Anatomy lectures Flashcards
Which cells are responsible for myelin sheaths in the CNS & PNS?
CNS = oligodendrocytes PNS = schwann cells
What route do sensory axons take when exiting the spinal cord?
Spinal nerve to posterior root the posterior rootlets then posterior horn of the spinal cord
Where do fibres in the STT cross over?
1-2 spinal nerve segments above point of entry
Where do fibres crossover in the corticospinal tract?
Crossover in medulla
Where does sympathetic outflow exit the spinal cord?
T1-L2 spinal nerves
Signs of horner’s syndrome
Ipsilateral ptosis
Ipsilateral miosis (pinpoint pupil)
Reduced sweating on affected side
How do presynaptic parasympathetic axons leave the CNS?
Via CN’s III, VII, IX & X and via sacral spinal nerves
Where do the extrinsic back muscles attach?
Upper limb & pectoral girdle
What is the function of the extrinsic back muscles?
Move the upper limb
What are the main extrinsic back muscles?
Trapezius
Latissimus dorsi
Levator scapulae
Rhomboid major & minor
What is the function of intrinsic back muscles?
Maintain back posture
Move the spine
What are the two min groups of intrinsic back muscles?
Erector spinae (superficial) Transversospinalis (deep)
Strain of which muscle is likely to cause low back pain?
Erector spinae
Which ligament connects adjacent laminae posterior to the spinal cord?
Ligamentum flavum
Which ligament is narrow and weak but prevents over-flexion of the spine?
Posterior longitudinal ligament
Which broad, strong ligament prevents over-extension of the spine?
Anterior longitudinal ligament
Which vertebral level is the first palpable spinous process?
C7
Where is anaesthetic injected into incausal anaesthesia?
Sacral hiatus ( to anaesthetise sacral spinal nerve roots fo the cauda equina)
At what level does the spinal cord end?
L2
Why might a laminectomy be needed to relieve pressure on thespinal cord or nerve roots?
Tumour
Herniated disc
Bone hypertrophy
Where is the somatosensory cortex found?
Post-central gyrus
Where is the somatomotor cortex found?
Pre-central gyrus
Which nerve innervated the anterior compartment of the arm?
Musculocutaneous nerve (C5,6,7)
Where is the extracranial part of CN I?
Within the olfactory mucosa in the nasal cavity
Which foramnia doesCN I pass through?
Cribriformplate of the ethmoid bone
Where do olfactory nerves synapse?
Olfactory bulb
What foramina does CN II pass through/
Optic canal
Where does CN III connect with the CNS?
Midbrain
Which foramen does CN III pass through?
Superior Orbital Fissure
Which foramen does CN IV pass through?
Superior orbital fissure
What does CN IV supply?
The superior oblique muscle
Where does CN VI connect with the CS?
Pontomedullary junction
Which foramen does CN VI pass through?
Superior orbital fissure
What foramen does the vestibulocochlear nerve pass through?
Internal acoustic meatus
Where does CN XI connect with the CNS?
Cervical spinal cord
Which foramen does CN XI pass through?
Jugular foramen
How do you clinically test CN IX?
Shrug shoulders
Turn head to flex neck on both sides
Where doesthe hypoglossal nerve connect with the CNS?
Via many rootlets lateral to the pyramids of the medulla oblongata
Which foramen does CN XII exit through?
Hypoglossal canal
How do you test CN XII?
Ask patient to stick tongue out - tongue goes towards side of nerve injury
Which division of the trigeminal nerve carries both sensory & motor fibres?
CN V3
What are the 3 pairs of jaw closing muscles?
Masseter
Temporalis
Medial pterygoid
What is the only pair of jaw opening muscles?
Lateral pterygoid
What is the chorda tymani a branch of and what does it supply?
Branch of CN VII - supplies taste buds of the anterior 2/3rds of tongue
What movements of the face allow testing of motor function of CN VII?
Raise eyebrows
Close eyes tightly
Smile
Puff out cheeks and hold air
What is the parasympathetic nerve supply of the parotid glad?
CN IX
How can CN IX be tested?
Gag reflex
What nerve supplies general & special sensory to the posterior 1/3rd of the tongue?
CN IX
What does the vagus nerve run within in the neck?
Carotid sheath
Where does the LEFT recurrent laryngeal pass?
Off the vagus and curves under the arch of the aorta
Where does the RIGHT recurrent laryngeal pass?
Under the right subclavian artery
Does the uvula move towards or away from the affected side?
Away from non-functioning side
What are the layers of the scalp?
S =Skin C = Connective tissue A = Aponeurosis L = Loose connective tissue P = Pericranium
Why are sutures in the skull good in fractures?
Minimise propagation to prevent skull fractures from spreading
Which artery courses over the deep aspect of the pterion?
Middle meningeal artery
What is the falx cerebri?
A midline structure made of dura mater that attaches to the deep aspect of the skull and separates the left & right hemispheres
Where is the circle of willis found?
Inferior to the midbrain, closely related to the pituitary stalk and optic chiasm within the subarachnoid space
How is CSF reabsorbed?
Into the durl venous sinuses via arachnoid granulations
Where is CSF produced?
Choroid plexus of the ventricles
What is hydrocephalus?
Excessive production,obstruction to flow or inadequate reabsorption leads to increased CSF volume
How is hydrocephalus treated?
Ventricular peritoneal shunt
Where does an extradural haemorrhage occur?
Between the bone & the dura
Which artery is damaged in an extradural haemorrhage?
Ruptured middle meningeal artery
What sort of injury could cause an extradural haemorrhage?
Trauma to the pterion
Where is the bleed in a subdural haemorrhage?
Between dura & arachnoid?
What structure indamaged in subdural haemorrhage?
Torn cerebral veins
What type of injury can cause a subdural haemorrhage?
Falls in the elderly
What structure tends to be damaged in subarachnoid haemorrhage?
Ruptured Circle of Willis (“Berry” aneursym)
What tends to be the cause of a subarachnoid haemorrhage?
Congenital aneurysm
What is a very dangerous complication of an epidural anaesthesia & LP?
Damage to extradural venous plexus resulting in an epidural haematoma compressing the spinal cord or cauda equina
In what cases should an LP not be performed?
Raised ICP
