and cricothyroid muscle

📦 Content:

• External branch of superior laryngeal nerve (EBSLN) enters this space.

🎯 Clinical Importance:

• Open and inspect this space to preserve EBSLN.

• Retraction of the thyroid lobe here reveals Joll’s triangle.

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🧩 Summary Table

📝 Final Notes

Out of the seven triangles,

✅ Two triangles relate to the external branch of superior laryngeal nerve:

• Joel’s Triangle
• Cricothyroid Space of Reeves

⚠️ Five triangles involve the recurrent laryngeal nerve, either as a content or boundary.