By P. Chris. University of Wisconsin-Superior.
Oculodentodigital in the BaJler-Gerold syndrom e: report of a mildly affected patient dysplasia purchase wellbutrin without prescription. Oculodentodigital dysplasia syndrom e with angle-closure heterogeneity or variable expression? A family w ith oculoden Chotzcn syndrom e with familial translocation at chrom osom e 7p22 order wellbutrin online from canada. Due sequencing technologies enable the recognition of single to the size of a cytogenetically detectable chromosomal base pair changes generic wellbutrin 300 mg, single base pair deletions/duplications, change, more than one gene is disrupted. Molecular ‘Ihe material presented in this chapter will be confined strategies create a more sensitive means of detecting copy to “pure” chromosomal aberrations. For example, ifa deletion number variation throughout the genome, which may or of lp occurs in association with a partial trisomy of 4q may not be pathogenic. This has allowed for another dimen (a 1:4 chromosomal translocation), the resulting phenotype sion of genetic diagnosis. In this chapter, only the phenotypes associ microarray or chip technology using arrayed primer exten ated with either the isolated deletion of lp or isolated trisomy sion system that can be used as a rapid, cost-effective initial of 4q will be discussed. It is hoped that the reader will step to simultaneously sequence a number of exons contain therefore be familiar with the phenotypes associated with ing known mutations in either a single gene (eg. ЛВСЛ4) abnormalities of individual chromosomes so that when more or a num ber of related genes associated with the same than one chromosome is altered, features of each separate clinical disease (eg. Whole exome sequencing involves sequencing determine the exact breakpoints in chromosomal anomalies the entire genome. These latter two methodologies detect have become more sophisticated over the years. In fact, known mutations, new mutations and variations of unknown deletions and ring chromosomes were not even recognized significance which need further research. V In addition, many malities for specific ocular disorders are covered elsewhere articles in the non-ophthalmologic literature fail to provide throughout this book and this chapter will be limited to adequate ophthalmic information, sometimes precluding aberrations that are cytogenetically visible by karyotype the exclusion of ocular malformations. Normal ophthalmologic assessment of children who are known to individuals begin life as one diploid cell containing 46 chro have chromosomal aberrations is of great value. Mechanisms for creating partial structure consists of a centromere, a short arm (p for “petit”) aneuploidy (partial trisomy or monosomy) include rear and a long arm (q). One short and one long arm together rangement, duplication, or deletion within a chromosome are known as a single chromatid chromosome. The cclls have been stained with Duplications can also involve the whole genome, result Giemsa, which causes a striped or banded pattern to appear ing in a triploid, tetraploid, or polyploid fetus; these are not for each chromosome. Each band may contain hundreds compatible with long-term viability even if the fetus survives of genes. Triploid fetuses result from double fertilization of chromosomes based on the size, centromere position, (66%), fertilization with a diploid sperm (24%), or the and banding pattern. The deletion can be large enough to result in the loss of part Duplications (Trisomies) of a gene, all of a gene (loss of heterozygosity), or several Meiotic non-disjunction may result in the presence of two genes located close together (contiguous gene syndrome). A trained cytotechnologist can identify each pair of chromosomes based cn the size, centromere position and bandirg pattern. A microdeletion involving pass through cell division unaltered, but others are unstable. Individuals with balanced trans somc fuse or when a chromosome loses the tip of both the p locations may first be identified by karyotype analysis following and q arms and the exposed broken ends fuse. The second results in a monosomy of part of both p Translocations most commonly occur between auto- and q terminal ends of the involved chromosome. In autosome/X chromosome translocations, the normal X is usually preferentially inactivated to maintain Intrachromosomal Duplications activation of the complete genomic complement. Ophthalmologists would observe repeats exist, there is a risk of slippage during meiosis. These duplications tend to occur