This investigation has been more useful Discussion in the assessment of nonsquamous tumors and in the detection of infraclavicular or metastatic disease buy antabuse 500 mg low price medicine 801. A diagnosis can be obtained in more than 90% of patients; therefore discount 500mg antabuse medicine 014, open lymph–node biopsy is usually not necessary and is not recom- mended buy cheap antabuse on-line treatment kennel cough. Early radia- hot spot was seen in the nasopharynx, and there tion effects include radiation dermatitis and mucosi- was no evidence of any systemic disease. For a large, infiltrative mass in the upper neck, radical Recommendation neck dissection may be necessary, but one or more The patient is seen and assessed in a multidiscipli- of the internal jugular vein, spinal accessory nerve, nary clinic, and is offered surgical treatment in the or sternomastoid muscle may be preserved in an form of a comprehensive right neck dissection, to be attempt to reduce the morbidity of the procedure, as followed by adjuvant radiotherapy to the neck. She is seen regularly in follow-up and remains well and free of disease 3 years following her surgery, with the primary tumor never having been found. Discussion As is the case for management of the neck in cases of head and neck cancer with known primaries, treatment options generally include surgery, radio- therapy, or a combination of the two. For limited neck disease with no extracapsular tumor exten- sion, a single modality of treatment (either a neck dissection or neck irradiation alone) may be all that is necessary. Most patients, however, will present with advanced neck disease, and combination ther- apy is appropriate. Controversy exists regarding whether irradiation should be given only to the neck, or to all potential primary sites. There is doubt whether radiotherapy to the nasopharynx, hypopharynx, supraglottic lar- ynx, and oropharynx is associated with a reduction Figure 6. Intraoperative Report More extensive radiotherapy also does not appear to confer any additional survival advantage. On modified radical neck dissection, the single Primary tumors will become apparent in up to nodal mass proves to be quite mobile, and unin- 20% of patients, and are usually associated with a volved fascial planes over the sternomastoid mus- worse outcome because only a minority will be sal- cle and above the plane of the accessory nerve vaged. Up to 25% of patients overall may develop recurrence in the neck, with half or more of these in the contralateral neck. Ongoing surveil- lance is mandatory if these patients are to achieve Case Continued optimal outcomes. Cervical lymph node metastases of squamous cell carcinoma from an unknown primary. Oncologic rationale for tion for squamous cell carcinoma metastatic to cervical lymph bilateral tonsillectomy in head and neck squamous cell carci- nodes from an unknown primary site: outcomes and patterns noma of unknown primary source. Neck dissection and ipsi- radiotherapy and chemotherapy for high-risk squamous cell lateral radiotherapy in the management of cervical metastatic carcinoma of the head and neck. Tonsillectomy in the 18-labelled deoxyglucose positron emission tomography in diagnosis of the unknown primary tumor of the head and the investigation of patients with cervical lymphadenopathy neck. A 55-year-old, previously well man presents with a history of a painless, gradually enlarging mass in the region of the right parotid for about 7 months. He presents after noticing difficulty depressing the right Differential Diagnosis angle of his mouth, and being unable to close his This man has significant risk factors for mucosal right eye fully for the previous week. He gives a 90- carcinoma of the upper aerodigestive tract, and pack-year history of cigarette use and has chewed careful assessment is needed to exclude a mucosal tobacco for 40 years. However, the presence of a mass partially alcohol intake, but has drunk none in the past overlying the angle of the mandible, in association decade. There were, however, no symptoms related with facial nerve weakness, strongly suggests a to the upper aerodigestive tract. Examination reveals malignancy arising in, or metastatic to, the parotid facial asymmetry with weakness in the distribution salivary gland. In some adult populations, metasta- of upper and lower divisions of the facial nerve. No parotid malignancies may be the cause; mucoepi- mucosal lesions or cutaneous tumors are present. Nonepithelial primary malignancies such as sarco- ma and lymphoma are less likely, but should be considered. Most parotid tumors are benign, but these are rarely associated with facial nerve weak- ness. A primary neurogenic tumor or an inflamma- tory lesion involving the nerve is possible, as is a synchronous benign tumor and unrelated neuropa- thy; however, active