The basilar part of pons, also known as basis pontis, or basilar pons, is the ventral part of the

pons The pons (from Latin , "bridge") is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. The pons is also called the pons Varolii ("bridge of ...

(ventral pons) in 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 ...

; the dorsal part (dorsal pons) is known as the

pontine tegmentum The pontine tegmentum, or dorsal pons, is the dorsal part of the pons located within the brainstem. The ventral part or ventral pons is known as the basilar part of the pons, or basilar pons. Along with the dorsal surface of the medulla oblonga ...

. The basilar part of the pons makes up two thirds of the pons. It has a ridged appearance with a shallow

groove Groove or Grooves may refer to: Music * Groove (music) * Groove (drumming) * The Groove (band), an Australian rock/pop band of the 1960s * The Groove (Sirius XM), a US radio station * Groove 101.7FM, a former Perth, Australia, radio station ...

at the midline. This groove is the

basilar sulcus The basilar sulcus (groove for basilar artery) is a groove in the pons, part of the brainstem. The basilar sulcus is vertical directed and lies in the midline of the pons on its anterior (front) surface. The basilar artery The basilar artery ( ...

and is covered by the

basilar artery The basilar artery (U.K.: ; U.S.: ) is one of the arteries that supplies the brain with oxygen-rich blood. The two vertebral arteries and the basilar artery are known as the vertebral basilar system, which supplies blood to the posterior part o ...

. The basilar artery feeds into the

circle of Willis The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a circulatory anastomosis that supplies blood to the brain and surrounding structures in reptiles, birds and mammals, including huma ...

providing blood supply to the brainstem and

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 ridged appearance is due to the fibers that come out of the pons to enter the cerebellum. The basilar pons contains fibers from the

corticospinal tract The corticospinal tract is a white matter motor pathway starting at the cerebral cortex that terminates on lower motor neurons and interneurons in the spinal cord, controlling movements of the limbs and trunk. There are more than one million neu ...

(a descending pathway for neurons to reach other structures in the body),

pontine nuclei The pontine nuclei (or griseum pontis) are all the neurons of the ventral pons. Corticopontine fibres project from the primary motor cortex to the ipsilateral pontine nucleus; pontocerebellar fibers then relay the information to the contralater ...

, and transverse pontine fibers. The corticospinal tract carries fibres from the

primary motor cortex The primary motor cortex ( Brodmann area 4) is a brain region that in humans is located in the dorsal portion of the frontal lobe. It is the primary region of the motor system and works in association with other motor areas including premotor c ...

to 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 ...

, aiding in voluntary motor movement of the body. In addition to passing through the ventral pons, corticospinal tract fibers go through other structures of the brainstem, including 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 ...

and the

crus cerebri The cerebral crus (crus cerebri. ''crus'' means ‘leg’ in Latin.) is the anterior portion of the cerebral peduncle which contains the motor tracts, traveling from the cerebral cortex to the pons and spine. The plural of which is cerebral crura ...

. Integral to the basilar pons are the

. The pontine nuclei are responsible for projecting fibers that go to the opposite cerebellar hemisphere through the

middle cerebellar peduncle The middle cerebellar peduncle (or brachium pontis) is one of three paired cerebellar peduncles connecting the brainstem to the cerebellum. The connection is from the pons. It connects the pons to the cerebellum, with fibres originating from the ...

, changing the fibers into transverse pontine fibers. The fibers of the pontine nuclei are all important to motor function, including fiber bundles such as the corticospinal fibers and corticopontine-pontocerebellar system. Specifically, the basilar part of the pons contains all the corticofugal fibers, which include the

corticospinal The pyramidal tracts include both the corticobulbar tract and the corticospinal tract. These are aggregations of efferent nerve fibers from the upper motor neurons that travel from the cerebral cortex and terminate either in the brainstem (''cort ...

, corticobulbar (or corticonuclear), and corticopontine fibers. The basal pontine nuclei provides most of the cortical information to the cerebellum received from the corticopontine fibers.

Clinical significance

Tissue death (infarction), in this region can impair motor functioning. A

lacunar stroke Lacunar stroke or lacunar cerebral infarct (LACI) is the most common type of ischemic stroke, resulting from the Vascular occlusion, occlusion of small penetrating artery, arteries that provide blood to the brain's deep structures. Patients who pr ...

of the base of the pons is known to cause contralateral dysarthria-clumsy hand syndrome. The basilar pons undergoes

demyelination A demyelinating disease refers to any disease affecting the nervous system where the myelin sheath surrounding neurons is damaged. This damage disrupts the transmission of signals through the affected nerves, resulting in a decrease in their con ...

in the condition known as

central pontine myelinolysis Central pontine myelinolysis (CPM) is a neurological condition involving severe damage to the myelin sheath of nerve cells in the ''pons'' (an area of the brainstem). It is predominately iatrogenic (treatment-induced), and is characterized by ...

. This disorder is due to the rapid intravenous correction of

hyponatremia Hyponatremia or hyponatraemia is a low concentration of sodium in the Serum (blood), blood. It is generally defined as a sodium concentration of less than 135 mmol/L (135 mEq/L), with severe hyponatremia being below 120 mEq/L. Symp ...

References

External links

* https://web.archive.org/web/20080221222726/http://isc.temple.edu/neuroanatomy/lab/atlas/pmjdc/ * https://web.archive.org/web/20080602013108/http://pathcuric1.swmed.edu/PathDemo/cns1/cns1140.htm * https://web.archive.org/web/20080829001215/http://isc.temple.edu/neuroanatomy/lab/atlas/panfc/ * https://web.archive.org/web/20080526141946/http://www.sci.uidaho.edu/med532/pons.htm {{Authority control Pons