Ch. 56 Surgery of the Globe and Orbit

Question 1

a. Akinesia of the eyelids can be achieved by blocking the auriculopalpebral nerve, which innervates the orbicularis oculi muscle

b. The auriculopalpebral nerve, the palpebral branch of the frontal nerve, can be blocked at three locations

c. Analgesia of the central two thirds of the upper eyelid can be achieved by blocking the supraorbital nerve, a branch of the facial nerve

d. The auriculopalpebral nerve should be blocked as it emerges from the supraorbital foramen

Answer 1

a. Akinesia of the eyelids can be achieved by blocking the auriculopalpebral nerve, which innervates the orbicularis oculi muscle.

The auriculopalpebral nerve, the palpebral branch of the FACIAL nerve, can be blocked at three locations

Analgesia of the central two thirds of the upper eyelid can be achieved by blocking the supraorbital nerve, a branch of the FRONTAL nerve of the ophthalmic branch of the trigeminal nerve (CN V).

The SUPRAORBITAL nerve should be blocked as it emerges from the supraorbital foramen

Question 2

a. The periosteum that lines the orbital bones, optic foramen, and orbital foramen contributes to the periorbita and is continuous with the dural sheath of the optic nerve

b. The majority of the orbital blood supply is provided by the external ophthalmic artery, a branch of the facial artery.

c. lacrimal sac is positioned within the lacrimal fossa, an indentation in the zygomatic bone

d. The optic nerve and internal optic artery run through the ethmoidal foramen

Answer 2

a. The periosteum that lines the orbital bones, optic foramen, and orbital foramen contributes to the periorbita and is continuous with the dural sheath of the optic nerve

The majority of the orbital blood supply is provided by the external ophthalmic artery, a branch of the maxillary artery.

lacrimal sac is positioned within the lacrimal fossa, an indentation in the lacrimal bone

The optic nerve and internal optic artery run through the optic foramen
Ethmoidal nerve artery vein and nerve run through the ethmoidal foramen

Question 3

a. The orbital apex contains 4 major foramen; the orbital foramen, the ethmoidal foramen, sphenopalatine foramen and the rostral alar foramen

b. The orbital fascia allows precise and co-ordinated globe movements

c. The maxillary artery passes through the sphenopalatine foramen on its route to the nasal cavity

d. The majority of the orbital blood supply is provided by the internal ophthalmic artery, a branch of the maxillary artery.

Answer 3

b. The orbital fascia allows precise and co-ordinated globe movements

Orbital Apex contains four major foramina:
(1) Ethmoidal foramen = Most dorsal - ethmoidal artery, vein, and nerve

(2) Optic foramen = Ventral and slightly caudal - optic nerve and internal ophthalmic artery
The optic nerve (cranial nerve [CN] II) then travels within the extraocular muscle cone to insert on the globe.

(3) Orbital fissure = Ventral to optic foramen - oculomotor (CN III), trochlear (CN IV), ophthalmic branch of the trigeminal (CN V), and abducens (CN VI)

(4) Rostral alar foramen = Caudoventral to the orbital fissure - maxillary artery and nerve

c. The maxillary artery passes through the maxillary foramen on its route to the nasal cavity

d.The majority of the orbital blood supply is provided by the external ophthalmic artery, a branch of the maxillary artery.

Question 4

a. The eye has 5 extraocular muscles

b. The superior oblique rotates the dorsal aspect of the globe ventrad and lateral

c. The inferior oblique muscle rotates the globe superiorly and mediad

d. The maxillary, sphenopalatine and caudal palatine foramen are the 4 major foramen of the orbital apex

Answer 4

a. The eye has 7 extraocular muscles

b. The superior oblique rotates the dorsal aspect of the globe ventrad and mediad

c. The inferior oblique muscle rotates the globe superiorly and mediad

Orbital apex = 4 major foramen = ethmoidal, optic, orbital fissure, rostral alar foramen
Pterygopalatine Fossa = three major foramina:
1. Maxillary foramen - maxillary vessels and nerve -> infraorbital canal
2. Sphenopalatine foramen - sphenopalatine vessels and caudal nasal nerve -> the nasal cavity
3. Caudal Palatine Foramen - major palatine artery and nerve pass -> major palatine canal

Question 5

a. The caudal nasal nerve runs through the caudal palatine foramen

b. The caudal nasal nerve runs through the maxillary foramen

c. The majority of the orbital blood supply is provided by the internal ophthalmic artery, a branch of the maxillary artery

d. The maxillary artery passes through the rostral alar foramen

Answer 5

d. The maxillary artery passes through the rostral alar foramen

The caudal nasal nerve runs through the sphenopalatine foramen

Pterygopalatine Fossa
three foramina:
Maxillary foramen - maxillary vessels and nerve -> infraorbital canal
Sphenopalatine foramen - sphenopalatine vessels and caudal nasal nerve -> the nasal cavity
Caudal Palatine Foramen - major palatine artery and nerve pass -> major palatine canal

The majority of the orbital blood supply is provided by the external ophthalmic artery, a branch of the maxillary artery.