steps should be taken to exclude malignancy even if these diagnoses are suggested. Cell block (A) and Papanicolaou stain (B) show malignant cells with dense cytoplasms and high nuclear grades. Early radiation effects and specificity well over 90% with experienced include radiation dermatitis and mucositis, with the cytopathologists. In this case, the distinction needs to be made between a primary and a metastatic lesion that will effect management of the neck. Confirming the presence of malignancy allows appropriate counsel- ■ Surgical Approach ing about the management of the facial nerve. The parotid is approached via a right preauricular Imaging the parotid probably adds little to the incision that is extended into an upper neck skin assessment of benign lesions in the superficial lobe crease, raising a skin flap above the plane of the of the gland, but is necessary in an assessment of parotid fascia in the cheek and deep to the platysma malignancy to accurately define the site and extent in the neck. If skin infiltration is suspected, skin over of the tumor and its relationship to neural and vas- the tumor mass is excised in continuity. The presence or absence of tumor at the surgical resection margins has a significant Diagnosis impact on the prognosis of these carcinomas. The facial the right parotid gland and involving the facial nerve is transected as it leaves the stylomastoid nerve, with the tumor staged clinically as T4a N0 foramen. Frozen After assessmenThat a multidisciplinary clinic, the sections should be taken from the proximal and dis- patient is offered surgical treatment in the form of tal nerve margins because perineural tumor may be radical total parotidectomy with sacrifice of the presenThat sites distant from macroscopic disease. Primary reconstruction of the nerve negative neck in major salivary gland cancers is with a nerve graft is recommended. The suspicion of a high-grade lesion in therapy to the parotid bed will be required, and will this case implies a risk of nearly 50% that occult likely also be necessary for the neck. The patient is nodal disease is present, so treatment of the neck informed that nerve reconstruction will not result needs to be addressed. Indications already exist for in the immediate return of facial function, and the postoperative radiotherapy, and experience suggests importance of eye care postoperatively to avoid that, as in mucosal squamous cell carcinoma, sub- exposure keratosis and blindness is stressed. Complications of be entered to achieve an adequate margin on the the neck surgery discussed include wound collec- tumor mass, little additional morbidity will be tions due to hemorrhage or seroma, neck stiffness incurred to remove the upper neck nodes. The sural nerve is chosen for grafting because it is a branched sensory nerve easily harvested from the distal lateral leg, the loss of which causes little morbidity. As many branches as possible are grafted, with priority given to branches to the periorbital muscles. The facial nerve weakness is more pro- nounced, but there is adequate corneal cover initially. Tarsorrhaphy is ultimately required to improve ectropion, but the patient declines inser- tion of a gold weight to the upper lid and suffers no complication as a result. There is obvious perivascu- lar invasion, with gross tumor within the external jugular vein. Even without obvious nerve dysfunction, the findings of perineural invasion will double the chance of local failure.
For example buy antabuse 250mg without prescription medications safe while breastfeeding, when we fnd a human beings over age is shaped nearly like a bathtub (Figure B generic antabuse 500 mg with amex medicine grand rounds. This is a frequentist approach cheap antabuse 250mg without a prescription medications in mothers milk, decreasing fairly soon to a minimum, remaining low for a substan- pioneered by Ronald Fisher, considered by many as the father of sta- tial part of life, and then starting to climb again sometime around tistics. This is called the prior distribu- The Bayes rule has widespread applications, but this section is tion since it is based on prestudy knowledge. Medical knowl- used to “update” this prior distribution using the Bayes rule, and edge sometimes is such as to provide probabilities of the form this updated distribution is called the posterior distribution. In the case of testing of given disease, whereas the probabilities actually required in diag- a hypothesis, Bayesian procedure is to compute the probability of nostic process are the probability of disease given the complaints, the value of the parameter specifed in the null hypothesis given in namely, P(disease|complaints). One is the inverse of the other in the sense that the frst is written as P(θ|x), where θ is the parameter, x is the sample, and P the probability of