Items tagged “neuroanatomy”

The abducens nerve is the sixth cranial nerve (CN VI). It is a motor nerve responsible for abduction of the eye (TA: nervus abducens or nervus cranialis VI). It courses from the abducens nucleus, located in the dorsal pons, up to the cavernous sinus, via a long cisternal segment that is prone to...

Aberrant internal carotid artery is a variant of the internal carotid artery and represents a collateral pathway resulting from involution of the normal cervical portion (first embryonic segment) of the internal carotid artery 5. Gross anatomy There is consequent enlargement of the usually sma...

The cerebellum, meaning "the little brain", sits at the base of the brain in the posterior cranial fossa below the tentorium and behind the brainstem.  Gross anatomy The cerebellum has the following features: three surfaces: anterior (petrosal), superior (tentorial), inferior (suboccipital) ...

Arnold's nerve, also known as the auricular branch or mastoid branch, of the vagus nerve (CN X) is a small sensory nerve supplying the skin of the external acoustic meatus.  Terminology The greater occipital nerve has also been known in the past - confusingly - as the nerve of Arnold. The use...

Cavum septum pellucidum (CSP) is a normal variant CSF space between the leaflets of the septum pellucidum. Terminology While the term "cavum septum pellucidum" is generally accepted, it is grammatically incorrect. Since it denotes a space (cavum meaning cave) of the septum pellucidum, the seco...

The cavum vergae (CV), along with the cavum septum pellucidum (CSP) that lies immediately anterior to it, is a persistence of the embryological fluid-filled space between the leaflets of the septum pellucidum and is a common anatomical variant.  Terminology The cavum vergae has also been refer...

An understanding of brain arterial vascular territories is important in understanding stroke and complications from surgery and endovascular procedures.  Although one could be excused for thinking that within the brain, such a carefully organized organ, blood supply would be constant, the truth...

Dorello canal channels the abducens nerve (CN VI) from the pontine cistern to the cavernous sinus.  Gross anatomy Dorello canal is an interdural space (between the two layers of dura) found at the medial most end of the petrous ridge at the confluence of the inferior petrosal, basal, and caver...

The facial nerve is the seventh (CN VII) cranial nerve and comprises two roots, a motor root and a smaller mixed sensory, taste and parasympathetic root, known as nervus intermedius, which join together within the temporal bone (TA: nervus facialis or nervus cranialis VII). The facial nerve has...

The meninges (singular: meninx) is a collective term for the three membranes that cover the brain and spinal cord and are covered in separate articles: cranial meninges spinal meninges History and etymology The word meninges arises from the Classical Greek μηνιγξ (transliteration: m...

Arachnoid granulations, also known as Pacchionian granulations, are projections of the arachnoid membrane (villi) into the dural sinuses that allow CSF to pass from the subarachnoid space into the venous system. Epidemiology They increase in size and number with age and are seen in approximate...

The basilar artery is part of the posterior cerebral circulation. It arises from the confluence of the left and right vertebral arteries at the base of the pons as they rise towards the base of the brain. Summary origin: vertebral artery confluence course: ventral to pons in the pontine ciste...

The middle cerebral artery (MCA) is one of the three major paired arteries that supply blood to the brain. The MCA arises from the internal carotid artery as the larger of the two main terminal branches (the other being the anterior cerebral artery), coursing laterally into the lateral sulcus wh...

The diencephalon is connected above and in front of the cerebral hemispheres; behind the mid-brain. Its upper surface is concealed by the corpus callosum, and is covered by a fold of pia mater, named the tela choroidea of the third ventricle; inferiorly it reaches to the base of the brain. It c...

Mega cisterna magna refers to a normal variant characterized by a truly focal enlargement of the CSF-filled subarachnoid space in the inferior and posterior portions of the posterior cranial fossa. It is an incidental finding on neuroimaging, and no imaging follow up is necessary.  Epidemiology...

The corpus callosum (plural: corpora callosa) is the largest of the commissural fibers, linking the cerebral cortex of the left and right cerebral hemispheres. It is the largest white matter tract in the brain. Summary located inferior to the cerebral cortices, and superior to the thalamus co...

The superior anastomotic vein, also known as the vein of Trolard, is part of the superficial venous system of the brain.  It should not be confused with the venous circle of Trolard, the anastomotic venous circle of the base of the brain which is the inconsistently found venous homologue of the...

Alain Bouthillier et al. described a seven segment internal carotid artery classification system in 1996 1. It remains the most widely used system for describing the internal carotid artery segments. A helpful mnemonic for remembering ICA segments is:  C'mon Please Learn Carotid Clinical Organ...

Betz cells are pyramidal cell neurons located within the fifth layer of the primary motor cortex. They are some of the largest in the central nervous system, sometimes reaching 100 µm in diameter and send their axons down the corticospinal tracts to the anterior horn cells of the spinal cord.  ...

Rathke pouch, also known as hypophyseal diverticulum, is an ectodermal outpouching of stomodeum (primitive oral cavity lined by ectoderm) which forms at approximately 3-4 weeks gestation and goes on to form the adenohypophysis of the pituitary gland. Gross anatomy The anterior wall of the pouc...