within the arm of a chromosome (interstitial duplication) as opposed to involving the telomere. Robertsonian Translocation Five human chromosomes (13,14,15,21, and 22) have very Inversions small short arms and arc known as acrocentric chromosomes. Translocations involving these chromosomes are relatively When two breaks occur within one chromosome, the common (1 in 900 newborns) and usually involve two differ intervening segment may invert and reinsert. The resulting translocations arc called includes the centromere, the inversion is denoted as peri Robertsonian translocations. Isochromosomes Insertional Translocation Isochromosomcs have only two short arms or two long A chromosomal segment may be deleted from within a arms, separated by the centromere. Its removal may disrupt one or more in the middle of isochromosomes because one arm is genes at one or both breakpoints on the donor chromosome. When the donor chromosomc fragment inserts into another chromosome (recipient), it can disrupt a gene or insert Chromosomal Fragments (Marker Chromosomes) between two genes. If no genes are disrupted, lost, or dupli These fragments of chromosomes usually represent tri- cated on either the donor or recipient chromosome, the somic material. An inversion that occurs within the long arm or short arm arid without involving the centromere Is denoted as J J paracentric (Figure 13. Recurrence risks for parents of a child affected with A mosaic individual has at least two ccll lines that dilfer in an autosomal dominant or X-linked condition must include genotype or karyotype but were derived from a single a discussion of possible germline mosaicism. Mutations or aberrations can arise in a single cell in child is the product of an abnormal sperm or egg from a either prenatal or postnatal life, giving rise to clones of cells mosaic population of germ cells, then the risk of recurrence is genetically different from the original zygote. The etfects of reduced since subsequent pregnancies can occur from concep mosaicism depend on the stage of development when the tion of a normal egg and sperm. If a mutation or chromosomal aberration takes example, swirling hyperpigmentation following the lines of place in the very early blastocyst stage, the placenta could Blaschko may represent a clone of cells resulting from the be mosaic and the embryonic cells could all be normal, or product of a late-occurring mutation in a surface ectoderm both the placenta and the embryo could carry the aberration cell. Somatic mutations that occur postnatally cause many types of cancer, including Genomic imprinting is a term used to explain the variation 85% of cases of unilateral retinoblastoma. For any given pair of genes, either the maternally or paternally inherited Germline Mosaicism copy may not be functional in normal individuals. For example, when the paternal 15qll-ql3 division several hundred times before meiosis. Mutations allele is deleted the phenotype is Prader-Willi syndrome, thus have many opportunities to occur during germ cell characterized by obesity, short stature, small hands and feet, 193 Parent A Parent В Norm al cell Cell with a balanced translocation Gametes (sperm and ova) Zygotes (fertilized ova) B alanced Down syndrom e M onosomy M onosom y Trisomy Phenotypes Normal translocation (5% of cases) 21 14 14 carrier like parent = Trisomy 21 N on-viable! M iscarriage figure 133 W nen chrom osom es involved in э balarce d translocatior. Cclls in vivo and in vitro do not divide in a synchro cally different from Prader Willi syndrome. To achieve synchronization, colchicine is Uniparental disomy occurs when an individual has added to the culture medium, arresting cell division in inherited both copies of all or part of a chromosome from metaphase. Hypotonic solutions are used to swell the cells only one parent, with no contribution for that chromosome and disperse the chromosomes. When the whole chromosome from microscopic slides, causing the cells to burst open, resulting parent is present in duplicate, the term “isodisomy” is used. Chromosomes “Heterodisomy” refers to situations in which only part of a can then be stained with different substrates to cause different chromosome from one parent is duplicated.
