Cranial nerves

Overview What is the oculomotor nerve? The oculomotor nerve is one of 12 sets of cranial nerves. Many of these nerves are part of the autonomic nervous system. The autonomic nervous system supplies (innervates) organs, like your eyes. The oculomotor nerve is the third cranial nerve (CN III). It allows movement of the eye muscles, constriction of the pupil, focusing the eyes and the position of the upper eyelid. Cranial nerve III works with other cranial nerves to control eye movements and support sensory functioning. • Olfactory nerve (CN I) enables sense of smell. • Optic nerve (CN II) enables vision. • Trigeminal nerve (CN V) enables sensation in your face. • Vestibular and cochlear nerves (CN VII) enable balance and hearing. Function What is the function of the oculomotor nerve? It controls four of the six muscles that enable eye movement. CN III makes it possible to: • Elevate the upper eyelid. • Focus the eyes. • Respond to light by making the black center of the eye (pupil) smaller. • Move your eyes inward, outward, up and down and control torsion. How does CN III work? It coordinates eye movement with motions that include: • Accommodation, focusing on an object that’s moving closer to or further away from you. • Optokinetic reflex, changing eyes back to their previous position after focusing on an object. • Saccades, quick motions that shift your gaze from one object to another. • Smooth pursuit (visual tracking), which enables you to hold your gaze on a moving obje...

Nervous system (anterior view) In this article, we’ll discuss the peripheral nervous system and its divisions, as well as the peripheral nervous system (PNS) consists of all the nerves branching out of the The PNS is built almost entirely from nerves. There are two main types; somatic nervous systems. Both of these can be further subdivided; the former into It might sound complicated, but it’s not. Let’s take a closer look at all of the above terms in order to better understand the divisions of the nervous system. Key facts about the peripheral nervous system Definition A nervous system division composed of all the neural tissue found outside the cranial vault and vertebral canal. Anatomical components Peripheral nerves (spinal nerves, cranial nerves, autonomic nerves) Ganglia Functional components Autonomic nervous system (ANS) - involuntary part in control of cardiac, smooth and glandular cells. It consists of sympathetic and parasympathetic divisions. Somatic nervous system (SNS) - voluntary part in control of skeletal muscles and processing of somatic sensation. Function Transmits motor and sensory information between the central nervous system and peripheral body tissues. Peripheral nerves The workhorse of the peripheral nervous system are the peripheral nerves. Each nerve consists of a bundle of many nerve fibers ( tract’. Peripheral nerves that carry information towards the CNS are called afferent or sensory neurons, while the ones transmitting impulses from...

Your peripheral nervous system (PNS) is one of two main parts of your body’s nervous system. Your PNS feeds information into your brain from most of your senses. It carries signals that allow you to move your muscles. Your PNS also delivers signals that your brain uses to control vital, unconscious processes like your heartbeat and breathing. Overview The central and peripheral nervous systems. The peripheral nervous system branches outward from the spinal cord and brain to reach every part of your body. What is the peripheral nervous system? Your peripheral nervous system (PNS) is that part of your nervous system that lies outside your Some of those signals, like the ones to your heart and gut, are automatic. Others, like the ones that control movement, are under your control. What’s the difference between the peripheral and central nervous systems? Your Your peripheral nervous system is everything else and includes nerves that travel from your spinal cord and brain to supply your face and the rest of your body. The term “peripheral” is from the Greek word that means around or outside the center. Function What does the peripheral nervous system do? Your peripheral nervous system has two main subsystems: autonomic and somatic. • Autonomic: These are nervous system processes your brain runs automatically and without you thinking about them. • Somatic: These are functions you manage by thinking about them. Those two subsystems are how your peripheral nervous system does its ...

