The cerebral peduncles (In Latin, ''ped-'' means 'foot'.) are the two stalks that attach the

cerebrum The cerebrum (: cerebra), telencephalon or endbrain is the largest part of the brain, containing the cerebral cortex (of the two cerebral hemispheres) as well as several subcortical structures, including the hippocampus, basal ganglia, and olfac ...

to the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...

. They are structures at the front of the

midbrain The midbrain or mesencephalon is the uppermost portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum. It is functionally associated with vision, hearing, mo ...

which arise from the ventral pons and contain the large ascending (sensory) and descending (motor)

tracts Tract may refer to: Geography and real estate * Housing tract, an area of land that is subdivided into smaller individual lots * Land lot or tract, a section of land * Census tract, a geographic region defined for the purpose of taking a census ...

that run to and from the

from the pons. Mainly, the three common areas that give rise to the cerebral peduncles are the

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. It is the largest site of Neuron, neural integration in the central nervous system, and plays ...

, the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

and the

cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...

. The region includes the

tegmentum The tegmentum (from Latin for "covering") is a general area within the brainstem. The tegmentum is the ventral part of the midbrain and the tectum is the dorsal part of the midbrain. It is located between the ventricular system and distinctive b ...

, crus cerebri and

pretectum In neuroanatomy, the pretectal area, or pretectum, is a midbrain structure composed of seven nuclei and comprises part of the subcortical visual system. Through reciprocal bilateral projections from the retina, it is involved primarily in mediati ...

. By this definition, the cerebral peduncles are also known as the basis pedunculi, while the large ventral bundle of efferent fibers is referred to as the cerebral crus (''crus'' means ‘leg’ in Latin.) or the pes pedunculi (''pes'' means 'foot' in Latin.). The cerebral peduncles are located on either side of the midbrain and are the frontmost part of the midbrain, and act as the connectors between the rest of the

and the

thalamic nuclei This traditional list does not accord strictly with human thalamic anatomy. Nuclear groups of the thalamus include: * anterior nuclear group (anteroventral, anterodorsal, anteromedial) *medial nuclear group (medial dorsal nucleus, dorsomedial) * ...

and thus the

. As a whole, the cerebral peduncles assist in refining motor movements, learning new motor skills, and converting

proprioceptive Proprioception ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of propri ...

information into balance and posture maintenance. Important fiber tracts that run through the cerebral peduncles are the corticospinal, corticopontine, and

corticobulbar tract The corticobulbar (or corticonuclear) tract is a two-neuron white matter motor pathway connecting the motor cortex in the cerebral cortex to the Medullary pyramids (brainstem), medullary pyramids, which are part of the brainstem's medulla oblonga ...

s. Damage to the cerebral peduncles results in unrefined motor skills, imbalance, and lack of

proprioception Proprioception ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of propri ...

Structure

The descending upper fibers from the

internal capsule The internal capsule is a paired white matter structure, as a two-way nerve tract, tract, carrying afferent nerve fiber, ascending and efferent nerve fiber, descending axon, fibers, to and from the cerebral cortex. The internal capsule is situate ...

continue on through the midbrain and are then seen as the fibers in the cerebral peduncles. The corticopontine fibers are found in the outer and inner third of the cerebral peduncle, these are the cortical input to the pontine nuclei. The corticobulbar and corticospinal fibers are found in the middle third of the cerebral peduncle. The corticospinal tract exits the internal capsule and is seen in the mid portion of the cerebral peduncles.

Cranial nerves

Cranial nerve III (

oculomotor nerve The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements o ...

) appears ventrally between the two cerebral peduncles in the

interpeduncular fossa The interpeduncular fossa is a deep depression of the ventral surface of the midbrain between the two cerebral crus, cerebal crura. It has been found in humans and macaques, but not in rats or mice, showing that this is a relatively new evolutiona ...

. Cranial nerve IV (

trochlear nerve The trochlear nerve (), ( lit. ''pulley-like'' nerve) also known as the fourth cranial nerve, cranial nerve IV, or CN IV, is a cranial nerve that innervates a single muscle - the superior oblique muscle of the eye (which operates through the pu ...

) wraps around the lowest part of the cerebral peduncle.

Additional images

File:Gray677.png, Scheme showing the connections of several parts of the brain File:Gray684.png, Deep dissection of brain-stem (lateral view) File:Gray705.png, Dissection showing the projection fibers of the cerebellum File:Gray720.png, Median sagittal section of brain File:Gray773.png, The left optic nerve and the optic tracts File:Gray792.png, Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ File:Human brainstem anterior view 2 description.JPG, Human brainstem anterior view

References

External links

Diagram

NIF Search - Cerebral Peduncle
via the

Neuroscience Information Framework The Neuroscience Information Framework is a repository of global neuroscience web resources, including experimental, clinical, and translational neuroscience databases, knowledge bases, atlases, and genetic/ genomic resources and provides many aut ...

{{Authority control Cerebrum Central nervous system pathways

Structure

Cranial nerves

Additional images

See also

References

External links