5.1 - the medulla

Brain stem location and it’s parts

Posterior cranial fossa

Medulla oblongata, pons, midbrain

Medulla oblongata: Position and length

Begins at the pontomedullary junction

Ends at the foramen magnum, continuin as the spinal cord

key structures of the Anterior medulla

Anteriormedial sulcus (midline groove)

Pyramid (swelling from corticospinal tract)

Olivary swellings (due to inferior olivary nuclei)

Cranial nerves: 9-12

key structures on the posterior medulla

Gracile tubercle

Cuneate tubercle

Posterior median sulcus

Facial colliculi (from CN 7)

Hypoglossal forgone (CN 12 nucleus)

Vagal trigone (CN 10 nucleus)

key nuclei in the medulla (gray matter nuclei)

Nucleus gracilis & cuneatus (sensory info to thalamus)

Olivary nucleus (relays to cerebellum)

Sensory/motor nuclei of CN 8-11

Reflex centres (cardiac, respiratory, vomiting)

major tracts in the medulla (white matter tracts)

Ascending and descending tracts

Pyramidal swelling (corricospinal tract)

Spinothalamic tract (pain/temp)

Dorsal and Trigeminal tracts

Caudal medulla

Crossing (decussation) of pyramidal tract

Nucleus gracilis & cuneatus

Tracts of CN 5 - Trigeminal n.)

Rostral medulla

Inferior olivary nuclei

Crossing (decussation) of medial lemniscus

Cardiac/respiratory centres

Cranial nerves of the medulla

Glossopharyngeal (CN 9)

Vagus (CN 10)

Spinal accessory (CN 11)

Hypoglossal (CN 12)

landmarks of the floor of the 4th ventricle

Facial colliculus - CN 7

Striae medullaris (cochlear fibres)

Hypoglossal forgone - CN 12

Vagal trigone - CN 10

Vestibular area - CN 8

Reflexes controlled by the medulla

Cardiac centre (heart rate)

Respiratory centre (breathing)

Swallowing, vomiting, sneezing, coughing