BSO5 Flashcards
How many parts has the Skull got?
two parts (cranial Vault and Facial skeleton)
Cranial Vault
- neurocranium
- houses the brain
- roof = calvaria
- floor = cranial base
Facial Skeleton
viscerocranium
- anterior aspect of skull
- contains mouth, nose and orbits
How many bones are making up the cranial vault and what are they?
8 Bones
Frontal bone (“forehead”)
Occipital bone (“back head”)
Sphenoid bone (“wedge form”)
Ethmoid bone (“sieve form”)
2 parietal bones (“wall”)
2 temporal bones (“temples”)
How many bones are making up the fascial skeleton and what type of bones are they?
15 irregular bones
Name the bones that make up the fascial skeleton.
Mandible (“to chew”)
Vomer (“Plow share”)
Ethmoid (“sieve form”)
2 lacrimal bones (“tear”)
2 nasal bones (“Nose”)
2 maxillary bones (“upper jaw”)
2 zygomatic bones (“yoke”)
2 palatine bones (“palate”)
2 inferior nasal conchae (“shell shaped”)
Sutures in the Skull
fibrous joints, interlocking
between all except the mandible
Major Sutures
Coronal- between the frontal bone and the two parietal bones.
* Sagittal- between the two parietal bones.
* Lambdoidal (Lambda, Gr letter uppercase Λ) - between the occiput and the two parietal bones.
* Temporal (squamous)- where temporal meets the occipital and parietal bones.
Bony Landmarks of the Skull
Lambda - Junction of sagittal and lambdoidal sutures
Bregma - Junction of coronal and sagittal sutures
Pterion - H shaped, between sphenoid, temporal, frontal and parietal bones
Asterion - junction of the parietal, temporal and occipital bones
Embryology of the Skull - Fontanelles
- Bones in the calvaria form via intramembranous ossification.
- Bones in the cranial base form via endochondral ossification.
- Fontanelles are where the sutures meet in an infant skull, forming fibrous tissue membrane, representing the un-ossified bone.
- They are required during birth.
How many fontanelles are in the skull?
6
- anterior fontanelle - bregma (biggest)
- 2 anterolateral fontanelles - pterion
- 2 Posterolateral fontanelles - asterion
- posterior fontanelle - lambda
What type of joint is the Temporomandibular Joint (TMJ)?
- modified hinge type synovial joint
What does the TMJ articulate with?
- articulation b/w condylar process of mandible and ,mandibular fossa of temporal bone
TMJ - capsule facts
- loose fibrous capsule attaching to the temporal bone and neck of mandible
- two synovial membranes within capsule separated by fibrocartilaginous articular disc
Movements at the TMJ
- superior compartment allows protrusion and retrusion movements of the mandible (translation)
- inferior compartment allows depression & elevation of mandible (rotation)
- both movements have to occur for mandible to open and close the mouth
Which ligaments are found at the TMJ?
Lateral ligament, Stylomandibular ligament, Sphenomandibular ligament
Lateral ligament - temporomandibular ligament
- intrinsic ligament
- thickening of lateral joint capsule
- strengthens the TMJ laterally, helps prevent posterior dislocation
Stylomandibular ligament
- extrinsic ligament
- from styloid process to angle of mandible
- provides very little strength to joint
Sphenomandibular ligament
- extrinsic ligament
- from spine of sphenoid to lingula of mandible
acts as fulcrum for movement of TMJ & helps limit amount of movement occurring at the joints
Which muscles are acting on the TMJ?
- Muscles of mastication
- all supplied by Mandibular branch of Trigeminal Nerve (CN V3)
Temporalis, Masseter, Medial and lateral pterygoid
Biomechanics when opening the TMJ
- articular disc and condyle of mandible slide anteriorly on articular surface to articular tubercle (movement occurs in superior compartment
- simulataneously condylar process of mandible rotates on articular disc in inferior compartment
Biomechanics when closing the TMJ
- articular disc and condyle of mandible slide posteriorly on articular surface to articular tubercle (movement occurs in superior compartment
- simultaneously condylar process of mandible rotates on articular disc in inferior compartment
What is included in the oral region?
Oral cavity, teeth, gingivae, tongue, palate, region of palatine tonsils
Function of oral region
ingestion of food, preparation for digestion, food chewed by teeth, saliva from salivary glands assist in forming food bolus, deglutition = swallowing (voluntary), once pushes into pharynx (automatic phase of swallowing)
Functions of the tongue
mastication, taste, deglutition, articulation, oral cleansing
main functions: forming words during speech, pushing food into the pharynx when swallowing
What is the bulk of the tongue made up of?
Skeletal muscle
What are the muscles of the tongue supplied by?
by CN XII hypoglossal nerve, except palatoglossus mm
General sensation of the tongue
touch, temperature
anterior 2/3rds linguial nerve (CN V(3))
posterior 1/3rd lingual nerve (CN IX)
What makes up the orbit
bones, nerves, eyeball, muscles, vessels
what does recti mean
straight
How many vertebrae are in the cervical spine?
