Anatomy, Neuroanatomy, embryology, Histology Flashcards
(104 cards)
1
Q
What artery would result in insufficient perfusion of the urinary bladder?
A
Internal Iliac ( Hypogastric artery) It is the smaller terminal branch of the common iliac artery. Supplies the pelvic walls, pelvic viscera, external genitalia, perineum, buttock and medial part of the thigh.
2
Q
Insufficient perfusion
A
inadequate perfusion means decreased arterial blood flow to the extremities. Can be due to sudden embolic event obstructing arterial flow or chronic obstructive process leading to decreased arterial flow to extremities.
3
Q
36 y/o female stomach ulcer. Along greater cuvature, 4cm away pyloric sphincter. ulcer perforates. Aintra abdominal bleeding. ulcer eroded stomach wall dmaged artery supplying involved region of stomach. Which artery likely involved?
A
Right gastroepiploic
4
Q
Woman elevated prolactin. Gland responsible for secretion this horone is derived from what?
A
Rathke’s pouch
Rathke pouch, is also known as hypophyseal diverticulum, it is an ectodermal outpouching of the somodeum (primitive oral cavity lined by ectoderm) which forms at approximately 3-4 weeks gestation and goes on to form the adenohypophysis of the pituitary gland.
Adenohypophysis - Major organ of the endocrine system, the anterior pituitary. (also called the “adenohypophysis”).
Drive a FLAT PEG in the anterior pituitary.
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Adrenocorticotropic hormone (ACTH)
- Thyroid-stimulating hormone (TSH)
- Prolactin
- Endorphins
- Growth hormone (GH)
FLAT are tropic hormones while the PEG are all direct hormones.
5
Q
56 y/o, flu-like illness. nausea, vomiting, unilateral tingling in the leg. Headache involving the ye and forehead. Alert, fully oriented. Motor, sensory, gait, and coordination examinations are normal. Cranial nerve examination is normal, aside from the visual field disorder indicated.
Picture shows two circles indicating left eye and right eye. the left visual field in both eyes shows white, while the right visual field in both eyes is shaded in black.
the neurologic examination suggests an occlusion of which of the following vessels?
A
Left posterior cerebral artery
The posterior cerebral artery (PCA) is one of a pair of arteries that supply oxygenated blood to the occiptal lobe, part of the back of the human brain. The two arteries originate from the distal end of the basilar arter, where it bifurcates into the left and right posterior cerebral arteries.
Bifurcates - divides into two branches of forks.
6
Q
49 y/o man diagnosed tuberculosis. flocculent masses noted over lateral lumbar back and similar mass located in the ipsilateral groin. This pattern of involvement strongly suggests an abscess tracking along which of the following muscles?
A
Psoas Major
The psoas major is a lengthy fusiform (or spindle-shaped) muscle that is found on side of the lubar region of the vertebral column. Also adjacent to the brim of the lesser pelvis area. connects iliacus muscle to the iliopsosas. In some individuals the muscle is assisted by the psoas minor.
floccuent - resembling tufts of cotton or wool, denoting a fluid, numerous shreds of fluffy particles of gray-white or whit emucus.
Lateral - position farther from the median plane or midline of body.
ipsilateral - sitting on or affecting the same side
7
Q
24 y/o stabbed in neck. neurologic examination reveals left-sided hemiparesis. Complete loss of discriminatory joint position and vibration sensation below C8 on the left side. On the right side, there is loss of pain and temp sensation below C8. It can be expected that an MRI of the cervical spinal cord will show which of the following findings?
A
A Hemisection of the left side of the cord.
Hemiparesis (or unilateral paresis) - is a weakness of one entire side of the body. (Hemi means half). Hemiplegia is in its most severe from complete paralysis of half of the body.
spinal hemi paraplegia is caused by damage to one half of the spinal cord. example, hemisection of the spinal cord resulting in paralysis and loss of proprioception.
C8 spinal nerve - C8 level corresponds to the region in which nerve roots exit the spine between th crvical spines C7 vertebra and the thoracic spines T1 vertebra. There is not a coresponding vertebra for C8. This nerve root is responsible for controlling muscles in the finger and hands.