• 1 Origin of the Cranial Nerves • 2 Modalities • 3 Summary Table – Cranial Nerves • 4 Prosection Images The cranial nerves are a set of 12 paired nerves that arise directly from the brain. The first two nerves (olfactory and optic) arise from the cerebrum, whereas the remaining ten emerge from the brainstem. The names of the cranial nerves relate to their function and they are numerically identified in roman numerals (I-XII). In this article, we shall summarise the anatomy of the cranial nerves – their origin, course, and functions. Origin of the Cranial Nerves There are twelve cranial nerves in total. The olfactory nerve (CN I) and optic nerve (CN II) originate from the cerebrum. Cranial nerves III – XII arise from the brainstem (Figure 1). They can arise from a specific part of the brainstem (midbrain, pons or medulla), or from a junction between two parts: • Midbrain – the trochlear nerve (IV) comes from the posterior side of the midbrain. It has the longest intracranial length of all the cranial nerves. • Midbrain-pontine junction – oculomotor (III). • Pons – trigeminal (V). • Pontine-medulla junction – abducens, facial, vestibulocochlear (VI-VIII). • • Posterior to the olive: glossopharyngeal, vagus, accessory (IX-XI). • Anterior to the olive: hypoglossal (XII). The cranial nerves are numbered by their location on the brainstem (superior to inferior, then medial to lateral) and the order of their exit from the cranium (anterior to posterior) (Figures 1 & 2). Modaliti...

Function What is the purpose of the facial nerve? The facial nerve performs these motor (movement) and sensory functions: • Controls the muscles that make your facial expressions. • Controls muscle in your inner ear that moderates loudness of sound. • Helps make tears. • Sends information about tastes from your tongue to your brain. Anatomy Where is the facial nerve? The facial nerve is the seventh of 12 The facial nerve: • Starts in your • Travels through the base of your skull near the vestibulocochlear nerve, the eighth cranial nerve, which helps you hear and maintain • Enters your face through an opening in a bone near the base of your ear. • Branches out through an opening near your parotid gland, a major salivary gland. What are the facial nerve branches? The facial nerve has five branches that perform distinct motor functions: • Frontal (temporal): Controls your forehead muscles. • Zygomatic: Helps you close your eyes. • Buccal: Allows you to move your nose, blink and raise your upper lip and corners of your mouth to make a smile. • Marginal mandibular: Draws your lower lip down (like a frown) and travels through your middle ear to help you respond to loud noises. • Cervical: Controls movement in your chin and lower corners of your mouth. Conditions and Disorders What conditions and disorders affect the facial nerves? Several conditions can cause weakness or • Accidents and • • Cancer such as • • Facial surgery, including cosmetic procedures like • • • • Ramsay Hunt...

Facial nerve (lateral right view) You know when someone mentions cranial nerves and you roll your Cranial nerves anatomy is essential for almost any medical specialty since they control so many body functions, such as rolling your Key facts about the cranial nerves Definition A set of 12 peripheral nerves emerging from the brain that innervate the structures of the head, neck, thorax and abdomen. Nerves Olfactory nerve (CN I), optic nerve (CN II), oculomotor nerve (CN III), trochlear nerve (CN IV), trigeminal nerve (CN V), abducens nerve (CN VI), facial nerve (CN VII), vestibulocochlear nerve (CN VIII), glossopharyngeal nerve (CN IX), vagus nerve (CN X), accessory nerve (CN XI), and hypoglossal nerve (CN XII). Mnemonics: - Oh, Oh, Oh, To Touch And Feel Very Good Velvet, such- A Heaven - On, On, On, They Traveled And Found Voldemort Guarding Very Ancient Horcruxes. Types of nerves - Sensory: Olfactory nerve (CN I), optic nerve (CN II), vestibulocochlear nerve (CN VIII) - Motor: Oculomotor nerve (CN III), trochlear nerve (CN IV), abducens nerve (CN VI), accessory nerve (CN XI), hypoglossal nerve (CN XII). - Mixed (both): trigeminal nerve (CN V), facial nerve (CN VII), glossopharyngeal nerve (CN IX), vagus nerve (CN X). Mnemonic (by the numerical order): Some Say Money Matters, But My Brother Says Big Brains Matter Most [12 cranial nerves (diagram)] We’re sure that while reading textbooks, you encountered with afferent, efferent, mixed, general, visceral, specia...

