Transtentorial uncal herniation causes all except :
Answer is D (Decoicate rigidity): Decoicate rigidity is not seen as a manifestation of uncal herniation. All other features form pa of the spectrum. `Herniation or coning' is said to be occurring when pa of the brain is forced through a rigid hole. Uncal herniation Central herniation The uncus and the temporal lobe are forced through the cerebellar tentorium (tentorium that separates the cerebrum from the cerebellum) The diencephation i.e. the thalamus and related structures that lie between upper brainstem and cerebral hemispheres are forced through the tentorium. What happens What happens Sequential compression occurs of the - Ipsilateral third nerve Sequential compression occurs of the - Upper midbrain (first) - Contralateral brainstem (later) - Pons (later) - Whole brainstem (eventually) - Medulla (finally) Physical signs Physical signs Early Later Still later Early Later Still later * I/L dilated pupils * I/L hemiplegia * Tetraparesis * Errotic respiration * Cheyne * Fixed * Signs of supra * Progressive ptosis * B/e fixed dilated * Small reactive pupils. stokes dilated xentorial mass & third n palsy pupils * Increased limb tone respiration pupils lesions * Cheyne- stokes * Erratic respiration * Bilateral extensor * Decoicate * Deccrebrate respiration * Death plantar rigidity posturing
Ipsilateral dilated pupils
Ipsilateral hemiplegia
Cheyne stokes respiration
Decoicate rigidity