Oculomotor Nerve Diseases
Diseases of the oculomotor nerve or nucleus that result in weakness or paralysis of the superior rectus, inferior rectus, medial rectus, inferior oblique, or levator palpebrae muscles, or impaired parasympathetic innervation to the pupil. With a complete oculomotor palsy, the eyelid will be paralyzed, the eye will be in an abducted and inferior position, and the pupil will be markedly dilated. Commonly associated conditions include neoplasms, CRANIOCEREBRAL TRAUMA, ischemia (especially in association with DIABETES MELLITUS), and aneurysmal compression. (From Adams et al., Principles of Neurology, 6th ed, p270)
Oculomotor Nerve
The 3d cranial nerve. The oculomotor nerve sends motor fibers to the levator muscles of the eyelid and to the superior rectus, inferior rectus, and inferior oblique muscles of the eye. It also sends parasympathetic efferents (via the ciliary ganglion) to the muscles controlling pupillary constriction and accommodation. The motor fibers originate in the oculomotor nuclei of the midbrain.
Oculomotor Nerve Injuries
Ophthalmoplegia
Mydriasis
Trochlear Nerve
The 4th cranial nerve. The trochlear nerve carries the motor innervation of the superior oblique muscles of the eye.
Abducens Nerve
Anisocoria
Unequal pupil size, which may represent a benign physiologic variant or a manifestation of disease. Pathologic anisocoria reflects an abnormality in the musculature of the iris (IRIS DISEASES) or in the parasympathetic or sympathetic pathways that innervate the pupil. Physiologic anisocoria refers to an asymmetry of pupil diameter, usually less than 2mm, that is not associated with disease.
Ink
'Ink,' when used in a medical context, typically refers to a dark watery substance used in diagnostic procedures like Schirmer's test for measuring tear production or in certain artistic applications like tattooing, which is not to be confused with the pharmaceutical or medicinal usage of the term 'ink' that relates to a preparation intended for internal use.
Parasympathetic Fibers, Postganglionic
Blepharoptosis
Oculomotor Muscles
Cranial Nerve Neoplasms
Benign and malignant neoplasms that arise from one or more of the twelve cranial nerves.
Circle of Willis
A polygonal anastomosis at the base of the brain formed by the internal carotid (CAROTID ARTERY, INTERNAL), proximal parts of the anterior, middle, and posterior cerebral arteries (ANTERIOR CEREBRAL ARTERY; MIDDLE CEREBRAL ARTERY; POSTERIOR CEREBRAL ARTERY), the anterior communicating artery and the posterior communicating arteries.
Nerve Compression Syndromes
Abducens Nerve Diseases
Diseases of the sixth cranial (abducens) nerve or its nucleus in the pons. The nerve may be injured along its course in the pons, intracranially as it travels along the base of the brain, in the cavernous sinus, or at the level of superior orbital fissure or orbit. Dysfunction of the nerve causes lateral rectus muscle weakness, resulting in horizontal diplopia that is maximal when the affected eye is abducted and ESOTROPIA. Common conditions associated with nerve injury include INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; ISCHEMIA; and INFRATENTORIAL NEOPLASMS.
Cavernous Sinus
Surgical Instruments
Reflex, Pupillary
Cranial Nerve Diseases
Disorders of one or more of the twelve cranial nerves. With the exception of the optic and olfactory nerves, this includes disorders of the brain stem nuclei from which the cranial nerves originate or terminate.
Exotropia
A form of ocular misalignment where the visual axes diverge inappropriately. For example, medial rectus muscle weakness may produce this condition as the affected eye will deviate laterally upon attempted forward gaze. An exotropia occurs due to the relatively unopposed force exerted on the eye by the lateral rectus muscle, which pulls the eye in an outward direction.
Intracranial Aneurysm
Abnormal outpouching in the wall of intracranial blood vessels. Most common are the saccular (berry) aneurysms located at branch points in CIRCLE OF WILLIS at the base of the brain. Vessel rupture results in SUBARACHNOID HEMORRHAGE or INTRACRANIAL HEMORRHAGES. Giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the OCULOMOTOR NERVE. (From Adams et al., Principles of Neurology, 6th ed, p841)
Sciatic Nerve
A nerve which originates in the lumbar and sacral spinal cord (L4 to S3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the TIBIAL NERVE and the PERONEAL NERVE.
Hematoma, Subdural, Chronic
Petrous Bone
The dense rock-like part of temporal bone that contains the INNER EAR. Petrous bone is located at the base of the skull. Sometimes it is combined with the MASTOID PROCESS and called petromastoid part of temporal bone.
Peripheral Nerves
The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.
Optic Nerve
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
Nerve Fibers
Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.
Ganglia, Parasympathetic
Magnetic Resonance Imaging
Tuberculosis, Meningeal
A form of bacterial meningitis caused by MYCOBACTERIUM TUBERCULOSIS or rarely MYCOBACTERIUM BOVIS. The organism seeds the meninges and forms microtuberculomas which subsequently rupture. The clinical course tends to be subacute, with progressions occurring over a period of several days or longer. Headache and meningeal irritation may be followed by SEIZURES, cranial neuropathies, focal neurologic deficits, somnolence, and eventually COMA. The illness may occur in immunocompetent individuals or as an OPPORTUNISTIC INFECTION in the ACQUIRED IMMUNODEFICIENCY SYNDROME and other immunodeficiency syndromes. (From Adams et al., Principles of Neurology, 6th ed, pp717-9)
Carotid Artery, Internal
Cerebral Angiography
Dissection
Decompression, Surgical
Nerve Block
Interruption of NEURAL CONDUCTION in peripheral nerves or nerve trunks by the injection of a local anesthetic agent (e.g., LIDOCAINE; PHENOL; BOTULINUM TOXINS) to manage or treat pain.
Nerve Endings
Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.
Sural Nerve
A branch of the tibial nerve which supplies sensory innervation to parts of the lower leg and foot.
Median Nerve
A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand.
Facial Nerve
The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and SALIVARY GLANDS, and convey afferent information for TASTE from the anterior two-thirds of the TONGUE and for TOUCH from the EXTERNAL EAR.
Peripheral Nerve Injuries
Injuries to the PERIPHERAL NERVES.
Tibial Nerve
The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot.
Ulnar Nerve
A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm.