Anatomy of Speech & Hearing

Anatomy of Speech & Hearing Exam 1

label A

frontal lobe

label B

temporal lobe

label C

occipital lobe

label D

parietal lobe

label E

pre-central gyrus

label F

post-central gyrus

label G

central sulcus/central sulcus of Rolando/Rolandic fissure/fissure of Rolando

label H

deep sulcus/sulcus of Sylvian/lateral sulcus/Sylvian fissure

Brodmann’s area 44 & 45

Broca’s area

Brodmann’s area 22

Wernicke’s area

Brodmann’s area 6

pre-motor cortex

Brodmann’s area 40

supramarginal gyri

Brodmann’s area 39

angular gyrus

Brodmann’s area 41 & 42

primary auditory context

Brodmann’s area 4

pre-central gyrus

Brodmann’s area 1, 2, & 3

post-central gyrus

projection pathways function

communication between lower & higher regions in cerebrum

associational pathways function

communication within the same hemisphere

commissural pathways function

communication between hemispheres

dura mater

superficial layer of the meninges - tough mother

arachnoid mater

middle layer of the meninges - spider-like web

pia mater

deepest layer of the meninges - soft mother

diancephalon

contains the thalamus, epithalamus, hypothalamus, subthalamus

thalamus function

sensory processing relay station - every sensation passes through (excluding olfactory) before going to the somatosensory cortex

hypothalamus function

body temperature, hunger, thrist, mood, sex drive, blood pressure, sleep

epithalamus

pineal body, gonad development, olfactory reflex

control circuits (basal ganglia & cerebellum) function

coordinate, integrate, & help control the diverse activities of the many sturcture pathways involved in motor performance (integrate activities of direct and indirect pathways)

basal ganglia

contains caudate nucleus & lenitform nucleus (made of globus pallidus & putamen)

basal ganglia function

helps maintain a stable musculoskeletal environment & modulates excessive commands from cortex

damage to basal ganglia

results in hypokinesia or hyperkinesia dysarthria- greater impact on speech than lesions of the cortex

hypokinesia

reduced mobility/rigidity as a result of a loss of dopamine, i.e., Parkinsons

hyperkinesia

involintary movements as a result of excessive dopamine, i.e., tourrettes

hindbrain

contains cerebellum, pons & medulla oblongata

cerebellar control circuit

responsible for coodination of trunk zone, modulates equilibrium - dentate nuclei (in cerebellar hemispheres) are important for speech control, active in initiating movement, executing pre-planned motor tasks, and regulating posture

damage to cerebellum

ataxia (various forms of incoordination, i.e., gait disturbances, intention tremor, hypotonia), dysarthria (area impacted when intoxicated, think of someone insanely drunk)

intention tremor

occurs when trying to complete a movement

terminal tremor

tremor’s amplitude increases as the movement gets closer to completion

rest tremor

tremor/involuntary movement occurs at rest

pedoncles

how the pons connects to cerebrum (inferior, middle, superior)

sensory info travels on the ___ side

dorsal

motor commands travel on the ___ side

ventral

fasciculus gunneatis

relays sensory info from the waist up - contralateral processing

fasciculus gracilis

relays sensory info from below the waist - contralateral processing

decussation of pyramids

majority of motor commands cross over to the opposite side of the body to the target muscles to complete the movement

direct activation pathway/pyramidal system/motor system

contains corticobulbar tracts & corticospinal tracts - fiber tracts originate in motor cortex and terminate in cranial nerve motor nuclei in brainstem (corticobulbar) or originate in motor cortex and terminate in spinal nerve nuclei in spinal cord (corticospinal)

indirect activation pathway/extrapyramidal system/indirect motor system

“milk run,” originates in motor cortex and synapse with other structures (basal ganglia) before terminating in C.R. N and SP. N. motor nuclei in brainstem and spinal cord

upper motor neuron system

contains direct motor system and indirect motor system

final common pathway/lower motor neuron pathway

cranial nerves and spinal nerves that exit the brainstem and spinal cord- the peripheral mechanism through which all motor activity is mediated; the final link to speech muscles - carries out upper motor neuron commands for voluntary movements

damage to lower motor neuron pathway

prevents normal activation of muscle fibers - denervation (partial=paresis, complete=paralysis); voluntary & reflexive motor activities equally; can be bilateral or unilateral - atrophy resulting in hypotonia - spontaneous motor activity on the surface of the skin (fasciculations)

flaccid dysarthria

injury or malfunction of one or more of the cranial or spinal nerves - lesion is always between the brainstem or spinal cord and the muscle - results in hypotonia, diminished reflexes, atrophy, weakness (paralysis or paresis), fasciculations

damage to direct activation pathway

a loss or reduction in its ability to facilitate fine, discrete movements - reduced tone and weakness - positive Babinski sign - pathological oral reflexes (suck, snout)

damage to indirect activation pathway

usually occurs with damage to DAP - loss of inhibitory role in motor control, positive signs (overactivity) - increased muscle tone & spasticity - hyperactive reflexes

spastic dysarthia

bilateral damage to direct and indirect activation pathways - speech characteristics reflect a combo of weakness and spasticity (slow movement and reduced range and force)

cranial nerves that recieve bilateral input

C.R. N. V, VII, IX, X, XI

cranial nerves that recieve unilateral input

C.R. N. VII, XII

cranial nerve V - trigeminal

superficial facial sensory - for pressure, pain, temperature in oral cavity, not taste - dentist infuses numbing medication into this nerve

cranial nerve VII - facial

muscles for facial expression - taste for anterior 2/3 of tongue - controls salivary glands

cranial nerve IX - glossopharyngeal

sensation & taste for posterior 1/3 of tongue & entryway to pharynx - mediates gag reflex (sensory) - senses food/liquid & helps to trigger the pharyngeal swallow response - stylopharhyngeal muscle, elevates larynx during swallowing

cranial nerve X - vagus

closes velum during speech to prevent unwanted nasal sounds - pitch elevation - add/abduction of vocal folds (weak side is immobile) - sensory below larynx - prevents choking

cranial nerve XI - accessory

laryngeal & pharyngeal muscles w/ vagus nerve, innervates in stenocleidomastoid muscle & trapezius muscle

cranial nerve XII - hypoglossal

all intrinsic and extrinsic muscles of the tongue - not responsible for sensory

damage to cranial nerve VII - facial

facial drooping on the weak side - when retracting (smile), the movement will deviate to the strong side - when protruding (pucker), the movement will deviate to the weak side

damage to cranial nerve IX - glossopharyngeal

trouble swallowing

damage to cranial nerve X - vagus

damage can occur on any of the three branches or where it runs on the brainstem, superior damage impacts the inferior branches functions

pharyngeal branch of vagus nerve

soft palate & velum - responsible for closure during speech to prevent unwanted nasal sounds

superior laryngeal branch of vagus nerve

divides into external motor nerve and internal sensory nerve

recurrent laryngeal branch of vagus nerve

add/abduction of vocal folds - sensory below the larynx - prevents aspiration

external motor branch of vagus nerve

motor innervation to the cricothyroid muscle of the larynx (stretches and lengthens the vocal cords to control high-pitched vocalization)

internal sensory branch of vagus nerve

provides sensation to the larynx above the vocal folds - prevents choking

damage to cranial nerve XI - accessory

weakens head rotation (opposite side of weakness), reduce ability to shrug shoulders on side of lesion

damage to cranial nerve XII - hypoglossal

extraoralputrusion (sticking out your tongue) will deviate to the weak side - movements should be symmetrical