complaints conditioned on disease being known, stands for probability. On the other hand, in a frequentist approach, and the second is the probability of disease conditioned on com- our inference is based on P(x|θ). The Bayes rule is a tool that helps in fnding Note that the Bayes rule is central to the Bayesian inference. This rule helps to convert one conditional probability P(x|θ) into For simplicity and for generalizability, denote the set of com- its inverse P(θ|x) but requires knowledge of P(θ) and P(x). When some additional probabilities depend on the distribution of θ and the distribution of information is available, P(D|C) can be obtained from P(C|D) by x. While the distribution of the sample values x is easy to handle, using the Bayes rule. For this conversion, two additional probabili- the diffculty arises in postulating a prior distribution of θ. This is the prior probability of assumes that we know some properties of the parameter on the the disease in the absence of any information and is the same as the basis of which P(θ) can be postulated. For example, we may pos- prevalence of the disease in the subjects under investigation. This tulate on the basis of the previous experience that the chance of may be derived from, for example, the records of the health facility the next person in a renal clinic having a failed kidney is 1 in 15— where this is to be applied or may be available from a survey. The that is, the clinic has been receiving, on average, 1 out of 15 cases second is P(C). Special efforts may be required to compute P(C), cases turn out to have a failed kidney, our belief alters, refecting but it is worth the effort given the diffculty in obtaining P(D|C) the posterior probability. When a patient goes to a clinic with certain com- alternative method, given later in this section. Once these probabili- plaints, you mentally evaluate his/her chances of being affected ties are available, the required inverse probability P(D|C) can be by a particular disease on the basis of clinical fndings. When the computed from results of medical tests or radiological images are available, that belief may alter. They examined four prediction models and used their com- This gives the posterior probability after the complaints are bined prediction of the susceptibility for each test individual using known. If the group of complaints (abdominal pain, vomit- ties for multiple cancer classes. If that is so, we can fnd the probability of abdTb given those complaints by The basic premise of Bayes is to change our mind as new evidence using the following: emerges. Thomas Bayes described this rule in the 1740s, but it was Laplace who described it independently in 1774 and gave it a mod- Bayes rule (slightly expanded version): ern mathematical form . The following example illustrates its use and also the caution required in interpreting an inverse probability. Then, the preceding para- group designs because the subjects for before–after measurements graph says that P(D1) = 1/2000 = 0. Use the following to the same effect as compared with parallel control experiments. A major problem with the before–after design is that it assumes Since D1 and D2 are mutually exclusive (K = 2 in this case), an that nothing except the intervention is changing the outcome. But the expanded version of the Bayes rule gives observed effect could be at least partially due to psychological fac- tors that operate in a placebo group. The diffculty is in it being positive in 1% of the ioral treatments that separately reported the pooled estimate for con- subjects without the disease. And this group is very large: 1999 out trolled and uncontrolled studies and found the observed effect for of 2000 in this screening exercise. Thus, most positive results arise uncontrolled studies to be greater than that from studies with parallel from errors rather than from diseased cases. This explains why a before–after design is typically used smaller error rate is required to be effective in such a situation. Thus, P(D1|C) would be both these values are subject to sampling fuctuation and measure- much higher in a clinic setup than the one obtained earlier in a screen- ment errors, the differences are kind of doubly exposed to these ing example. Yale University Press, jected to before–after measurements, a commonsense approach to 2011. The before–after difference in the test group is compared with the before–after difference in the control group. One can hope that in the case of a difference in dif- bed–population ratio, see health ferences, these errors cancel out between the groups. The effcacy of psychological, educational, and behavioral treatment: Confrmation from meta-analysis. For Beherens–Fisher problem, see Welch test example, a study measuring tail-fick latency in mice exposed to heat before and after administration of an