Brain and Behaviour Anatomy Flashcards
Name the 6 bones of the cranium
Frontal, parietal, occipital, temporal, sphenoid and ethmoid
Name the 7 bones of the face
Mandible, maxilla, zygomatic, nasal, lacrimal, palatine and vomer
Describe the 3 processes of the temporal bone
Zygomatic process - forms part of zygomatic arch (cheek bone)
Describe the location of the temporal bone and the structures that pass through it
Thicker (petrous) part of bone houses middle and inner ear - external auditory meatus and internal auditory meatus (CN VIII and CN VII pass here - vestibulocochlear and facial)
What 5 foramen are within the sphenoid bone?
Superior orbital fissure, optic canals, foramen rotundum, foramen ovale, foramen spinosum
What is notable about the sphenoid bone?
It articulates with all of the cranial bones
Why is the temple (pterion) an important clinical landmark?
Position of anterior branches of middle meningeal artery
What is the pterion?
The pterion is the region where the frontal, parietal, temporal, and sphenoid join together. It is located on the side of the skull, just behind the temple
Where is the cribiform plate located?
Superior surface of ethmoid bone
What lies in the cribiform plate?
Olfactory bulbs of the olfactory nerve (CN I)
What 3 structures make up the nasal septum?
Anteriorly = cartilage Superiorly = perpendicular plate of ethmoid bone Inferiorly = vomer
Name and locate the sutures of the skull
Coronal suture - frontal bone from parietal bone
Lambdoid suture - parietal bone from occipital bone
Squamous suture - parietal bone from temporal bone
Sagittal suture - separating two parietal bones
Name and locate the 4 fontanelle
Anterior fontanelle - top of skull
Sphenoid fontanelle - superior aspect of sphenoid bone
Mastoid fontanelle - posterior to temporal bone
Posterior fontalle - back of skull
What passes through the optic canal?
CN II (Optic Nerve)
What passes through the olfactory foramen?
CN I (Olfactory Nerve)
What passes through the foramen rotundum?
CN V2 (maxillary branch of trigeminal nerve)
What passes through the superior orbital fissure?
CN III, IV, V1, VI (Oculomotor, Trochlear, Ophthalmic branch of trigeminal, Abducens)
What passes through the foramen ovale?
CN V3 (Mandibular branch of trigeminal nerve)
What passes through the internal acoustic meatus?
CN VII and VIII (Facial and Vestibulocochlear nerves)
What passes through the hypoglossal canal?
CN XII (Hypoglossal nerve)
What passes through the jugular foramen?
CN IX, X, XI (Glossopharyngeal, Vagus and Spinal Accessory Nerve)
What passes through foramen magnum?
CN IX (Spinal Accessory Nerve) enters here
What is the role of the anterior and posterior sacral foramina?
Transmit the anterior and posterior rami of the sacral spinal nerves
What is different between the first two cranial nerves and the rest?
Attach directly onto the forebrain whereas the other 10 are in the brainstem
What does the glossopharyngeal nerve do?
Parasympathetic –> parotid gland
Sensory: posterior 1/3 of tongue and oropharynx and supplies carotid sinus and carotid body (carotid sinus nerve)
What does the vagus nerve do?
Sensory: laryngopharynx and larynx (somatic) and visceral organs
Motor: palate, pharynx and larynx (somatic) and visceral motor (parasympathetic) to thoracic and abdominal organs
What does the spinal accessory nerve do?
Motor to sternocleidomastoid and trapezius
What does the hypoglossal nerve do?
Motor to the tongue
Which blood vessels enters the skull through the carotid canal?
Internal carotid artery
Which blood vessels enter the skull through the jugular foramen?
Internal jugular vein
Which blood vessels enter the skull through the foramen spinosum?
Middle meningeal artery
Describe the divisions of spinal nerves
Short, divides almost immediately after emerging from intervertebral foramen and divides into a small dorsal ramus and a larger ventral ramus (ramus are mixed)
What type of outflow is present in the parasympathetic nervous system?
Cranio-sacral (Cranial and S2-S4)
Name the 4 cranial nerves involved in the parasympathetic nervous system
Oculomotor (III), facial (VII), glossopharyngeal (IX), vagus (X)
What is the parasympathetic function of the oculomotor nerve?
Pupillary constriction
What is the parasympathetic function of the facial nerve?
Secretions at the lacrimal, submandibular and sublingual glands (and nasal mucosa)
What is the parasympathetic function of the glossopharyngeal nerve?
Stimulates secretions at parotid gland
What is the parasympathetic function of the vagus nerve?
Parasympathetic innervation to all organ viscera (rest and digest)
Where do all preganglionic fibres of the sympathetic nervous system arise from?
T1-L2
How is the sympathetic trunk connected to spinal nerves?
Via grey and white rami
What are white rami?
Connecting branch which contain axons of preganglionic, thinly myelinated axons from the sympathetic nervous system
What are rami?
a branch connecting two nerves or two arteries
What are grey rami?
Postanglionic, unmyelinated sympathetic neurones stemming from the sympathetic trunk
What do preganglionic sympathetic fibres have to pass through to get to the sympathetic trunk?
White rami communicantes
What happens once a preganglionic sympathetic axon reaches the sympathetic trunk?
Could synapse in same chain ganglion from the spinal segment from which they arose (paravertebral synapse), ascend or descend in the chain to synapse with postganglionic neurones higher or lower (paravertebral synapse) or pass through the trunk to synapse in prevertebral ganglia along the abdominal aorta
How do paravertebral ganglia differ from prevertebral ganglia?
Paravertebral ganglia lie next to the vertebral column whereas prevertebral ganglia tend to be unpaired and supply regions within the abdomen
What are the neurotransmitters of the sympathetic nervous system?
