Skeletal System - Head and Neck Anatomy Flashcards

A comprehensive set of questions and answers covering cranial/facial bones, sutures, foramina, sinuses, and skull fossae from the lecture notes.

What are the cranial bones?

Occipital, Frontal, Sphenoid, Parietal, Temporal, Ethmoid

What are the facial bones?

Vomer, Lacrimal, Nasal, Inferior Nasal Conchae, Zygomatic, Maxillary Bones, Mandible, Palatine Bones (grouped for learning)

What is the primary purpose of the facial bones?

To create facial features and serve as a base for the dentition (teeth).

What is the deep saddle-shaped depression on the sphenoid bone called?

Sella turcica (pituitary fossa).

What is the deepest part of the sella turcica and what does it contain?

Hypophyseal fossa; contains the pituitary gland (hypophysis).

What are the air-filled cavities within the body of the sphenoid bone called?

Sphenoidal sinuses (right and left) separated by a septum.

What three paired processes project from the body of the sphenoid bone?

Lesser wing, greater wing, and pterygoid process.

Which sphenoid bone process forms the orbital apex?

Lesser wing.

Describe the pterygoid process of the sphenoid bone.

Projects inferiorly; consists of a flattened lateral pterygoid plate and a thinner medial pterygoid plate; site of attachment for certain muscles of mastication; pterygoid fossa lies between the two plates.

Name three significant foramina/fissures in the sphenoid bone and the structures they carry.

Superior orbital fissure: ophthalmic nerve (and others); Foramen rotundum: maxillary nerve; Foramen ovale: mandibular nerve; Foramen spinosum: middle meningeal artery/vein and meningeal branch of the mandibular nerve.

What surgical procedure utilizes the close relationship between the sphenoid bone and the pituitary gland?

Endoscopic transsphenoidal surgery (ETSS).

Where is the ethmoid bone located relative to the sphenoid bone?

Anterior to the sphenoid bone, in the anterior part of the cranium.

Name the two unpaired plates forming the ethmoid bone.

Perpendicular plate and cribriform plate.

Which ethmoid plate forms part of the nasal septum?

Perpendicular plate.

What is the crista galli and its function?

A wedge-shaped projection of the perpendicular plate into the cranial cavity; serves as an attachment for the layers covering the brain.

What perforates the cribriform plate, and what passes through these perforations?

Numerous olfactory foramina; olfactory nerves pass through for sense of smell.

What structures does the lateral part of the ethmoid bone form within the nasal cavity?

Superior nasal concha and middle nasal concha.

What are the ethmoidal sinuses?

A variable number of small cavities (ethmoid air cells) within the lateral masses of the ethmoid bone.

Describe the vomer bone.

A thin, flat, single midline facial bone, almost trapezoidal in shape, located in the midsagittal plane within the nasal cavity.

What part of the nasal septum does the vomer form?

The posterior and inferior part.

Does the vomer have muscle attachments?

No.

With which bones does the vomer articulate?

Perpendicular plate of the ethmoid bone, sphenoid bone, and palatine processes of the maxillae, and horizontal plates of the palatine bones.

Describe the lacrimal bones.

Paired, irregular, and thin plates of bone; they are the smallest and most fragile of the facial bones.

What part of the orbit do the lacrimal bones form?

A small part of the anterior medial wall of the orbit.

What duct is formed at the junction of the lacrimal bone and the maxilla, and what is its function?

Nasolacrimal duct; drains lacrimal fluid (tears) into the inferior nasal meatus.

What do the nasal bones form?

The bridge of the nose.

With which bones do the nasal bones articulate?

Maxillae laterally and the frontal bone superiorly (frontonasal suture).

What is the clinical significance of the nasal bones' position and support?

Their protruding position and relative lack of support predispose them to fracture; they are the most commonly fractured bony structures of the maxillofacial complex.

What do the inferior nasal conchae form?

A part of the lateral walls of the nasal cavity.

How do the inferior nasal conchae differ from the superior and middle nasal conchae?

Inferior conchae are separate paired facial bones; superior and middle conchae are parts of the ethmoid bone.

What is the purpose of the nasal conchae?

Protect the nasal meatuses, which are air channels with openings to paranasal sinuses or the nasolacrimal duct.

What is another name for the zygomatic bone, and what features does it form?

Zygoma; forms the majority of the cheekbone and helps form the lateral wall and floor of the orbit.

Name the three processes of the zygomatic bone and what they help form or articulate with.

Frontal process: anterior lateral orbital wall; articulates with the frontal bone. Temporal process: forms the zygomatic arch with the temporal bone. Maxillary process: lateral part of the infraorbital rim; articulates with the maxilla.

Which bones articulate with the zygomatic bone?

Frontal, temporal, sphenoid, and maxilla.

What is the general shape of each palatine bone, and what are its two plates?

L-shaped; horizontal plate and vertical plate.

What do the horizontal plates of the palatine bones form?

Inferiorly, the posterior hard palate; superiorly, the floor of the nasal cavity.

What do the vertical plates of the palatine bones form?

Part of the lateral walls of the nasal cavity and a small part of bone to the orbital apex.

Name the two main foramina in the palatine bones and what they transmit.

Greater palatine foramen: greater palatine nerve and vessels. Lesser palatine foramen: lesser palatine nerve and vessels to the soft palate and tonsils.

What is the sphenopalatine foramen, and what passes through it?