analgesic does not have a parallel control group. Such a design is called a before–after design, bell-shaped distribution, see Gaussian distribution and the experiment is called a before–after study. Since there is no parallel control group in this setup, this is sometimes referred to Berkson bias as an uncontrolled design, although this is rather misleading since each subject serves as its own control. Many call this a quasi- This bias occurs when a conclusion is drawn from a special group of experimental design because of the lack of random allocation to a subjects that do not represent the target population. In a bacterial colony, the bacteria could can happen since hospital controls will usually have some disease and be counted initially, provided a specifc favorable environment this disease may also be related to the risk factor under study. If this study is done in a hospital setting using a case–control repeated measures design. In a clinical trial, one can measure oxi- design, you might take patients with diseases other than cancer from dative stress enzyme levels (e. However, these patients may also have disease, introduce an intervention to reduce this stress, and mea- a preponderance of smokers, as smoking can have manifestations sure again. A parallel control group is not necessary in this setup, other than lung cancer; for example, they may have asthma. Despite although some experiments may have a parallel group as well for being noncancer patients, asthma patients are not proper controls for observing the trend in them also after placebo. Controls should be chosen such backward elimination 41 butterfy effect that they have the same prevalence of the risk factor (in our example, Suppose there are K predictors (x1, x2, …, xK) to begin with, and the smoking) as in the general population. Under the best subset method, the relationship not be appropriate controls, since it is possible that smokers get more of y with each xk, of y with pairs xk and xk*, of y with each triplet of fractures than nonsmokers. Fortunately, statistical packages can easily handle these calcula- tions, and the subset of predictors that provide the best prediction can be identifed. In a multiple linear regression setup, for which the best sub- set method is commonly used, only the linear combinations are examined.
On Т2-weighted imaging (b order cheap antabuse on line medicine z pack,c) and Т1-weighted imaging (d) antabuse 500 mg cheap treatment anemia, a difuse tumour growth is seen in the basal ganglia bilaterally with involve- ment of midbrain order 500mg antabuse medications causing hair loss, pons, and the lef cerebellar hemisphere Infratentorial Tumours 689 Fig. The bottom of fossa rhomboidea is evagi- nated, and the fattened fourth ventricle is displaced backwards Fig. Т2-weighted imaging (b) and Т1-weighted imaging (c,d), clearly visualises the intrabrainstem location of the tumour Infratentorial Tumours 691 Fig. However, on microscopy, infltra- It is important to ascertain the distribution of the exophyt- tive growth is revealed, with destruction of brain tissue. We usually observed it within the tumours are usually malignant primitive neuroepithelial tu- lumen of the fourth ventricle (32%; Fig. If an exophytic component was absent, or signal changes are combined, and calcifcations and cysts then an endophytic tumour was diagnosed. High frequency of implantation metastases along gioreticulomas, melanoma metastases, etc. On ment of such parameters as topography, type of growth, his- T1-weighted imaging, a hypointensive, and on T2-weighted tology if available, and presence of cystic and exophytic com- imaging, a hyperintensive signal, are revealed. On T2- On Т1-weighted imaging (b,c), hyperintensive foci are revealed in weighted imaging (а), a tumour of heterogeneous structure is seen the tumour stroma (haemorrhages within a tumour) with an exophytic component. On Т2-weighted imaging (а) and Т1-weighted imaging (b), a tumour of pons is revealed with expan- sion onto midbrain. Т2-weighted imaging (d,e) shows difuse involvement of pons with an exophytic component (in the fourth ventricle). Т2-weighted imaging (а) and Т1-weighted imaging (b) show a tumour of the right half of pons, which has hyperintensive signal on Т2-weighted imaging and hypointensive signal to brain tissue Т1-weighted imaging. The tumour is hypointensive to brain tissue on Т1-weighted imaging and intensively accumulates contrast medium. On autopsy, only the brain tissue is typical for the latter and not only tegmen- 6–9% of all intra-axial haemorrhages are brainstem haemor- tal, but also brainstem base involvement occurs. In addition, in many patients brainstem haemorrhages severe, irreversible, and ofen fatal. Surgical removal of such are missed, being diagnosed as inoperable brainstem tumours, tegmental haemorrhages is not