Preganglionic = ACh Postganglionic = Noradrenaline
What are the neurotransmitters of the parasympathetic nervous system
ACh
What is the conus medullaris?
Nearing the end of spinal cord (appears slightly cone shaped)
Outline the 3 layers of the meninges
Dura mater - tough outer layer
Arachnoid mater - delicate middle layer (avascular)
Pia mater - inner layer firmly attached to surface of spinal cord (rich blood supply)
What is the filum terminale?
Extension of the pia mater that is attached to the coccygeal segments
What is the subarachnoid space formed by?
Between the arachnoid and the pia mater in the meninges and is full of CSF
What are denticulate ligaments?
Ligament made up of the pia mater which run along the sides of the spinal cord
What are the two enlargements in the spinal cord, and why do they exist?
Cervical enlargement and lumbar enlargement (supply the innervation to upper and lower limbs)
What is the epidural space?
Space between dura mater and vertebral ligaments; contain tissue, fat and internal vertebral venous plexus
What information does the DCML pathway convey?
Discriminative touch - touch, pressure and vibration perception
What information does the spinothalamic tract convey?
Pain and temperature (itch and tickle included) - located in the ventrolateral funiculus
What information does the spinocerebellar tract convey?
Proprioception, including receptors for muscle stretch, tendon tension and joint position - located at the lateral edge of the lateral funiculus
Where does the DCML pathway decussate?
Medulla
Where does the spinothalamic tract decussate?
In spinal cord
Where does the spinocerebellar tract decussate?
Decussates twice –> functionally doesn’t decussate (ipsilateral)
What information does corticospinal tract convey?
Motor stimulation to voluntary muscles - located in the lateral funiculus
Where does the corticospinal tract decussate?
Pyramids of the medulla
What are laminae I to IV involved with?
Exteroceptive sensation (comprise dorsal horn)
What are laminae V and VI involved with?
Proprioceptive sensations
What are laminae VII involved with?
Relay between muscle spindle to midbrain and cerebellum
What are laminae VIII-IX involved with?
Comprise ventral horn and mainly motor neurones to skeletal muscle
What are laminae X involved with?
Surrounds the central canal and contains neuroglia
Where is there a lateral horn in the spinal cord and what does it contain?
Thoracic and sacral levels, containing autonomic preganglionic fibres
What 3 arteries supply the spinal cord?
Two posterior spinal arteries (PSA) and single larger anterior spinal artery (ASA)
What do radicular arteries supply in the spinal cord?
Dorsal and ventral roots and don’t connect to anterior or posterior spinal arteries
Describe the venous drainage of the spinal cord
3 anterior and 3 posterior spinal veins which drain outwards along the nerve roots
Which cranial nerves are associated with the pons?
Pairs of CN V,VI,VII,VIII (5-8)
Which cranial nerves are associated with the midbrain?
Pairs of CN III-IV (3-4)
Which cranial nerves are associated with the medulla?
Pairs of CN IX-XII (9-12)
What are the inferior and superior colliculi of the midbrain involved in?
Visual and auditory reflexes
Describe the movement of CSF from the 4th ventricle superiorly and inferiorly.
Superiorly - ascends in the cerebral aqueduct
Inferiorly - drains into central canal of the spinal cord
What is the fovea centralis in the eye?
Site of highest visual acuity on the retina
What is the purpose of the aqueous humour?
Mostly responsible for the intraocular pressure in the eye which maintain eyeball shape and prevents collapse as well as supplying oxygen and nutrients to the lens and cornea
Which muscle is used to close the eyelids?
Orbicularis oris (innervated by CN VII)
What is the consequence of a lesion at the optic nerve?
Blindness in that eye
What is the consequence of a lesion at the optic chiasm?
Bitemporal hemianaopia - lateral portion of vision dissipated on both sides
Define hemianopia
blindness over half the field of vision.
Define homonymous
affecting the same part of the visual field of each eye
What is the consequence of a lesion at the optic tract?
Homonymous hemianopia, if it is on the right tract –> left homonymous hemianopia (cannot see in left quadrant in either eye)
What is the consequence of a lesion at the right upper optic radiations (after the optic chiasm)
Left homonymous superior quadrantanopia due to the involvement of the upper right optic fibres (top left portion of vision is absent in both eyes)
What is the consequence of a lesion at the right occipital lobe?
Macular-sparing left homonymous hemianopia
What are the divisions of the ophthalmic nerve (CN V1)?
Frontal, nasociliary and lacrimal nerve
Name the 4 muscles of mastication
Temporalis, masseter, medial and lateral pterygoid
What nerve palsy can lead to the development of a hoarse voice?
Recurrent laryngeal nerve
How can you distinguish oculomotor nerve palsy and Horner syndrome?
Both have ptosis but in Horner’s the pupil is constricted (unopposed parasympathetic action) and in oculomotor palsy there is complete ptosis and a dilated pupil (unopposed sympathetic innervation)
How does CSF return to the venous system?
Through the arachnoid villi (occur in clusters known as arachnoid granulations)
How is the 3rd ventricle connected to the 4th ventricle?
By cerebral aqueduct
How do the lateral ventricles communicate with the 3rd ventricle?
Through the interventricular foramen (of Munro)
Where is CSF produced?
Choroid plexi of ventricles
What are 3 main functions of the ventricular system?
Produces CSF which:
Prevents implosion by reducing brain weight, protects brain and spinal cord from trauma and nourishes brain
Describe the anterior circulation to the brain
Internal carotid gives off the middle and anterior cerebral arteries and the anterior communicating arteries connect the structure to the posterior circulation
Describe the posterior circulation to the brain
Vertebral arteries supply the brain and give rise to the basilar and posterior cerebral arteries
