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Behind the posterior apertures of the nose and in front of the foramen magnum are the sphenoid bone and the basilar part of the occipital bone l-arginine erectile dysfunction treatment zudena 100 mg line. The occipital condyles should be identified; they articulate with the superior aspect of the lateral mass of the first cervical vertebra erectile dysfunction blogs discount zudena 100 mg fast delivery,the atlas otc erectile dysfunction pills that work order zudena 100mg with visa. Superior to the occipital condyle is the hypoglossal canal for transmission of the hypoglossal nerve (Fig erectile dysfunction doctor in bangalore safe zudena 100 mg. Posterior to the foramen magnum in the midline is the external occipital protuberance erectile dysfunction drugs and glaucoma zudena 100mg fast delivery. Below erectile dysfunction doctors in nc cheap 100mg zudena with mastercard, the parietal bones articulate with the squamous part of the occipital bone at the lambdoid suture. In the midline of the occipital bone is a roughened elevation called the external occipital protuberance, which gives attachment to muscles and the ligamentum nuchae. On either side of the protuberance, the superior nuchal lines extend laterally toward the temporal bone. Occasionally, the two halves of the frontal bone fail to fuse, leaving a midline metopic suture. Inferior View of the Skull If the mandible is discarded, the anterior part of this aspect of the skull is seen to be formed by the hard palate (Fig. The palatal processes of the maxillae and the horizontal plates of the palatine bones can be identified. Above the posterior edge of the hard palate are the choanae (posterior nasal apertures). These are separated from each other by the posterior margin of the vomer and are bounded laterally by the medial pterygoid plates of the sphenoid bone. The inferior end of the medial pterygoid plate is prolonged as a curved spike of bone, the pterygoid hamulus. Posterolateral to the lateral pterygoid plate, the greater wing of the sphenoid is pierced by the large foramen ovale and the small foramen spinosum. Behind the spine of the sphenoid,in the interval between the greater wing of the sphenoid and the petrous part of the temporal bone, is a groove for the cartilaginous part of the auditory tube. In childhood, the growth of the mandible, the maxillary sinuses,and the alveolar processes of the maxillae results in a great increase in length of the face. Most of the skull bones are ossified at birth, but the process is incomplete, and the bones are mobile on each other, being connected by fibrous tissue or cartilage. The bones of the vault are not closely knit at sutures, as in the adult, but are separated by unossified membranous intervals called fontanelles. Clinically, the anterior and posterior fontanelles are most important and are easily examined in the midline of the vault. The anterior fontanelle is diamond shaped and lies between the two halves of the frontal bone in front and the two parietal bones behind (Fig. The fibrous membrane forming the floor of the anterior fontanelle is replaced by bone and is closed by 18 months of age. The posterior A Brief Review of the Skull 191 Sagittal suture Parietal Superior temporal line Occipital Inferior temporal line Lambdoid suture External occipital protuberance Parietomastoid suture Superior nuchal line Mastoid process Styloid process Mandible A Nasal Frontal Coronal suture Sagittal suture Parietal Lambdoid suture B Figure 5-4 Bones of the skull viewed from the posterior (A) and superior (B) aspects. By the end of the first year, the fontanelle is usually closed and can no longer be palpated. The tympanic part of the temporal bone is merely a C-shaped ring at birth, compared with a C-shaped curved plate in the adult. The mandible has right and left halves at birth, united in the midline with fibrous tissue. The Cranial Cavity the cranial cavity contains the brain and its surrounding meninges, portions of the cranial nerves, arteries, veins, and venous sinuses. Vault of the Skull the internal surface of the vault shows the coronal, sagittal, and lambdoid sutures. In the midline is a shallow sagittal groove that lodges the superior sagittal sinus. Several narrow grooves are present for the anterior and posterior the Cranial Cavity 193 Crista galli Foramen cecum Lesser wing of sphenoid Cribriform plate Orbital plate of frontal Optic canal Anterior clinoid process Tuberculum sellae Sella turcica Posterior clinoid process Dorsum sellae Hiatus for greater petrosal nerve Foramen rotundum Foramen lacerum Foramen ovale Groove for middle meningeal artery Foramen spinosum Squamous part of temporal Petrous part of temporal Internal acoustic meatus Arcuate eminence Groove for sigmoid sinus Groove for superior petrosal sinus Jugular foramen Groove for transverse sinus Basilar part of occipital Foramen magnum Internal occipital crest Hypoglossal canal Internal occipital protuberance Figure 5-6 Internal surface of the base of the skull. The anterior cranial fossa is separated from the middle cranial fossa by the lesser wing of the sphenoid, and the middle cranial fossa is separated from the posterior cranial fossa by the petrous part of the temporal bone. Anterior Cranial Fossa the anterior cranial fossa lodges the frontal lobes of the cerebral hemispheres. It is bounded anteriorly by the inner surface of the frontal bone, and in the midline is a crest for the attachment of the falx cerebri. Its posterior boundary is the sharp lesser wing of the sphenoid, which articulates laterally with the frontal bone and meets the anteroinferior angle of the parietal bone, or the pterion. The medial end of the lesser wing of the sphenoid forms the anterior clinoid process on each side, which gives attachment to the tentorium cerebelli. The median part of the anterior cranial fossa is limited posteriorly by the groove for the optic chiasma. The floor of the fossa is formed by the ridged orbital plates of the frontal bone laterally and by the cribriform plate of the ethmoid medially (Fig. The crista galli is a sharp upward projection of the ethmoid bone in the midline for the attachment of the falx cerebri. Between the crista galli and the crest of the frontal bone is a small aperture, the foramen cecum, for the transmission of a small vein from the nasal mucosa to the superior sagittal sinus. Alongside the crista galli is a narrow slit in the cribriform plate for the passage of the anterior ethmoidal nerve into the nasal cavity. The upper surface of the cribriform plate supports the olfactory bulbs, and the small perforations in the cribriform plate are for the olfactory nerves. Middle Cranial Fossa the middle cranial fossa consists of a small median part and expanded lateral parts (Fig. The median raised part is formed by the body of the sphenoid, and the expanded lateral parts form concavities on either side, which lodge the temporal lobes of the cerebral hemispheres. It is bounded anteriorly by the sharp posterior edges of the lesser wings of the sphenoid and posteriorly by the superior borders of the petrous parts of the temporal bones. Laterally lie the squamous parts of the temporal bones, the greater wings of the sphenoid, and the parietal bones. The floor of each lateral part of the middle cranial fossa is formed by the greater wing of the sphenoid and the squamous and petrous parts of the temporal bone. The sphenoid bone resembles a bat having a centrally placed body with greater and lesser wings that are outstretched on each side. The body