With the help of the stroma and the gap junctions purchase wellbutrin 300mg on-line, the mechanical as well as electrical activities of the cells are coupled cheap wellbutrin 300 mg fast delivery, so that contraction occurs in an inte- grated and coordinated fashion purchase 300 mg wellbutrin visa. Innervations of Smooth Muscles Smooth muscles exhibit a spontaneous, slow wave rhythm. Branches of the autonomic nervous system innervate the smooth muscles, most of which are supplied by sympathetic as well as parasympa- thetic fibers: 1. Since the release of neurotransmitters is not confined attached to the cell membrane. Those associated with the cell membrane are often lar junctions are absent in smooth muscles. Dense bodies are functionally transmitters are not gathered at the neuromuscular analogous to the Z lines in skeletal muscle fibers. Thin Filaments In smooth muscles, thin filaments are composed of actin Electrical Properties and tropomyosin molecules but troponin protein complex Unlike the skeletal muscle where the stimulus arrives in is absent. The smooth muscles react to a the relationship between the thick and thin filaments is variety of stimuli, which may be neural (sympathetic or poor and they are less well organized. In cross sections through the overlap region of the serotonin, histamine, angiotensin, vasopressin, oxytocin, filaments, the geometric pattern as found in striated estrogen, and progesterone); chemical (hypoxia, hypercap- muscles are not seen. Because of the absence of a highly organized arrange- impulse in sympathetic and parasympathetic nerves sup- ment of contractile apparatus, the length tension rela- plying visceral muscles and properties of visceral muscle tionship in the smooth muscles is very much flexible. The actin filaments anchor to Scientists contributed the dense bodies by means of the protein α-actinin. During the sliding-filament mechanism, the gap between the actin filaments reduces and the shorten- ing force is transmitted through the dense bodies to the plasma membrane producing contraction of the muscle fiber. Organization of Muscle Fibers the smooth muscle fibers are organized in sheets and the Sir Henry Hallett Dale Otto Loewi cells are connected to adjacent cells by short strands of (1875–1968) (1873–1961) connective tissue. Their pioneering works were in the field of gap junctions, by which many cells are activated at a transmission of nerve impulses, especially its chemical basis. Dale had also studied the details of smooth muscle functions time by single action potential. Chapter 29: Smooth Muscle and Cardiac Muscle 279 Characteristic Electrical Activities later part of repolarization. When the stimulus is excitatory, the membrane poten- muscle cells contract without any change in membrane tial decreases and it increases in response to an inhibi- potential. The membrane potential of visceral smooth muscles Junctional Potential is variable (no fixed resting potential), ranging from Generally, action potentials are not observed in multiunit –30 mV to –70 mV with an average of –50 mV. The visceral smooth muscle shows spontaneous oscil- like Ach, local depolarization called junctional potential is lations in a wave like pattern. Some of the oscillations recorded that spreads electrotonically along the muscle lead to action potentials that may occur in the rising or fiber and decreases the membrane potential causing falling phase of the wave. The multiunit smooth muscles do not discharge spon- channels, leading to contraction. Most of the visceral smooth muscles generate action potentials inherently; any stimulus acting on it only In addition to action potentials, pacemaker potentials alters the rate and pattern of action potentials formed. The shapes of action potentials vary widely, which cardiac muscle, the pacemaker activity is not generated may be a spike, or action potential with a prolonged at a fixed location; rather it shifts from place to place. In plateau, or multiple spikes, superimposed on the visceral smooth muscles like intestine, pacemaker activi- membrane potential (Fig. Other forms of spikes ties occur at several sites at the same time and then they or action potentials of smooth muscle have been travel for a short distance in the muscle. In some cells, in response to stimuli like hormones or Mechanism of Contraction mechanical stretch, the membrane potential shows a graded change that may culminate into an action Role of Calcium potential. As in other muscle types, changes in sarcoplasmic calcium Action Potential ion concentration plays a major role in smooth muscle the action potentials are generally of low amplitude, contraction. Accordingly, the change in cytosolic cal- of actions potential is prolonged in smooth muscles, cium concentration may be minute, more or very high, ++ producing different degrees of contraction. The repolarization phase occurs due ++ by entry