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By K. Redge. Georgian Court College.

Although the use of single letters or numbers these abbreviations with minimal reference to the accompa- results in minimal clutter on the figure buy generic lioresal 25 mg on line muscle relaxant otc, a major drawback is nying list purchase lioresal 10mg on line muscle relaxant drugs flexeril. In addition, a subtle advantage of this method of the fact that the same number or letter may appear on sev- labeling is that, as the reader looks at the abbreviation and eral different figures and designate different structures in all momentarily pauses to ponder its meaning, he or she may cases. Consequently, no consistency occurs between num- form a mental image of the structure and the complete bers and letters and their corresponding meanings as the word. Because neuroanatomy requires one to conceptualize reader examines different figures. This atlas uses a combi- and form mental images to more clearly understand CNS nation of complete words and abbreviations that are clearly relationships, this method seems especially useful. References: In response to suggestions made by those using this book Bruxton, RB. Introduction to Functional Magnetic Resonance over the years, the number of abbreviations in the sixth edi- Imaging, Principles and Techniques. Cambridge: Cambridge tion has been reduced, and the number of labels using the University Press, 2002. Magnetic Resonance Imaging and Computed To- plete names and abbreviations have been used together in nd mography of the Head and Spine. Cranial MRI plete name, but the same structure in the accompanying and CT. New York: McGraw-Hill Health Profes- MRI is labeled with a corresponding abbreviation (see sions Division, 1999. CHAPTER 2 External Morphology of the Central Nervous System 10 External Morphology of the Central Nervous System Posterior View C2 Posterior root (PR) Posterior spinal Dura artery Arachnoid C3 PR Denticulate ligament C4 PR Posterior spinal medullary artery C5 PR Anterior View C2 Anterior root (AR) Dura Denticulate ligament C3 AR Arachnoid Anterior spinal medullary artery C4 AR Anterior spinal artery C5 AR 2-1 Posterior (upper) and anterior (lower) views showing the gen- Figure 2-3 on facing page) follow their respective roots. The dura and spinal artery is found medial to the entering posterior rootlets (and the arachnoid are reflected, and the pia is intimately adherent to the spinal dorsolateral sulcus), while the anterior spinal artery is in the anterior cord and rootlets. Posterior and anterior spinal medullary arteries (see median fissure (see also Figure 2-2, facing page). The Spinal Cord 11 Posterior View Sulci: Posterior median Posterior intermediate Posterolateral C7 Posterior root Spinal (posterior root) ganglion Fasciculus gracilis Fasciculus cuneatus Anterior View Anterior spinal artery C7 Anterior root Anterior radicular artery Anterior funiculus Anterior median fissure 2-2 Posterior (upper) and anterior (lower) views showing details of the spinal cord as seen in the C7 segment. The posterior (dorsal) root ganglion is partially covered by dura and connective tissue. Posterior spinal arteries Arterial vasocorona Basilar artery Posterior inferior cerebellar arteries Vertebral arteries Anterior spinal artery Posterior spinal medullary artery Posterior radicular artery (on dorsal root) Sulcal arteries Anterior spinal medullary artery Anterior radicular artery (on ventral root) Segmental artery 2-3 Semidiagrammatic representation showing the origin and gen- medullary arteries) arise at intermittent levels and serve to augment eral location of principal arteries supplying the spinal cord. The artery of Adamkiewicz is an rior and posterior radicular arteries arise at every spinal level and serve unusually large spinal medullary artery arising usually on the left in low their respective roots and ganglion. The anterior and posterior spinal thoracic or upper lumbar levels (T9–L1). The arterial vasocorona is a medullary arteries (also called medullary feeder arteries or segmental diffuse anastomotic plexus covering the cord surface. This space contains the anterior and posterior views of the lower thoracic, lumbar, sacral, and coccygeal spinal cord roots from the lower part of the spinal cord that collectively form the segments and the cauda equina. The cauda equina is shown in situ in A, and in B the nerve conus medullaris through the lumbar cistern to attach to the inner sur- roots of the cauda equina have been spread laterally to expose the conus face of the dural sac. The dural sac ends at about the level of the S2 ver- medullaris and filum terminale internum. This latter structure is also tebra and is attached to the coccyx by the filum terminale externum called the pial part of the filum terminale. A lumbar puncture is made by insert- pages 84–87 for cross-sectional views of the cauda equina. This sample may be used for a number of di- intervertebral discs and the bodies of the vertebrae are clear. The insula, as a whole, is On the lateral aspect, the central sulcus (of Rolando) separates separated from the adjacent portions of the frontal, parietal, and tem- frontal and parietal lobes. The lateral sulcus (of Sylvius) forms the bor- poral opercula by the circular sulcus. The occipital lobe is located On the medial aspect, the cingulate sulcus separates medial portions caudal to an arbitrary line drawn between the terminus of the parieto- of frontal and parietal lobes from the limbic lobe. A horizontal line drawn tinuation of the central sulcus intersects with the cingulate sulcus and from approximately the upper two-thirds of the lateral fissure to the forms the border between frontal and parietal lobes. The parieto- rostral edge of the occipital lobe represents the border between pari- occipital sulcus and an arbitrary continuation of this line to the preoc- etal and temporal lobes.

