OCULAR MOTOR NERVES

Question 1

III nuclear complex - where

Answer 1

midbrain at the level of the superior colliculus, ventral to the Sylvian aqueduct

Question 2

Levator subnucleus - where and what causes lesion

Answer 2

unpaired caudal midline structure that innervates both levator muscles. Lesions → bilateral ptosis

Question 3

Superior rectus subnuclei - what innervates and what causes lesion

Answer 3

are paired: each innervates the respective contralateral superior rectus. A nuclear third nerve palsy will therefore spare the ipsilateral, and affect the contralateral, superior rectus

Question 4

Medial rectus, inferior rectus and inferior oblique subnuclei- what innervate and what causes lesion

Answer 4

are paired and innervate their corresponding ipsilateral muscles. uncommon. The most frequent causes are vascular disease, primary tumours and metastases

Question 5

Involvement of the paired medial rectus subnuclei - what causes

Answer 5

cause a wall-eyed bilateral internuclear ophthalmoplegia (WEBINO), characterized by exotropia with defective convergence and adduction

Question 6

WEBINO

Answer 6

Involvement of the paired medial rectus subnuclei cause a wall-eyed bilateral internuclear ophthalmoplegia (WEBINO), characterized by exotropia with defective convergence and adduction. Lesions involving the entire nucleus are often associated with involvement of the adjacent and caudal fourth nerve nucleus

Question 7

Benedikt syndrome

Answer 7

involves the fasciculus as it passes through the red nucleus and is characterized by ipsilateral third nerve palsy and contralateral extrapyramidal signs such as hemitremor

Question 8

Weber syndrome

Answer 8

involves the fasciculus as it passes through the cerebral peduncle and is characterized by ipsilateral third nerve palsy and a contralateral hemiparesis

Question 9

Nothnagel syndrome

Answer 9

involves the fasciculus and the superior cerebellar peduncle and is characterized by ipsilateral third nerve palsy and cerebellar ataxia

Question 10

Claude syndrome

Answer 10

combination of Benedikt and Nothnagel syndromes (hemitremor and cerebellar ataxia)

Question 11

III - pathway

Answer 11

Nuclear complex, Fasciculus, Basilar, Intracavernous, Intraorbital

Question 12

Superior division innervates

Answer 12

levator and superior rectus muscles

Question 13

Inferior division innervates

Answer 13

the medial rectus, inferior rectus and inferior oblique muscles. The branch to the inferior oblique also contains preganglionic parasympathetic fibres from the Edinger–Westphal subnucleus, which innervate the sphincter pupillae and the ciliary muscle

Question 14

Lesions of the inferior division - sings

Answer 14

limited adduction and depression, together with a dilated pupil

Question 15

pupillary involvement as the only sign of third nerve palsy - causes

Answer 15

basal meningitis, uncal herniation