performed. Elastic and Angiography does not usually reveal any signs of vascu- muscle tissues are absent, and an argyrophilic matrix is identi- lar malformation. The pons is the usual location of telangi- teries, typical for a mass lesion in the brainstem, is found. Walls of these cavities are lined with malformation is small, or is self-destroyed afer haemorrhage. If located at the level of in- thromboses, sclerosis, and calcifcations are found. The origin ferior brainstem, artefacts caused by bone may hinder imag- of sclerotic changes is unequivocal; they are due to organi- ing of the haemorrhage. Reactive glial changes stained yellow are typi- brainstem haemorrhage is hyperdensive (Fig. Afer liquefaction and resorp- ten accumulations of branching vessels resembling capillaries tion of a blood clot, which starts on a haemorrhage periph- are seen on the periphery of a malformation. Abnormally located small veins in the lef half of the posterior fossa are seen in the venous phase, which drain into a single hypertrophied vein—the “brush” sign (arrows) 702 Chapter 7 Fig. In the acute stage (several minutes to blood–brain barrier impairment in the newly formed vessels several hours), a formed clot contains oxyhemoglobin, which of a newly formed haemorrhage capsule (Fig. Tis is why the a haemorrhage becomes hypodensive, which represents the quality of imaging of an acute haemorrhage is determined by liquefaction and resorption of the blood clot (Fig. In the presence of water molecules—they look isointensive on rare cases of chronic haemorrhages, sedimentation phenom- Т1-weighed images and hyperintensive on Т2-weighted imag- enon may be seen due to sedimentation of blood elements es. Later, oxyhemoglobin transforms into deoxyhaemoglobin, and remnants of the blood clot that have not yet undergone which shortens Т2 in the area of a haemorrhage, but the latter lysis (Fig. By that time, the haemorrhage acquires hyper- bin-oxidising derivates, which have paramagnetic proper- intensive signal of its centre and hypointensive signal at the ties. Other factors determining the appearance of brainstem periphery in all sequences (Fig. The density of brainstem haemorrhage content is lower than that of brain tissue 704 Chapter 7 Fig. On Т1-weighted imaging (b), haemorrhage has high signal intensity due to methaemoglobin. On CТ (а,b) a round, hypodensive lesion in the right half of pons is seen—chronic haemorrhage. Sedimentation phenomenon is seen in the inferior part of haemorrhage as a hyper- densive area Infratentorial Tumours 705 Fig. Т2-weighted imag- ing (а) and Т2-weighted imaging (b) shows the round mass lesion in the pons. The brainstem density with a mass lesion does malformation on T2-weighted imaging are considered acute not change, or, it may be hypodensive due to oedema. In some cases, the pon- (on Т1- and Т2-weighted images) correspond to subacute hae- tine cisterns remain free. But absence of oedema, tumour tissue bleeding, haemorrhage, then its density would have gradually changed and perifocal hypointensive area (especially on T2-weighted (Fig. It should be remembered that imaging of a small malforma- tion within the site of haemorrhage is impossible, as the latter overwhelms all other features. Lung and breast cancers are the most fre- (heterogeneous) structure, consisting of areas of hypointen- quent sources of infratentorial metastases. Tus, bronchiogen- sive and hyperintensive signal (in all sequences), surrounded ic carcinoma accounts for cerebral metastases in 30% of cases. On Т2-weighted imaging (b), the haemorrhage is hypoin- structures is seen within the site of haemorrhage Fig. On Т2-weighted imaging (а) and Т1-weighted imaging (b,c), ery (on Т1-weighted imaging), which corresponds to free methae- a round mass lesion is seen in the lef half of the pons and the lef moglobin Infratentorial Tumours 707 Fig. Axial Т2-weighted imaging (а) and Т1- imaging, an additional area of signal change is seen besides the hy- weighted imaging (b) shows an area of heterogeneous signal changes perintensive area, which represents a haemorrhagic component. Peripheral part of the lesion is markedly hypointensive latter spreads into the ventral part of pons on T2-weighted imaging. T2-weighted imaging (g) performed part of the lesion, an area hypointensive on Т2-weighted imaging and on the back (supine) and on the abdomen (prone) (h) visualises the hyperintensive on Т1-weighted imaging is seen—sedimentation phe- displacement of blood components into the hematoma’s cavity 710 Chapter 7 Fig. Т2-weighted perintensive signal in all sequences in the right half of the bottom imaging (а,b) and Т1-weighted imaging (c) identifes a small cellular of fossa rhomboidea. Tis area is encircled by a hypointensive ring (heterogeneous) area consisting of zones of hypointensive and hy- better seen on Т2-weighted imaging Fig. It has a patchy picture and is located forward Т2-weighted imaging (b) and Т1-weighted imaging (c) shows an an- of the haemorrhage gioma with signs of subacute haemorrhage (hyperintensive signal on Infratentorial Tumours 711 Fig.
