Identify the muscle indicated by the blue arrow in the following image:
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Options:
explanation: The image shows the posterior view of a model of the right orbit with the roof and lateral wall removed and the eyeball and associated muscles in view. The medial aspect of the orbit is towards the left of the image because the optic chiasm is towards the left and it is normally found in the midline. The medial rectus muscle is a muscle attached to the medial aspect of the eyeball. It is innervated by the oculomotor nerve (CN III) and contributes to eyeball adduction. It is not immediately visible in the image, as this shows a posterolateral view of the eyeball in the orbit. However, the blue arrow indicates the superior rectus muscle, which runs from the top of the eyeball and is innervated by the oculomotor nerve (CN III).
name: Medial rectus muscle
label: e
answer: no
explanation: The image shows the posterior view of a model of the right orbit with the roof and lateral wall removed and the eyeball and associated muscles in view. The medial aspect of the orbit is towards the left of the image because the optic chiasm is towards the left and it is normally found in the midline. The levator palpebrae superioris is a muscle which lies superior to the muscle indicated by the arrow. It is innervated by the oculomotor nerve (CN III) and contributes to eyelid elevation. However, the blue arrow indicates the superior rectus muscle, which runs from the top of the eyeball and is innervated by the oculomotor nerve (CN III).
name: Levator palpebrae superioris muscle
label: c
answer: no
explanation: The image shows the posterior view of a model of the right orbit with the roof and lateral wall removed and the eyeball and associated muscles in view. The medial aspect of the orbit is towards the left of the image because the optic chiasm is towards the left and it is normally found in the midline. The inferior rectus muscle runs from the inferior aspect of the eyeball and it is not directly visible in the image. It is innervated by the oculomotor nerve (CN III). However, the blue arrow indicates the superior rectus muscle, which runs from the top of the eyeball and is innervated by the oculomotor nerve (CN III).
name: Inferior rectus muscle
label: b
answer: no
explanation: The image shows the posterior view of a model of the right orbit with the roof and lateral wall removed and the eyeball and associated muscles in view. The medial aspect of the orbit is towards the left of the image because the optic chiasm is towards the left and it is normally found in the midline. The lateral rectus muscle is a muscle attached to the lateral aspect of the eyeball. It is innervated by the abducens nerve (CN VI) and contributes to eyeball abduction. It is visible in the image inferolateral to the muscle indicated by the arrow. However, the blue arrow indicates the superior rectus muscle, which runs from the top of the eyeball and is innervated by the oculomotor nerve (CN III).
name: Lateral rectus muscle
label: d
answer: no
explanation: The image shows the posterior view of a model of the right orbit with the roof and lateral wall removed and the eyeball and associated muscles in view. The medial aspect of the orbit is towards the left of the image because the optic chiasm is towards the left and it is normally found in the midline. The blue arrow indicates the superior rectus muscle, which runs from the top of the eyeball and is innervated by the oculomotor nerve (CN III).
name: Superior rectus muscle
label: a
answer: yes

Correct answer: a