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Kardon generic 10mg lioresal amex spasms quadriplegia, Tissues and Organs: A Text-Atlas of Scanning Electron Microscopy buy lioresal 25mg mastercard muscle relaxant elderly. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 522 Unit 5 Integration and Coordination FIGURE 15. The scala vestibuli and the scala tympani, which contain perilymph, are continuous at the helicotrema. The cochlear duct, which con- tains endolymph, separates the scala vestibuli and the scala tympani. Sounds of low frequency (blue arrow) cause pressure waves of perilymph to pass through the helicotrema and displace the basilar membrane near its apex. Sounds of medium frequency (green arrow) cause pressure waves to displace the basilar membrane near its center. Sounds of high frequency (red arrow) cause pressure waves to displace the basilar membrane near its base. For example, striking the high C on a piano produces a high frequency of sound that has a high pitch. Pathways for Hearing The intensity, or loudness of a sound, is directly related to the amplitude of the sound waves. Sound intensity is measured Sound Waves in units known as decibels (dB). A sound that is barely audible— Sound waves travel in all directions from their source, like rip- at the threshold of hearing—has an intensity of zero decibels. These waves of energy are Every 10 decibels indicates a tenfold increase in sound intensity: characterized by their frequency and their intensity. The fre- a sound is 10 times higher than threshold at 10 dB, 100 times quency, or number of waves that pass a given point in a given higher at 20 dB, a million times higher at 60 dB, and 10 billion time, is measured in hertz (Hz). The healthy human ear can detect very related to its frequency—the higher the frequency of a sound, small differences in sound intensity—from 0. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 Chapter 15 Sensory Organs 523 Thalamus Auditory cortex (temporal lobe) Inferior colliculus Medial geniculate Midbrain body of thalamus Cochlear nucleus Medulla oblongata Vestibulocochlear nerve From spiral organ (of Corti) FIGURE 15. A snore can be as loud as 70 dB, as compared with 105 dB Sounds of low pitch (with frequencies below about 50 Hz) for a power mower. Frequent or prolonged exposure to sounds cause movements of the entire length of the basilar membrane— with intensities over 90 dB (including amplified rock music) can result in hearing loss. Higher sound frequencies result in maximum displacement of the basilar membrane closer to its Sound waves funneled through the external acoustic canal base, as illustrated in figure 15. Displacement of the basilar membrane and hair cells by Movements of the tympanum during ordinary speech (with an movements of perilymph causes the hair cell microvilli that are average intensity of 60 dB) are estimated to be equal to the di- embedded in the tectorial membrane to bend. As the vestibular window is displaced, pressure waves pass Neural Pathways for Hearing through the fluid medium of the scala vestibuli (fig. Movements of Cochlear sensory neurons in the vestibulocochlear nerve (VIII) perilymph within the scala tympani, in turn, displace the synapse with neurons in the medulla oblongata, which project to cochlear window into the tympanic cavity. Neurons in this When the sound frequency (pitch) is sufficiently low, there area in turn project to the thalamus, which sends axons to the is adequate time for the pressure waves of perilymph within the auditory cortex of the temporal lobe, where the auditory sensa- scala vestibuli to travel around the helicotrema to the scala tym- tions (nerve impulses) are perceived as sound. As the sound frequency increases, however, these pressure waves do not have time to travel all the way to the apex of the cochlea. Instead, they are transmitted through the vestibular Mechanics of Equilibrium membrane, which separates the scala vestibuli from the cochlear Maintaining equilibrium is a complex process that depends on duct, and through the basilar membrane, which separates the continuous input from sensory neurons in the vestibular organs cochlear duct from the scala tympani, to the perilymph of the of both inner ears. The distance that these pressure waves travel, pal source of sensory information for equilibrium, the photore- therefore, decreases as the sound frequency increases. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 524 Unit 5 Integration and Coordination proprioceptors of tendons, muscles, and joints also provide sen- Eyes Joint, tendon, sory input that is needed to maintain equilibrium (fig. Vestibular apparatus muscle, and The vestibular organs provide the CNS with two kinds of cutaneous receptors receptor information. One kind is provided by receptors within the saccule and utricle, which are sensitive to gravity and to lin- ear acceleration and deceleration of the head, as occur when rid- Cerebellum Vestibular nuclei (brain stem) ing in a car. The other is provided by receptors within the semicircular ducts, which are sensitive to rotational movements, as occur when turning the head, spinning, or tumbling. When the hair cells are displaced in the direc- (control of eye movements) movements) tion of the kinocilium, the cell membrane is depressed and becomes depolarized.

