Blood Supply: Middle Meningeal Artery

Middle Meningeal Artery

• Supplies blood to the skull and meninges, primarily involved in cranial protection.
• Key structures in the skull include the squamous part, which provides structural integrity and muscle attachment.

Temporal Bones

• Classified as irregular bones, consisting of squamous, petrous, tympanic, mastoid, and styloid parts.
• Articulates with the parietal, occipital, and zygomatic bones.
• Blood supply includes the middle meningeal artery, posterior auricular artery, and stylomastoid artery.
• Functions include protecting the brain and serving as attachment points for muscles related to the tongue and larynx.

Ethmoid Bone

• An irregular, small, unpaired bone part of the orbital complex.
• Its lightweight, spongy structure relates to its Greek origin "ethmos," meaning sieve.
• Contributes to the medial wall of the orbit and anterior cranial fossa, and separates the nasal cavity from the cranial cavity.

Features of the Ethmoid Bone

• Comprises four parts: cribriform plate, perpendicular plate, and ethmoid labyrinths.
• Cribriform plate: Forms the roof of the nasal cavity and is perforated by olfactory fibers.
• Perpendicular plate: Makes up the upper two-thirds of the nasal septum.
• Ethmoid labyrinths: Contain ethmoid air cells, functioning as sinuses that warm inhaled air.

Clinical Relevance of Ethmoid Bone

• Fractures in the cribriform plate can lead to anosmia (loss of smell) and rhinorrhea (cerebrospinal fluid leakage).

Skull Overview

• Comprised of 22 bones, divided into the neurocranium (cranial bones) and viscerocranium (facial bones).
• Functions of the neurocranium include brain protection, as well as serving as attachment sites for facial expression and mastication muscles.

Sutures of the Skull

• Major sutures include the coronal, sagittal, lambdoid, and squamosal sutures.
• Coronal suture: Joins the frontal bone with the parietal bones at the crown of the head.
• Sagittal suture: Unites the two parietal bones along the midline.
• Lambdoid suture: Connects parietal bones to the occipital bone.
• Squamosal suture: Attaches the temporal bone to the parietal bones.

Pterygopalatine Fossa

• An inverted pyramidal space located between the infratemporal fossa and nasopharynx.
• Forms are made from the maxilla, palatine, and sphenoid bones.
• Contains crucial neurovascular structures: the maxillary nerve, pterygopalatine ganglion, and the maxillary artery.
• Features seven foramina that connect to nearby cavities and structures.

Summary of Learning Outcomes

• Ability to name and label the cranial bones and their sutures.
• Familiarity with important facial features, particularly regarding the sphenoid and ethmoid bones.
• Understanding the clinical significance of structures like the pterygopalatine fossa.