All Subjects • Anatomy and Chemistry Basics • • • • • • • • • • • The Cell • • • • • • • • • Tissues • • • • • • • • • • The Integumentary System • • • • • • • • • • • Bones and Skeletal Tissues • • • • • • • • • • • • • • • The Skeletal System • • • • • • • • • • • • • • • • • • • Articulations • • • Muscle Tissue • • • • • • • • • • • • The Muscular System • • • • • • • • • Nervous Tissue • • • • • • • • • • • The Nervous System • • • • • • • • • • • • • • • • • • • • • • • The Sensory System • • • • • • • • • • • • • • • The Endocrine System • • • • • • • • • The Cardiovascular System • • • • • • • • • • • • • • • • • • • • • • • • The Lymphatic System • • • • • • • • • The Immune System and Other Body Defenses • • • • • • • • • • • • • • • • • • • • The Respiratory System • • • • • • • • • • • • • • • • • The Digestive System • • • • • • • • • • • • • • • • • • • • • • • • • • The Urinary System • • • • • • • • • • • The Reproductive System • • • • • • • Anatomy and Physiology Quizzes Cranial Nerves Cranial nerves are nerves of the PNS that originate from or terminate in the brain. There are 12 pairs of cranial nerves, all of which pass through foramina of the skull. Some cranial nerves are sensory nerves (containing only sensory fibers), some are motor nerves (containing only motor fibers), and some are mixed nerves (containing a combination of sensory and motor nerves). Characteristics of the cranial nerves, which are numbered from anterior to posterior as they attac...

• 1 Anatomical Position • 2 External Anatomy • 2.1 Anterior Surface • 2.2 Posterior Surface • 3 Internal Anatomy • 4 Cranial Nerve Nuclei • 5 Vasculature • 6 Clinical Relevance – Cerebellopontine Angle Syndrome The pons is the largest part of the brainstem, located above the pons is Latin for bridge). The pons develops from the embryonic metencephalon (part of the hindbrain, developed from the rhombencephalon), alongside the cerebellum. In this article, we will look at the anatomy of the pons – its location, structure and function, blood supply and clinical relevance. Anatomical Position The pons is a horseshoe-shaped collection of nerve fibres located in the anterior part of the Its anatomical relations are as follows: • Posteriorly – the cerebellum, separated by the fourth ventricle. • Inferiorly – the medulla oblongata. • Superiorly – the midbrain lies immediately above the pons. External Anatomy Anterior Surface The anterior or ventral surface of the pons is marked by a bulging formed by the transverse pontocerebellar fibres. These fibres wrap around the otherwise vertically oriented brainstem. It measures around 2.5 cm in adults. The basilar groove demarcates the midline of the ventral surface and is where the basilar artery is located. The pontomedullary junction is an important anatomical landmark defined by the angle between the lower border of the pons and the superior border of the medulla. Several cranial nerves originate from the ventral surface of the pons: • ...

What are Cranial Nerves? “Nerves that extend throughout the body on both sides emerging directly from brain and brain stem are called cranial nerves.” Cranial nerves carry information from the brain to other parts of the body, primarily to the head and neck. These nerves are paired and present on both sides of the body. They are mainly responsible for facilitating smell, vision, hearing, and movement of muscles. Cranial nerves are concerned with the head, neck, and other facial regions of the body. Cranial nerves arise directly from the brain in contrast to spinal nerves and exit through its foramina. Most of the cranial nerves originate in the brain stem and pass through the muscles and sense organs of the head and neck. There are twelve cranial nerves which are numbered using Roman numerals according to the order in which they emerge from the brain (from front to back). Cranial nerves are considered as a part of the peripheral nervous system, although olfactory and optic nerves are considered to be part of the Central nervous system. Most of the cranial nerves belong to the somatic system. Some of the cranial nerves are responsible for sensory and motor functions as they contain only sensory fibres and motor fibres. Others are mixed nerves because they include both sensory and motor fibres. Only cranial nerves I and II are purely sensory and are responsible for the sense of smell and vision (optic nerve II). The rest of the cranial nerves contain both afferent an...