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The 14 facial median length of the skull between the anterior and posterior bones form the framework for the facial region and support the fontanels generic lioresal 10mg online spasms right upper quadrant. Variation in size cheap 25mg lioresal overnight delivery muscle relaxant vecuronium,shape,and density of the facial bones is to the anterolateral fontanel. A lambdoid suture extends from a major contributor to the individuality of each human face. A squa- The facial bones,with the exception of the mandible (“jaw- mous suture connects the posterolateral fontanel to the antero- bone”),are also firmly interlocked with one another and the lateral fontanel. The bones of the skull contain numerous foramina (see The skull has several cavities. Various nasal cavity is formed by both cranial and facial bones and is partitioned into two chambers, or nasal fossae, by a nasal sep- tum of bone and cartilage. Skeletal System: © The McGraw−Hill Anatomy, Sixth Edition Introduction and the Axial Companies, 2001 Skeleton Chapter 6 Skeletal System: Introduction and the Axial Skeleton 145 Anterior fontanel Coronal suture Parietal bone Frontal bone Posterior fontanel Squamous suture Anterolateral fontanel Lambdoid suture Nasal bone Occipital bone Sphenoid bone Posterolateral Zygomatic bone fontanel Maxilla Temporal bone Mandible (a) Frontal bone Anterior fontanel Coronal suture Sagittal suture Parietal bone Posterior fontanel Occipital bone (b) FIGURE 6. The frontal bone forms the anterior roof of the cranium,the forehead, Although the hyoid bone and the three paired auditory os- the roof of the nasal cavity,and the superior arches of the orbits, sicles are not considered part of the skull, they are associated which contain the eyeballs. The supraorbital margin is a Cranial Bones The cranial bones enclose and protect the brain and associated sensory organs. Skeletal System: © The McGraw−Hill Anatomy, Sixth Edition Introduction and the Axial Companies, 2001 Skeleton 146 Unit 4 Support and Movement TABLE 6. Slightly medial to its midpoint Temporal Bone is an opening called the supraorbital foramen, which provides pas- The two temporal bones form the lower sides of the cranium sage for a nerve,artery,and veins. Each temporal bone is joined to The frontal bone also contains frontal sinuses, which are its adjacent parietal bone by the squamous suture. The squamous part is the flattened plate of bone at the sides of the skull. On the inferior surface of the The two parietal bones form the upper sides and roof of the cra- squamous part is the cuplike mandibular fossa, which nium (figs. The coronal suture separates the forms a joint with the condyle of the mandible. This artic- frontal bone from the parietal bones, and the sagittal suture ulation is the temporomandibular joint. The inner concave surface of each parietal bone, as well as the inner concave surfaces of other cranial bones, is marked by shallow impressions from convolutions of the brain and vessels serving the brain. Skeletal System: © The McGraw−Hill Anatomy, Sixth Edition Introduction and the Axial Companies, 2001 Skeleton Chapter 6 Skeletal System: Introduction and the Axial Skeleton 147 Frontal bone Parietal bone Temporal bone Lacrimal bone Nasal bone