Anatomy of the Head, Face, and Neck

Note: Descriptions marked (C) are accurate. The remaining descriptions have been supplemented with correct information and clarifications.

1. Skull

• Correct Description: The skull consists of the base and the vault.
• Additional Information: The skull is composed of 22 bones, including 8 cranial bones and 14 facial bones.
• Note:
  • All cranial bones are connected to each other by immovable joints (suture, squamous suture, plane joint).
  • The nasal cavity is formed by 14 facial bones, with 10 bones forming the outer wall and 4 bones forming the inner wall. The orbital cavity is formed by 7 facial bones.
  • The orbital part of the frontal bone forms the upper and anterior portions of the roof of the orbit.

2. Frontal Bone

• Correct Description: The trochlear fossa is the attachment site for a muscle innervated by the fourth cranial nerve.
• Additional Information:
  • The trochlear fossa is the attachment site for the superior oblique muscle, which is innervated by the trochlear nerve (cranial nerve IV).
  • The frontal sinus (sinus frontalis) lies within the orbital part of the frontal bone and communicates with the nasal cavity.
  • The lacrimal fossa (fossa lacrimalis) is located on the anteromedial aspect of the inferior orbital part of the frontal bone, housing the lacrimal gland.
  • The supraorbital arch (arcus supercilii) is located between the frontal squama and the orbital part of the frontal bone, providing protection for the eye.
• Incorrect Description: The orbital part of the frontal bone forms the entire floor of the anterior cranial fossa.
• Correction: The floor of the anterior cranial fossa is formed by the ethmoid (cribriform plate) and the sphenoid (lesser wings).

3. Temporal Bone

• Correct Description:
  • It consists of three parts: squamous, petrous, and tympanic.
  • The superior border of the petrous part is the boundary between the middle and posterior cranial fossae.
• Additional Information:
  • The squamous part of the temporal bone (pars squamosa) lies on the inferolateral surface of the skull.
  • The petrous part of the temporal bone (pars petrosa) is located in the base of the skull, between the sphenoid and occipital bones.
  • The tympanic part (pars tympanica) lies inferior and anterior to the petrous part, surrounding the external auditory canal.
• Incorrect Description: It only articulates with three bones: occipital, sphenoid, and parietal.
• Correction: The temporal bone articulates with five bones: parietal, occipital, sphenoid, maxilla, and zygoma.
• Incorrect Description: The zygomatic process of the temporal bone lies posterior to the stylomastoid foramen.
• Correction: The zygomatic process of the temporal bone (processus zygomaticus) lies anterior to the stylomastoid foramen (foramen stylomastoideum).

4. Sphenoid Bone

• Correct Description:
  • The posterior border of the lesser wing of the sphenoid ends medially at the anterior clinoid process.
  • The hypophyseal fossa lies behind the sella turcica.
  • Surgically, the pituitary gland can be accessed through the nasal cavity and the body of the sphenoid bone.
• Additional Information:
  • The greater wing of the sphenoid (ala major) forms the anterior and lateral portions of the floor of the middle cranial fossa.
  • The sphenoid bone participates in forming the lateral wall of the orbit (lesser wing) and the floor of the middle cranial fossa (greater wing).
  • The sphenoid bone articulates with 7 other bones: parietal, occipital, ethmoid, temporal, maxilla, zygoma, and palatine.
• Incorrect Description: The greater wing of the sphenoid forms the entire floor of the middle cranial fossa.
• Correction: The lesser wing of the sphenoid contributes to the anterior portion of the floor of the middle cranial fossa.
• Incorrect Description: The sphenoid bone does not contribute to the walls of the orbit.
• Correction: The lesser wing of the sphenoid forms the anterior portion of the roof of the orbit.
• Incorrect Description: The sphenoid bone does not articulate with the parietal and ethmoid bones.
• Correction: The sphenoid articulates with the parietal bone through the squamous portion and with the ethmoid bone through the cribriform plate.
• Incorrect Description: The two ends of the anterior optic groove communicate with the two optic canals.
• Correction: The two ends of the anterior optic groove communicate with the two optic canals, each optic canal housing the optic nerve (cranial nerve II) and the ophthalmic artery.
• Incorrect Description: The sphenoidal sinus has no relation to the sphenoid bone.
• Correction: The sphenoidal sinus (sinus sphenoidalis) lies within the body of the sphenoid bone and communicates with the nasal cavity.