of calcium from the interstitial fluid (calcium to closure of Ca channels, which occurs slowly. Open- + influx) or to some extent by its release from cytoplas- ing of voltage-gated K channels contributes toward the mic calcium stores (calcium release). Calcium Influx ++ Calcium influx occurs through voltage-gated Ca channels, ++ ligand-gated Ca channels and a few leaky channels. This high inwardly directed gradient favors calcium entry into the smooth muscle as soon as calcium channels open. Binding of calcium to calmodulin starts when cytoplasmic −7 calcium concentration is above 10 M and is completed −4 at 10 M. In smooth muscles, tension is generated in the same manner as in skeletal muscles, by the attachment of ener- gized cross-bridges to actin, followed by detachment from and reattachment to actin. The following step-wise processes take place sequentially to culminate in muscle contraction. The cross-bridge cycle continues as long as the req- myosin light-chain is regulated by respective rise and uired cytoplasmic calcium concentration is maintained, fall of cytosolic calcium concentration. Chapter 29: Smooth Muscle and Cardiac Muscle 281 Phasic and Tonic Contractions: Unlike the skeletal Table 29. Morphological properties traction waves on stimulation, the smooth muscles exhibit 1. Absence of Ttubules In phasic type, the degree of phosphorylation, the rate of 4. Absence of welldeveloped neuromuscular junctions cross-bridge cycle and the cytoplasmic calcium concentra- B. Electrical properties tion return to the resting value following the phase of con- 5. Variable action potentials During tonic contraction, the above-mentioned parame- C. Mechanical properties ters do not return to the resting value, rather they remain 9. Force–velocity relationship possible due to the operation of latch-bridge mechanism. Muscle hypertrophy Latch-Bridge Mechanism Muscle Tone Muscle in this state is known as the latch-state, in which Visceral smooth muscles are continuously in a state of dephosphorylation of attached cross-bridges occurs in an spontaneous irregular contraction known as tonus, which environment of elevated cytosolic calcium level. This attached cross-bridges following dephosphoryla- tion are known as the latch-bridges. In this process the Length–Tension Relationship rate of cross-bridge cycle is decreased due to slower rate of detachment of cross-bridges. That means the Unlike the skeletal and cardiac muscles, where the ten- cross-bridges spend more time in an attached state. When a smooth muscle is stretched, it initially shortens visceral smooth muscles to have sustained contrac- and exerts tension. The force of this sustained contraction can be graded increased, the tension may not rise proportionately or over a wide range because the cytosolic calcium con- at a particular length, the tension may increase consi- centration can be finely regulated over a wide range.
In terms of frequency: tubular (65%–80% of cases) > tubulo-villous (10%–25%) > villous (5%–10%) order wellbutrin in india. In terms of malignant potential: villous (40% risk of harbouring cancer) > tubulo- villous (22% risk of cancer) > tubular (5% risk of cancer) discount wellbutrin 300 mg overnight delivery. Malignant transformation Ulceration Bleeding Infection Intussusception Protein and potassium loss Diverticula What is a diverticulum? A diverticula = An abnormal outpouching of a hollow viscus into the surrounding tissues purchase discount wellbutrin on-line. They can be classified by: Aetiology Congenital (Meckel’s diverticulum) versus acquired Pulsion versus traction. Traction diverticula are much less common and are mostly a consequence of fibrotic healing in lymph nodes secondary to chronic granulomatous disease exerting traction on the neighbouring bowel wall. Zenker’s diverticulum, small intestine, large intestine) Mesenteric (small intestine) versus anti-mesenteric location (Meckel’s diverticulum) Architecture True (Meckel’s diverticulum) versus false (sigmoid colon, pharyngeal pouch) What complications might they undergo? Complications: Perforation Inflammation +/− infection Bleeding Fistulae Strictures Malignancy (e. A thrombus is defined as ‘solid material formed from the constituents of blood in flowing blood’ (when formed in stationary blood = clot). An embolus is defined as ‘an abnormal mass of undissolved material that is carried in the bloodstream from one place to another’. Thrombus Fat Air Atheromatous material Amniotic fluid Tumour cells Foreign material (e. It is reversible upon removing the injurious agent (hence