of the sphenoid contains the sphenoid air sinuses, which are lined with mucous membrane and communicate with the nasal cavity; they serve as voice resonators. Anteriorly, the optic canal transmits the optic nerve and the ophthalmic artery, a branch of the internal carotid artery, to the orbit. The superior orbital fissure, which is a slitlike opening between the lesser and greater wings of the sphenoid, transmits the lacrimal, frontal, trochlear, oculomotor,nasociliary,and abducent nerves,together with the superior ophthalmic vein. The sphenoparietal venous sinus runs medially along the posterior border of the lesser wing of the sphenoid and drains into the cavernous sinus. The foramen rotundum, which is situated behind the medial end of the superior orbital fissure,perforates the greater the Cranial Cavity 195 wing of the sphenoid and transmits the maxillary nerve from the trigeminal ganglion to the pterygopalatine fossa. It perforates the greater wing of the sphenoid and transmits the large sensory root and small motor root of the mandibular nerve to the infratemporal fossa. The small foramen spinosum lies posterolateral to the foramen ovale and also perforates the greater wing of the sphenoid. The foramen transmits the middle meningeal artery from the infratemporal fossa into the cranial cavity. The artery then runs forward and laterally in a groove on the upper surface of the squamous part of the temporal bone and the greater wing of the sphenoid see Fig. The anterior branch passes forward and upward to the anteroinferior angle of the parietal bone (see Fig. Here, the bone is deeply grooved or tunneled by the artery for a short distance before it runs backward and upward on the parietal bone. It is at this site that the artery may be damaged after a blow to the side of the head. The posterior branch passes backward and upward across the squamous part of the temporal bone to reach the parietal bone. The large and irregularly shaped foramen lacerum lies between the apex of the petrous part of the temporal bone and the sphenoid bone (Fig. The inferior opening of the foramen lacerum in life is filled by cartilage and fibrous tissue, and only small blood vessels pass through this tissue from the cranial cavity to the neck. The carotid canal opens into the side of the foramen lacerum above the closed inferior opening. The internal carotid artery enters the foramen through the carotid canal and immediately turns upward to reach the side of the body of the sphenoid bone. Here, the artery turns forward in the cavernous sinus to reach the region of the anterior clinoid process. At this point, the internal carotid artery turns vertically upward, medial to the anterior clinoid process, and emerges from the cavernous sinus (see p. Lateral to the foramen lacerum is an impression on the apex of the petrous part of the temporal bone for the trigeminal ganglion. On the anterior surface of the petrous bone are two grooves for nerves; the largest medial groove is for the greater petrosal nerve, a branch of the facial nerve; the smaller lateral groove is for the lesser petrosal nerve, a branch of the tympanic plexus. The greater petrosal nerve enters the foramen lacerum deep to the trigeminal ganglion and joins the deep petrosal nerve (sympathetic fibers from around the internal carotid artery), to form the nerve of the pterygoid canal. The abducent nerve bends sharply forward across the apex of the petrous bone,medial to the trigeminal ganglion. The arcuate eminence is a rounded eminence found on the anterior surface of the petrous bone and is caused by the underlying superior semicircular canal. The tegmen tympani, a thin plate of bone, is a forward extension of the petrous part of the temporal bone and adjoins the squamous part of the bone (Fig. From behind forward, it forms the roof of the mastoid antrum, the tympanic cavity, and the auditory tube. This thin plate of bone is the only major barrier that separates infection in the tympanic cavity from the temporal lobe of the cerebral hemisphere. The median part of the middle cranial fossa is formed by the body of the sphenoid bone (Fig. In front is the sulcus chiasmatis, which is related to the optic chiasma and leads laterally to the optic canal on each side. Behind the elevation is a deep depression, the sella turcica, which lodges the hypophysis cerebri. The sella turcica is bounded posteriorly by a square plate of bone called the dorsum sellae. The superior angles of the dorsum sellae have two tubercles, called the posterior clinoid processes, which give attachment to the fixed margin of the tentorium cerebelli. The cavernous sinus is directly related to the side of the body of the sphenoid (see p. It carries in its lateral wall the third and fourth cranial nerves and the ophthalmic and maxillary divisions of the fifth cranial nerve (see Fig. The internal carotid artery and the sixth cranial nerve pass forward through the sinus. Posterior Cranial Fossa the posterior cranial fossa is deep and lodges the parts of the hindbrain,namely,the cerebellum, pons, and medulla oblongata. Anteriorly, the fossa is bounded by the superior border of the petrous part of the temporal bone; posteriorly, it is bounded by the internal surface of the squamous part of the occipital bone (Fig. The floor of the posterior fossa is formed by the basilar, condylar, and squamous parts of the occipital bone and the mastoid part of the temporal bone. The roof of the fossa is formed by a fold of dura, the tentorium cerebelli, which intervenes between the cerebellum below and the occipital lobes of the cerebral hemispheres above (see Fig. The foramen magnum occupies the central area of the floor and transmits the medulla oblongata and its surrounding meninges,the ascending spinal parts of the accessory nerves, and the two vertebral arteries. The hypoglossal canal is situated above the anterolateral boundary of the foramen magnum (Fig. The jugular foramen lies between the lower border of the petrous part of the temporal bone and the condylar part of the occipital bone. It transmits the following structures from before backward: the inferior petrosal sinus; the 9th, 10th, and 11th cranial nerves; and the large sigmoid sinus. The inferior petrosal sinus descends in the groove on the lower border of the petrous part of the temporal bone to reach the foramen. The sigmoid sinus turns down through the foramen to become the internal jugular vein. It transmits the vestibulocochlear nerve and the motor and sensory roots of the facial nerve. The internal occipital crest runs upward in the midline posteriorly from the foramen magnum to the internal occipital protuberance; to it is attached the small falx cerebelli over the occipital sinus. On each side of the internal occipital protuberance is a wide groove for the transverse sinus (Fig. This groove sweeps around on either side, on the internal surface of the occipital bone, to reach the posteroinferior angle or corner of the parietal bone. The groove now passes onto the mastoid part of the temporal bone; at this point, the transverse sinus becomes the sigmoid sinus. The superior petrosal sinus runs backward along the upper border of the petrous bone in a narrow groove and drains into the sigmoid sinus. As the sigmoid sinus descends to the jugular foramen, it deeply grooves the back of the petrous bone and the mastoid part of the temporal bone.
