Anatomy Practical Flashcards
What are the two divisions of the bones in the skull
- cranial bones
- facial bones
name the bones of the cranium
frontal bone parietal bone occipital bone temporal bone sphenoid bone ethmoid bone
Name the facial bones
mandible maxilla zygomatic bone nasal bone lacrimal bone palatine bone vomer
name the cranial fossa parts
anterior cranial fossae
middle cranial fossae
posterior cranial fossae
describe the structure of the temporal bone
- has a thicker part called the pertrous part
- has an external auditory meatus and an internal auditory meatus
- has the zygomatic process which forms the part of the zygomatic arch of the cheek bone
- mastoid process (anchoring site for some neck muscles
- styloid process
What does the petrous part of the temporal bone house
The thicker part of the bone (the petrous part) houses the middle and inner ear.
What two cranial nerves pass through the internal auditory meatus
the nerve of hearing and balance, the vestibulocochlear nerve CNVIII, and the facial nerve CNVII)
What is the styloid process in the temporal bone an attachment site for
The needle like styloid process (often broken off) is an attachment for tongue and pharynx muscles.
Describe the structure of the sphenoid bone
= The sphenoid bones is a butterfly shaped bone.
- It is made up of the central body, the greater wings and the lesser wings and 4 pterygoid plates.
- There are a number of important foramina in the sphenoid bone. These include the superior orbital fissure, the optic canals, the foramen rotundum, foramen ovale and foramen spinosum.
what bone in the skull articulates with all other cranial bones
sphenoid
Name the foramen in the sphenoid bone
superior orbital fissure, the optic canals, the foramen rotundum, foramen ovale foramen spinosum.
What is the pterion
- marks where the frontal, parietal, temporal and sphenoid bones come together
- it is the thinnest part of the skull
Why is the pterion clinically important
- marks the position of the anterior branches of the middle meningeal artery
- the middle meningeal artery supplies the dura and bone
- this is often implicated in intracranial haemorrhage
from what artery does the middle meningeal artery branch of
maxillary artery from the ECA
what foramen does the middle meningeal artery go through
foramen spinosum
describe the ethmoid bone
- delicate and severe like a sieve through which the air can pass
- on the superior surface of the ethmoid bone is the cribriform plate where the olfactory bulbs of the olfactory nerve sit
name the fontanelle present in the skull at birth
anterior fontanelle
posterior fontanelle
sphenoid fontanelle
mastoid fontanelle
name the sutures present in the skull at birth
- sagittal
- coronal
- lambdoid
- squamous
What three structures make up the nasal septum
- perpendicular plate of ethmoid bone.
- vomer bone.
- septal nasal cartilage
Which bones make up the anterior, middle and posterior cranial fossa
Anterior - the frontal bone, ethmoid bone and sphenoid bone.
middle - the sphenoid bone and the two temporal bones.
posterior - the occipital bone and the two temporal bones.
What brain structures are found in the anteiror, middle and posteiror cranial fossae
Anterior - lots of nerves
middle - the pituitary gland, and two lateral portions, which accommodate the temporal lobes of the brain.
posterior - the brainstem and cerebellum.
what endocrine structure is found in the sella turcicia of the sphenoid bone
pituitary gland
name the air sinuses and what they do
- frontal
- maxillary
- sphenoid
- ethmoid
- these lighten the skull and enhance the resonance of the voice
How many vertebrae are in the spine
33
what do intervertebral discs do
- act as shock absorbers
How many vertebrae are present in each vertebral section
Cervical - 7 throacic - 12 lumbar 5 sacrum - 5 fused coccyx - 4 fused
what is the common things that all vertebrae have
- The body
- The vertebral arch forms a vertebral foramen through which the spinal cord passes
- The transverse and spinous process is an attachment for the muscles of the back
describe C1 and C2
CI The Atlas articulates with occipital condyles of the skull (re: Greek Mythology)
C2 The Axis. More similar to a typical vertebra but has a dens process which acts like a pivot, and allows the atlas to pivot around the horizontal axis (ie shaking head to say no)
what are the differential features of the cervical, thoracic and lumbar vertebrae
Cervical
- Bifid spinous process
(Exceptions to this are C1 (no spinous process) and C7 )
- Transverse foramina – the vertebral arteries travel to the brain in this
- Triangular vertebral foramen
thoracic
- demi facets, they have facets superior and inferior as well as costal facets (on the transverse process) to articulate with the ribs
- The spinous processes of thoracic vertebrae are longer
- vertebral foramen is circular
lumbar
- large vertebral bodies
- triangular-shaped vertebral foramen
- spinous processes are shorter
what is the name of the foramen where the spinal nerves emerge from the vertebral column
vertebral foramen
what does the sacrum articulate with laterally
the 2 hip bones to form the sacroiliac joints
describe the foramina in the sacrum and what they do
The anterior and posterior sacral foramina transmit the anterior and the posterior rami of the sacral spinal nerves.