the importance of risk factor modification and primary prevention strategies). The ‘response to injury’ hypothesis seems most plausible in terms of explaining the underlying pathogenesis. It explains how the biggest risk factors (namely tobacco toxins, hypertension and turbulent blood flow, lipids and glycosylated haemoglobin in diabetes mellitus) exert their influence and why risk factor modification is so effective in modifying the disease process. Complications of atherosclerosis include: Distal ischaemia Vessel occlusion Plaque ulceration, rupture Thrombosis Haemorrhage into a plaque Embolism – Lipid or thrombus Calcification Aneurysm formation Necrosis and apoptosis What is necrosis? There are several different types of necrosis: Coagulative (structured) necrosis – the most common form of necrosis. Seen in organs supplied by end arteries such as the kidney, heart, liver and spleen. Liquefactive (colliquative) necrosis – Occurs in tissues rich in lipid where lysosomal enzymes denature the fat and cause liquefaction of the tissue. Caseous (unstructured) necrosis – Gross appearance is of soft, cheesy friable material. Fibrinoid necrosis – Seen in the walls of arteries that are subjected to high pressures as in malignant hypertension. Gangrenous necrosis – This is irreversible tissue death characterised by putrefaction. Apoptosis Necrosis Energy dependent (active) Energy independent Internally programmed (suicide) Response to external injury Affects single cells Affects groups of cells No accompanying inflammation Accompanied by inflammation Physiological or pathological Always pathological Plasma membrane remains intact Loss of plasma membrane integrity Cell shrinkage, fragmentation and Cell swelling and lysis formation of apoptotic bodies Hypersensitivity reactions What is a hypersensitivity reaction? A hypersensitivity reaction is a condition in which undesirable tissue damage follows the development of humeral or cell mediated immunity. It represents an exaggerated response of the host’s immune system to a particular stimulus. Hypersensitivity reactions can be classified into four classes according to the Gell and Coombs classification. The original description by Gell and Coombs was based on four classes, with a fifth class subsequently being added later. Gell and Coombs Classification of Hypersensitivity Reactions Type I – Mast cell degranulation mediated by pre-formed IgE bound to mast cells. Humoral antibodies participate directly in injuring cells by pre-disposing them to phagocytosis or lysis. Good examples are transfusion reactions, autoimmune haemolytic anaemia and Goodpasture’s syndrome. Type V – (more recent addition to the original classification): Due to the formation of stimulatory autoantibodies in autoimmune conditions such as Graves’ disease and myasthenia gravis. An ulcer is a break in an epithelial surface the commonest leg ulcers are: Venous (70% of cases) Arterial Neuropathic Other causes include: Infections, e. A tumour marker is a substance reliably found in the circulation of a patient with neoplasia which is directly related to the presence of the neoplasm, disappears when the neoplasm is treated and reappears when the neoplasm recurs. Diagnostic purposes Prognostic information (tumour load) Monitoring response to treatment Surveillance to detect recurrence Screening Colitis What is colitis? Colitis can be classified by aetiology into: Inflammatory – Ulcerative colitis, Crohn’s colitis, indeterminate colitis Infective colitis (also includes pseudomembranous colitis caused by Clostridium difficile – See Chapter 3) Ischaemic colitis Radiation colitis Collagenous colitis Microscopic colitis (and lymphocytic/eosinophilic colitis) Malignant melanoma What is malignant melanoma? There are several different subtypes including: Superficial spreading (most common, accounting for 70% cases) Nodular Hutchinson’s freckle (lentigo maligna melanoma) Acral lentiginous Amelanotic What macroscopic features in naevi are suggestive of melanoma? Only 10%–20% of melanomas form in pre-existing naevi, with the remainder arising de novo. Macroscopic features in a pre-existing naevus that suggest malignant change include: Asymmetry Border irregularity Colour variegation Diameter >6 mm Elevation As well as changes in size, shape and colour, there may also be tingling, itching, crusting, serosanguinous discharge or the presence of satellite lesions. Breslow’s depth is more accurate than Clarke’s level because skin thickness varies in different parts of the body. The Breslow thickness is defined as the