Hypoglossal canal

Synonyms

The hypoglossal canal is a bilateral structure located at the base of the skull.
It is situated along the lateral margin of the anterior half of the foramen magnum.
Anatomically, the canal is approximately 5 mm above the junction of the posterior and middle third of the occipital condyle.
The canal's position is significant, as it lies near critical structures at the skull base.

The hypoglossal canal is close to the jugular foramen and the nerves that pass below it.
- The canal is located medial to the jugular foramen.

It is also near the occipital condyle and the foramen magnum, which are key landmarks in skull base anatomy.

The hypoglossal nerve (Cranial Nerve XII) passes through this canal.
- The rootlets pass from the preolivary sulcus to the canal.
The nerve is responsible for motor control of the tongue muscles.
Structures such as the styloglossus, stylopharyngeal, and stylohyoid muscles are within this canal.

The hypoglossal canal and nerve are crucial considerations in surgeries involving the skull base, particularly in the region of the foramen magnum.
Lesions or pathologies affecting the hypoglossal canal can lead to hypoglossal nerve palsy, characterized by tongue weakness or paralysis.
The nerve's proximity to the jugular foramen makes it susceptible to involvement in jugular foramen syndromes.
Understanding the canal's anatomy is vital for procedures like suboccipital craniectomies, where inadvertent damage to the hypoglossal nerve can have significant functional implications.

Access to the hypoglossal canal requires careful navigation to avoid damaging the hypoglossal nerve.
It can be exposed extradurally for increased access to the front of the brainstem, especially in complex skull base surgeries.
Surgical approaches must account for the canal's proximity to other cranial nerves and vascular structures.