Rostral, caudal, dorsal, ventral: the direction words, shown on the brain
Rostral means toward the beak (the face), caudal toward the tail; dorsal toward the back, ventral toward the belly. Because we stand upright, the brain’s axis bends about 90° where the midbrain meets the diencephalon: above the bend rostral means anterior and dorsal means superior; below it, in the brainstem, rostral means superior and dorsal means posterior. [1]
The 3D brain needs JavaScript. The table below still lists both ends of every pair, on each axis.
Pair
Axis
Where the words turn: Because humans stand upright, the nervous system is considered to bend about 90° at the junction of the midbrain and the diencephalon, and the terminology changes on either side of that junction. [1]
Rostral, blue: Prefrontal cortex. Caudal, orange: Occipital lobe. Above the bend rostral is the same as anterior and caudal the same as posterior: the frontal pole is rostral, the occipital lobe caudal. [1]
Rostral, blue: Midbrain. Caudal, orange: Medulla oblongata, Spinal cord (central canal). Below the bend rostral is the same as superior and caudal the same as inferior: the midbrain is rostral to the medulla, which is rostral to the spinal cord. [1]
Dorsal, blue: Superior colliculus, Inferior colliculus, Fourth ventricle. Ventral, orange: Cerebral peduncles, Pons. Below the bend dorsal is the same as posterior and ventral the same as anterior: the colliculi and the fourth ventricle lie on the back of the brainstem, the cerebral peduncles and the bulge of the pons on its front. [1]
Anterior, blue: Prefrontal cortex. Posterior, orange: Occipital lobe, Cerebellum. These words follow the body, not the bent axis, so they never turn: the occipital lobe and the cerebellum are posterior to the frontal lobe. [1][3]
Anterior, blue: Prefrontal cortex. Posterior, orange: Occipital lobe, Cerebellum. These words follow the body, not the bent axis, so they never turn: the occipital lobe and the cerebellum are posterior to the frontal lobe. [1][3]
The first word’s end is lit in blue, the second word’s in orange. Rostral/caudal and dorsal/ventral change with the axis; the other three pairs follow the body and stay the same. Drag to turn, pinch or scroll to zoom; turn to the front to see medial and lateral best.
Rostral and caudal: Rostral comes from the Latin rostrum, beak, and caudal from cauda, tail. In animals with a straight nervous system they mean toward the snout and toward the tail. [1]
Dorsal and ventral: Dorsal comes from the Latin dorsum, back, and ventral from venter, belly. In a fish the dorsal fin is on top and the ventral fins underneath. [1][2]
Medial and lateral: Medial describes what lies close to the median plane, or closer to it than another structure; lateral describes what lies toward the sides. Temporal has a similar meaning to lateral but is used only for the head. [2][3]
Anterior and posterior: Anterior describes the front or the direction toward the front of the body, posterior the back. OpenStax’s whole-body list gives ventral as another word for anterior and dorsal for posterior, the usage that holds in the brainstem and spinal cord. [3][2]
Superior and inferior: Superior (or cranial) describes a position above another part of the body, inferior (or caudal) a position below it, toward the tail. The superior and inferior colliculi are named this way. [3][2]
Why the words turn at the midbrain
The rostro-caudal axis of the human central nervous system makes a near 90° bend at the level of the midbrain and continues through the brainstem and spinal cord, a bend that allows forward vision while the body is upright. [1]
Usage is not perfectly uniform: the same article also says that in human anatomy the occipital lobes and the back of the head are posterior but not caudal to the frontal lobes and the face, since caudal means toward the tail, not toward the back of the cranial cavity. This page follows the article’s rule for each side of the bend, so check which one a course uses. [1]
In the whole-body terms superior is also called cranial and inferior caudal, anterior is also called ventral and posterior dorsal. Those synonyms hold for the brainstem and spinal cord, but not for the forebrain, where dorsal points up, not back. [3][1]
Of the skull, the dorsal side is the top, which matches dorsal meaning superior in the forebrain. [2]
Medial and lateral do not bend: they are measured from the median plane, the sagittal plane down the middle, on both sides of the bend. [2][3]
Measured from the model [4]: the line from the centre of the medulla oblongata to the centre of the midbrain is 52 mm long and leans 7° forward of straight up, so on this one brain the brainstem axis meets the forebrain axis (straight forward) at 83°, close to the textbook 90°. Each part’s position is the average of its meshes’ bounding-box centres; every lit set on this page is checked to lie at its end of the axis.