Calvaria, Sutures, and Mandibular Clinical Anatomy

Cranial Sutures and Landmarks

• Bregma: This is the specific anatomical point where the sagittal suture meets the coronal suture.

• Lateral Sutures of the Cranium:

  • Squamous Suture: Positioned between the parietal bone and the temporal bone.

  • Sphenofrontal Suture: Positioned between the frontal bone and the sphenoid bone.

  • Sphenoparietal Suture: Positioned between the sphenoid bone and the parietal bone.

  • Occipitomastoid Suture: Positioned between the occipital bone and the mastoid process of the temporal bone.

  • Temporozygomatic Suture: Positioned between the temporal bone and the zygomatic bone.

• Inferior Sutures of the Cranium:

  • Median Palatine Suture: Located at the midline within the palatine bone and the maxilla.

  • Transverse Palatine Sutures: Positioned between the maxilla and the palatine bone.

  • Petro-occipital Suture: Positioned between the petrous part of the temporal bone and the occipital bone.

  • Spheno-occipital Suture: Positioned between the sphenoid bone and the occipital bone.

  • Petrosquamous Suture: Positioned between the petrous and squamous parts of the temporal bone.

  • Petrotympanic Suture: Located between the temporomandibular joint (TMJ) and the tympanic cavity.

Clinical Applications of Facial and Cranial Anatomy

• Injury to Superciliary Arches:

  • A blow to these arches results in skin laceration and bleeding.

  • Bruising and "Black Eyes": Tissue fluid and blood accumulate in the surrounding connective tissue. This fluid subsequently migrates to the upper eyelid and regions around the eye.

• Malar Flush:

  • This is defined as a reddening of the skin covering the zygomatic process.

  • It occurs in response to a rise in body temperature.

Fractures of the Maxilla and Other Bones

• Le Fort Fractures: There are $3$ primary types of maxillary fractures classified under the Le Fort system:

  • Le Fort I: Also known as a "Floating Palate."

  • Le Fort II: Described as a "Pyramidal" fracture.

  • Le Fort III: Referred to as "Craniofacial Dysfunction."

Fracture of the Mandible

• General Patterns: Mandibular fractures typically involve $2$ fractures occurring on opposite sides of the bone.

• Specific Types of Mandibular Fractures:

  • A) Fracture of the Coronoid Process of the Mandible: This type is uncommon and typically found on only one side.

  • B) Fracture of the Neck of the Mandible: Often involves a transverse fracture and may result in the dislocation of the Temporomandibular joint (TMJ).

  • C) Fracture of the Angle of the Mandible: This is an oblique fracture that may involve the alveolus (socket) of the $3^{rd}$ molar tooth.

  • D) Fracture of the Body of the Mandible: These fractures typically pass through the socket of a canine tooth.

• Key Mandibular Anatomical Structures:

  • Condylar process

  • Ramus

  • Coronoid process

  • Alveolar process

  • Angle

  • Body

  • Mental foramen

Resorption of Alveolar Bone and Dental Loss

• Bone Breakdown: The extraction or removal of teeth causes the alveolar bone to resorb (break down) in the affected area.

• Clinical Consequences of Resorption:

  • In certain cases, the mental foramen will disappear due to bone loss.

  • The disappearance of the foramen exposes the mental nerves to potential injury.

• Loss of All Teeth:

  • The total loss of teeth leads to a decrease in the vertical facial dimension.

  • This condition results in mandibular prognathism, also known as overclosure.