Zygomatic bone Inferior nasal concha Maxilla Vomer Mandible FIGURE 6. Coronal suture Parietal bone Frontal bone Lambdoid suture Sphenoid bone Squamous suture Ethmoid bone Temporal bone Lacrimal bone Occipital bone Nasal bone Zygomatic bone External acoustic meatus Infraorbital foramen Mastoid process Maxilla Condylar process Coronoid process of mandible of mandible Styloid process Zygomatic process Mental foramen Mandibular notch Mandible Angle of mandible Creek FIGURE 6. Skeletal System: © The McGraw−Hill Anatomy, Sixth Edition Introduction and the Axial Companies, 2001 Skeleton 148 Unit 4 Support and Movement Incisors Premolars Canine Incisive foramen Molars Median palatine suture Zygomatic bone Palatine process of maxilla Palatine bone Sphenoid bone Greater palatine foramen Medial and lateral Zygomatic process pterygoid processes of sphenoid bone Vomer Foramen ovale Mandibular fossa Foramen lacerum External acoustic meatus Carotid canal Jugular fossa Styloid process Stylomastoid foramen Mastoid process Foramen magnum Occipital condyle Mastoid foramen Temporal bone Parietal bone Superior nuchal line Condyloid canal Occipital bone External occipital protuberance Creek FIGURE 6. Parietal bone Frontal Temporal bone bone Occipital bone Nasal bone Maxilla Mandible Palatine bone Vomer FIGURE 6. Skeletal System: © The McGraw−Hill Anatomy, Sixth Edition Introduction and the Axial Companies, 2001 Skeleton Chapter 6 Skeletal System: Introduction and the Axial Skeleton 149 Squamous suture Supraorbital margin Mandibular condyle Mandibular fossa Zygomatic arch External acoustic meatus Coronoid process of mandible Mastoid process of temporal bone Styloid process Ramus of mandible of temporal bone Jugular foramen Mental protuberance Lambdoid suture Angle of mandible Occipitomastoid suture Condyloid canal Digastric fossa Occipital condyle Mandibular foramen Foramen magnum FIGURE 6. Frontal bone Sphenoid bone Temporal bone Parietal bone Occipital bone FIGURE 6. Skeletal System: © The McGraw−Hill Anatomy, Sixth Edition Introduction and the Axial Companies, 2001 Skeleton 150 Unit 4 Support and Movement Frontal bone Ethmoid bone Zygomatic bone Middle nasal concha Maxilla Inferior nasal concha Vomer FIGURE 6. Skeletal System: © The McGraw−Hill Anatomy, Sixth Edition Introduction and the Axial Companies, 2001 Skeleton Chapter 6 Skeletal System: Introduction and the Axial Skeleton 151 Ethmoidal Frontal sinus sinus Sphenoidal sinus Frontal sinus Ethmoidal sinuses Sphenoidal sinus Maxillary sinus Maxillary sinus (a) (b) FIGURE 6. The structures of the middle ear and inner ear are housed in this dense part of Region of the Orbit Contributing Bones the temporal bone. Floor (inferior) Maxilla; zygomatic bone; palatine bone The carotid canal allows blood into the brain via the inter- Lateral wall Zygomatic bone nal carotid artery, and the jugular foramen lets blood drain Posterior wall Greater wing of sphenoid bone from the brain via the internal jugular vein. Three cranial Medial wall Maxilla; lacrimal bone; ethmoid bone nerves also pass through the jugular foramen (see table 6. Superior margin Frontal bone Lateral margin Zygomatic bone The mastoid process of the temporal bone can be easily pal- Medial margin Maxilla pated as a bony knob immediately behind the earlobe.

