summary of pure sensory cranial nerve

Pure Sensory cranial nerve:  olfactory nerve, optic nerve and vestibulocochlear nerve (1, 2, 8)

Function of sensory nerve in short:

1. Olfactory nerve : carry smell
2. Optic nerve : responsible for vision
3. Vestibulocochlear nerve : vestibular part responsible for balance and cochlear nerve responsible for vision

No.	Sensory nerve	Component	Name of the opening through which nerve enter  into the cranium	Arises from
I	Olfactory nerve	SVA	Cribriform plate of ethmoid	Axon of olfactory nerve arises from the Olfactory  cells which are situated in the nasal mucosa
II	Optic nerve	SSA	Optic canal	Optic nerve fibres are arises from  the ganglionic cells of the retina
VIII	Vestibulocochlear  nerve	SSA	Internal acoustic meatus	Nerves are arises from inner ear (hair cells)

 

summary of trigeminal nerve

Trigeminal nerve (V)

It has three parts

	Foramen	Type	Functional component	Function	Nucleus of trigeminal nerve
Ophthalmic nerve	Superior orbital fissure	sensory nerve	GVA	Carry sensation from cornea, Upper part of face( Scalp, forehead, upper eyelid) ,	Motor nucleus of trigeminal nerve Spinal nucleus of trigeminal nerve Main sensory nucleus of trigeminal nerve and  mesencephalic nucleus of trigeminal nerve
Maxillary nerve	Foramen Rotundum	sensory nerve	GVA	Carry sensation from Middle part of face (skin over the maxilla) upper jaw, maxillary sinus
mandibular nerve	Foramen ovale	Mixed : both sensory and motor	GVA SVE	Sensory : Lower part of face (skin over the mandible, temporomandibular joint & general sensation from the ant 2/3 of tongue Motor : muscles of mastication, tensor tympani, tensor veli palatine

 

Reid’s base line

Reid’s base line:

It is represented by a horizontal line which extends posteriorly from the lowest point of the infra-orbital margin through the centre of the external acoustic meatus.

The cerebrum lies entirely above this line, whereas the cerebellum occupies the area immediately below the posterior third of this line.

Horizontal views (sections) of C.T. scan or M.R.I. of the brain are made by superimposed lines parallel to the Reid’s base line to represent the levels of images.

 

Frankfurt’s plane

 

The Frankfurt plane or Frankfort plane (both spellings are widely used, and the term is entered as Frankfort horizontal plane in several medical dictionaries, although Frankfurt is the modern standard spelling of the city it is named for) was established at the World Congress on Anthropology in Frankfurt am Main, Germany in 1884, and decreed as the anatomical position of the human skull. 

It was decided that a plane passing through the inferior margin of the left orbit (the point called the left orbitale) and the upper margin of each ear canal or external auditory meatus, a point called the porion, was most nearly parallel to the surface of the earth, and also close to the position the head is normally carried in the living subject.

 

The plane is also called the auriculo-orbital plane.

Note that in the normal subject, both orbitales and both porions lie in a single plane. However, due to pathology, this is not always the case. The formal definition specifies only the three points listed above, sufficient to describe a plane in three-dimensional space.

For purposes of comparison of human skulls with those of some other species, notably hominids and primates, the skulls may be studied in the Frankfurt plane; nonetheless, the Frankfurt plane is not considered to be the anatomical position for most non-primate species.

The Frankfurt plane may also be used as a reference point in related fields. For example, in prosthodontics, the Frankfurt-Mandibular plane Angle (FMA) is the angle formed at the intersection of the Frankfurt plane with the mandibular plane.

It is almost identical with Reid’s base line, except that the posterior point passes through the upper margin of the external acoustic meatus. This plane is accepted by the physical anthropologists as the standard orientation of the human skulls for the study of characteristics of different races.