Name the parts of the development of the brain and what they develop into
- Telencephalon (cerebral hemispheres)
- Diencephalon (thalamus, hypothalamus)
- Mesencephalon (midbrain)
- Metencephalon (pons, cerebellum)
- Myelencephalon (medulla oblongata)
What structures make up the forebrain and hindbrain
The Hindbrain is composed of the medulla, the pons, and the cerebellum
the forebrain includes the thalamus, the hypothalamus, the limbic system, and the cerebrum.
which structure sits at the junction between the forebrain and hindbrain
midbrain
What makes up the brainstem
- medulla oblongata
- pons
- midbrain
What is the brainstem important for
- regulation of cardiac function
- regulation of respiratory function
- maintaining consciousness
- regulating sleep cycle
describe the ventral surface of the brainstem
- Midbrain is short and very little can be seen
- cerebral peduncles can be seen
- corticospinal tract is on the ventral surface
- pons has a birdge like surface
- medulla has pyramids on the ventral surface (the pyramids mark the decussation for the corticospinal tracts
- inferior olive - these are functionally asscoiated with the cerebellum
what cranial nerves are associated with the pons
CNV - VIII
What cranial nerves are associated with the medulla
IX - XII
What cranial nerves are associated with the midbrain
CNIII- IV
What cranial nerves emerge lateral to the inferior olive
X
IX
XI
which cranial nerves emerge between the inferior olive and pyramids
CN XII
name the cranial nerve general function and its exit opening
- olfactory
- optic
- oculomotor
- trochlear
- trigeminal
- abducens
- facial
- vestibulocochlear
- glossopharyngeal
- vagus
- accessory
- hypoglossal
- olfactory - smell - cribriform plate of ethmoid
- optic - sight, optic canal
- oculomotor - eye movement, superior orbital fissure
- trochlear - eye movement, superior orbital fissure
- trigeminal - sensory to the face, motor to the msucles of mastication, V1 - SOF, V2 - foraman rondtum, V3 - foramen ovale
- abducens - eye movement, superior orbital fissure
- facial - msucles of facial expression, taste of anterior 2/3 of the tongue, internal acoustic meatus
- vestibulocochlear - hearing and balance, internal acoustic meatus
- glossopharyngeal - sensory to pharynx, taste posterior 1/3 of the tongue, jugular foramen
- vagus - msucles of pharynx and layrnx, parasympathetic to abdomen, jugular foramen
- accessory - trapezius, SCM, jugular foramen
- hypoglossal - intrinsic tongue muscles, hypoglossal canal
describe the dorsal surface of the brainstem
- the dorsal surface of the midbrain has 2 paired swellings - inferior and superior colliculi
- gracile and cuneate tubercles like on either side of the most caudal part of the 4th ventricle, this opens to form the central canal about 1/3 of the way up the medulla - this is the point is called the obex
- ## rostral to this level is the dorsal surface of the medulla which is the floor of the caudal part of the 4th ventricle
what are the inferior and superior colliculi invovled in
- auditory and visual reflexes
what does the 4th ventricle contain
the 4th ventricle contains CSF that drains into the central canal of the spinal cord inferiorly and into the cerebral aqueduct superiorly
When is the medulla considered opened and closed
As the 4th ventricle is present, the medulla is considered ‘open’, as it opens up to the cerebellum via the 4th ventricle. This is the rostal medulla.
As the 4th ventricle closes and forms the central canal for the spinal cord, the medulla is considered ‘closed’ and is the most caudal point of the brainstem
in the midbrain what is visible at the ventral surface
cerebral peduncles
describe the blood supply to the brainstem
- arises from vertebral arteries
- these joint together to form the basilar artery
- basilar artery runs the length of the pons and splits into the posterior cerebral artery close to the pontine midbrain junction
- the posterior cerberal artery gives of several branches such as the anterior inferior cerebellar artery and the superior cerebellar artery
- the posterior inferior cerebellar artery is derived from the vertebral arteries
Where are the olfactory nerves
- these are in the olfactory epithelium in the roof of the nasal cavity
How do the oflactory nerves ascend into the nasal cavity
- They ascend through the cribiform plate of the ethmoid bone to reach the olfactory bulbs in the anterior cranial fossa.
- These nerves synapse on neurons in the bulbs.
What is loss of smell associated with
- it is frequently associated with upper respiratory tract infections, sinus diseases and head trauma
what does loss of olfactory fibres occur with
- this occurs with ageing
- injury to the nasal mucsoa or to the olfactory bulbs and tracts
- olfactory neurones can be torn away as they pass through the fractured cribiform plate
what are the optic nerves surrounded by
- extensions of the cranial meninges and subarachnoid space which is filled with CSF
where does the optic nerve pass
- passes posteromedially in the orbit through the optic canal to enter the middle cranial fossa where it forms the optic chiasm
- the fibres from the medial nasal half of each retina decussate and then join uncrossed fibres from the lateral nasal half of the retina to form the optic tract
If there was a direct trauma to the right orbit, with a fracture involving the optic canal, why might there be a loss of pupillary constriction? What type of blindness may result?
optic nerve is damaged - looses accomodation and light reflex
if a pituitary tumour compressed the optic chiasam what visual field defect would occur
loss of peripheral vision