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It is therefore essential that diagnostic imaging spe- tral to the diagnosis of abuse generic 10mg lioresal muscle relaxant uses. In infants buy lioresal 25 mg low price muscle relaxant uses, certain lesions cialists involved with cases of alleged abuse conduct their are sufficiently characteristic to point strongly to the di- studies in a thorough and conscientious fashion that will agnosis of inflicted trauma (Table 1). Other fractures are provide the greatest likelihood of a correct diagnosis that less specific for abuse, but when correlated with other can be sustained in a highly adversarial legal arena. In the 50 years since Caffey’s original description, ra- Classic Metaphyseal Lesion diologists have become familiar with the imaging fea- tures of commonly encountered inflicted skeletal injuries The corner fracture and bucket handle lesions de- scribed in 1957 by Caffey are frequent findings in young abused infants. Specificity of radiologic findings (From with permission) by assailants. Repro- duced with permis- High specificitya sion from) Classic metaphyseal lesions Rib fractures, especially posterior Scapular fractures Spinous process fractures Sternal fractures Moderate specificity Multiple fractures, especially bilateral Fractures of different ages Epiphyseal separations Vertebral body fractures and subluxations Digital fractures Complex skull fractures Common but low specificity Subperiosteal new bone formation Clavicular fractures Long bone shaft fractures * This chapter originally appeared in: von Schulthess GK, Zolli- Linear skull fractures kofer Ch L (2001) Musculoskeletal Diseases - Diagnostic Imaging and Interventional Techniques. Springer-Verlag Italia, Milan a Highest specificity applies in infants 170 P. Kleinman extends in a planar fashion through the primary spon- fracture may extend partially or completely across the giosa. The fractures are most common in seous junction, and peripherally, the fracture veers the distal femur, proximal and distal tibia, and proxi- from the physis to undercut a larger peripheral seg- mal humeri and are much less common at the elbow, ment encompassing the subperiosteal bone collar. Corner fracture and bucket-handle patterns of the classic b metaphyseal lesion (CML). Fractures (arrows) extend adjacent to the chondroosseous junction and then veer toward the diaphysis to under- cut the large peripheral segment that encompasses the subperiosteal bone collar. The frac- tures may also occur with the sudden acceleration and Most cases of osteogenesis imperfecta are accompa- deceleration of the extremities as the infant is shaken nied by blue sclera, frank bony demineralization and violently while grabbed by the thorax. When present in other typical clinical and radiologic features (Type I). However, a variety of bone fractures involve the shafts or metadiaphyseal differential considerations for the classic metaphyseal regions. The presence of demineralization Rickets and other radiologic features of osteogenesis imper- fecta confirm the diagnosis. Paterson and colleagues Metaphyseal irregularity, cupping, physeal widening and have described a group of children with metaphyseal bony demineralization are the hallmarks of rickets, how- lesions as well as other osseous injuries characteristic ever, on occasion discrete osseous fragments resembling of abuse. They coined the term “temporary brittle corner fractures may be identified in the absence of more bone disease” to explain these injuries. The diagnosis may be particu- has been widely criticized, and the lack of rigorous larly difficult if the metabolic disturbance is partially scientific methodology in their publications makes it treated because demineralization may be modest and the impossible to draw any meaningful conclusions from density of the zone of provisional calcification may be their work [8, 9]. His work has physeal fractures indistinguishable from the CML, and been strongly criticized on methodologic grounds infants with rickets undergoing vigorous passive range of. Developmental Variants Birth Injury The subperiosteal bone collar, an osseous ring that sur- Caffey noted that metaphyseal injuries identical to those rounds the primary spongiosa of the metaphysis and to occurring with abuse can result from birth injury. The tractional and torsional an abrupt step-off of the metaphyseal cortex as it ap- forces can produce metaphyseal lesions, particularly in proaches the physis. The injuries can be overlooked extend beyond the metaphysis forming a discrete lin- at birth and may be identified within the first few weeks ear mineralized spur at the periphery of the physis. These fractures are uncommon in the modern ob- These findings are most common at the knees and stetrical era and can be readily excluded by a detailed birth history. Inherited Bone Dysplasias Rib Fractures Although metaphyseal irregularity and fragmentation are seen in a variety of skeletal dysplasias, the presence Rib fractures are the most common fractures noted in of an underlying disease is usually apparent on clinical infants dying with inflicted injury. Certain bone dysplasias, anywhere along the rib arc, but are most common near however, may manifest only modest osseous changes in the costovertebral articulations. These fractures, as well early infancy, and the bony metaphyseal fragments in as fractures near the costochondral junction are the most these cases may raise strong concerns of inflicted injury. Fractures Metaphyseal chondrodysplasia, Schmid type, may pre- at the costovertebral junctions will become more visible sent in an infant of normal stature with metaphyseal on follow-up studies at two weeks; fractures at the cos- fragments indistinguishable from abuse. Similar tochondral junctions tend to heal with little subpe- findings have been described in spondylometaphyseal riosteal new bone and tend to become less distinct with dysplasia, corner fracture type. Most fractures occur with thoracic compression survey will generally point to the diagnosis. Evidence supports that excessive leverage of up skeletal survey in several weeks will show no change the ribs over the transverse processes with anteroposte- in the metaphyseal fragments in contrast to features of rior compression of the chest results in fractures of the healing noted with the CML.

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