Basilar artery V2 (intraforaminal -C6-C1) segmentThe basilar artery forms from the confuence of the vertebral arteries at the pontomedullary junction order antabuse online from canada treatment yeast infection nipples breastfeeding. It ascends approxi- mately in the midline in the pontine system and grooves the surface of the anterior pons purchase antabuse in india symptoms zoloft. Superiorly it courses a little pos- teriorly before dividing into the posterior cerebral arteries purchase generic antabuse from india medicine 8 - love shadow. Troughout the length of the basilar artery, small penetrating branches pass posteriorly into the brainstem, which are at risk Fig. It usually rises well above the foramen magnum lateral branch then courses around the focculus and a medial but may arise below it. Tere is a reciprocal arrangement branch supplies the biventral lobule and cerebellar hemisphere. It runs laterally around the branches of the posterior cerebral artery are the parieto- brainstem and comes to lie inferior to the oculomotor nerve, occipital and calcarine arteries. The smaller calcarine artery which separates it from the posterior cerebral artery. At the is seen angiographically to pursue a straight course, running lateral border of the pons it turns posteriorly over the middle between the parieto-occipital branch posteriorly and the cerebellar peduncle as the ambient segment and the tentorium posterior temporal branch inferiorly on the lateral projection. The ambient segment The posterior pericallosal arteries arch over the splenium and parallels the course of the trochlear nerves, and it is notable arise from either the posterior cerebral or parieto-occipital that the basal vein, the posterior cerebral artery and the free arteries. Tere is some variation between individuals as to edge of the tentorium are also in this plane. It is not nal cistern both superior cerebellar arteries approach the uncommon to encounter the so-called fetal origin of the midline. The posterior cerebral artery Each posterior cerebral artery can be divided into a number of Diencephalon segments (Fig. The P1 or pre-communicating segmentThe diencephalon comprises a large aggregate of grey matter, extends from the basilar bifurcation to the origin of the posterior which lies between the cerebral hemispheres and brainstem communicating artery. It courses aroundThe hypothalamus forms the roof of the interpeduncular the cerebral peduncles to lie above the tentorium. The P2 segment may be compressed against the tentorialThe pineal gland (or body) hangs by a stalk joined to the edge when there is uncal pressure on the midbrain in the posterior aspect of the diencephalon and third ventricle. It usually gives rise to the inferior temporal artery and a single is not protected by the blood–brain barrier and consequently medial and multiple lateral posterior choroidal arteries. Like the pineal gland, the pituitary gland, the infundibulum and the tuber cinereum enhance normally with contrast due to the absence of a blood–brain barrier. The neurohypophysis ofen has a conspicuous appear- sphenoid sinus in between the cavernous sinuses (Fig. It ance on T1W images due to the presence of vasopressin/ is suspended from the pituitary stalk, or infundibulum, which oxytocin – the so-called pituitary ‘bright spot’ (Fig. A B Gyrus rectus Temporal lobe Prepontine cistern Sylvian fissure Amygdala Pons Suprasellar cistern Superior Cerebral cerebellar peduncle peduncle Inferior Fourth ventricle colliculus Occipital lobe Cerebellar Occipital lobe hemisphere Inter- C hemispheric D fissure Medial orbital gyrus Gyrus rectus Uncus Mammillary Inferior recess body of third Ambient cistern ventricle Cerebral aqueduct with periaqueductal grey matter Quadrigeminal cistern Calcarine sulcus Fig. The basal ganglia comprise several deep grey matter nuclei Normal sizes (measured from superior to inferior) of the within the forebrain, midbrain and diencephalon (Figs. The head of the caudate nucleus indents the frontal 24 Chapter 1: The skull and brain I J Motor ‘hand knob’ Centrum Central sulcus semiovale K Superior frontal sulcus Precentral sulcus Precentral Body of corpus gyrus callosum Splenium of Central sulcus corpus Postcentral callosum gyrus V. The limbic system is a complex arrangement of interrelated Insula cortical and subcortical structures that play a major role in memory, olfaction and emotion. The following is a list of its core components: External capsule • hippocampal formation Claustrum • parahippocampal gyrus Putamen • amygdala Globus pallidus • hypothalamus. It forms a border (limbus) around