PAT: Skull anatomy (Cranium, facial, and auditory bones) Flashcards
How many bones are in the human body?
206
How many bones are in the cranium? List them.
8 bones. frontal, parietal (2 - paired), temporal (2 - paired), occipital, ethmoid, sphenoid.
How many facial bones are there? List them.
14 facial bones. maxilla (2), mandible (1), palatine (2), zygomatic/zygoma (2), nasal (2), lacrimal (2), vomer (1), inferior nasal conchae (2).
How many bones are there in the skull? List them.
28 bones of the skull: 8 - cranium, 14 - face, 6 - auditory (ear)
What is the word for above?
Superior.
What is the word for below?
Inferior.
What is the word for front?
Anterior.
What is the word for behind?
Posterior.
What is the word for close to the centre?
Medial.
What is the word for away from the centre?
Lateral.
What cells form bone?
Osteoblasts.
What 2 primary minerals give bone it’s regidity?
Calcium and phosphate.
What are the 3 layers of bone?
- Periosteum 2. Compact bone (aka Cortical bone/plate) 3. Cancellous bone
Describe the difference between the 3 layers of bone.
- Periosteum : thin layer of whitish connective tissue which contains nerves and blood vessels.
- Compact bone (Cortical bone/plate) : Is very dense and strong and forms the outer layer of the bone.
- “Spongy bone” : is found inside the bone, have trabeculae that form the pattern of spaces that are filled with bone marrow.
What are the functions of bone?
- Give body shape and form
- Protect its vital structures
- Provide support
- Form blood cells
*** bone also serve as attachments for various tissues such as muscle, ligaments and tendons
Name the landmarks of the cranium. Describe what each one is.
- Sutures - thin layer of fibrous tissue that appears as a jagged line. It unites or joins bones to form a joint that is immoveable.
- Ridges - a long narrow elevation in the bone
- Foramen - a natural opening in the bone or tooth which blood vessels, nerves and ligaments pass through
- Protuberances - a bony projection or bulge
- Process - an extension of bone from its main body. it acts as attachment or insertion sites for muscles and ligaments
- Fossas - a shallow depression in bone
- Eminence - a rounded elevation or projection on a bone
- Meatus - the external opening of a canal
What are the functions of the maxilla?
Maxilla is composed of 2 bones united by the median palatine suture. Functions include: forms shape of the upper part of the face, supports max dentition, forms floor or the nose, forms part of the orbital cavity
What are the Maxilla Processes and how many are there?
4 processes: 1. alveolar, frontal/nasal, zygomatic, palatine
What are the (2) sutures of the maxilla?
- Median palatine suture 2. transverse suture
What are the (3) Foramina’s of the maxilla?
- Infraorbital - superior to the maxillary bicuspids (external/vestibular surface) 2. posterior superior alveolar - superior to the 17 & 27 distal buccal root (external/vestibular surface) 3. Incisive - posterior to the central incisors (internal/palate surface)
List the landmarks of the maxilla. Describe each one.
- Infraorbital foramina - superior to the maxillary bicuspids
- Posterior superior alveolar foramina - superior to the 17 & 27 distal buccal root
- Incisive foramen - posterior to the central incisors
- Maxillary tuberosity - Two tuberosities that are part of the maxilla bone, distal to the last molar on each side. A tuberosity is a smooth round protuberance, which slants, in an upward and backward direction
- Maxillary sinuses - two sinuses which are in the shape of a triangle with the base of the triangle toward the nose
- Nasal cavity
- Infraorbital ridges
What is the alveolar process?
An extension of the maxilla and is responsible for supporting the dentition
Why is the maxilla bone lighter than the mandible bone?
- Less cortical plate and more cancellous bone 2. presence of the maxillary sinuses
What is the lamina dura?
It’s part of the alveolar process, it’s bone which lines the tooth socket, its also more compact, contains many openings for blood vessels, nerve, and lymph tissue which supply the periodontal ligament, the fibers of the periodontal ligament are firmly embedded in this bone
What is the palatine bone?
Forms the posterior portion of the palate
What is the function of the mandible?
forms shape for lower half of the face. forms floor of the mouth by allowing tissue attachment. supports mandibular dentition, allows movement for speech, mastication, etc.
What is the symphysis menti?
Line of fusion where the two halves of the body of mandible meet
How is the TMJ formed?
Condyle of the mandible inserts into the glenoid fossa of the temporal bone
What does articulation mean?
Location of where two or more bones come together
What are the landmarks of the mandible (external)?
- body
- angle
- ramus
- condyloid process (or condyle)
- coronoid process
- coronoid notch
- mandibular notch
- external oblique ridge
- alveolar process
- mental foramina
- symphysis menti
- mental protruberance
What are the landmarks of the mandible (internal)?
- mandibular foramina
- mylohyoid groove
- internal oblique ridge
- mental or genial tubercles
What is the difference between the alveolar process of the maxillary versus mandibular?
Maxillary - less cortical plate and more cancellous bone, presence of maxillary sinuses (stores warm air)
Mandibular - cortical plate is much thicker, sometimes cancellous bone is completely missing. Thickness of cortical plate is a big factor in the choice of local anesthetic injection techniques.
How many bones of the ear are there? List each name.
6 bones of the ear - Malleus (2), Incus (2), Stapes (2)
What is the bone that is suspended by muscles between the mandible and larynx? What is it’s function and why is it special?
Hyoid bone. It’s not a bone of the skull, but connects to the skull by ligaments - stylohyoid ligaments. It functions as the primary support for the tongue and other muscles