tumour invasion depth from the top of the granular layer of the epidermis to the deepest point of the tumour. Thus, 5-year survivals according to Breslow depths are as follows: <1 mm – 95%–100% 5-year survival 1–2 mm – 80%–96% 5-year survival 2. It is usually obtained by fine needle aspiration or brushings from epithelial surfaces. Histology studies cells within the context of tissues and provides information about tissue architecture. Cytology advantages: Simple to perform, rapid Minimally invasive Cheap and requires minimal equipment Cytology disadvantages: Tells you nothing about the tissue architecture. For example, it cannot distinguish a thyroid follicular adenoma from a carcinoma because it cannot assess invasion. This can result in sampling error, or insufficient material for definitive diagnosis. Needs experienced cytologist Operator dependent Potential for spread of malignant cells Less amenable to further studies (e. Although only one station, this station can often mean the difference between passing and failing as it is often neglected by many candidates sitting for the exam. This chapter covers the common topics that candidates are expected to be familiar with for the exam. Bacteria can be classified according to their Staining properties – Gram-positive, Gram-negative, acid-fast etc. Morphology – Round (cocci), rods (bacilli), spiral (spirochaetes), comma- shaped (vibrio), flagellated, possession of a capsule etc.
Once the cyst is identified discount wellbutrin 300 mg amex, careful attention is paid to its relationship to surrounding structures (see Figs order wellbutrin 300mg on line. Color Doppler will help identify adjacent vessels and vascularity involving the ganglion itself that may be damaged during injection purchase wellbutrin 300mg with visa, drainage, or surgical removal (Figs. Proper ultrasound transducer placement for evaluation and localization of ganglion cysts of the dorsal wrist. Transverse ultrasound image of the wrist demonstrating the clasic anechoic appearance of a ganglion cyct that arises from the scapholunate joint. Note the posterior acoustic enhancement, which is characteristic of larger ganglion cysts. Transverse ultrasound image demonstrating a palmar wrist ganglion involving the radial artery. Transverse color Doppler image demonstrating the radial artery lying within the ganglion cyst. Longitudinal Doppler ultrasound showing a small superficial artery coursing over a low echogenicity volar radial aspect ganglion. A: Transverse sonogram shows a well- circumscribed oval-shaped mass of mixed echogenicity. Gray-scale and color Doppler sonographic appearances of nonsubungual soft-tissue glomus tumors. Longitudinal view of the dorsal wrist demonstrates a tortuous neck (arrows) extending from a ganglion cyst (C) toward the deep joint space. Sagittal sonogram over the dorsal radiocarpal joint shows an anechoic ganglion cyst (arrow) with lobular margins and communication to the adjacent radiocarpal joint (arrowheads). Ultrasound imaging of the ganglion cyst and adjacent areas will help with the diagnosis of this occult wrist and hand pathology. Ultrasound-guided aspiration and biopsy may also aid in the diagnosis of questionable cases (Fig. Ruptured ganglion cysts may not exhibit the classic anechoic appearance with posterior enhancement of the intact ganglion cyst, and may look more like a solid tumor. In this setting, magnetic resonance imaging may help clarify the character of the soft tissue mass. The primary function of the first carpometacarpal joint is to aid in orientation of the thumb to allow pinching movements as well as flexion and extension in the plane of the palm of the hand, abduction and adduction in a plane at right angles to the palm, circumduction, and opposition. The joint is lined with synovium and the ample synovial space allows for intra-articular placement of needles for injection and aspiration. Because of the extensive and diverse range of motion of the first carpometacarpal joint combined with a relatively weak and slack joint capsule, the joint is especially susceptible to trauma including subluxation and fractures or the base of the metacarpal through the articular surface which can result in the development of arthritis (Fig. The joint is also susceptible to overuse and misuse with resultant inflammation and arthritis. Much of the joints’ strength is derived from the three intracapsular and two extracapsular ligaments and the surrounding tendons (Fig. The first carpometacarpal (trapeziometacarpal) joint is a saddle joint that allows a variety of