7 vertebrae
How many vertebrae are in the thoracic spine?
12 vertebrae
How many vertebrae are in the lumbar spine?
5 vertebrae
How many vertebrae are in the sacrum spine?
5 fused vertebrae
How many vertebrae are in the coccyx spine?
3-5 fused vertebrae
How many vertebrae are in the vertebral column
31
Features of the vertebra
- vertebral body (anteriorly)
- vertebral arch (middle)
- vertebral foramen
- spinous process 1x
- 2x transverse processes
- 2x superior articulate processes
- 2x inferior articulate processes
What is primary ossification?
- begins in foetus
- complete ossification of the vertebrae by about 1 yr in the Cx and 6 yr in the Lx
What is secondary ossification?
- centres develop in puberty
- usually complete by 25 yrs
What type of ossification is the vertebrae?
Endochondral ossification
Cervical vertebrae features
Body, spinous process, transverse process (transverse foramen), superior and inferior articulate processes, Pericles, lamina
Which cervical vertebrae are classified as typical?
C3-C6
Features of typical Cx vertebrae
Vertebral body (uncinate processes), vertebral arch, vertebral foramen, spinous process (short and bifid), transverse processes , superior articulate processes, inferior articular processes
C7 Atypical Vertebra features
Vertebral body (larger), spinous process (not bifid), transverse processes (smaller transverse foramen containing only vertebral vein)
C1 Atypical vertebra (atlas)
Anterior arch (anterior tubercle, facet for dens), posterior arch (posterior tubercle, groove for vertebral artery), lateral masses (superior facet, inferior facet)
C2 atypical vertebra (axis)
Vertebral arch, vertebral foramen, spinous process (bifid), transverse processes, transverse foramen, inferior articular processes
Atypical features:
- vertebral body has a superior projection called the odontoid process (dens)
- superior articular facets are directly superiorly to support C1 atlas
Hyoid bone
Found in neck, doesn’t articulate with another bone
Anterior surface = concave
Posterior surface = convex
Greater horns - either side of body, projects posterosuperiorly and laterally from the body
Lesser horns - small projection on superior surface, located at Union of greater horns and body
Suspended from styloid process by stylohyoid ligaments, which insert onto lesser horns
Joints of Cervical spine
- zygapophyseal (facets) joints
Zygapophyseal joints features
- also known as facet joints
- between the superior and inferior articular processes of adjacent vertebrae
- plane synovial, permits gliding
- Each joint innervated by two spinal nerves
- cervical facets have and oblique orientation
Ligaments of the zygapophyseal joints
- ligaments flavum
- intertranverse ligament
- interspinous ligament
- supraspinous ligament
- unchallenged ligament
Uncovertebral joints
- also known luschka
- formed by unicate processes of c3-c6 and the vertebral body above
- considered synovial joints
- located at the lateral and posterior lateral margins of IVD
Atlanto-Occipital Joint (OA)
- joints between lateral mass of C1 and occipital condyles
- condyloma synovial joints
- permits nodding of head
- very limited rotation and side bending
What connects C1 to the skull?
- anterior atlanto-occipital membrane (arising from anterior arch)
- posterior atlanto-occipital membrane (arising from posterior arch)
Pathway of the vertebral artery
Runs up through the transverse foramina the runs through posterior atlanto-occipital membrane to get into vertebral canal and then pass up through foramen magnum to supply the skull
Atlanto-axial joint (AA or C1-2)
- only rotation movement available, skull and C1 rotate as unit on C2
- 1 pivot synovial joint (median AA joint) - between dens of C2 and anterior arch of C1
- 2 plane synovial joints (lateral AA joint) - b/w superior articular facets of C2 and inferior articular facets of C1
How many joints are in the atlanto-axial joint?
Three atlanto-axial joints
Which ligaments support the Atlanto-Axial joint?
- 1x apical ligament
- 2x alar ligaments (coming of dens like wing)
- 1x crucially ligament with three bands (transverse ligament of atlas, superior longitudinal lig, inferior longitudinal lig)
- tectorial membrane (very strong superior continuation of PLL)
What are the spinal ligaments?
- anterior longitudinal ligament
- posterior longitudinal ligament
- ligamentum flavum
- intraspinous ligament
- supraspinous ligament
- intratransverse ligament
Nuchal ligament - facts
- known as ligamentum nuchae
- in the median plane on posterior surface of neck
- triangular membrane that forms a median fibrous septum b/w muscles of two sides of the neck
- attached to spinous processes of cervical vertebrae, EOP & EO crest
What type of joints are the intervertebral disc?
Secondary cartilaginous joint (symphysis)
Function of IVD
Designed for weight bearing and strength
Vary in shape with the spinal curvatures and movement
Location of IVD
Between the bodies of adjacent vertebra (absent at C1-2)
What doe IVD’s consist of?
