By J. Charles. Glenville State College. 2018.
The coracoclavicu- associated with radial shortening and malalignment at the lar distance may be assessed by comparison to the oppo- distal radial ulnar joint buy forzest 20 mg cheap. This combination is referred to as site side with both sides included on a crosswise AP im- the Essex-Lopresti fracture purchase forzest 20 mg on line. These may be associated with fractures of the Fractures of the coronoid process of the ulna are an- greater tuberosity or with compression fractures of the other common fracture at the elbow forzest 20mg cheap. These are almost al- posterolateral aspect of the humeral head (Hill-Sachs de- ways seen in association with or following posterior dis- formity) discount forzest 20mg. Fractures of the olecranon are of- (bony Bankart deformity) may also be identified; these ten displaced and readily identified cheap forzest 20mg on-line, but some olecranon are best seen on axillary views of the shoulder. Knowledge of the normal rela- ly missed; it is estimated that nearly half are missed on tionship of the anterior cortex of the humerus to the the initial evaluation. A line drawn along the ante- illary view, or scapular-Y view facilitates diagnosis. On the in- sects the anterior third of the condyle, there may be a pos- ternal and external views, a clue may arise from the fact teriorly displaced supracondylar fracture. Fractures of the that the technologist is unable to obtain images in exter- lateral condyle and medial epicondyle are also common. Compression fractures of the anteromedial The most common dislocation of the adult elbow is the aspect of the humeral head are found in association with posterior dislocation. These are usually quite obvious and posterior dislocations, analogous to the Hill-Sachs defect not difficult to diagnose. These compression de- the Monteggia fracture-dislocation, in which an angulat- formities of the anteromedial aspect of the humeral head ed or displaced fracture of the proximal ulna is associat- present as a trough in the humeral head and are often best ed with a radial head dislocation. When doubt exists concerning overlap of the radial head on the capitellum on the AP im- the presence of a posterior dislocation, CT may be ex- age should indicate the presence of a dislocation. A line tremely valuable to determine that a dislocation is present drawn along the long axis of the radial neck should in- and to assess fracture of the humeral head. The history tersect the capitellum in every projection (radio-capitel- may be helpful in patients with posterior dislocations, lar line). Dislocations at the wrist include perilunate and lu- Radiographic examination of the wrist usually consists of nate dislocations. Perilunate dislocations are frequently three views: PA, lateral, and pronation-oblique projec- associated with fractures through the scaphoid waist (a tions. Additional views, including angle views of the trans-scaphoid perilunate dislocation). Virtually all per- scaphoid (with ulnar deviation), a “clenched fist” view, ilunate dislocations are dorsal. Lunate dislocations, in and carpal tunnel views, may be helpful in specific situ- contrast, are virtually all volar in direction and are rarely ations. Recently, a semisupinated oblique view was rec- seen in association with other fractures at the wrist. Scapho-lunate dissociation (rotary subluxation of the The most common fracture at the wrist in the adult scaphoid) results in abnormal rotation of the scaphoid population is the Colles fracture, which is much more fre- and is due to a disruption in the scapho-lunate and volar quent in elderly women than in men. This may occur alone or be part of oth- is a resultant dorsal tilt to the distal radial articular sur- er more complex injuries about the lunate axis. Subtle injuries may be difficult to detect when dis- The Galeazzi fracture is a fracture is of the distal radi- placement is minimal; these may be recognized only by al shaft associated with a dislocation at the distal radial the loss of the normal volar tilt to the distal radial artic- ulnar joint (i. Fractures of the distal radius are frequently Isolated dislocations at the distal radioulnar joint are ex- associated with injuries to the ulnar side of the wrist, in- tremely difficult to diagnose because slight degrees of ro- cluding tears of the triangular fibrocartilage, dislocation tation of the wrist from the lateral projection may cause of the distal radio-ulnar joint and fractures of the ulnar difficulty. Such injuries often give rise to ulnar-sided wrist bility of distal radioulnar dislocations, CT is the recom- pain with instability and the ulnar abutment syndrome, mended technique for evaluation. In the carpus, fracture of the scaphoid is by far the Less common injuries at the wrist include fractures of most common fracture, accounting for approximately the hook of the hamate and of the pisiform or capitate. A scaphoid CT may be needed to demonstrate these fractures; refor- fracture may be virtually impossible to detect on conven- matted images in coronal and sagittal planes should be a tional imaging but clinically suspected due to pain in the part of the examination. If there is a strong Hands suspicion and an immediate diagnosis is necessary, MRI is an expensive but highly accurate method of diagnosis. Conventional imaging of the hand should include PA, a At least one author stated that MRI is cost effective in pa- lateral view, and pronation oblique views. The internal tients with negative X-rays in whom there is a strong clin- oblique view may detect fractures that were overlooked or ical suspicion of a scaphoid fracture. The diagnosis significantly underestimated on standard views of the can be made with a brief limited examination.
