Frontal nerve

The anterior half of the scalp is innervated by the frontal nerve. In its intraorbital journey, this nerve divides into the internal and external frontal nerves. The nerve branches emerge from the supraorbital foramen and innervate the front of the skuU after traveling vertically upwards. Blocking these nerve branches anesthetizes the forehead as well as the first 6-10 cm of the area normally covered in hair. For more details, see Chapter 33. 

The lateral regions of the scalp are not innervated by the frontal nerve, but by branches of the lesser cervical plexus or the auriculotemporal nerve. 

PAN Y, ANTHONY M, CLARKSON T B (1999a) Effect of estradiol and soy phytoestrogens on choline acetyltransferase and nerve growth factor mRNAs in the frontal cortex and hippocampus of female rats. Proc Soc Exp Biol Med. 221 118-25. 

Chin The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve, [nih]... 

This could happen in the frontal cortex, the area of the brain that solves complex problems and plans for the future. If inhalants make their way into the brain s cerebellum, which controls movement and coordination, they can make a person move more slowly or clumsily. Studies also show that nerve cells in the brain s hippocampus can be damaged by inhalants. Since the hippocampus controls memory, a person who repeatedly uses inhalants may lose the ability to learn new things, or may have a hard time keeping track of simple conversations. 

The most frequently cited possible cause of mental illnesses is an abnormal hyperactivity of the dopamine neurotransmitter system in the brain. Neuroleptics inhibit dopamine nerve transmission in the frontal lobes and in the limbic system—the emotion-regulating brain structures. Inhibiting this portion of the brain causes diffuse CNS depression and disrupts an individual s behavior entirely—reducing psychotic thoughts, perceptions, and agitation. 

Ronde P, Nichols RA (1998) High calcium permeability of serotonin 5-HT3 receptors on presynaptic nerve terminals from rat striatum. J Neurochem 70 1094-1103 Rosenstein RE, Chuluyan HE, Cardinali DP (1990) Presynaptic effects of gamma-aminobutyric acid on norepinephrine release and uptake in rat pineal gland. J Neural Transm 82 131—40 Rousseau SJ, Jones IW, Pullar IA, Wonnacott S (2005) Presynaptic [alpha]7 and non-[alpha]7 nicotinic acetylcholine receptors modulate [3H]d-aspartate release from rat frontal cortex in vitro. Neuropharmacology 49 59... 

Electron microscopic examination of the NTS demonstrated peroxidase immunoreactivity in small unmyelinated axons and axon terminals (159). A similar distribution of the 5-HT3 immunoreactivity to fine axons and axon terminals was subsequently documented in the frontal and entorhinal cortex, amygdala, hippocampus, spinal nucleus of the trigeminal nerve, and dorsal hom of spinal cord (183). Immunostaining within cell bodies, dendrites, and/or dendritic spines was then observed in all of these regions as well as in the NTS, but less frequently than the axonal labeling, except in the hippocampus. 

Kolb B, Wishaw IQ. Performance of schizophrenic patients on tests sensitive to left or right frontal, temporal, or parietal function in neurological patients. J Nerv Mental Pis 1983 171 435-443. 

The basal ganglia are part of what is referred to as the brain s extrapyra-midal system of motor control, so called to distinguish it from the pyramidal nerve tracts that control voluntary movement. The extrapyra-midal system is most directly associated with involuntary aspects of movement such as muscle tone and posture. However it has extensive connections with other parts of the brain, especially the frontal cortex, the seat of personality and rationality. This functional network... mediates volitional motor activity, saccadic eye movements, emotion, motivation, cognition and social behaviour (Wonodi, Hong, Thaker 2005, p. 340). Thus conditions that effect neurotransmission in the basal ganglia can be expected to have far-reaching functional consequences. 

The so-called clinical effect of neuroleptics, their chemical loboto-mizing impact, is primarily caused by the blockade of dopaminergic nerves, especially the D2 receptors, in the ventral striatum, with their connections to the limbic system and frontal lobes (chapters 1 and 2). However, blockade of the same D2 receptors in the dorsal striatum is the probable cause of extrapyramidal reactions, including TD (Ethier et al., 2004 Seeman, 1995). Hence, as described in chapter 1, the so-called therapeutic effect is inextricably entwined with some of the worst adverse effects. 

Experimentally, the macrocyclic trichothecenes satra-toxin G, isosatratoxin F, and roridin A have been shown to cause nasal and pulmonary toxicity when administered intranasally or intratracheally to mice. Intranasal exposure of satratoxin G and roridin A induced apoptosis of olfactory sensory neurons resulting in atrophy of the olfactory epithelium and olfactory nerve layer of the olfactory bulb in the frontal brain (Islam et al, 2006, 2007). Alveolar-type II cells and alveolar macrophages were injured following intratracheal instillation of isosatratoxin F or Stachybotrys spores with marked changes in surfactant synthesis and secretion (Rand et al, 2002). 

A frontal FNB anesthetizes the supraorbital nerve, the supratrochlear nerve and the external nasal nerve (Figures 33.2a-c, 33.3a,b). The quantities required to anesthetize the whole of the frontal region are two times 1.5 cm of 2% lidocaine without adrenaline. 

The mid-face block anesthetizes the lower eyelid, part of the cheek, part of the nose and the upper lip. This second phase is done after the phenol has been applied to the frontal area. The infraorbital nerve can be reached from the outside (Figure 33.4a,b) or from inside the mouth. The internal route is preferable, as it is easier to anesthetize the upper lip, the nostrils and the tip of the nose (Figure 33.5). It is best to anesthetize the upper eyelid from the outside, however. 

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