motions of the thumb. Opposition, the action bringing the tip of the thumb in contact with the pads of the other fingers (e. The components of opposition are medial rotation at the carpometacarpal joint and abduction and flexion of the metacarpophalangeal joint. The first carpometacarpal joint capsule is relative lax and weak, making the joint susceptible to subluxation. Osteoarthritis of the joint is the most common form of arthritis that results in first carpometacarpal joint pain and functional disability, with rheumatoid arthritis, posttraumatic arthritis, and crystal arthropathy also causing arthritis of the first carpometacarpal joint (Fig. Less common causes of arthritis-induced first carpometacarpal joint pain include the collagen vascular diseases, infection, villonodular synovitis, and Lyme disease. Acute infectious arthritis of the first carpometacarpal joint is best treated with early diagnosis, with culture and sensitivity of the synovial fluid and prompt initiation of antibiotic therapy. The collagen vascular diseases generally manifest as a polyarthropathy rather than a monoarthropathy limited to the first carpometacarpal joint, although first carpometacarpal pain secondary to the collagen vascular diseases responds exceedingly well to ultrasound-guided intra-articular injection of the first carpometacarpal joint. Interestingly, osteoarthritis of the thumb occurs over 20 times more frequently in elderly females when compared with elderly males. This is thought to be due to sexual dimorphism in the shape of the joint with the female joint having a significantly smaller trapezial articular surface when compared with males of the same age. Calcium pyrophosphate dihydrate crystal deposition disease involving the joints of the wrist and hand. Calcification of the triangular cartilage is evident in the ulnar compartment of the wrist (arrow). Also noted is exuberant degenerative change in the first carpometacarpal joint, secondary to crystal deposition. Activity, including pinching and gripping motions, makes the pain worse, with rest and heat providing some relief. Sleep disturbance is common with awakening when patients roll over onto the affected upper extremity. Some patients complain of a grating, catching, or popping sensation with range of motion of the joint, and crepitus may be appreciated on physical examination. Watson stress test is positive in patients who suffer from inflammation and arthritis of the carpometacarpal joint of the thumb. Watson test is performed by having the patient place the dorsum of the hand against a table with the fingers fully extended and then pushing the thumb back toward the table (Fig. Watson stress test is positive in patients who suffer from inflammation and arthritis of the carpometacarpal joint of the thumb. Watson test is performed by having the patient place the dorsum of the hand against a table with the fingers fully extended and then pushing the thumb back toward the table. Functional disability often accompanies the pain associated with many pathologic conditions of the first carpometacarpal joint. Patients will often notice increasing difficulty in performing their activities of daily living and tasks that require gripping or pinching objects such as writing with a pen or pencil or opening a jar. If the pathologic process responsible for the first carpometacarpal pain is not adequately treated, the patient’s functional disability may worsen and muscle wasting and ultimately a frozen first 520 carpometacarpal joint may occur. Plain radiographs are indicated in all patients who present with first carpometacarpal joint pain (Fig. Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. The ulnar aspect of the first carpometacarpal joint opens approximately 35 degrees with radially directed stress which is strongly suggestive of a complete tear of the ulnar collateral ligament. The transducer is placed on the ulnar side of the thumb for long- and short-axis scans. The thin hyperechoic band superficially is the adductor aponeurosis (solid arrow), which can be demonstrated by flexing the interphalangeal joint of the thumb. A small linear high-frequency ultrasound transducer is placed in a longitudinal parallel axis over the base of the first metacarpal lying against the volar radial aspect of the thumb and a survey scan is taken (Fig. The transducer is slowly moved proximally along the volar radial aspect of the thumb until the hypoechoic cleft between the base of the thumb and the distal articular surface of the trapezium is in the center of the image (Fig.