Refer to free earlobes as a result of a dominant allele is symbolized EE; a figure 22 order forzest 20mg on line. In both of these instances buy forzest 20mg with visa, the trait may be expressed in a child of parents who are heterozygous discount forzest 20 mg on line. Developmental © The McGraw−Hill Anatomy 20mg forzest overnight delivery, Sixth Edition Development Anatomy forzest 20mg with amex, Postnatal Companies, 2001 Growth, and Inheritance 784 Unit 7 Reproduction and Development Phenotypes of the parents dark hair dark hair free free earlobes earlobes FIGURE 22. Any of the combinations of genes that have a D and chart, and the female gametes (ova) at the top, as in figure 22. Three of the possible combinations The four spaces on the chart represent the possible combinations have two alleles for attached earlobes (ee) and at least one allele for of male and female gametes that could form zygotes. Three of the combina- bility of an offspring having a particular genotype is 1 in 4 (. These are indicated with a for homozygous dominant and homozygous recessive and 1 in 2 square (I). The remaining possibility has the genotype eedd for at- tached earlobes and light hair. Normal color vision (designated C) are followed from parents to offspring is referred to as a dihybrid dominates. The term hybrid refers to an offspring de- depends entirely on the X chromosomes. The genotype possibili- scended from parents who have different genotypes. The al- C c X X Normal female carrying the recessive allele lele for red-green color blindness, for example, is determined by a c c X X Color-blind female In order for a female to be red-green color-blind, she must have the recessive allele on both of her X chromosomes. Her fa- Punnett square: from Reginald Crundall Punnett, English geneticist, 1875–1967 ther would have to be red-green colorblind and her mother Van De Graaff: Human VII. Developmental © The McGraw−Hill Anatomy, Sixth Edition Development Anatomy, Postnatal Companies, 2001 Growth, and Inheritance Chapter 22 Developmental Anatomy, Postnatal Growth, and Inheritance 785 would have to be a carrier for this condition. A male with only concern for developmental anatomy are such topics as ectopic one such allele on his X chromosome, however, will show the pregnancies, so-called test-tube babies, multiple pregnancy, fetal characteristic. Because a male receives his X chromosome from monitoring, and congenital defects. Abnormal Implantation Sites Hemophilia is a sex-linked condition caused by a recessive al- lele. If H represents normal clotting and h rep- H side the uterus or in an abnormal site within the uterus resents abnormal clotting, then males with X Y will be normal and males with XhY will be hemophiliac. Occasionally, implantation occurs near the Knowledge Check cervix, where development of the placenta blocks the cervical opening. Define genetics, genotype, phenotype, allele, dominant, reces- serious bleeding. Ectopic pregnancies will not develop normally sive, homozygous, and heterozygous. List several dominant and recessive traits inherited in hu- the first trimester. Depending on the location and the stage of develop- for color blindness of an XcY male and an XCXc female. In Vitro Fertilization CLINICAL CONSIDERATIONS and Artificial Implantation Pregnancy and childbirth are natural events in human biology Reproductive biologists have been able to fertilize a human and generally progress smoothly without complications. Prenatal oocyte in vitro (outside the body), culture it to the blastocyst development is amazingly precise, and although traumatic, child- stage, and then perform artificial implantation, leading to a full- birth for most women in the world takes place without the aid of term development and delivery. The physician’s is used to aspirate the preovulatory egg from a mature vesicular knowledge of what constitutes normal development and what ovarian follicle. The oocyte is then placed in a suitable culture factors are responsible for congenital malformations ensures the medium, where it is fertilized with spermatozoa. When the zygote embryo and fetus every possible chance to develop normally. In vitro fertilization with what might be referred to as applied developmental biology.