An opening between the sphenoid bone and orbital processes of the palatine bone, opening into the nasal cavity. Passes branches from the pterygopalatine ganglion, sphenopalatine arteries, nasopalatine nerves, posterior superior nasal nerves, and the sphenopalatine artery.

Describe the maxillae.

The upper jaw, consisting of two fused maxillae at the intermaxillary suture; each has a pyramid-shaped body and four processes.

What are the four processes of the maxilla?

Frontal, zygomatic, palatine, and alveolar processes.

What air-filled spaces are contained within the bodies of the maxillae?

Maxillary sinuses.

Which fissure separates the maxilla's orbital surface from the sphenoid bone?

Inferior orbital fissure.

Where is the infraorbital foramen located on the maxilla, and what passes through it?

On the facial surface of each maxilla; transmits the infraorbital nerve and blood vessels; located about 10 mm inferior to the midpoint of the infraorbital rim.

What is the canine eminence, and why is it significant?

A prominent facial ridge over the roots of the maxillary canines; landmark for the anterior superior alveolar block.

What is the maxillary tuberosity?

A rounded, roughened elevation on the posterior part of the body of the maxilla, just posterior to the most distal molar.

What structures pass through the incisive foramen?

Branches of the right and left nasopalatine nerves and sphenopalatine arteries from the nasal cavity to the anterior hard palate.

How does the density of the alveolar process of maxillary teeth compare to that of mandibular teeth?

It is generally less dense and more porous, allowing a greater incidence of clinically adequate local anesthesia with supraperiosteal injections.

What is a sinus lift procedure?

An oral maxillofacial surgery procedure that augments bone mass in the maxilla to increase the likelihood of successful dental implant placement, especially when the maxillary sinus has enlarged due to alveolar bone loss.

Describe the mandible.

A single facial bone that forms the lower jaw; the only freely movable bone of the skull and the strongest facial bone.

What are the prominent landmarks on the anterior view of the mandible?

Mental protuberance (chin) and the mental foramen.

What changes in direction does the mental foramen's opening undergo?

From anterior to posterosuperior as mandibular growth proceeds in young children.

What passes through the mental foramen?

Mental nerve and blood vessels.

What is the mandibular ramus?

A stout flat plate rising up from the angle of the mandible; extends superiorly and posteriorly; primary site for muscle attachments.

What is the coronoid notch, and why is it important?

The greatest depression on the anterior border of the mandibular ramus; landmark for administering the inferior alveolar block.

What two parts make up the condyloid process?

The mandibular condyle and its neck.

What are the genial tubercles?

Four small projections near the mental symphysis on the medial surface of the mandible; muscle attachments.

What is the mylohyoid line (internal oblique ridge)?

A line on the medial surface of the mandible; attachment for the mylohyoid muscle; forms the floor of the mouth.

What two fossae are divided by the mylohyoid line, and what do they contain?

Sublingual fossa (sublingual gland) and Submandibular fossa (submandibular gland).

Where is the mandibular foramen located, and what is its significance for dental procedures?

On the medial surface of the mandibular ramus; opening of the mandibular canal; landmark for inferior alveolar and Vazirani-Akinosi blocks.

What is the lingula?

A bony spine overhanging the mandibular foramen; attachment for the sphenomandibular ligament.

What are common weak sites of the mandible liable to fracture?

The angle of the mandible (especially with an impacted third molar), the alveolus of the canine tooth, and the condylar neck.

How does alveolar process resorption due to tooth loss affect the mandibular canal?

The canal ends up nearer to the superior border of the mandible; in severe cases it may disappear, leaving the inferior alveolar nerve without bony protection.

What are paranasal sinuses, and what are their purposes?

Paired air-filled cavities within the bones of the head; lighten the skull bones, act as sound resonators, and provide mucus for the nasal cavity.

Name the four main paranasal sinuses.

Frontal, Sphenoidal, Ethmoidal, and Maxillary sinuses.

Which sinuses can be palpated during an extraoral examination?

Frontal sinuses and maxillary sinuses.

What makes drainage of the maxillary sinus complicated, and what can this lead to?

The ostium drains higher than the floor when upright, promoting prolonged or chronic sinusitis.

What is primary sinusitis?

Inflammation and congestion of the sinus mucous membranes due to allergies or infection within the sinus.

What is secondary sinusitis?

Inflammation of a sinus from another source, such as infection of adjacent teeth.

What is a perforation in the context of sinusitis?

An abnormal hole formed in the wall of the sinus due to inflammation.

What is balloon sinuplasty (BSP)?

A newer therapy for chronic sinusitis that uses a balloon to open blocked drainage pathways.

Name the two large skull depressions discussed.

Temporal fossa and Infratemporal fossa.

Which five bones contribute to the formation of the temporal fossa?

Zygomatic bone, frontal bone, sphenoid bone (greater wing), temporal bone, and parietal bone.

What forms the inferior border between the temporal fossa and the infratemporal fossa?

The infratemporal crest on the greater wing of the sphenoid bone.

Name some structures found within the infratemporal fossa.

Part of the maxillary artery and its branches (middle meningeal artery, inferior alveolar artery, posterior superior alveolar artery), the pterygoid plexus of veins, pterygoid muscles, and part of the mandibular nerve (including inferior alveolar and lingual nerves).

How do structures pass from the infratemporal fossa into the orbit?

Through the inferior orbital fissure, located at the anterior and superior end of the fossa.