The neuroimaging findings of the participants with comparable levels of mental rotation performance demonstrated that both sexes activated a common neural substrate (superior parietal lobe erectile dysfunction pills dischem generic 100 mg zudena amex, dorsolateral premotor cortex erectile dysfunction treatment natural remedies order zudena 100 mg without a prescription, and extrastriate occipital regions) erectile dysfunction psychological proven 100 mg zudena. However erectile dysfunction pump implant video generic 100 mg zudena fast delivery, activation differences were evident in the mental rotation of hands erectile dysfunction doctor in nj order zudena 100 mg with amex, with females showing greater involvement of the left ventral premotor cortex and males demonstrating greater activation of the lingual gyrus erectile dysfunction pump images generic zudena 100mg mastercard. These, as well as other studies, demonstrate the effects that task variations might have on neuropsychological performance both across and between the sexes. Moreover, task variations may contribute to the failure of investigators to replicate results and likely account for contradictory findings. Although a number of studies report that females show greater facility with verbal skills, particularly verbal fluency, conflicting studies are also evident. Similar to the findings with spatial tasks, different verbal tasks may recruit different neural substrates for males and females. Males showed greater activation of the left inferotemporal and other left hemisphere regions than females. In contrast, females demonstrated greater activation of the right inferior frontal gyrus and right precentral cortex, as compared to males who evidenced less activation or actual deactivation of these regions. These differences suggest that men and women use different strategies in processing similar contents. Men and women were presented two visual tasks: one task required visual discrimination and another required visual object construction. The visual discrimination task required the participants to judge whether pairs of square fragments were the same or different, whereas the visual object construction task required a determination of whether square fragments, when visually assembled and related, would make a "perfect square. However, the sexes did differ with respect to the visual object construction task, with females showing predominately left-sided activation, and males exhibiting both left and right hemisphere activation. The finding of increased right hemisphere activation was specific to the performance of men. The difference in performance between males and females could not be attributed to the features of the task employed, and thus reflected the cognitive operations recruited. That is, the two sexes appeared to utilize different cognitive strategies to solve the visual constructive tasks. Wager, Phan, Liberzon, and Taylor (2003) conducted a meta-analysis of 65 neuroimaging studies related to sex, emotions, lateralization, and other relevant variables. These results indicate that the relationship between sex, brain activation, and emotional responses is much more complex than originally believed. Both sexes showed similar lateralized activation patterns for emotion, although men showed these patterns to a greater degree. Differences in neural activation by sex were most evident at the regional, rather than the hemispheric, level. At the regional level, the sexes recruited relatively distinct but overlapping areas, with some regions lateralized left and others right. When processing emotions, males activated the left inferior frontal cortex and posterior cortex, and females more reliably involved the midline limbic regions, including the subcallosal anterior cingulate, thalamus, midbrain, and cerebellum. Moreover, females showed left involvement in regions surrounding the amygdala (sublenticular nuclei), and males activated right-sided regions near the hippocampus. Based on these findings, Wager and colleagues speculate that males may be more biased toward processing the sensory aspects of emotional stimuli with regard to action, whereas females direct more attention to the subjective experience of emotion or, alternatively, show greater overt response to emotion. Finally, whether these regional and lateralized sex differences relate to actual or meaningful behavioral differences awaits further study. The impact of sociocultural opportunities, resources, expectations, and attitudes regarding sex differences cannot be underestimated. For example, greater facility with mathematics has been attributed to males relative to females. Although some have maintained that this greater facility is sex determined, Neuropsychology in Action 6. In summary, there are indications that females show an advantage in verbal abilities, while males tend to demonstrate superiority in visuospatial ability, particularly related to mental rotation tasks. However, these differences are not uniformly supported, and sex differences may be a consequence of sociocultural rather than neurobiological influences, or the interaction of these factors. Finally, differences in emotional processing are evident for males and females that do not conform to a simple left or right hemispheric specialization. The principal functions of the androgen hormones include the masculinization of the fetus, production of sperm, and development of secondary sexual characteristics. The ovarian hormones (estrogens and progestins) are primarily secreted by the ovaries. These hormones are responsible for the in utero "feminization" of the brain, regulation of the ovarianreproductive cycle, secondary sexual characteristics, and menopause. The organization effect relates to the effects of early exposure to hormones during prenatal development, whereas the activation effect refers to the effects of hormones during later development; that is, prenatal exposure to hormones organizes the way behavior is activated by hormones later in development. The masculinization and feminization of the prenatal brain exemplifies the organizing effects of sex hormones, while the physical and psychological changes associated with puberty and menstruation illustrate the activating effects. Notably, male and female hormones are not restricted to either sex in that both sexes produce androgen and ovarian hormones. Sex differences are evident in the hormonalinduced organization of the brain and the ratio of maleto-female circulating hormones in the respective sexes. Studies of healthy subjects show a possible inverted U-shaped curve regarding the effects of androgens on spatial performance (Moffat & Hampson, 1996); that is, a positive correlation is evident between testosterone levels and spatial task performance for females, but a negative correlation exists for males. Additional investigations with healthy participants indicate that average, not extreme, levels of testosterone relate to optimal spatial performance; that is, high levels of testosterone for males and low levels for females are each associated with reduced spatial performance (McCormick & Teillon, 2001). Similarly, transsexuals undergoing cross-sex hormonal treatment also demonstrate differences in spatial performance. Individuals moving from a male to female gender demonstrate decreased spatial performance when administered antiandrogens and estrogen, whereas those moving from a female to male gender demonstrate improved spatial performance when treated with testosterone supplements (van Goozen, 1994; van Goozen, Cohen-Kettenis, Gooren, Frijda, & Van de Poll, 1995). Overall, these findings suggest that increased levels of male androgens enhance the spatial performance of females, but have a "demasculinizing" effect on