Download Slide ()

The extraocular muscles and their innervation. The medial rectus muscle has been sectioned and retracted in this drawing of the right eye to show the
position of the extraocular muscles. The course of cranial nerves (CNs) III (oculomotor, superior and inferior divisions), IV (trochlear), and VI (abducens)
are shown as they enter the orbit through the superior orbital fissure to innervate the extraocular muscles. Note that CN IV enters the orbit outside of the
annulus of Zinn. The action of each of the extraocular muscles is a logical consequence of its insertion on the globe and direction of action. The medial and
lateral rectus muscles insert anterior to the equator of the globe and pull directly posteriorly, rotating the globe in the horizontal plane. Similarly, the
superior and inferior rectus muscles move the eye in the vertical plane. However, the superior and inferior rectus muscles insert at a slight angle relative to
Source: Ocular Motility Disorders: Extraocular Muscles and the Neuromuscular Junction, Practical Neuroophthalmology
the visual axis, so they also cause some torsion and adduction of the globe (inset). The oblique muscles insert posterior to the equator and pull
Citation:
JJ.oblique
Practicaldepresses
Neuroophthalmology;
2013oblique
Available
at: http://mhmedical.com/
Accessed:
April
anteromedially
(inset).Martin
Thus,TJ,
theCorbett
superior
and the inferior
elevates.
The torsional forces
generated
by30,
the2017
oblique muscles
Copyright
©
2017
McGraw-Hill
Education.
All
rights
reserved
should be evident from this diagram.