Cerebral areas
This large bundle of white matter fibers connects the left and right cerebral hemispheres and allows them to communicate.
What is corpus callosum
This muscle abducts the eye and is the only extraocular muscle innervated by the abducens nerve (CN VI).
What is the lateral rectus
This Cranial Nerve is responsible for smell
What is Cranial Nerve I
The four main arteries supplying blood to the circle of Willis.
What are the L and R vertebral and internal carotid arteries
The main muscle of mastication and the strongest muscle in the body relative to size.
What is the masseter
A thin, transparent membrane in the midline of the brain that separates the right and left lateral ventricles.
What is septum pellucidum
This muscle primarily elevates the upper eyelid and is innervated by the superior division of the oculomotor nerve. Its paralysis produces ptosis without affecting eye position.
What is levator palpebrae
This Cranial Nerve acts as a cable carrying nerve impulses from over a million retinal ganglion cells, enabling sight.
What is Cranial Nerve II
This artery connects the left and right anterior cerebral arteries and completes the anterior portion of the Circle of Willis.
What is the anterior communicating artery
One of the main salivary glands. The duct crosses over the masseter to pierce the buccinator and enters the mouth at the level of the second molar.
This region of the brain regulates body temperature, hunger, thirst, circadian rhythms, and serves as the link between the nervous and endocrine systems through its connection to the pituitary gland.
What is the hypothalamus
When the eye is fully adducted, this muscle becomes the primary elevator of the globe. Dysfunction results in inability to look up and medially.
What is the inferior oblique
Cranial Nerves running through the internal auditory meatus.
What are CN VII and VIII
An infarct of this artery, a branch of the internal carotid that courses within the longitudinal fissure, would most likely cause contralateral lower extremity weakness and sensory loss, along with possible urinary incontinence due to involvement of the medial frontal lobe.
A patient presents with inability to puff out their cheeks and difficulty keeping food between their teeth and cheek. Dysfunction of this muscle, innervated by the buccal branch of CN VII, is most responsible.
What is the buccinator
This small midline endocrine structure develops from the roof of the third ventricle, lies posterior to the thalamus, and secretes a hormone that regulates the sleep–wake cycle. Tumors in this region may cause vertical gaze palsy due to compression of nearby midbrain structures.
What is the pineal body/gland
A patient presents with vertical diplopia that worsens when walking downstairs and improves when tilting the head away from the affected side. The involved muscle passes through a fibrocartilaginous pulley and primarily intorts and depresses the eye when it is adducted.
What is the superior oblique
Lesions to this Cranial Nerve often caused due to surgical trauma in the posterior triangle of the neck with symptoms including drooping shoulders and scapular winging.
What is CN XI
Occlusion of this artery, the largest branch of the internal carotid artery, most commonly causes contralateral face and upper limb weakness and may produce Broca or Wernicke aphasia if the dominant hemisphere is affected.
What is the middle cerebral artery.
Following a neck laceration just inferior to the mandible, a patient can still smile, close their eyes, and elevate their eyebrows symmetrically, but cannot tense the skin of the anterior neck or depress the mandible’s lower lip effectively. Injury to the cervical branch of the facial nerve has most likely paralyzed this thin, superficial muscle that originates in the fascia overlying the pectoralis major and deltoid and inserts into the inferior border of the mandible and skin of the lower face.
What is the platysma
This brainstem structure contains the cardiorespiratory centers that regulate breathing, heart rate, and blood pressure. It houses the pyramids, where most corticospinal fibers decussate, and nuclei for cranial nerves VIII through XII, which mediate hearing, balance, swallowing, and tongue movements. Key ascending sensory tracts, including the gracile and cuneate fasciculi, synapse here before crossing in the medial lemniscus. Lesions can cause contralateral hemiplegia, loss of fine touch and vibration, dysphagia, dysarthria, and life-threatening autonomic dysfunction.
What is the medulla.
A patient with a partial oculomotor nerve palsy can adduct the eye and depress it in abduction but cannot elevate it when the eye is adducted. The affected muscle originates from the common tendinous ring and inserts onto the superior aspect of the sclera anterior to the equator of the globe.
What is the superior rectus
This cranial nerve exits the brainstem at the pontomedullary junction, travels through the internal acoustic meatus alongside CN VIII, traverses the facial canal of the temporal bone, and exits the skull via the stylomastoid foramen. A lesion proximal to the chorda tympani branch would cause ipsilateral facial paralysis, hyperacusis, loss of taste to the anterior two-thirds of the tongue, and decreased lacrimation.
What is Cranial Nerve VII
Aneurysm or infarct of this terminal branch of the basilar artery can result in contralateral homonymous hemianopia with macular sparing due to collateral circulation from the middle cerebral artery.
What is the posterior cerebral artery
A patient can elevate the corners of the mouth during a genuine smile but cannot retract them laterally to produce a forced grin without elevation. The paralyzed muscle originates from the parotid–masseteric fascia and inserts into the modiolus at the angle of the mouth. It is innervated by the buccal branch of the facial nerve and functions primarily to draw the angle of the mouth straight laterally rather than superiorly.
What is the rizorius muscle