The ability of a hormone to affect a particular cell depends on the presence of receptor molecules in the cell or specific receptor sites on its cell membrane forzest 20 mg mastercard. Endocrine System © The McGraw−Hill Anatomy forzest 20mg, Sixth Edition Coordination Companies buy forzest 20 mg visa, 2001 Chapter 14 Endocrine System 459 Hormone Secretes Receptor hormone A Cell membrane Adenylate cyclase ATP Cyclic AMP 5′AMP Phosphodiesterase Secretes Protein hormone B kinase (inactive) Inhibitory subunit Protein kinase (active) FIGURE 14 buy forzest 20mg on line. Hormones arrive at target cells through body fluids and attach to specific receptor sites on the cell mem- brane buy 20mg forzest amex. This causes molecules of adenylate cyclase to diffuse into the Control of Hormone Secretion cytoplasm and promote the change of ATP into cyclic AMP. The rate of secretion of a particular hormone and the rate of usage by the target cells are closely balanced. The stability of hormone levels is maintained by a negative feedback system and autonomic neural impulses. An en- Steroid hormones are soluble in lipids and can readily pass docrine gland will continue to secrete hormones that affect tar- through a cell membrane. Once inside a cell, the steroid get cells until messages come back from the cells reporting that combines with a protein to form a steroid-protein complex sufficient amounts of these hormones are present. This complex is necessary for the synthesis of specific sages are generally in the form of hormones secreted by the target kinds of messenger RNA molecules. This chemical feedback information signals the endocrine Protein and amine hormones are insoluble in lipids and gland to inhibit secretion (fig. The primary endocrine therefore must attach to specific receptor sites on the cell mem- gland will resume secretions when the blood levels of inhibiting brane. These hormones do not enter the cell, but their attach- chemicals become low again. In the presence of cause certain endocrine glands, such as the adrenal medulla, to adenylate cyclase, ATP molecules in the cell are converted to secrete hormones. One specialized kind of neural impulse in- cyclic AMP (adenosine monophosphate), which in turn dis- volves the hypothalamus and the pituitary gland (fig. In perses throughout the cell to cause changes in cellular processes this system, chemical secretions from neurosecretory cells in the (fig. These changes may include increasing protein syn- hypothalamus called releasing factors influence specific target thesis, altering membrane permeability, or activating certain cells in the pituitary gland. Endocrine System © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 460 Unit 5 Integration and Coordination PITUITARY GLAND The neurohypophysis of the pituitary gland releases hormones that are produced by the hypothalamus, whereas the adenohy- pophysis of the pituitary gland secretes its own hormones in re- sponse to regulation from hypothalamic hormones. The secretions of the pituitary gland are thus controlled by the hypothalamus, as well as by negative feedback influences from the target glands. Objective 6 List the hormones secreted by the adenohypophysis and neurohypophysis. Objective 7 Describe, in a general way, the actions of anterior pituitary hormones. Objective 8 Explain how the secretions of anterior and posterior pituitary hormones are controlled by the hypothalamus. Objective 9 Explain how the secretion of anterior pituitary hormones is regulated by negative feedback. It is covered by the dura mater and is supported by the sella turcica of the sphenoid bone. The cerebral arterial circle surrounds the highly vascular pituitary gland, providing it with a FIGURE 14. The adenohypophysis consists of two parts in adults: (1) the pars distalis (anterior pituitary) is the bulbar portion, and (2) the hypothalamus continues to secrete the releasing factor until a given pars tuberalis is the thin extension in contact with the in- level of hormones is present in the body fluids and is detected by fundibulum (fig. A pars intermedia, a strip of tissue be- the hypothalamus through a negative feedback mechanism. During fetal development, its cells mingle with those of the anterior Knowledge Check lobe, and in adults they no longer constitute a separate structure. What are some of the ways in which endocrine and ex- The neurohypophysis is the neural part of the pituitary ocrine glands differ structurally? How are the nervous and endocrine systems functionally which is in contact with the adenohypophysis, and the funnel- related? Also list the organs that serve other body functions, in addition to secreting hormones. Using diagrams, describe the mechanism of steroid hor- mone action and the mechanism of protein hormone ac- tion within cells. List the three kinds of hormones, give examples of each, into the nasal cavity) and describe their chemical compositions. Endocrine System © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 Chapter 14 Endocrine System 461 Anterior Third ventricle cerebral artery Optic chiasma Cerebral cortex Hypothalamus Optic nerve Oculomotor nerve Pituitary stalk Trochlear nerve Posterior Anterior lobe lobe of of pituitary pituitary gland gland Sphenoidal Basilar artery sinus Sphenoid Sella turcica bone Waldrop (a) FIGURE 14.