male spatial performance. Notably, however, male androgens are not the only hormones that effect spatial performance. For example, higher levels of estrogen are associated with poorer spatial performance (Jones, Braithwaite, & Healy, 2003). Young women regularly taking oral contraceptives have near postmenopausal levels of estradiol and also perform more poorly on some spatial tasks than women not taking oral contraceptives (Mohn, Spiers, & Sakamoto, 2005). The circulating levels of both male and female hormones warrant consideration when sex differences are the subject of investigation. In this study, the estrogen, progesterone, androstenedione (natural hormone that is a direct precursor to testosterone), and testosterone circulating levels of healthy elderly women were compared with measures of neurocognitive functioning. The results showed that high levels of estrogen were associated with better delayed verbal memory and retrieval, whereas low levels were correlated with better immediate and delayed visual memory. Interestingly, testosterone levels were positively associated with verbal fluency, but levels of progesterone and androstenedione did not have any relationship to cognitive performance. In addition, circulating levels of female hormones may interact with brain organization. For example, as discussed earlier, right-handers are largely considered left hemisphere dominant for speech; however, sex may influence bilateral expression of speech or other abilities. It may also be that other brain organizing factors, such as degree of left-handedness in the family, termed familial sinistrality, may interact with the sexual organization of the brain. Increasingly, we are realizing that the variables that interact with sex hormones and gender are multiple and not fully understood. Illustrating this issue is a relatively recent investigation (van Goozen, Gooren, Slabbekoorn, Sanders, & Cohen-Kettenis, 2002) in which individuals undergoing transsexual hormonal treatment did not demonstrate the predicted shift in spatial performance. Previous studies have frequently used "mixed" transsexual groups composed of right- and left-handed transsexuals who were either homosexual or heterosexual. The transitioning transsexuals were treated with the appropriate sex hormone supplements and pretested and post-tested with a battery of spatial measures. Results regarding levels of pretest and post-test spatial performance were as follows: heterosexual male control participants showed a higher level of performance than homosexual males transitioning to female gender, who, in turn, demonstrated greater proficiency than homosexual females transitioning to male gender. Heterosexual female control participants achieved significantly lower scores than the previous three groups. Pretesting to post-testing did not demonstrate a significant effect of sex hormone treatment on spatial performance. The authors speculate that the failure to find the predicted effect may have been due to the unique composition of the transsexual group. Accordingly, their level of spatial performance would more closely approximate the opposite sex before sex hormone treatment; thus, the degree or magnitude of possible change in performance would be limited ("ceiling effect") after the introduction of sex hormones. Second, the authors report that left-handed individuals are more sensitive to neuroendocrinologic interventions, and the omission of this group may have accounted for the failure to find an activating effect of sex hormone treatment. Although replication and expansion of this study is warranted, it serves to capture the difficulty of disentangling the effects of sex hormones on gender performance. Investigations of individuals with developmental disorders that affect reproductive hormones have identified similar relations between androgen levels and visuospatial performance. In a similar vein, individuals with androgen insensitivity (genetic males who produce androgens but whose androgen receptors are not responsive to the hormone) demonstrate lower performance relative to verbal intelligence when contrasted with male and female control participants (ImperatoMcGinley, Pichardo, Gautier, Voyer, & Bryden, 1991). The measure of performance intelligence involved tasks requiring visual, visuospatial, and visuomotor abilities. For verbal abilities, a number of studies demonstrate that women, during the high-estrogen phase of their menstrual cycle, demonstrate enhanced cognitive skills in color naming and color reading, mental flexibility, and pairedassociate learning (see Erlanger et al. A comparison (Phillips & Sherwin, 1992) of the cognitive performance of women before and after hysterectomies who received either an estrogen supplement or a placebo revealed that the women who maintained their presurgical estrogen levels demonstrated comparable memory recall (paragraph recall). In contrast, those in the postsurgery placebo group exhibited a significant decline in memory performance. A similar decrement in memory performance has been documented in women who have been administered estrogensuppressing agents (Sherwin & Tulandi, 1996). One group was treated for 21 days with estrogen, and the second group received a placebo. The estrogen-treated group showed greater left hemisphere activation during encoding and increased activation in the right frontal superior frontal gyrus during retrieval. Increased activation of the inferior parietal lobe was evident during storage of verbal information, and deceased activation of the inferior parietal lobe was observed during the storage of nonverbal information. Interestingly, the two groups, despite their differences in regional activation, performed in a comparable manner on the measures of verbal and nonverbal memory. The mixed results suggest that certain hormone regimens may have an enhancing (although subtle) effect on specific cognitive and memory processes. When the ovaries stop producing estrogen, only estrone (a weaker sex hormone produced by the adrenal glands) remains. Initially, it was believed that the risk for stroke, heart disease, vascular dementia, and osteoporosis were associated with decreased estrogen production. Although estrogen augmentation has been associated with improved cognitive performance in menopausal women, particularly in the area of verbal memory, other studies have provided contradictory results. A meta-analysis of studies (Yaffe, Sawaya, Lieberburg, & Grady, 1998) suggests that improved cognitive performance is evident only in women receiving estrogen therapy who were recently menopausal. More disturbing have been recent large-scale studies (Nelson, Humphrey, Nygren, Teutsch, & Allan, 2002; Shumaker et al. An increased risk for dementia appears to be evident for women 65 years or older (Espeland et al. In contrast, elderly women who continued estrogen treatment beyond 10 years exhibited increased prefrontal deterioration and a greater rate of decline on the measures of executive function. Currently, the increases in physical and cognitive risk associated with prolonged estrogen therapy in postmenopausal women appear to over-ride the modest gains initially evident in cognitive functioning. Studies of varied gender groups show that sex hormones have either an enhancing or depressing effect on cognitive performance depending on such factors as the levels of circulating hormones, the specific sex hormone manipulated, type of task introduced, and age of the participants. Notably, similar neural substrates are often implicated in the cognitive processing