Cranium, Facial Bones, Paranasal Sinuses, and Biliary Anatomy

Flashcards covering cranial and facial anatomy, paranasal sinuses, ear structures, skull morphology, radiographic positioning lines, clinical pathologies, and biliary system anatomy.

Cranium

The bony skeleton of the head which rests on the superior end of the vertebral column; it is divided into 8 cranial bones and 14 facial bones.

Calvarium (Skullcap)

The upper portion of the cranium consisting of the frontal, right parietal, left parietal, and occipital bones.

Frontal Bone

The bone of the calvarium that forms the forehead and the superior part of each orbit, consisting of a squamous (vertical) portion and an orbital (horizontal) portion.

Glabella

The smooth, raised prominence between the eyebrows just above the bridge of the nose.

Supraorbital groove (SOG)

The slight depression above each eyebrow that corresponds to the floor of the anterior fossa of the cranial vault.

Supraorbital margin (SOM)

The superior rim of each orbit.

Ethmoidal notch

The area separating each orbital plate of the frontal bone where the ethmoid bone fits.

Parietal tubercles (eminences)

The location where the widest portion of the entire skull is found.

Inion (External Occipital Protuberance)

The prominent bump or protuberance at the inferoposterior portion of the skull.

Foramen magnum

The large opening at the base of the occipital bone through which the spinal cord passes as it leaves the brain.

Atlantoccipital joint

The two-part articulation between the occipital condyles of the skull and the first cervical vertebra (atlas).

Zygomatic arch

Formed by the union of the zygomatic process of the temporal bone and the temporal process of the zygomatic bone.

Temporomandibular (TM) fossa

The depression on the temporal bone into which the mandible fits to form the temporomandibular joint.

Petrous portion (Petrous pyramid)

The thickest and densest bone in the cranium, situated in the temporal bone, which houses the organs of hearing and equilibrium.

Internal acoustic meatus

An opening on the posterior surface of the petrous pyramid that transmits the nerves of hearing and equilibrium.

Sella turcica

A central, saddle-shaped depression on the body of the sphenoid bone that protects the pituitary gland (hypophysis cerebri).

Dorsum sellae

The posterior portion of the sella turcica of the sphenoid bone.

Clivus

A shallow depression extending posteriorly from the dorsum sellae to the foramen magnum, forming a base of support for the pons and basilar artery.

Superior orbital fissures

Irregularly shaped openings in the sphenoid bone that provide communication with the orbits for cranial nerves and blood vessels.

Cribriform plate

The horizontal portion of the ethmoid bone containing many small foramina for the olfactory nerves.

Crista galli

A superior projection of the ethmoid bone derived from words meaning "rooster's comb."

Sutures

Immovable (synarthrodial) fibrous joints that connect the bones of the adult cranium.

Bregma

The anterior end of the sagittal suture.

Lambda

The posterior end of the sagittal suture.

Fontanels

Membrane-covered "soft spots" in an infant's cranium where sutures join and ossification is incomplete.

Auditory ossicles

Three small bones in the middle ear: the malleus (hammer), incus (anvil), and stapes (stirrup).

Maxillae

The two largest immovable bones of the face that assist in forming the mouth, nasal cavity, and orbit.

Acanthion

A surface landmark at the midline point where the nose and the upper lip meet.

Gonion

The lower posterior angle on each side of the jaw (mandible).

Symphysis menti

The anterior midline union of the two halves of the mandible.

Antrum of Highmore

An older term for the maxillary sinus.

Osteomeatal complex

The drainage pathways of the frontal, maxillary, and ethmoid sinuses.

Mesocephalic skull

The shape of the average head, where the width is $75\%$ to $80\%$ of the length.

Brachycephalic

A short, broad head shape where the width is $80\%$ or greater than the length.

Dolichocephalic

A long, narrow head shape where the width is less than $75\%$ of the length.

Orbitomeatal line (OML)

The positioning line located between the outer canthus and the EAM.

Infraorbitomeatal line (IOML)

Also known as Reid's base line or the anthropologic base line, it is formed by connecting the infraorbital margin to the EAM.

Blowout fracture

A fracture of the floor of the orbit caused by an object striking the eye straight on.

Tripod fracture

A fracture caused by a blow to the cheek, resulting in the zygoma being fractured in three places: the orbital process, maxillary process, and arch.

Paget disease (osteitis deformans)

A skeletal disease characterized by a stage of bony destruction followed by repair, often resulting in a "cotton-wool" radiographic appearance.

Bile

A substance manufactured by the liver and stored in the gallbladder that aids in the digestion and absorption of fats.

Cholecystokinin (CCK)

A hormone secreted by the duodenal mucosa when fats are present, causing the gallbladder to contract.

Spiral valve

Membranous folds within the cystic duct that prevent its distention or collapse.

Hepatopancreatic sphincter (Sphincter of Oddi)

A circular muscle fiber near the terminal opening of the common bile duct into the duodenum.

Cholelithiasis

The condition of having abnormal calcifications or stones in the gallbladder.

Deglutition

The medical term for the act of swallowing.