REVIEW OF HEAD AND NECK CRANIAL NERVES AND EVERYTHING ELSE

Transcription

1 REVIEW OF HEAD AND NECK CRANIAL NERVES AND EVERYTHING ELSE

2 OLFACTORY NERVE CN I ANTERIOR CRANIAL FOSSA CRISTA GALLI OF ETHMOID OLFACTORY FORAMINA IN CRIBIFORM PLATE OF ETHMOID BONE CN I OLFACTORY NERVE

3 ETHMOID BONE (posterior view)

4 I - OLFACTORY NERVE OLFACTORY BULB OLFACTORY NERVE BRANCHES (fila olfactoria) DAMAGE - loss of sense of smell

5 renumbered 283

6 CT CORONAL PLANE OF HEAD ANTERIOR CRANIAL FOSSA CRISTA GALLI OF ETHMOID ORBIT ETHMOID SINUS MAXILLARY SINUS INFERIOR CONCHA (TURBINATE) NASAL CAVITY NASAL SEPTUM

7 CLINICAL QUESTION: BLOW TO NOSE PRODUCES LEAKAGE OF FLUID FROM NOSE; FRACTURE CRIBRIFORM PLATE OF ETHMOID ANT. CRANIAL FOSSA Crista galli of ethmoid bone Nasal Bones Nasal Septum 1)Septal Cartilage 2)Ethmoid (Perpendicular Plate) 3)Vomer NOSE ETHMOID Fracture of nose can break cribriform plate, floor of Ant. Cranial fossa - leak CSF from nose; spread of infection

8 Nerves 1.Olfactory N. - SVA smell; Olfactory Area NERVES of NASAL CAVITY 2.General Sensation GSA - touch, pain, etc. - V1 Anterior Ethmoidal N. [- V2 Nasal Branches - V2 Nasopalatine N.] ANT. ETHMOIDAL N. OLFACTORY N. NASAL BR. PTERYGO- PALATINE GANGLION 3. Mucous Glands of nose - Parasympathetics - VII - Facial N. by Pterygopalatine Ganglion (hitchhike with branches of V2) NASOPALATINE N.

9 OPTIC FORAMEN CN II OPTIC NERVE, OPHTHALMIC ARTERY MIDDLE CRANIAL FOSSA

10

11 OPHTHALMIC ARTERY

12 II - OPTIC NERVE OPHTHALMIC ARTERY ENTERS ORBIT WITH OPTIC NERVE Optic Nerve NASAL CAVITY FORE- HEAD Optic Nerve CENTRAL ARTERY OF RETINA OPHTHALMIC ARTERY - from Int. Carotid

13 CLINICAL QUESTION: SUDDEN ONSET BLINDNESS IN ONE EYE OPHTHALMOSCOPE VIEW BRANCHES OF CENTRAL ARTERY AND VEINS RETINA CENTRAL ARTERY OF RETINA - BRANCH OF OPTHALMIC ART. NO ANASTOMOSES; OCCLUSION RESULTS IN BLINDNESS

14 OPTIC NERVE FUNCTION COMPROMISED BY INCREASED CSF PRESSURE PAPILLEDEMA - engorgement of retinal veins (correspond to branches of central artery) CSF IN SUBARACH SPACE DURA & SUBARACHNOID SPACE (CSF) EXTEND AROUND OPTIC NERVE; INCREASE IN CSF CAN EFFECT VISION Clinical - slow onset; headaches

15 SUPERIOR ORBITAL FISSURE CN III, IV V1, VI, OPHTHALMIC VEINS MIDDLE CRANIAL FOSSA

16 EYE MOVEMENTS DIAGRAM ELEV ABD ADD DEP RESTING POSITION OF EYE: DETEMINED BY BALANCE OF ACTION OF OPPOSING MUSCLES

17 III 278 III V IV IV? VII, VIII IX X XI VI XII VI C1

18 III 1073 III IV V VII, VIII IX X XI VI XII V IV? C1

19 ABDUCENS NERVE DAMAGE PATIENT WITH ABDUCENS (VI) NERVE DAMAGE X SYMPTOM: DIPLOPIA ABDUCENS (VI): AT REST MEDIAL STRABISMUS (CROSS-EYED) DUE TO DAMAGE/PARALYZE LATERAL RECTUS

20 TROCHLEAR (IV) NERVE DAMAGE: INABILITY TO TURN EYE DOWN AND OUT; ALSO HEAD TILT NORMAL HEAD EYE EYE PATIENT CANNOT LOOK DOWN AND OUT Symptoms - Difficulty walking down stairs; HEAD TILTED Rotation - occurs when tilt head; rotate ipsilateral eye medially when tilt head laterally X HEAD AFTER IV DAMAGE - eye rotated laterally; PATIENT TILTS HEAD TO OPPOSITE SIDE so both eyes rotated (chin toward side of lesion)

21 OCULOMOTOR (III) NERVE DAMAGE AT REST - LATERAL STRABISMUS (WALL- EYED) DUE TO PARALYZE MEDIAL RECTUS ALSO - PTOSIS - DROOPING EYELID- PARALYZE LEV. PALPEBRAE SUPERIORIS - DILATED PUPIL - PARALYZE PUPILLARY CONSTRICTOR

22 ANATOMY: LEVATOR PALPEBRAE SUPERIORIS LEVATOR PALPEBRAE skeletal muscle III smooth muscle sympathetics TARSAL PLATE LEVATOR PALPEBRAE SUPERIORIS MUSCLE - ORIGIN FROM TENDINOUS RING - COMPOSED OF SKELETAL (CN III) & SMOOTH (SYMPATHETICS) MUSCLE PARTS DAMAGE INNERVATION PTOSIS = DROOPING EYELID

23 PTOSIS = DROOPING EYELID; CAN BE SIGN OF DAMAGE TO OCULOMOTOR NERVE (III) OR SYMPATHETICS SKELETAL MUSCLE PART SMOOTH MUSCLE PART OCULOMOTOR NERVE PALSY other symptoms: - Pupil is dilated - denervate pupillary constrictor (mydriasis) - Also affect Eye movements - Accomodation SYMPATHETICS - HORNER'S SYNDROME - - Miosis - constricted pupil - Anhydrosis - lack of sweating (Sympathetic pathway: out spinal cord T1 and T2; ascend sympathetic chain; synapse Superior Cervical ganglion; distribute with arteries(ophthalmic A.))

24 EYE- STRUCTURE OF EYEBALL- VASCULAR LAYER PUPIL IRIS - PIGMENTED, CONTRACTILE LAYER SURROUNDING PUPIL DILATOR PUPIL- RADIAL SMOOTH MUSCLE; SYMPATHETICS CONSTRICTOR PUPIL- CIRCULAR SMOOTH MUSCLE; PARASYMPATHETICS III

25 PARASYMPATHETIC MECHANISM OF ACCOMODATION CILIARY BODY- ATTACHES SUSPENSORY LIGAMENTS OF LENS CONTAINS CILIARY MUSCLES SUSPENSORY LIGAMENTS OF LENS CILIARY MUSCLES CILIARY MUSCLES- ACCOMODATION- THICKEN LENS FOR NEAR VISION; PARASYMPATHETIC CONTROL- III (CILIARY GANGLION) SMOOTH MUSCLES CONTRACT PRODUCE - RELAXATION OF LIGAMENTS - THICKENING LENS