of the sexes, and identified differences are often more of degree than type. In addition, differences in activated or recruited neural substrates do not necessarily translate into observable or meaningful differences in cognitive performance. Summary In this chapter, we examined the major structures and functions of the cortex, setting the stage for examining the systematic interaction of brain regions (cortical and subcortical) that support the complex behaviors that are presented in subsequent chapters. Hemispheric differences exist, but they are not consistent with the simple notion that people are either "right-brained" or "left-brained" in their behavior. Generally, the brain functions as a cohesive whole with interconnected pathways and regions performing both distinct and overlapping functions. However, certain functions, such as speech, tend to be lateralized to one hemisphere or the other. Lateralization does not imply that the other hemisphere is not providing a complementary function. For example, the left hemisphere is generally specialized for verbal speech, whereas the right hemisphere plays an equally important role in providing the prosodic aspects to speech. Sex differences in the performance of neuropsychological tasks are evident, although the sexes overlap in their performance and the actual differences are small. Morphologic and functional brain differences have been identified; however, there is a lack of empirical consensus. Because of the organizing and activating influence of sex hormones, the relation of these hormones to neuropsychological performance has been the subject of considerable investigation. Androgens appear to have an enhancing effect on visuospatial performance, whereas the bolstering effect of estrogen on verbal performance has received less support. Certainly, the relation of sex hormones to neuropsychological performance is complex, and additional studies are warranted to identify the factors that mediate this relation. Critical Thinking Questions How would you explain the functional differences between the right and left hemispheres?
On examination 60784 impotence of organic origin order zudena 100mg fast delivery, the patient tended to perform all his movements slowly erectile dysfunction ugly wife cheap 100 mg zudena with mastercard, and his face had very little expression and was almost masklike erectile dysfunction doctors in colorado springs purchase zudena 100mg online. When asked to stand up straight impotence young generic 100 mg zudena, the patient did so but with a stooped posture impotence specialists generic zudena 100mg without prescription, and when he walked herbal erectile dysfunction pills uk order 100mg zudena with amex, he did so by shuffling across the examining room. The neurologist made the diagnosis of Parkinson disease, based on her knowledge of the structure and function of the basal ganglia and their connections to the substantia nigra of the midbrain. She was able to prescribe appropriate drug therapy, which resulted in a great improvement in the hand tremors. A 316 C H A P T E R O B J E C T I V E To describe the basal nuclei, their connections, and their functions and relate them to diseases commonly affecting this area of the nervous system the basal nuclei play an important role in the control of posture and voluntary movement. Unlike many other parts of the nervous system concerned with motor control, the basal nuclei have no direct input or output connections with the spinal cord. Caudate Nucleus the caudate nucleus is a large C-shaped mass of gray matter that is closely related to the lateral ventricle and lies lateral to the thalamus (Fig. The lateral surface of the nucleus is related to the internal capsule,which separates it from the lentiform nucleus (Fig. The head of the caudate nucleus is large and rounded and forms the lateral wall of the anterior horn of the lateral ventricle (Fig. The head is continuous inferiorly with the putamen of the lentiform nucleus (the caudate nucleus and the putamen are sometimes referred to as the neostriatum or striatum). Just superior to this point of union, strands of gray matter pass through the internal capsule,giving the region a striated appearance, hence the term corpus striatum. The body of the caudate nucleus is long and narrow and is continuous with the head in the region of the interventricular foramen. The body of the caudate nucleus forms part of the floor of the body of the lateral ventricle. The tail of the caudate nucleus is long and slender and is continuous with the body in the region of the posterior end of the thalamus. It follows the contour of the lateral ventricle and continues forward in the roof of the inferior horn of the lateral ventricle. Clinicians and neuroscientists use a variety of different terminologies to describe the basal nuclei. The subthalamic nuclei, the substantia nigra, and the red nucleus are functionally closely related to the basal nuclei, but they should not be included with them. The interconnections of the basal nuclei are complex, but in this account, only the more important pathways are considered. The basal nuclei play an important role in the control of posture and voluntary movement. The term striatum is used here because of the striated appearance produced by the strands of gray matter passing Lentiform Nucleus the lentiform nucleus is a wedge-shaped mass of gray matter whose broad convex base is directed laterally and whose blade is directed medially (Fig. It is buried deep in the white matter of the cerebral hemisphere and is related medially to the internal capsule, which separates it from the caudate nucleus and the thalamus. A vertical plate of white matter divides the nucleus into a larger,darker lateral portion, the putamen, and an inner lighter portion, the globus pallidus (Fig. The paleness of the globus pallidus is due to the presence of a high concentration of myelinated nerve fibers. Inferiorly at its anterior end, the putamen is continuous with the head of the caudate nucleus (Fig. Thalamus Posterior column of fornix Body of lateral ventricle Body of caudate nucleus Posterior horn of lateral ventricle Head of caudate nucleus Anterior horn of lateral ventricle Frontal pole Occipital pole Tail of caudate nucleus Hippocampus Lentiform nucleus Amygdaloid nucleus Temporal lobe Inferior horn of lateral ventricle Figure 10-1 Lateral view of the right cerebral hemisphere dissected to show the position of the different basal nuclei. The amygdaloid nucleus is considered to be part of the limbic system and is described in Chapter 9. In the sense of fear, for example, it can change the heart rate, blood pressure, skin color, and rate of respiration. Thalamostriate Fibers the intralaminar nuclei of the thalamus send large numbers of axons to the caudate nucleus and the putamen (Fig. The neurons of the substantia nigra are dopaminergic and inhibitory and have many connections to the corpus striatum. The neurons of the subthalamic nuclei are glutaminergic and excitatory and have many connections to the globus pallidus and substantia nigra. Nigrostriate Fibers Neurons in the substantia nigra send axons to the caudate nucleus and the putamen. Brainstem Striatal Fibers Ascending fibers from the brainstem end in the caudate nucleus and putamen. Striatopallidal Fibers Striatopallidal fibers pass from the caudate nucleus and putamen to the globus pallidus (Fig. Striatonigral Fibers Striatonigral fibers pass from the caudate nucleus and putamen to the substantia nigra (Fig. The globus pallidus forms the major site from which the