the diencephalon and mid- Habenula brain, which is composed of three C-shaped arches one inside Pineal body the other, viewed from a lateral perspective (Fig. Outer arch: • parahippocampal gyrus • cingulate gyrus • subcallosal gyrus Middle arch: • hippocampus proper (cornu ammonis) Fig. Its body curves upwards and pos- • paraterminal gyrus teriorly from the head, following the contour of the body of Inner arch: the lateral ventricle before continuing in an arch to its thinnest • fornix and fmbria. DuringThe subthalamic nucleus is an ovoid aggregation of grey development, this area of cortex becomes rolled up into matter that lies medial to the internal capsule, lateral to the an S-shape, which forms at the medial (also called mesial) hypothalamus and superolateral to the red nucleus (Fig. It comprises It establishes connections with both internal and external the hippocampus proper (also called the cornu ammonis), segments of the globus pallidus and with the thalamus. The subiculum lies Damage to this nucleus results in contralateral hemiballismus – inferior to the hippocampus proper and blends into the uncontrolled jerks of the limbs. The hippocampi are closelyThe fmbria of the hippocampal formation continues as scrutinized by the neuroradiologist for mesial temporal the crus of the fornix, a fbre bundle that sweeps backwards, sclerosis in the context of temporal lobe epilepsy. The upwards and medially around the posterior aspect of the tha- hippocampus can be recognized in the coronal plane as lamus ( Figs. The two crura then pass forwards a protrusion into the medial temporal horn of the lateral and converge in the midline, forming the body, where they ventricle. The border between the parahippocampal gyrus are attached to the septum pellucidum. The body continues (medially) and the occipitotemporal gyrus (also known as the forwards before separating, just above the foramen of Monro, fusiform gyrus) is demarcated by the collateral sulcus (also into the columns of the fornices. OnlyThe uncus is the most medial portion of the temporal lobe the hippocampus proper and the subicular region project and is continuous with the parahippocampal gyrus posteriorly fbres into the fornix. The amygdala is just lateral to the uncus and situ-The hippocampal tail tapers into a thin neuronal lamina, ated anterior to the temporal horn of the lateral ventricle. The the indusium griseum, which arches around the corpus amygdala is thus anterior and superior to the hippocampus. The olfactory bulb receives in patients with Wernicke-Korsakof syndrome, in whom they tiny fbres from the nasal mucosa through the cribriform plate may be atrophied as a result of chronic thiamine defciency. The deeper forated substance (so-called because it is the point of entry for and more anatomically constant sulci are known as fssures. The lateral (Sylvian) fssure marks the superior margin ofThe mamillary bodies (or nuclei) are part of the hypothala- the temporal lobe, while the parieto-occipital fssure divides mus and are situated at the ends of the columns of the fornices. The central sulcus marks the 28 Chapter 1: The skull and brain Cingulate gyrus A and cingulum Indusium griseum Choroid plexus Septum Alveus pellucidum Column of fornix Fimbria of fornix Dorsal fornix Isthmus Olfactory bulb Uncus Amygdala Subiculum Fimbria of Para- Dentate nuclear complex fornix hippocampal gyrus gyrus Tail of caudate nucleus Anterior B commissure Temporal horn of ventricle Hippocampus Ammon’s horn Fornix Dentate gyrus Fimbria Fig. The insula is an • Superolateral surface supplies upper limb area of invaginated cortex lying deep within the Sylvian fssure, • Medial aspect supplies lower limb. The parietal lobe also contains two further important gyri: Cortical anatomy is subject to individual variation but the the supramarginal and angular gyri, which are involved more constant gyri and sulci are illustrated in Fig. The dominant hemisphere of the frontal lobe also contains The temporal lobe also contains Wernicke’s area (in the domi- Broca’s area (involved with motor aspects of speech). It is situ- nant hemisphere), which is involved with the receptive aspects ated in the pars opercularis, which lies in the posterior aspect of speech and is situated in the posterior part of the superior of the inferior frontal gyrus. Occipital lobe • Posterior to parieto-occipital fssure Parietal lobe • Primary visual cortex is situated on medial occipital lobe • Posterior to central fssure (calcarine cortex) • Lies above and in front of occipital lobe (divided by parieto- • Anterior margin marked by the temporo-occipital occipital fssure (Fig. E The medial surface of the occipital lobe is made up of the cuneus (above) and the lingula (below) (Fig. Fornix Tere are, however, a number of useful tips, which can help determine the position of the central sulcus.