5. Occipital Bone

• Correct Description:
  • Two transverse sigmoid grooves lie on either side of the internal occipital crest.
  • The clivus is located on the inferior surface of the basilar part of the occipital bone.
• Additional Information:
  • The occipital condyles (condylus occipitalis) lie on the superior aspect of the occipital bone and articulate with the axis (second cervical vertebra) of the vertebral column.
  • The internal occipital crest (crista occipitalis interna) lies above the internal occipital tubercle (tuberculum internum).
• Incorrect Description: The rootlets of the eleventh cranial nerve do not pass through the foramen magnum.
• Correction: The rootlets of the eleventh cranial nerve (accessory nerve) pass through the foramen magnum.
• Incorrect Description: The internal occipital crest lies above the internal occipital tubercle.
• Correction: The internal occipital crest (crista occipitalis interna) lies below the internal occipital tubercle (tuberculum internum).
• Incorrect Description: The occipital bone has a foramen for the twelfth cranial nerve to pass through.
• Correction: The foramen for the twelfth cranial nerve (hypoglossal nerve) is located on the inferior surface of the basilar part of the occipital bone, near the occipital condyle.

6. Maxilla

• Correct Description:
  • The orbital surface forms the part of the floor of the orbit.
  • The maxillary sinus lies within the body of the maxilla.
  • The palatine process of the maxilla is larger than the horizontal plate of the palatine bone.
• Additional Information:
  • The anterior surface (facial surface) has the infraorbital foramen (foramen infraorbitale), which transmits the infraorbital nerve and vessels.
  • The anterior and orbital surfaces of the body communicate through the infraorbital canal (canalis infraorbitalis).
• Incorrect Description: The anterior and orbital surfaces of the body communicate with each other through the infraorbital canal.
• Correction: The anterior and orbital surfaces of the body communicate with each other through the infraorbital canal.
• Incorrect Description: The maxillary sinus opening is located on the inferolateral surface of the body of the maxilla.
• Correction: The maxillary sinus opening (apertura sinus maxillaris) is located on the posterior surface of the body of the maxilla, communicating with the nasal cavity.

7. Mandible

• Correct Description:
  • The body of the mandible consists of a base below and an alveolar part above.
  • The mental foramen is the exit point of the inferior alveolar nerve from the mandible.
  • The mylohyoid line is the origin of the mylohyoid muscle.
• Additional Information:
  • The submandibular fossa (fossa submandibularis) lies on the lateral surface of the body of the mandible, housing the submandibular gland.
  • The mental protuberance (protuberantia mentalis) is located in the middle of the anterior surface of the base of the mandible, serving as the attachment site for the mentalis muscle.
  • The inferior mental spine (spina mentalis inferior) is located on the lateral surface of the angle of the mandible, serving as the attachment site for the geniohyoid muscle.
  • The angle of the mandible (angulus mandibulae) is the angle between the two halves of the body of the mandible.
  • The coronoid process (processus coronoideus) is the insertion site for the temporalis muscle, forming the anterior part of the ramus.
• Incorrect Description: The submandibular fossa (for housing the submandibular gland) lies on the mylohyoid line of the mandible.
• Correction: The submandibular fossa lies on the lateral surface of the body of the mandible, posterior to the mylohyoid line.

8. Temporomandibular Joint

• Correct Description:
  • The articular disc lies between the articular surfaces of the temporal bone and the head of the mandible.
  • The lateral ligament is located on the lateral aspect of the joint.
• Additional Information:
  • The tendon of the lateral pterygoid muscle attaches to the neck of the mandibular condyle and the articular disc.
  • The lateral and medial ligaments are thickened portions of the joint capsule, helping to stabilize the joint.
• Incorrect Description: The lateral and medial ligaments are thickened portions of the joint capsule.
• Correction: The lateral and medial ligaments are thickened portions of the joint capsule, helping to stabilize the joint.

