Note: This frame is for identification of structures and description of imaging features. For several entries, more complete discussions can be found in the Neuroanatomy Glossary. Entries that are highlighted are linked to the corresponding entry in the glossary. If you follow the link, you can return to this frame by clicking the Back arrow at the top of the screen on the left.
1. Alveus - the alveus is consists of axons from neurons in the hippocampal formation. They lie on the ventricular surface of the hippocampus and become the fimbria of the fornix medially.
2. Amygdala - on CT and MR images, the amygdala is a large region of gray matter contiguous with the uncus of the medial temporal lobe and the most anterior portion of the hippocampus, the pes hippocampi.
4. Anterior nucleus of the thalamus
5. Anterior Perforated Substance - on CT images, this region is immediately posterior to the gyrus rectus. It is in the most anterior part of the basal forebrain. On CT image 4 number region 6, it is labeled as the basal forebrain.
6. Basal Forebrain - on CT and MR images, the basal forebrain is a rather featureless region on the ventral surface of the brain. It contains both regions of gray and white matter in a heterogeneous fashion that are best appreciated on T1 and T2 weighted MR coronal images. See discussion on the basal forebrain in Self Test question 1.
8. Bed Nucleus of the Stria Terminalis - the main point of termination of the stria terminalis. It lies immediately above the anterior commissure and is the inferior lateral wall of the anterior horn of a lateral ventricle.
9. Caudate Nucleus: 9a - Head, 9b - Body, 9c - Tail - an elongated mass of gray matter that is closely related to the lateral ventricle. Around the rostral border of the internal capsule, it is fused with the putamen of the lentiform nucleus while its tail terminates in close relationship to the amygdala.
10. Body of the fornix - the body of the fornix is best appreciated in coronal sections where it is seen "hanging" from the thin superior portion of the septum pellucidum.
11. Cingulate Gyrus, 11a - Isthmus of Cingulate Gyrus - part of the limbic system. It is joined posterior to the splenium to the parahippocampal gyrus by the isthmus.
12. Cingulum - the main fiber tract in the white matter of the cingulate gyrus. It extends through the isthmus into the parahippocampal gyrus.
13. Cistern of the Lamina Terminalis - the part of the subarachnoid space anterior to the lamina terminalis.
16. Dentate Gyrus - a component of the hippocampal formation.
17. Diagonal Band of Broca - a white matter tract that has a posterior horizontal component in innominate substance and a vertical component in the medial frontal lobe within the paraterminal gyrus.
20. Fornix: 20a - Columns, 20b - Body, 20c - Crus
21. Gyrus rectus - the most medial gyrus of the orbital surface of the frontal lobe. It is bounded laterally by the olfactory sulcus. Posteriorly, it is continuous with anterior perforated substance.
23. Hippocampal formation - : the hippocampus, the dentate gyrus, and the subiculum.
24. Hippocampus: 24a - Body, 24b - Pes Hippocampi -The hippocampus is one of the three components of the hippocampal formation. The bulbous pes hippocampi is its most anterior portion. It lies at a right angle to the body, helping to create the uncus.
27. Lamina Terminalis - the anterior wall of the third ventricle.
28. Limen insulae
29. Mammillary Body - a small, round, paired cell group that protrudes into the interpeduncular fossa from the inferior aspect of the hypothalamus.
30. Mammillothalamic tract - white matter tract connecting the anterior nucleus of the thalamus and the mammillary body. It has a vertical orientation above the mammillary nucleus.
31. Nucleus Accumbens - although this is a rather large nucleus, it is continuous with the inferior portion of the head of the caudate nucleus and the anterior inferior portion of the putamen. Thus, on all imaging sequences, it is not seen as a separate structure distinct from these other two structures. It is located adjacent and inferior to the inferior portion of the frontal horn of the left lateral ventricle. See MR coronal images 1 to 5, especially image 3 where on the left side, the nucleus accumbens (#31) is shown joining the inferior portion of the caudate nucleus medially with medial portion of the putamen laterally.
32. Olfactory Tubercle - a structure in ventral forebrain lying immediately below the nucleus accumbens. It consists of gray matter.
33. Optic Chiasm; 33a - Optic Tract
35. Parahippocampal Gyrus and Entorhinal Cortex- The parahippocampal gyrus is a part of the limbic lobe. It is separated from the more laterally placed hippocampus by the hippocampal fissure. The entorhinal cortex in the anterior portion of the lobe is a major source of input to the hippocampal formation.
36. Paraterminal Gyrus - the most medial portion of the frontal lobe below the corpus callosum. It lies immediately anterior to lamina terminalis.
37. Parolfactory Gyrus, Parolfactory area, Posterior and Anterior Parolfactory Sulci - Subdivisions of the subcallosal area.
38. Putamen
39. Rostrum of the Corpus Callosum -
43. Stria Terminalis and Terminal Vein - In the body of the lateral ventricle, the stria terminalis is immediately adjacent to the superior thalamostriate vein (the terminal vein). In the CT and MR images, it is easier to identify the superior thalamostriate vein than the stria terminalis, and the arrow indicating these structures uses the terminal vein to identify their positions. Both of these structure occupy the caudothalamic groove in the floor of the body of the lateral ventricle.
44. Subcallosal Area
45. Subiculum - the part of the hippocampal formation in the parahippocampal gyrus medial to the hippocampus. It forms the medial portion of the hippocampal sulcus (hippocampal fissure).
46. Substantia Innominata - on CT and MR imaging, this region lies on the ventral surface of the frontal lobe in the region where the frontal lobe and temporal lobe become joined as seen on coronal images. It lies in the mid portion of the basal forebrain.
47. Supraoptic recess of the third ventricle - a diverticulum extending forward from the anterior part of the third ventricle above the optic chiasm.
48. Uncinate Fascisculus - a major fiber tract connecting the anterior temporal lobe to the orbital cortex of the frontal lobe. On coronal images, it is a white matter tract immediately above the amygdala that is seen in the first coronal section, going from anterior to posterior, where the temporal lobe become joined to the rest of the brain.
49. Uncus - lies immediately lateral to the suprasellar cistern. It contains gray matter: the amygdala anteriorly and the pes hippocampi posteriorly, separated by the anterior portion of the temporal horn of the lateral ventricle. This portion of the temporal horn forms a right angle with the main portion of the temporal horn which lies posteriorly.
50. Ventral Tegmental Area - One of the two major primary dopamine cell groups in the brain. It is located dorsal to the interpeduncular fossa.
51. Ventricles: 51a - Lateral, 51b - Third, 51c Infundibular Recess of Third Ventricle
52. Transverse Cerebral Fissure - A CSF space between the temporal lobe and the diencephalon. It is readily visible on all imaging modalities