Unit III - Sphenoid bone

Question 1

What are the 4 parts of the sphenoid bone?

Answer 1

body

greater wings

lesser wings

pterygoid process

Question 2

What are the 5 parts of the body of the sphenoid bone?

Answer 2

sulcus chiasmatis

optic canal

sella turcica

carotid groove

sphenoid sinus

Question 3

What travels through the optic canal?

Answer 3

optic nerve and opthalmic artery

Question 4

what are the two parts of the sella turcica?

Answer 4

hypophyseal fossa (houses pituitary)

posterior clinoid processes

Question 5

What does the carotid groove house?

Answer 5

internal carotid a. and carotid n.

Question 6

What are the 8 parts of the greater wings of the sphenoid bone?

Answer 6

cerebral surfaces

foramen rotundum

foramen ovale

spine

foramen spinosum

lateral surface

orbital surface

foramen lacerum

Question 7

What is transmitted through the foramen rotundum?

Answer 7

maxillary n.

Question 8

What is transmitted through the foramen ovale?

Answer 8

mandibular n., accessory meningeal a.

Question 9

what attaches to the spine of the greater wings of the sphenoid bone?

Answer 9

tensor palatini muscle
attachment: scaphoid fossa, cartilage of auditory tube, and spine of sphenoid –> palatine aponeurosis (after deflecting around the hamulus)
function: unilateral deviation and bilateral tension of soft palate
innervation: mandibular n.
blood supply: ascending palatine, greater palatine, lesser palatine a.

sphenomandibular ligament

Question 10

What is transmitted through the foramen spinosum?

Answer 10

middle meningeal a., meningeal (recurrent) branch of mandibular n.

Question 11

what attaches to the lateral surface of the greater wings of the sphenoid bone?

Answer 11

(1) temporalis muscle
attachment: temporal fossa –> coronoid process and temporal crest of ramus of mandible
function: elevation and retraction (posterior aspect only) of mandible
innervation: mandibular n.
blood supply: deep temporal a.

(2) lateral pterygoid muscle
attachment: infratemportal surface of sphenoid and lateral surface of lateral pterygoid plate –> pterygoid fovea of mandible and TMJ disc
function: protraction of mandible and acts with ipsilateral medial pterygoid to rotate the mandible to produce side-to-side movements during trituration of food
innervation: mandibular n.
blood supply: pterygoid and ascending palatine a.

Question 12

What is transmitted through the superior orbital fissure of the orbital surface of the greater wings of the sphenoid bone

Answer 12

opthalmic n., oculomotor n., trochlear n., abducens n., opthalmic v.

Question 13

What muscle attaches to the lesser wings of the sphenoid bone, and what structure attaches to the anterior clinoid processes of the lesser wings of the sphenoid bone?

Answer 13

(1) levator palpebrae superioris
attachment: inferior aspect of lesser wing of sphenoid –> tarsus and skin of upper lid
function: elevation of upper lid
innervation: superior ramus of oculomotor n.
blood supply: opthalmic & supraorbital n.

(2) tentorium cerebelli

Question 14

what are the five parts of the pterygoid process of the sphenoid bone?

Answer 14

pterygoid fossa

scaphoid fossa

pterygoid canal

lateral pterygoid plate

medial pterygoid plate

Question 15

what attaches to the pterygoid fossa of the sphenoid bone?

Answer 15

medial pterygoid muscle
attachment: medial surface of lateral pterygoid plate and adjacent pterygoid fossa –> medial aspect of angle of mandible
function: elevation of mandible and acts with ipsilateral lateral pterygoid to rotate the mandible to produce side-to-side movements during trituration of food
innervation: mandibular n.
blood supply: pterygoid a.

Question 16

What attaches to the scaphoid fossa of the sphenoid bone?

Answer 16

tensor palatini muscle
attachment: scaphoid fossa, cartilage of auditory tube, and spine of sphenoid –> palatine aponeurosis (after deflecting around the hamulus)
function: unilateral deviation and bilateral tension of soft palate
innervation: mandibular n.
blood supply: ascending palatine, greater palatine, lesser palatine a.

Question 17

what is transmitted through the pterygoid canal?

Answer 17

nerve of the pterygoid canal

Question 18

what attaches to the lateral pterygoid plate?

Answer 18

(1) lateral pterygoid muscle
attachment: infratemportal surface of sphenoid and lateral surface of lateral pterygoid plate –> pterygoid fovea of mandible and TMJ disc
function: protraction of mandible and acts with ipsilateral medial pterygoid to rotate the mandible to produce side-to-side movements during trituration of food
innervation: mandibular n.
blood supply: pterygoid and ascending palatine a.

(2) medial pterygoid muscle
attachment: medial surface of lateral pterygoid plate and adjacent pterygoid fossa –> medial aspect of angle of mandible
function: elevation of mandible and acts with ipsilateral lateral pterygoid to rotate the mandible to produce side-to-side movements during trituration of food
innervation: mandibular n.
blood supply: pterygoid a.

Question 19

what is the function and what attaches to the pterygoid hamulus of the medial pterygoid plate?

Answer 19

function: deflects tendon of tensor palatini muscle

(1) buccinator muscles
attachment: alveolar processes of maxilla and mandible, pterygoid hamulus, and pterygomandibular raphe –> buccal angle
function: compresses cheek
innervation: facial n. (buccal branch)
blood supply: facial and buccal a.

(2) superior constrictor muscle
attachment: pterygoid hamulus and pterygomandibular raphe –> median pharyngeal raphe
function: general sphincteric and peristaltic action in swallowing
innervation: pharyngeal plexus (X)
blood supply: ascending pharyngeal and tonsilar a.

(3) pterygomandibular raphe
attachment: pterygoid hamulus –> posterior mylohyoid line