Which anatomical structure is indicated by the blue arrow in the image below?
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Options:
explanation: The image shows a coronal view of a brain and the prosection is cut towards the posterior aspect, as the brainstem and the cerebellum are visible in the centre of the image. The spinal cord is the extension of the central nervous system from the brainstem into the vertebral canal. In the prosection, the slice has been cut in front of the level of the spinal cord, so it is not visible, but the bones of the vertebral column at the cervical level are visible. Thus, the blue arrow indicates the odontoid peg of the C2 cervical vertebra (axis) which is a bony process extending superiorly from the anterior aspect of the vertebra.
name: Spinal cord
label: d
answer: no
explanation: The image shows a coronal view of a brain and the prosection is cut towards the posterior aspect, as the brainstem and the cerebellum are visible in the centre of the image. The epiglottis is a leaf-shaped elastic cartilage found at the superior border of the larynx and attached to the anterior aspect of the thyroid cartilage. It flattens and is displaced posteriorly during swallowing to prevent aspiration of food contents into the larynx and the airway. It is not visible in the image, as this prosection is cut more posteriorly compared to the anatomical position of the epiglottis. However, the blue arrow indicates the odontoid peg of the C2 cervical vertebra (axis) which is a bony process extending superiorly from the anterior aspect of the vertebra.
name: Epiglottis
label: b
answer: no
explanation: The image shows a coronal view of a brain and the prosection is cut towards the posterior aspect, as the brainstem and the cerebellum are visible in the centre of the image. The atlas is the C1 cervical vertebra which articulates with the occipital bone of the skull. It has a unique structure, having no vertebral body and no spinous process. However, the blue arrow indicates the odontoid peg of the C2 cervical vertebra (axis) which is a bony process extending superiorly from the anterior aspect of the vertebra.
name: Altas
label: c
answer: no
explanation: The image shows a coronal view of a brain and the prosection is cut towards the posterior aspect, as the brainstem and the cerebellum are visible in the centre of the image. The medulla oblongata is the most inferior structure of the brainstem, located at the junction with the spinal cord. It is visible in the image superior to the structure indicated by the blue arrow which is the odontoid peg of the C2 cervical vertebra (axis) which is a bony process extending superiorly from the anterior aspect of the vertebra.
name: Medulla oblongata
label: e
answer: no
explanation: The image shows a coronal view of a brain and the prosection is cut towards the posterior aspect, as the brainstem and the cerebellum are visible in the centre of the image. The blue arrow indicates the odontoid peg of the C2 cervical vertebra (axis) which is a bony process extending superiorly from the anterior aspect of the vertebra. It articulates with the arch of the atlas (C1 cervical vertebra), forming the atlanto-axial joint allowing head rotation.
name: Odontoid peg
label: a
answer: yes

Correct answer: a