Читать книгу Anatomy for the Royal College of Radiologists Fellowship - Malcolm Sperrin - Страница 17

1 Name the arrowed structure.

2 Name the arrowed structure.

3 Name the arrowed structure.

4 Name the arrowed structure.

5 Name the arrowed structure.

Answers

1 Third ventricle.

2 Left lateral sulcus (or lateral fissure/Sylvian fissure).

3 Right hippocampus.

4 Right superior temporal gyrus.

5 Septum pellucidum.

Comments:

The hippocampus is a grey matter structure most readily identifiable on coronal images. It lies on the medial side of the temporal lobe, immediately inferior to the temporal horn of the lateral ventricle. The amygdala is anterior to the hippocampus, and curls round to lie anterior and superior to the temporal horn of the lateral ventricle.

The fornix is a C-shaped white matter tract that arises posteriorly from the hippocampus. One crux of the fornix arises from each hippocampus, and curls superiorly and anteriorly until it joins with the contralateral crux. These form the body of the fornix which lies immediately below the septum pellucidum. As it continues anteriorly, the fornix splits again into two columns. Each column travels in an inferoposterior arc behind the anterior commissure and then lateral to the third ventricle. It then meets the ipsilateral mamillary body. The mamillary bodies lie at the base of the brain below the third ventricle and are seen anterior to the midbrain on MRI.

Exam tip:

 The distinction between the hippocampus and the amygdala is difficult on a single coronal image. However, the amygdala is located more anteriorly, and we would not expect to see it together with the brainstem on the same coronal image.