Anatomy: The Extraocular Muscles Flashcards
Name the muscle shown in blue
Inferior rectus
Name the origin of the recti muscles
All originate from common tendinous ring
Name the muscles which synergistically depress eyes by working antagonistically as adductors/abductors
Superior oblique and inferior rectus
Name the cranial nerve which supplies all of the extra-ocular muscles with the exception of the lateral rectus and the superior oblique?
CN III (oculomotor nerve)
The medial rectus can only _____ the eyeball
Adduct
When in adduction, the superior oblique can only ______
Depress
What is indicated by the arrow?
Superior tarsus muscle
Which nerve supplies the levator palpebrae superioris?
CN III
The lateral rectus can only _____ the eyeball
Abduct
What is indicated by the arrow?
Orbicularis oculi
How would you test the function of the superior rectus muscle?
Ask patient to look laterally and upward
Name the muscles which synergistically elevate the eyes by working antagonistically as rotators
Superior rectus and inferior oblique
Name the origin of levator palpebrae superioris
Lesser wing of sphenoid
How would you test the function of the inferior rectus muscle?
Ask patient to look laterally and downward
How would you test the function of the lateral rectus muscle?
Ask patient to look laterally
Describe the innervation of the superior tarsal muscle (Mueller’s muscle)
Sympathetic fibres from the superior cervical ganglion
When in abduction, the superior rectus can only ______
Elevate
The tendon of the _______ oblique passes through a trochlea (loop of connective tissue) before inserting onto the eyeball
Superior
Which cranial nerve supplies the superior oblique?
CN IV (trochlear nerve)
Name the only muscle involved in raising the superior eyelid
Levator palpebrae superioris
Name the insertion of the oblique muscles
Both insert onto sclera
When in adduction, the inferior oblique can only ______
Elevate
Name the insertion of the recti muscles
All insert onto sclera
Name the muscle shown in purple
Superior rectus
Name the insertion of levator palpebrae superioris
Skin and tarsus of superior eyelid
Describe the clinical anatomy of Mueller’s muscle relevant to Horner’s syndrome
The Mueller’s muscle assists the levator in elevating the top eyelid
It receives sympathetic innervation which may be compromised in Horner’s syndrome causing ptosis
Name the origin of the superior oblique
Originates from sphenoid bone
Name the muscle shown in orange
Inferior oblique
When in abduction, the inferior rectus can only ______
Depress
How would you test the function of the inferior oblique muscle?
Ask patient to look medially and upward
Name the muscle shown in red
Levator palpebrae superioris
How would you test the function of the medial rectus muscle?
Ask patient to look medially
Name the muscle shown in pink
Medial rectus
What is indicated by the arrow?
Tendon of levator palpebrae superioris (LPS) muscle
Which cranial nerve supplies the lateral rectus?
CN VI (abducent nerve)
Name the muscle shown in green
Lateral rectus
Name the muscle shown in yellow
Superior oblique
How would you test the function of the superior oblique muscle?
Ask patient to look medially and downward
Name the action of the superior tarsal muscle (Mueller’s muscle)
Assists the levator palpebrae superioris in opening the eyelid
What is indicated by the arrow?
Tarsal gland
Name the origin of the inferior oblique
Orbital plate of maxilla