9. Muscles of Mastication

• Correct Description:
  • The lateral pterygoid muscle inserts into the neck of the mandibular condyle.
  • The medial pterygoid muscle is an elevator of the mandible.
  • The inferior head of the lateral pterygoid muscle attaches to the medial surface of the lateral pterygoid plate.
  • The masseter muscle inserts into the medial surface of the angle and ramus of the mandible.
• Additional Information:
  • The origin of the masseter muscle (musculus masseter) is on the zygomatic arch, it is very thick and strong, and is the main muscle in chewing.
  • The lateral pterygoid muscle (musculus pterygoideus lateralis) is the only muscle responsible for protraction of the mandible.
  • The digastric muscle (musculus digastricus) is a two-bellied muscle that helps depress the mandible, opening the mouth, and protracting the mandible.
  • The anterior belly of the digastric muscle (venter anterior) lies inferior to the mylohyoid muscle, innervated by the mandibular nerve.
• Incorrect Description: Most of the muscles in the four groups of mastication muscles depress the mandible.
• Correction: Most of the muscles of mastication elevate the mandible.
• Incorrect Description: The anterior part of the temporalis muscle protracts the mandible.
• Correction: The anterior part of the temporalis muscle (pars anterior) protracts the mandible.
• Incorrect Description: The lateral pterygoid muscle works together with the mylohyoid muscle and the anterior belly of the digastric muscle during the act of opening the mouth.
• Correction: The lateral pterygoid muscle works together with the mylohyoid muscle and the anterior belly of the digastric muscle during the act of protraction of the mandible.
• Incorrect Description: Besides the four muscles of mastication, there are no other muscles that move the mandible.
• Correction: Besides the four muscles of mastication, there are other muscles involved in elevating, depressing, protracting, and retracting the mandible, such as the mylohyoid muscle and the digastric muscle.

10. Muscles Around the Mouth

• Correct Description: The levator anguli oris muscle lies deeper than the levator labii superioris muscle.
• Additional Information:
  • The group of muscles around the mouth is more numerous than the group around the orbit.
  • The zygomaticus minor muscle (musculus zygomaticus minor) elevates the upper lip.
  • The risorius muscle (musculus risorius) is the only muscle that causes the act of smiling.
• Incorrect Description: The zygomaticus minor muscle depresses the lower lip.
• Correction: The zygomaticus minor muscle (musculus zygomaticus minor) elevates the upper lip.

11. Anterior Cervical Triangle

• Correct Description:
  • It is separated from the posterior cervical triangle by the sternocleidomastoid muscle.
  • It is bounded superiorly by a line drawn along the inferior border of the mandible.
  • It is divided into smaller triangles by the digastric and the superior belly of the omohyoid muscles.
• Additional Information:
  • The anterior cervical triangle is divided into 4 smaller triangles:
    • Submental triangle.
    • Carotid triangle.
    • Muscular triangle.
    • Submandibular triangle.
• Incorrect Description: The posterior belly of the digastric muscle is a border of the muscular triangle.
• Correction: The anterior border of the muscular triangle is the posterior border of the sternocleidomastoid muscle.
• Correction: The posterior belly of the digastric muscle (venter posterior) lies inferior to the omohyoid muscle (musculus omohyoideus), forming a border of two triangles: the submental triangle and the carotid triangle.

12. Posterior Cervical Triangle

• Correct Description:
  • This is the path for the external jugular vein.
  • The anterior border of the posterior cervical triangle is the posterior border of the sternocleidomastoid muscle.
  • The third part of the subclavian artery runs within the posterior cervical triangle.
• Additional Information:
  • The posterior cervical triangle (posterior triangle of the neck) is bounded by 3 sides:
    • The superior side is a line drawn from the mastoid process to the external occipital protuberance.
    • The posterior side is the anterior border of the trapezius muscle.
    • The anterior side is the posterior border of the sternocleidomastoid muscle.
• Incorrect Description: The eleventh cranial nerve does not pass through the posterior cervical triangle.
• Correction: The eleventh cranial nerve (accessory nerve) passes through the posterior cervical triangle.
• Incorrect Description: The anterior border of the posterior cervical triangle is the posterior border of the sternocleidomastoid muscle.
• Correction: The anterior border of the posterior cervical triangle is the posterior border of the sternocleidomastoid muscle.