output leaves the basal nuclei. Basically, the corpus striatum receives afferent information from most of the cerebral cortex, the thalamus, the subthalamus, and the brainstem, including the substantia nigra. The information is integrated within the corpus striatum, and the outflow passes back to the areas listed above. The activity of the basal nuclei is initiated by information received from the premotor and supplemental areas of the motor cortex, the primary sensory cortex, the thalamus, and the brainstem. Motor cerebral cortex Sensory cerebral cortex, thalamus, brainstem (substantia nigra, red nucleus) Caudate nucleus, putamen Globus pallidus Cranial nerve motor nuclei Anterior horn cells of spinal cord Final common pathway to muscles Figure 10-5 Diagram showing the main functional connections of the basal nuclei and how they can influence muscle activity. Thus, the basal nuclei control muscular movements by influencing the cerebral cortex and have no direct control through descending pathways to the brainstem and spinal cord. In this way, the basal nuclei assist in the regulation of voluntary movement and the learning of motor skills. Writing the letters of the alphabet, drawing a diagram, passing a football, using the vocal cords in talking and singing, and using the eye muscles when looking at an object are a few examples where the basal nuclei influence the skilled cortical motor activities. Destruction of the primary motor cerebral cortex prevents the individual from performing fine discrete movements of the hands and feet on the opposite side of the body (see pp. However, the individual is still capable of performing gross crude movements of the opposite limbs. If destruction of the corpus striatum then takes place,paralysis of the remaining movements of the opposite side of the body occurs. The basal nuclei not only influence the execution of a particular movement of, say, the limbs but also help prepare for the movements. This may be achieved by controlling the axial and girdle movements of the body and the positioning of the proximal parts of the limbs. The activity in certain neurons of the globus pallidus increases before active movements take place in the distal limb muscles. This important preparatory function enables the trunk and limbs to be placed in appropriate positions before the primary motor part of the cerebral cortex activates discrete movements in the hands and feet. Hyperkinetic disorders are those in which there are excessive and abnormal movements, such as seen with chorea, athetosis, and ballism. Hypokinetic disorders include those in which there is a lack or slowness of movement. Computed tomography scans show enlarged lateral ventricles due to degeneration of the caudate nuclei. Chorea In chorea, the patient exhibits involuntary, quick, jerky, irregular movements that are nonrepetitive. The antigens of the streptococcal bacteria are similar in structure to the proteins present in the membranes of striatal neurons. This results in the production of choreiform movements, which are fortunately transient, and there is full recovery. Huntington Disease Huntington disease is an autosomal dominant inherited disease, with the onset occurring most often in adult life. The disease affects men and women with equal frequency and unfortunately often reveals itself only after they have had children. Choreiform movements first appear as involuntary movements of the extremities and twitching of the face (facial grimacing). Later, more muscle groups are involved, so the patient becomes immobile and unable to speak or swallow. This results in the dopasecreting neurons of the substantia nigra becoming overactive; thus, the nigrostriatal pathway inhibits the caudate nucleus and Hemiballismus Hemiballismus is a form of involuntary movement confined to one side of the body. It usually involves the proximal extremity musculature,and the limb suddenly flies about out of control in all directions. The lesion, which is usually a small stroke, occurs in the opposite subthalamic nucleus or its connections; it is in the subthalamic nucleus that smooth movements of different parts of the body are integrated. Parkinson Disease Parkinson disease is a progressive disease of unknown cause that commences between the ages of 45 and 55 years. It is associated with neuronal degeneration in the substantia nigra and, to a lesser extent, in the globus pallidus, putamen, and caudate nucleus. This leads to hypersensitivity of the dopamine receptors in the postsynaptic neurons in the striatum. It should be distinguished from the intention tremor seen in cerebellar disease, which only occurs when purposeful active movement is attempted. This differs from the rigidity caused by lesions of the upper motor neurons in that it is present to an equal extent in opposing muscle groups. If the tremor is absent,the rigidity is felt as resistance to passive movement and is sometimes referred to as plastic rigidity. If the tremor is present, the muscle resistance is overcome as a series of jerks,called cogwheel rigidity. The movements are slow, the face is expressionless, and the voice is slurred and unmodulated. The normal brain image shows large amounts of the compound (yellow areas) distributed throughout the corpus striatum in both cerebral hemispheres. In the patient with Parkinson disease, the brain image shows that the total amount of the compound is low, and it is unevenly distributed in the corpus striatum. Since the corticospinal tracts are normal, the superficial abdominal reflexes are normal, and there is no Babinski response. Postencephalitic parkinsonism developed following the viral encephalitis outbreak of 191617 in which damage occurred to the basal nuclei. Meperidine analogues (used by drug addicts) and poisoning from carbon monoxide and manganese can also produce the symptoms of parkinsonism. Unfortunately, dopamine cannot cross the blood-brain barrier,but its immediate precursor L-dopa can and is used in its place. L-Dopa is taken up by the dopaminergic neurons in the basal nuclei and converted to dopamine. Selegi- line, a drug that inhibits monoamine oxidase, which is responsible for destroying dopamine, is also of benefit in the treatment of the disease. There is evidence that selegiline can slow the process of degeneration of the dopa-secreting neurons in the substantia nigra. Transplantation of human embryonic dopamine-producing neurons into the caudate nucleus and putamen has been shown to lead to improvement in motor function in Parkinson disease (Fig. Autotransplantation of suprarenal medullary cells can be a source of dopa-producing cells, but in the future, genetically engineered cells could be another source of dopa. Since most of the symptoms of Parkinson disease are caused by an increased inhibitory output from the basal nuclei to the thalamus and the precentral motor cortex, surgical lesions in the globus pallidus (pallidotomy) have been shown to be effective in alleviating parkinsonian signs. Drug-Induced Parkinsonism Although Parkinson disease (primary parkinsonism) is the most common type of parkinsonism found in clinical practice, druginduced parkinsonism is becoming very prevalent. Drugs that block striatal dopamine receptors (D2) are often given for psychotic behavior. Athetosis Athetosis consists of slow,sinuous,writhing movements that most commonly involve the distal segments of the limbs. Degeneration of the globus pallidus occurs with a breakdown of the circuitry involving the basal nuclei and the cerebral cortex. In the panel on the far left, an axial (horizontal) section through the caudate nucleus and putamen of a normal subject shows intense uptake of 18-F-fluorodopa (red). On the right side,the upper panels show preoperative and 12-month postoperative scans in a patient in the transplantation group. Before surgery, the uptake of 18-Ffluorodopa was restricted to the region of the caudate nucleus. After transplantation,there was increased uptake of 18-F-fluorodopa in the putamen bilaterally. The lower panels show 18-F-fluorodopa scans in a patient in the sham-surgery group. A 10-year-old girl was seen by a neurologist because of the gradual development of involuntary movements. To begin with,the movements were regarded by her parents as general restlessness, but later, abnormal facial grimacing and jerking movements of the arms and legs began to occur. The child was now having difficulty in performing normal movements of the arms, and walking was becoming increasingly difficult. The abnormal movements appeared to be worse in the upper limbs and were more exaggerated on the right side of the body. The movements were made worse when the child became excited but disappeared completely when she slept. A 40-year-old man complaining of rapid and jerky involuntary movements involving the upper and lower limbs was seen by his physician. He said that he was extremely worried about his health because his father had developed similar symptoms 20 years ago and had died in a mental institution.
Syndromes
Each aspect of the lower kinetic chain xeloda impotence generic 100 mg zudena mastercard, including trunk vyvanse erectile dysfunction treatment purchase zudena 100mg mastercard, is evaluated for the multiple components of efficient neuromuscular control erectile dysfunction blue pill zudena 100 mg for sale. A frequently identified dysfunctional component is poor control of dorsiflexion with eversion and hip internal rotation in the flexion-abduction pattern erectile dysfunction over 65 discount zudena 100mg. As the technique is being applied erectile dysfunction at age 28 order 100mg zudena fast delivery, the status of the dysfunction continues to be evaluated erectile dysfunction caused by anabolic steroids order 100 mg zudena free shipping. If an improvement is noted during the treatment process the facilitation techniques used are gradually eliminated until the pattern can be performed with minimal facilitation. The improved pattern is integrated into more complex patterns of movement and functional activities, specifically those movements and activities that have been previously assessed as symptomatic or dysfunctional. As coordination, muscle recruitment, strength, and control improves normal activities become less stressful upon the symptomatic structures and the potential of reinjury is reduced. Once a technique is selected and applied, the therapist evaluates the results and proceeds by choosing from the list of options (Table 11. The following techniques were developed in response to clinically identified dysfunctions. Evaluate whether the technique w as effectively applied, and if not, correct the technique and apply again, or b. Teach p atient self exercise program to maintain and enhance gains between treatments, or d. Judiciously reduce use of facilitory technique and train patient to move efficiently against resistance without facilitation, or b. In preparation to apply the technique, the patient is positioned in a posture conducive to relaxation. The technique is divided into three distinct components; passive, active, and resisted. The technique is initiated by requesting the patient to relax and allow the therapist to perform the desired motion passively. When a smooth and rhythmical passive motion is achieved, the therapist asks the patient to minimally assist with the motion. The goal is to slowly increase r esistance with each repetition while maintaining the same rhythm and excursion of motion. The rhythmic initiation technique can be helpful to progressively facilitate active and resistive contractions in patients with acute pain. For acute lumbar symptoms, passive pelvic motion in pain-free range can provide oscillatory inhibition. As the patients relax and allow the motion, they are requested to provide a minimal active contraction. This active contraction can begin to inhibit pain and spasm, and provide a muscular pumping action for the region. If the active contraction is built to a point where resistance can be added, it is added minimally at first and, if possible, with traction. The exact timing and speed of the transitions will depend upon the individual patient and the goals of treatment. When a dysfunction is identified the technique is initiated by utilizing the type of contraction the patient performs best. Included arePoor Concentric Control: Problems with initiation, power of concentric contraction, coordination, and direction of motion are treated through use of maintained and eccentric contractions. If the patient is unable to easily move a body part to a specific target position, the body part is placed at that point. A maintained contraction is built followed by a short-range eccentric contraction with an immediate concentric contraction to return to the target position. T his procedure is r epeated until the concentric contraction can be performed to the target point. Poor Eccentric Control: Difficulty in controlled eccentric contractions with appropriate strength is treated through utilization of maintained and concentric contractions. A ratchety quality of an eccentric contraction performed against appropriate resis- 262 tance. Once the ratchety type of contraction begins, a maintained contraction is initiated, then a short-range concentric followed by an eccentric. This procedure is repeated until optimal control is gained, which is determined by reassessing motion quality. Inefficient Maintained Isotonic: The inability to perform a maintained contraction, with optimal strength and endurance is treated through utilization of concentric and eccentric contraction. The inability to hold a position would be u·eated by slowly switching between shortrange concenu·ic and eccentric contractions until a maintained one can be established. Inefficient N euromuscular Control: the goal is to be able to functionally combine these three contractions in a smooth and coordinated manner. It can be performed from elongation or it can be superimposed upon an existing contraction. A contraction is initiated by a stretch stimulus and coordinated with a timed verbal command. The reflex contraction is reinforced through the immediate application of appropriate resistance. The part is then passively or actively returned to the elongated position and process repeated. Because the stretch reflex is facilitory, the motion can be repeated multiple times to enhance the learning, strengthening, and conditioning process, with minimal fatigue. Initial training begins with resisted gait to facili tate the proper pelvic and lower extremity mechanics. Once developed, resistance is applied to the upper extremiti es through direct or indirect (use of a dowel) to train ~ough combi nation of isotonics appropriate weight shift, weight acceptance, balance, force production, and shoulder gi rdle stability. Push-pull activities broken down into: A) resisted gait; B) direct resistance through the extremities; C) indirect resistance through a dowel. This is possible because resistance maintains tension on the contracting muscles, to which a stretch reflex is superimposed, followed by immediate resistance applied to the subsequent reflex contraction. The