Clinical Anatomy Flashcards
What is Berry Aneurysm?
• Dilatation of any artery of the Circle of Willis
• Most common site-
1. Junction between Anterior Cerebral Artery and Ant. Communicating artery
2. Bifurcation of Int. Carotid artery
•Rupture of berry aneurysm causes Subarachnoid Haemorrhage
Carotid Siphon?
- B/w the Cavernous part and the Cerebral part , the ICA has multiple bends.
- This part produces an S-shaped shadow in an angiogram called Carotid Siphon.
- The carotid siphon helps to dampen the pulsations of the ICA in the cranial cavity.
What are the features of Parkinsonism?
TRAP
Tremors - Resting tremors
Rigidity - Cogwheel(upper limb) and Lead-pipe (lower limb) and Mask like face due to loss of control of facial muscles
Akinesia- General Slowing Down of movements and loss of associated movements
Postural Disturbances- Stooped Posture
What is Hemiballismus? Cause of Hemiballismus?
A violent burst of irregular involuntary movements , characterised by sudden flinging of the limbs in all directions.
Occurs on the contralateral side of lesion.
Cause- Vascular Lesion of Subthalamic Nucleus
What is athetosis? What is its cause?
Slow writhing movements, usually of the distal parts of the limbs eg. fingers and thumbs.
Cause- Lesion of Globus Pallidus
2 types of Chorea?
Sydenham’s Chorea
Huntington’s Chorea
Cause of Huntington’s Chorea?
Degeneration of GABA-ergic neurons of striatum. Absence of inhibition of dopaminergic neurons of substantia nigra. Overactivity of nigrostriate pathway.
Jerky , involuntary and purposeless movements occur.
Features of Split Brain Syndrome?
- Hemialexia - Cannot read matter in the left hemivisual field
- Left Ideomotor Apraxia - Cannot perform tasks with left hand in response to verbal command
- Left Agraphia - Cannot write using left hand
- Left Tactile Anomia - Cannot identify and object using left hand without visual aid
Features of Lesion of Middle Cerebral Artery?
- Contralateral Hemiplegia- due to damage to the Primary motor and SS area
- Aphasia- Due to damage to motor speech area (broca) if the dominant hemisphere is involved
- Homonymous Hemianopia - due to involvement of optic radiation
Enlarged Pituitary causes what type of vision defect?
Bitemporal Heteronymous Hemianopia. (Tunnel Vision)
Damage to central part of optic chiasma where nasal fibres cross.
Destruction of Left Lateral Geniculate body causes which type of vision defect?
Right Homonymous Hemianopia.
If there is a lesion on one side, there is loss of opposite half of field of vision
Lesion of the Right Optic Radiation causes——-?
Left homonymous Hemianopia.
Left visual fields of both eyes are lost
Damage of Right Meyer’s Loop causes?
Left Superior Quadrantic Anopia.
Whole Optic Radiation damage causes loss of left visual field of both eyes.
However damage only to the Meyer’s loop causes loss of only the superior half of the left visual field of both eyes.
What type of vision defect occurs in Glaucoma?
Peripheral loss of vision.
Because increased intraocular pressure in glaucoma compresses the peripheral fibres of optic nerve.
Cause and features of Medial Medullary Syndrome?
Cause- Thrombosis of Ant. Spinal Artery (supplies whole of medial part of medulla)
Features-
•Contralateral loss of fine touch, vibration and proprioceptive sensation in limbs and trunk.(medial lemniscus damage)
• Contralateral hemiplegia (pyramids damaged)
• Paralysis of ipsilateral tongue muscles and tongue deviates to side of lesion on protrusion (damage to XIIth nerve)