MRI is a use- Hematogenous osteomyelitis develops as a result of a ful imaging modality to distinguish these two causes of blood-borne infection settling into a focus of bone 20 mg forzest with amex. The pattern of marrow destruction is distinct from is common in children and intravenous drug abusers the appearance of an occult bone infarct best forzest 20mg. Another type of osteomyelitis is direct extension cation of an infarct cheap forzest 20 mg mastercard, its rectilinear delineation purchase forzest 20mg with visa, absence of from a contiguous source of infection generic forzest 20 mg on-line. An example of cellulitis in the surrounding soft tissue, and absence of si- this would be open fractures that allow organisms to nus tract, distinguishes an infarct from osteomyelitis. Images of the lumbar spine of a person who uses illicit drugs intravenously. The infection remains localized to this level and does not extend into the epidural space 140 D. Kilcoyne The Diabetic Foot Features of Septic Arthritis Cellulitis and ulcers are common complications of dia- Clinical Presentation and Methods of Spread betes. The radiologist is frequently asked to determine whether there is extension of infection to the adjacent The infected joint is a medical emergency [9, 10]. MRI is the imaging modality of choice, giv- earlier the diagnosis is made and the organism is de- ing more precise anatomic information than nuclear med- tected, the greater the chance that the joint can be sal- icine scans (Fig. Bacteria may enter a joint by several images detects bone-marrow edema and fluid in the joint. Attention must be teomyelitis), direct implantation (penetrating injury, paid to the position of the toes, aligning the image along aspiration, arthrography) [14, 15, 16], and following the axis of the toe on the sagittal slices to facilitate inter- arthroplasty. Prime targets are the elderly, patients with chronic ill- Diabetic patients with cellulitis or foot ulcers and nor- ness or immunosuppression, and those with preex- mal appearing bones on conventional radiography are isting joint disease. Both the host’s ability to resist dis- classic candidates for MRI evaluation of the extent of in- ease as well as the virulence of the organism are factors fection. Even patients whose films show destructive in the fate of the infected joint. The surgeon needs to define the Pathophysiology of Septic Arthritis proximal extent of the bone-marrow involvement in order to determine the site of amputation. An acute inflammatory response is initiated when In the presence of neuropathic osteoarthropathy or fractures, the diagnosis of a superimposed infection by bacteria enter the joint. Marrow edema is present within the gins with the response by polymorphonuclear leuco- bones of a neuropathic joint. In this situation, one must cytes, which release proteolytic enzymes, while lyso- look carefully for evidence of destructive changes of the zomes are released from the synovial membrane. If present, infection of these enzymes contribute to the degradation of the should be suspected. The neuropathic foot may also be proteoglycan matrix of the collagen and cartilage investigated by a combination of Tc99-MDP and tagged ground substance. Comparison with plain films is useful in tended to protect the joint ultimately leads to its de- nearly all cases. The ones of clinical concern are the soft-tissue swelling over the medial side of the forefoot and the dislocation of the second metatarsal-phalangeal joint. Jason Mehrling, Denver, Colorado, USA Osteomyelitis and Septic Arthritis 141 Organisms Related to Septic Arthritis Management Neisseria gonorrhoeae and Staphylococcus aureus are The goal is to prevent joint destruction. With typical clinical signs of infection and easy ac- teria (Pseudomonas aeruginosa and Escherichia coli) are cess to the joint fluid, the radiologist is generally not in- associated with intravenous drug abuse or urinary tract in- volved in the diagnostic workup of the patient with acute fection. Fungal infection occurs in patients with decreased monoarticular arthritis. Haemophilus influen- volving the radiologist are useful in the more difficult zae is seen in children from 6 months to 3 years of age. Computed tomography or fluoroscopy is recom- mended for guidance of needle placement, with injection Clinical Findings of contrast at the end of the procedure to confirm the in- traarticular position of the needle. This is particularly use- The typical patient presents with acute onset of pain, ful in joints such as the hip, sacroiliac joint and shoulder. If the in- If there is a question of monoarticular inflammatory fection is due to hematogenous spread, there may be signs arthritis, MRI may be useful to demonstrate the presence of systemic illness. Establishing the presence of fluid in the proper clinical situation then mandates aspiration using The radiographic changes reflect the underlying pathophys- CT guidance. Hyperemia causes juxtaarticu- Tuberculous Arthritis lar demineralization.
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