Genial Tubercle: Anatomy, Muscle Attachments, and Clinical Significance
By Dr. Paul Mirdamadi
The genial tubercles are critical anatomic landmarks located on the lingual surface of the anterior mandible. Although small in size, they serve as the attachment points for key muscles involved in tongue position, swallowing, mandibular movement, and airway patency. A thorough understanding of genial tubercle anatomy is essential in oral and maxillofacial surgery, orthognathic surgery, trauma management, and obstructive sleep apnea treatment.
Anatomy of the Genial Tubercles
The genial tubercles—also referred to as mental spines—are typically arranged as four small bony projections on the midline of the lingual mandible, just superior to the mandibular symphysis. They are classically described as:
-
Two superior genial tubercles
-
Two inferior genial tubercles
Although variation exists, their functional significance lies in the muscles that originate from these structures.
Muscle Attachments of the Genial Tubercle
Several important muscles attach directly to the genial tubercles:
The genioglossus muscle originates from the superior genial tubercles and is the primary muscle responsible for tongue protrusion and depression. It plays a crucial role in maintaining upper airway patency, particularly during sleep.
The geniohyoid muscle arises from the inferior genial tubercles and functions to elevate the hyoid bone and assist in mandibular depression. Its position makes it highly relevant in airway-focused surgical procedures.
The anterior belly of the digastric contributes to mandibular depression and hyoid elevation, while the anterior fibers of the mylohyoid help form the floor of the mouth and support the tongue during swallowing and speech.
Importantly, the hyoglossus muscle does not attach to the genial tubercles. As a result, it does not advance with genial tubercle or genioglossus advancement procedures, a key concept in airway surgery planning.
Clinical Relevance in Oral and Maxillofacial Surgery
The genial tubercles are encountered in multiple surgical contexts, including:
-
Genioplasty
-
Mandibular advancement procedures
-
Trauma involving the mandibular symphysis
-
Resection of benign or malignant lesions
-
Obstructive sleep apnea surgery
Damage to or displacement of the genial tubercles can affect tongue position and swallowing mechanics, making careful surgical planning essential.
Genial Tubercle Advancement and Airway Surgery
Genial tubercle advancement (GTA) is a well-established surgical technique used in the management of obstructive sleep apnea (OSA). By advancing the genial tubercles, the attached genioglossus and geniohyoid muscles are repositioned anteriorly, reducing posterior tongue collapse during sleep.
Because the hyoglossus muscle remains fixed to the hyoid and lateral tongue, GTA selectively improves airway patency through anterior tongue base stabilization rather than global tongue movement.
GTA is often performed as:
-
A standalone airway procedure in select patients
-
An adjunct to maxillomandibular advancement (MMA)
-
A component of multi-level sleep surgery
Trauma and Fracture Considerations
In mandibular symphyseal fractures, the genial tubercles may be displaced along with the lingual cortex. Disruption of the attached muscles can contribute to:
-
Airway compromise
-
Dysphagia
-
Altered tongue posture
Recognition of genial tubercle involvement is important when evaluating trauma imaging and planning fixation.
Board Exam and Clinical Pearl
-
Genioglossus and geniohyoid attach to the genial tubercles
-
Hyoglossus does NOT attach and does NOT advance with GTA
-
Advancement of the genial tubercles improves tongue base position and airway patency
Conclusion
The genial tubercles, though often overlooked, play a central role in mandibular anatomy, tongue function, and airway stability. Their muscle attachments make them highly relevant in orthognathic surgery, trauma management, and obstructive sleep apnea treatment. Mastery of genial tubercle anatomy is essential for safe surgical execution and optimal functional outcomes.
