Brainstem FX
connects diencephalon to cpinal cord and genetically wired auto-control mechanism
Brainstem doesn’t require experience t/f
true
brainstem structures
- midbrain
- pons
- medulla
Corticospinal fibers include
- corona radiata
- internal capsule
- pes peduncle/crus cerebri
- diffuse cotricospinal fibers
- pyramidal tract
- lateral corticospial tract
Corona Radiata
cerebrum
internal capsule
Diencephalon
Pes Peduncle/Crus Cerebri
Brainstem
Diffuse Corticospinal Fibers
Pons
Pyramidal Tract
Medulla
Lateral Corticospinal Tract
Spinal Cord
Lateral and third ventricles
butterfly
wings: 2 lateral ventricles
vertical slit: third ventricle
cerebral aqueduct
aperture in midbrain connecting third and fourth ventricles
Fourth ventricle
dorsal to pons
Corticospinal tracts: MOTOR
- lateral corticospinal
2. anterior corticospinal
lateral corticospinal
crosses @ pyramidal decussation and fine movements of limbs
anterior corticospinal
crosses within spinal column and central axial and girdle muscles
Dorsal columns of corticospinal
sensory: fine touch and proprioception: both cross @ medial lemniscus in lower medulla, fasciculous gracilis (sacral and lumbar), and fasciculous cuneatus (thoracic and cervical)
Anterolateral system
cross in spinal column usually after ascending a segment or two
- Spinothalamic (pain and temp)
- Spinoreticular (arousal in response to pain)
- Spinotectal (orients head to stimuli)
Brainstem Anatomical
- ascending and descending fiber tracts
2. nuclei groups related to cranial nerve functions and vital visceral (cardiac and respiratory) and reflexive functions
Anatomic structures of midbrain: caudal
- cerebral aqueduct
- inferior colliculus
- superior cerebellar peduncle and decussation
- medial lemniscus
Anatomic structures of midbrain: Rostral
- pes pedunculi (crus cerebri)
- substantia nigra
- red nucleus
- superior colliculus
- central gray
- cerebral aqueduct
- oculomotor nucleus and nerve
- medial lemniscus
Midbrain syndromes
- ipsilateral paralysis of upper and lower limbs and trunk
- ipsilateral paralysis of eyeball muscle with eye fixed
- contralateral limb incoordination (ataxia)
- loss of contralateral discriminative touch
- cranial nerve symptoms and frequent altered consciousness
Pontine syndromes
- ipsilateral hemiplegia (upper and lower extremities)
- contralateral losses of discriminative (position and vibratory sensation) touch
- medially deviated eye (paralysis of ipsilateral lateral rectus muscle)
- diplopia (double vision) on gaze toward side of lesion (involving abducens nerve)
- unsteady gait
- ipsilateral facial palsy
- vertigo, nausea, and deafness in ipsilateral ear
Medullary Syndromes: Medial Medullary (anterior spinal artery) syndrome
hypoglossal (CN-XII) Nucleus/nerve, medial lemniscus fibers, and pyramidal (corticospinal) tract fibers all affected
Deficits of Medial medullary syndrome
contralateral hemiplegia, contralateral hemianesthesia, dysarthria and dysphagia
Medullary syndromes: Lateral medullary (posterior/inferior cerebellar artery) Syndrome
Affects Vagus, glossopharyngeal, vestibular, spinal trigeminal tract and nucleus, inferior cerebellar peduncle, spinothalamic tract
Deficits of Lateral Medullary Syndrome
loss of pain and temp from ipsilateral face, dysphagia, dysarthria, vertigo, ataxia in ipsilateral upper and lower limbs, and contralateral loss of pain and temperature