13. Infrahyoid Muscles

• Correct Description:
  • The sternothyroid muscle lies deeper than the sternohyoid muscle.
  • The insertion of the sternothyroid muscle is closer to the midline than its origin.
  • The insertions of the sternohyoid muscles on either side enclose a triangle with its base directed inferiorly.
  • The insertions of the sternohyoid muscles on either side meet at the midline of the hyoid bone.
  • The insertion of the sternothyroid muscle on the thyroid cartilage is also the origin of the thyrohyoid muscle.
• Additional Information:
  • The origin of the sternohyoid muscle (musculus sternohyoideus) is on the posterior surface of the manubrium of the sternum.
  • All 4 infrahyoid muscles are innervated by the ansa cervicalis for their motor function.
  • The omohyoid muscle (musculus omohyoideus) elevates the hyoid bone and depresses the mandible.
• Incorrect Description: The origin of the sternohyoid muscle is not on the clavicle.
• Correction: The origin of the sternohyoid muscle (musculus sternohyoideus) is on the posterior surface of the manubrium of the sternum.
• Incorrect Description: The omohyoid muscle has the same action as the sternohyoid muscle.
• Correction: The omohyoid muscle (musculus omohyoideus) elevates the hyoid bone and depresses the mandible.

14. Suprahyoid Muscles

• Correct Description:
  • The mylohyoid muscles on either side meet at the midline.
  • The anterior belly of the digastric muscle lies inferior to the mylohyoid muscle.
  • The stylohoid muscle and the posterior belly of the digastric muscle are innervated by the facial nerve.
• Additional Information:
  • The suprahyoid muscles elevate the hyoid bone, depress the mandible, and protract the hyoid bone.
• Incorrect Description: All of the suprahyoid muscles elevate the hyoid bone and depress the mandible.
• Correction: The suprahyoid muscles elevate the hyoid bone, depress the mandible, and protract the hyoid bone.

15. Sternocleidomastoid Muscle

• Correct Description:
  • It lies between the anterior and posterior regions of the neck.
  • It is innervated by the cervical plexus for its motor function.
  • It separates the anterior cervical triangle from the posterior cervical triangle.
• Additional Information:
  • It depresses the clavicle and rotates it anteriorly.
• Incorrect Description: Its origin is on the posterior surface of the manubrium of the sternum.
• Correction: The origin of the sternocleidomastoid muscle (musculus sternocleidomastoideus) is on the posterior surface of the manubrium of the sternum and the superior surface of the clavicle.
• Incorrect Description: It separates the anterior cervical triangle from the posterior cervical triangle.
• Correction: It separates the anterior cervical triangle from the posterior cervical triangle.

16. Carotid Triangle

• Correct Description:
  • The external carotid artery runs through the carotid triangle.
• Additional Information:
  • The carotid triangle (carotid triangle) is one of the 4 smaller triangles of the anterior cervical triangle, located between the omohyoid muscle and the sternocleidomastoid muscle.
  • It is bounded by 3 sides:
    • The superior side is the inferior border of the mandible.
    • The anterior side is the posterior border of the sternocleidomastoid muscle.
    • The posterior side is the anterior border of the omohyoid muscle.
• Incorrect Description: The mylohyoid muscle forms the floor of the carotid triangle.
• Correction: The omohyoid muscle forms the floor of the carotid triangle (carotid triangle).
• Incorrect Description: The posterior border of the triangle is the anterior border of the sternocleidomastoid muscle.
• Correction: The posterior border of the carotid triangle is the anterior border of the omohyoid muscle.

Note: The above information is only a basic overview of the anatomy of the head, face, and neck. For a more in-depth understanding of the structure and function of each part, consult specialized medical literature or anatomy textbooks.