number and frequency of repeated quick stretches varies according to the dysfunction and the goal of treatment. Multiple repetitions of the motion can be performed while applying repeated quick stretches through the range. The goal of treatment is to train tl1e patient to maintain a stable neutral lumbar spine, while the therapist resists tl1e lower extremities. Often specific components of a lower extremity pattern do not initiate and/or fire during the range of the movement. This control is essential to produce efficient interaction between the demands for mobility and stability. When an antagonist fails to work in accordance with the demand of the activity, function is immediately impaired. The technique is begun by initiating a concentric contraction, ei ther through a verbal command alone or one that is timed with a stretch reflex. At the point in the range, if a reversal of directions is desired the therapist smoothly shifts from applying resistance with both hands to one (usually freeing the proximal hand). The free hand then applies manual contact to the antagonistic surface, and for a brief time the hands are contacting both surfaces. A reversal of direction is elicited through a verbal command and if necessary a quick stretch. The goal is to train the patient to shift smoothly and effectively from one pattern to the other. When there is difficulty in reversing direction smoothly, the therapist may use a maintained isotonic to the agonistic motion. This maintained isotonic contraction will facilitate the antagonists motion and allow the therapist time to change manual contacts. As the patient learns to reverse directions smoothly with simple nonweight-bearing patterns the skills are advanced to more complex functional activities. The goals of the technique are to improve stability around a segment, to increase positional neuromuscular awareness, to improve posture and balance, and to enhance strength or stretch sensitivity of extensors in the shortened range. Manual contacts can be placed either on one side of the trunk or extremity, or on both sides. This matching or isometric contraction is built to a maximal level without promoting a concentric response. Once the contraction has plateaued, the therapist can slowly change the manual contacts to place a varying demand on the stabilizing muscles. To shift a manual contact, one hand must adjust resistance to maintain the contraction while the other hand slowly releases its resistance. The transition must be smooth, not allowing for any relaxation or initiation of attempted motion. If the patient is not able to perform an isometric contraction a maintained isotonic contraction is used. A good illustration is the application of resistance to the shoulder girdle region to promote trunk stability in sitting. As the patient is instructed to maintain a balanced position, the therapist slowly begins to apply resistance to the trunk through manual contacts at the shoulder region. If the resistance is applied too quickly, the patient may respond with an active isotonic contraction of the shoulder girdle muscles. By applying the resistance slowly, the therapist not only encourages an isometric contraction of the shoulder girdle region, but facilitates irradiation to the trunk muscles in an isometric mode. At this time, the therapist slowly changes the manual contacts in a smooth and coordinated manner, so as to 266 maintain the isometric nature of the trunk contraction (Fig. Contract relax utilizes the development of muscle tension through an concentric or maintained contraction to facilitate relaxation and stretching of the intrinsic connective tissue elements of that muscle. To increase range of motion of the myofascial unit, by facilitating relaxation and improving extensibility of the myofascial tissues. Relaxation of unnecessary muscle tension may also serve to improve local circulation. All components of the pattern should be resisted and a few degrees of motion allowed to occur. Special emphasis should be placed on the rotatory component of the pattern, as it will facilitate a more complete contraction and relaxation. The duration and intensity of the contraction should be sufficient to generate a strong contraction within the target muscles. Following the contraction, the patient is asked to completely relax, and upon full relaxation the segment is passively or actively taken into the new available range. Resisted motion into the new range can be used for reinforcement, strengthening, or further reciprocal inhibition. In the presence of pain or when the concentric contraction is overpowering, an isometric contraction provides greater control of the procedure. The part is placed in a painfree portion of the range and the isometric contraction is slowly built. In cases with highly irritable symptoms the facilitated contraction may be minimal. In some cases, the technique is most effectively applied to a pain-free portion of the body to create indirect relaxation through irradiation. The segment may then be moved actively or passively to the new range, or the technique may be repeated without motion to gain further relaxation or pain reduction. The first aspect of treatment is to identify positions which reduce symptoms and provide appropriate supports. In addition, an important adjunct to treatment is the use of ice, which is most effective if utilized while treatment techniques are being applied. The authors personally prefer the icing system developed by Kabat and Knott, which uses towels soaked in a bucket of shaved ice and water. These towels are wrung out and placed over the painful and surrounding regions, and changed every few minutes. These techniques are applied to components which facilitate appropriate irradiation. As relaxation occurs and if symptoms reduce, controlled use of combinations of isotonics can begin to assist in improving mobility, circulation, and relaxation of the symptomatic region. Also mid - range active short-arc motions can provide oscillatory inhabition and relaxation. If symptoms are minimally irritable the primary goal of treatment is to assess for dysfunctions (characteristics of neuromuscular control) and to provide appropriate manual therapy (soft tissue and joint mobilization and neuromuscular reeducation). Pain is rarely localized to the primary dysfunctional structure, partially due to the compensatory movement patterns and altered postures. These compensations, if chronic, precipitate muscular imbalances and strength loss. Secondary dysfunctions serve to reinforce the primary dysfunction and ultimately need to be addressed. Patients suffering from cervical pain and demonstrating restricted cervical movements, often have restriction of scapula patterns as well. Since the cervical spine and shoulder girdles share many of the same muscles, treatments of shoulder girdle dysfunction often have dramatic effects on cervical dysfunctions and symptoms. In addition, in highly irritable patients in which the cervical spine cannot be treated, the shoulder girdle may often be successfully utilized. Muscle tension reduction may produce immediate changes in arthrokinematics, extensibility, and proprioceptive input of the shoulder girdle and cervical spine. As compensations are resolved, the therapist can work directly into the primary dysfunction, much like peeling the layers of an onion. Limited Functional Excursion and Muscular Imbalance Dysfunctional effects occur secondary to limited myofascial excursion, muscle play, and muscular imbalance.
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