Brainstem Anatomy PDF

Brainstem The brainstem consists of the medulla oblongata, the pons and the midbrain. It connects the spinal cord to cerebrum. Medulla oblongata  Bulbopontine sulcus Anterior median fissure Anterolateral sulcus Retro-olivary sulcus Anterior surface s o...

Brainstem The brainstem consists of the medulla oblongata, the pons and the midbrain. It connects the spinal cord to cerebrum. Medulla oblongata  Bulbopontine sulcus Anterior median fissure Anterolateral sulcus Retro-olivary sulcus Anterior surface s of brainste m Foramen cecum Pyramid Olive Inferior olivary nucleus Pyramidal decussation 6 7 8 9 1 1 2 0 1 1 Posterior surfaces of medulla oblongata Tuberculum cuneatus Tuberculum gracilis Posterior median sulcus Posterior intermedial sulcus Posterolateral Fasciculus gracilis Fasciculus Obe cuneatus x Pons Pontocrural sulcus 3 4 5 Basilar sulcus 6 78 Bulbopontine sulcus  Medial eminence Rhomboid fossa Sulcus limitans Stria medullares Dorsal median 4th sulcus ventricle Superior cerebellar peduncle Loculus coeruleus Facial colliculus Median Vestibular cerebell area ar peduncl Trigonum e nervi Inferior hypoglossi cerebell ar Trigonum nervi peduncl vagi e  Oculomotor nucl. Edinberg-Westphal nucl. Mesencephalic nucl. Trochlear (V) nucl. Pontine nucl. (V) Vestibular Motor nucl. of nucl. trigeminal Abducens n. nucl. Cochlear nucl. Facial Spinal nucl. (V) nucl. Superior salivatory nucl. Inferior salivatory nucl. Ambiguus nucl. Dorsal nucl. of Tractus solitarius vagus nucl. Accessory Hypoglossal nucl. nucl. Midbrain  Crus cerebri Interpeduncular fossa 3 Posterior 4 perforate substanc e  Dorsal surfaces Superior colliculus (vision) 4 Inferior colliculus (hearing) Corpus quadrigeminy Tectum  Crus cerebri Tegment um Tectum Cerebral Posterior cerebral a. Basilar a. Vertebral a. DEVELOPMENT OF THE BRAIN Medial medullary syndrome It occurs due to blockage of anterior spinal artery. Contralateral hemiplegia - due to damage to pyramid of medulla. Loss of sense of vibration and position due to damage to medial lemniscus Paralysis of muscles of tongue on the same side due to injury to XII cranial nerve.  Lateral medullary syndrome Occurs due to blockage of posterior inferior cerebellar artery. Ipsilateral paralysis of most of muscles of soft palate, pharynx and larynx due to injury to nucleus ambiguus which gives fibers to IX, X and XI cranial nerves Loss of pain and temperature on same side of face due to involvement of spinal nucleus and spinal tract of trigeminal nerve Loss of pain and temperature on opposite side of the posterior inferior cerebellar artery body due to involvement of lateral spinothalamic tract Giddiness due to involvement of vestibular nuclei Injury to lower part of medulla oblangata Injury in this part may be fatal due to injury to the vital centers like respiratory center and vasomotor center. Pontine hemorrhage Bilateral paralysis of face and limbs due to involvement of VII nerve nucleus and all corticospinal fibers Deep coma due to damage to the reticular formation Hyperpyrexia due to cutting off of the temperature regulating fibers from the hyputhalamus Pin point pupil due to damage to sympathetic ocular fibers Pontine hemorrhage is usually fatal  Cerebellopontine angle The anatomical structures located in the cerebellopontine angle include choroid plexuses of IV ventricle, flocculus, VII and VIII cranial nerves. A tumor, acoustic neuroma in this angle arises usually in relation to VIII nerve. Ipsilateral facial paralysis and loss of taste in anterior two-thirds of tongue due to damage to fibers of facial nerve Deafness and vertigo due to damage to both the parts of VIII nerve Ataxia on the affected side due to involvement of the flocculus Absence of corneal reflex on the side of lesion due to damage to nucleus of V nerve including its spinal tract  Millard-Gubler’s syndrome In this condition, there is damage to fires of VI and VII nerves along with pyramidal fibers. Paralysis of VII nerve on the same side due to damage to VII nerve fibers Ipsilateral loss of abduction of the eye due to damage to VI nerve Contralateral hemiplegia due to lesion of the  Weber's syndrome This syndrome involves III nerve nucleus and corticospinal fibers. Hemiplegia on the opposite side due to involvement of corticospinal fibers Pupil points downwards and laterally due to paralyses of III CN  Benedict In this condition, most ofsyndrome tegmentum of midbrain is damaged. Lesion includes loss of the medial lemniscus, red nucleus, superior cerebellar peduncles and fibers of III CN. Loss of proprioception due to lesion of medial lemniscus. Pupil points downwards and laterally due to injury to III nerve Tremors and twitching of opposite side due to damage to red nucleus and superior cerebellar peduncle.  Parinaud's syndrome Lesion of superior colliculi leads to this syndrome. Weakness of upward gaze and, vertical nystagmus due to lesion of superior colliculus  Argyll-Robertson pupil In this condition, light reflex is lost but accommodation reflex is retained due to lesion in the vicinity of pretectal nucleus