- anulus fibrosus (outer layer of the IVD composed of lamellae of fibrocartilage)
- nucleus pulposus, gelatinous central mass highly elastic, high water content (middle of IVD
Fascia of the neck
2 different types of fascia
- superficial fascia
- deep fascia
Superficial fascia of the neck
- contains cutaneous nerves, blood vessels, lymph nodes and vessels
- in cervical superficial fascia it contains platysma
Deep fascia of the neck
- allows the various structures in neck to Slide Over one another , during movements of the head and during visceral functions such as swallowing
4 parts
- investing layer, pretracheal layer, prevertebral layer, carotid sheath
Investing layer of deep fascia
- surrounds the entire neck, deep to superficial fascia
- invests the trapezius and SCM muscles
Pretracheal Layer of Cervical Fascia
- only present in anterior part of neck
- extends from hyoid bone to pericardium
- thin muscular part, encloses infrahyoid muscles
- visceral part, encloses thyroid gland, trachea and oesophagus
Prevertebral Fascia of the neck
Forms a tubular sheath for the vertebral column and the muscles associated with it
Carotid sheath
- two sheaths (left and right)
-tubular fascia sheath - blends with other fascia
What does the carotid sheath contain?
Common carotid artery and ICA
Internal jugular vein
Vagus nerve CN X
Deep cervical lymph nodes
Other small nerve fibres
Triangles of the neck
Divides into separate anatomical areas bilaterally
Anterior triangles (in front of SCM)
Posterior triangles/lateral cervical region (behind the SCM)
Smaller triangular divisions within each of the larger triangles
Posterior Triangles of the Neck
Occipital triangle and subclavian triangle
Anterior triangles of the neck
Submental triangle, carotid triangle, submandibular triangle, muscular triangle
How many bones are in the external nose?
Nasal bones, frontal processed of maxillae, nasal parts of frontal bone and it’s nasal spine
How many cartilages are in the external nose?
10
5 main cartilages, 2 lateral cartilages, 2 alar cartilages, a septal cartilage
What does the skeleton of the external nose consist of?
Bone and hyaline cartilage
Nasal septum facts
Divides nose into 2 cavities
Consists of largely 3 parts
What is found in the Nasal septum?
- perpendicular plate of ethmoid
- vomer (posterior inferiorly)
- septal cartilage, continuous inferiorly and anteriorly with bony septum
- small sections of palatine and maxillae (nasal crests)
Nasal Cavities
- enter anteriorly through nares (nostrils)
- vestibules are lined with skin and stiff hairs
- vestibules are a cavity situated at the entrance to a hollow
- it opens posteriorly into the nasopharynx through the choanae
- lined with mucous membranes
- mucous membranes are firmly bound to adjacent periosteum and perichondrium
Mucous membranes are continuous with the lining of all chambers
Boundaries of nasal cavity
Lateral wall
- consists of three scroll shaped protrusions projecting inferiorly
How many Paranasal Sinuses are there?
Frontal paranasal sinuses (pair)
Maxillary paranasal sinuses (pair)
Ethmoid paranasal sinuses (many spaces within ethmoid bone)
Sphenoid sinuses (2)
Special Sensation of Tongue
- taste (anterior 2/3rd CN VII, fascia nerve & posterior 1/3rd CN IX, Glossopharyngeal
- root of tongue: sensory and special sensory (taste) vagus CN X
Where can you find the Palate?
Arched roof of the mouth
Floor of nasal cavities
What does the Palate do?
Separates oral cavity from nasal cavities and nasopharynx
Hard and soft palate
Facts about the hard Palate
Concave shape
Forms anterior 2/3 of palate
At rest space below the hard palate is filled with tongue
Consists of bony skeleton palatine processes of the maxillae
Horizontal plates of palatine bones
Where is the soft palate?
Posterior 1/3 of palate
Suspends posteriorly from hard palate
Soft palate consist of
No bony skeleton
Consists of fibromuscular tissue
Function of the Soft Palate
Initially palate tenses during swallowing
Tongue can then press against it
Squeezing the bolus of food posteriorly in mouth
Then elevated posteriorly and superiorly to prevent food from passing into nasopharynx
Muscles of the Soft palate and supply
5 mm arise from base of cranium of soft palate
Supplied by pharyngeal branch of vagus CN X via pharyngeal plexus (except tensor veli palatini, CN V (3))
Where are the palatine tonsils?
Between palatoglossal and palatopharyngeal arches
In region oropharynx
Mostly lymphoid tissue
Where is the Pharynx? And what function has it?
Part of the digestive system posterior to nasal cavities, oral cavity and larynx
Extends from base of skull to inferior base of cricoid cartilage and inferior border of C6 posteriorly
Respiratory function
Into which regions is the Pharynx divided?
3 regions
Nasopharynx - posterior to nasal cavity and superior to soft palate
Oropharynx - posterior to mouth and oral cavity
Laryngopharynx - posterior to larynx
