Introduction The accessory nerve is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles. It is considered the eleventh of twelve pairs of cranial nerves, or simply cranial nerve XI, as part of it was formerly believed to originate in the brain. The accessory nerve divides it into a spinal part and a cranial…
INTRODUCTION The vagus nerve is the longest and most complex of the 12 pairs of cranial nerves that emanate from the brain. It transmits information to or from the surface of the brain to tissues and organs elsewhere in the body. The name “vagus” comes from the Latin term for “wandering.” This is because the…
INTRODUCTION : The glossopharyngeal nerve, known as the ninth cranial nerve (CN IX), is a mixed nerve that carries afferent sensory and efferent motor information. It exits the brainstem out from the sides of the upper medulla, just anterior (closer to the nose) to the vagus nerve. Sensory: Innervates the oropharynx, carotid body and sinus,…
Introduction The vestibulocochlear nerve (auditory vestibular nerve), known as the eighth cranial nerve, transmits sound and equilibrium (balance) information from the inner ear to the brain. The vestibulocochlear nerve is the eighth paired cranial nerve. It is comprised of two parts – vestibular fibres and cochlear fibres. Both have a purely sensory function. Anatomy The…
INTRODUCTION : The abducens nerve (or abducent nerve) is the sixth cranial nerve (CNVI), in humans body that controls the movement of the lateral rectus muscle, responsible for outward gaze. It is a somatic efferent nerve. ANATOMY OF ABDUCENS NERVE : The abducens nerve arises from the abducens nucleus in the pons of the brainstem….
INTRODUCTION: The frontalis muscle is a thin, wide, four-sided muscle located at the top front of the skull. The frontalis muscle only serves for facial expressions. It lifts the eyebrows while looking up thus creating a expression. ORIGIN: It originates from the Galea aponeutorica. INSERTION: This muscle has no bony attachments. The medial fibers continues…
INTRODUCTION : The trochlear nerve, also called the fourth cranial nerve or CN IV, is a motor nerve (a somatic efferent nerve) that innervates only a single muscle: the superior oblique muscle of the eye, which operates through the pulley-like trochlea. The trochlear nerve is unique among the cranial nerves in several respects: The trochlear…
INTRODUCTION : The oculomotor nerve is the third cranial nerve (CN III). It enters the orbit via the superior orbital fissure and innervates extrinsic eye muscles that enable most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that enable pupillary constriction and accommodation…
Introduction of Olfactory Nerve : The olfactory nerve (CN I) is the first and shortest cranial nerve. It is a special visceral afferent nerve, which transmits information relating to smell. Embryologicallly, the olfactory nerve is derived from the olfactory placode (a thickening of the ectoderm layer), which also give rise to the glial cells which…
Introduction: The wrist extensor muscles of the hand are located in the back of the forearm and have long tendons connecting them to bones in the hand, where they exert their action. The wrist extensors includes extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB), extensor digitorum (ED), extensor digiti minimi (EDM), extensor carpi…
