ANATOMY HNS; Lecture 1, 2, 3 - Cranium, meninges and brain, Vertebral column, Neck Flashcards
What are the bones in the head?
Skull: 22 total (w/out ossicles of ear); mandible, cranium, viscerocranium
What are the meninges?
3 layers -> Dura mater, arachnoid mater, pia mater
What is the dura mater?
Thick and inelastic with 2 layers (periosteal and meningeal - most places fused together but sometimes periosteal breaks away and it is filled with blood called sinuses which drain the csf impurities
What is the arachnoid mater?
Avascular, elastic - spider-like projections
What is the pia mater?
Innermost, thin, delicate layer
What is a herniation and give examples?
Space occupying lesion (e.g. blood, tumour, oedema, cyst) in any compartment may raise intracranial pressure and lead to herniation of part of brain.
What are the 3 herniation types?
Subfalcine (no clinical significance), uncal (Affects midbrain causing unconciousness) and tonsillar (affects medulla causing cardiorespiratory failure)
What holds the bones of the skull together?
By fibrous joints called sutures - fontinelles present in babies for ease of birth through birth canal and fuse later in life
Why is the sphenoid bone important?
Middle meninges artery is behind this bone, which means that a rupture can cause a huge build up of pressure leading to the need to drill to open up and reduce the pressure
What passes through the formaina in the skull base?
CN and vessels supplying the brain
What are the 3 divisions of the cranial fossa?
Anterior, middle and posterior holding different parts of the brain - ant.=frontal lobe, middle = temporal and post= cerebellum
What are the major holes in the skull and what goes through them?
X
Where is the epidural space in the CNS?
In the spine which can be used for epidural injections for labour, whereas in brain there is no extra space
What are the different dural folds?
Have issues due to being rigid so herniatin can occur if there is a space occupying lesion, causing imtracranial pressure to increase
Why is the cavernous sinus a clinically relevant structure?
Artery is present inside the sinus, and if a thrombus is present the could impinge on CN (3 or 4 different ones)
What is are the 2 main functions of the vertebral column?
Support and protection; movement
What are the support and protection functions of the vertebral column?
Body weight, transmits forces, supports the head and upper limbs, protects the spinal cord
What does the vertebral column aid in movement?
Upper limbs and ribs (extrinsic muscles), postural control and movement (intrinsic muscles)
What are the 5 regions of the vertebral column?
Cervical, thoracic, lumbar, sacrum, coccyx
What are the curvatures of the vertebral column in adult vs newborn?
x
What are the different types of curvatures?
1ry is the same as the fetal position and 2ry is in the other direction -> Lordosis is common in pregnant women, scoliosis is most common in pre-pubescent girls (thought to be associated with hormonal changes)
How many bones in the vertebral column and how many in each section?
33 vertebrae -> 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused), 4 coccygeal (fused); size of vertebrae increase due to increase of weight on the vertebrae
How does a typical vertebra look?
How is a typical vertebrae adapted for its function?
Vertebral body is the major weight bearing part; vertebral arch forms roof of vertebral canal, has projections for attachments of muscles and ligaments, has sites of articulation for adjacent vertbrae; pedicles anchor the vertebral arch to the vertebral body
How do the typical vertebrae of the cervical, thoracic and lumbar look?
Foramen transversarium is for the cerebral arteries to move through (don’t exist on other parts of the vertebral column)
What are the atypical vertebrae?
Atlas (C1), axis (C2)
How does atlas look and differ from the other vertebrae?
NB: Allows movement in many directions; the articulate surface articulates with the skul; also no vertebral body