8
Q
2 y/o boy brought to pediatrician by his mother because he has had several episodes of rectal bleeding. evaluation with technetium-99m perfusion scan reveals a 3-cm ileal outpouching located 60cm from the ileocecal valve. This structure most likely contains which of the following types of ectopic tissue?
A
Gastric tissue
ileal outpouching - The ileum is the third and final part of the small intestine. It follows the jejunum and ends at the ileocecal junction where the terminal ileum communicates with the cecum of the large intestine through the ileocecal valve.
9
Q
A 34 y/o man stab wound to superolateral aspect of the thoracic wall at the level of the third rib. Little bleeding and no difficulty breathing. The medial border of the scapula on the injured side pulls away from the body wall when the arm is raised. The arm cannot be abducted above the horizontal, which of the following muscles is paralyzed?
A
serratus anterior
10
Q
A histologist is examing cells arrested at various stages of oogenesis. he discovers a follicle within the stroma of the ovary that has developed an antrum. This follicle would be classified as?
A
Secondary.
Antrum - A natural chamber or cavity in a bone or other anatomical structure.
Seconary follicle - secondary follicles look very similar to primary follicles, except that they are larger, there are more follicular cells, and there are small accumulations of fluid in the intracellular spaces called follicular fluid (nutritive fluid for the oocyte). These gradually coalesce to form an antrum.
Graffian Follicle - A fluid-filled structure in the mammalian ovary within which an ovum develops before ovulation.
11
Q
54 y/o has cirrhosis, with obstruction of the portal circulation within the liver. Portal blood could still be conveyed to the caval system via which of the following?
A
Azygos and hemiazygos veins
The esophageal venous plexus, which drains into the azygos and hemiazygos veins within the thorax, has anastomoses with branches of the left gastric vein. Thus, following blockage of the portal vein, portal blood may enter the superior vena cava via the azygos system.
Anastomoses - Is the connection of two things that are normally diverging. Typically refers to a connection between blood vessels or between two loops of the intestine.
12
Q
47 y/o presents neurologist with unsteady, broad-based gait and slow, slurred speech. Neurologic examination reveals dysdiadochokinesia, intention, tremor, hypotonia, and nystagmus. the patients lesion is in a brain structure that derives from which of the following embryonic structures?
A
Metencephalon
The patient has a cerebellar lesion. Cerebellar dysfunction can lead to a variety of motor dysfunctions, including truncal ataxia (appearin similar to the gait of an intoxicated individual). Intention tremor (uncontrolled shaking of affected extremity present only with purposeful movement).
Dysdiadochokinesia - the inability to perform rapid and regular alternating movements.
Dysmetria - Inability to stop movements at the desired point.
Dysarthria - ataxic speech
Hypotonia - decreased muscle tone. healthymuscles are never fully relaxed.
During the 4th week of embryonic development the anterior end of the neural tube develops three vesicles, the prosencephalon (forebrain), the mesencephalon (Midbrain) and the rhombencephalon (Hindbrain) By the 6th week five vesicles develop.
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon
Telencephalon.
The rhombencephalon has now developed into the metencephalon and the myelencehalon. The cerebellum and pons derive from the metencephalon.
13
Q
47 y/o female history rheumatic fever. Examination significant for low-pitched, rumbling, diastolic murmur preceded by an opening snap. The affected valve can be best evaluated by auscultation at which of the following locations?
A
Left fifth intercostal space
This question tests two facts. First requires recognize patient has mitral stenosis. Classic clues to this diagnosis are low-pitched, rumbling, diastolic murmur, opening snap, and rheumatic fever. The mitral valve is the most commonly affected valve in rheumatic fever, followed by the aortic and tricuspid valves.
Question then asks you where sounds generated by a faulty mitral valve will be best heard on physical exam. The mitral valve is most audible over the left fifth intercostal space at the mid clavicular line.
Auscultation is a method used to listen to sounds of the body uring a physical examination
14
Q
Newborn has abnormal accomodation of the lens. Further evaluation reveals an abnormal production of aqueous humor. A malformation of the structure responsible for these functions that is continuous posteriorly with the choroid might be due to abnormal development of?
A
Neuroectoderm of the optic cup
The optic cups derive from the optic vesicles, which are evaginations of the diencephalon. The anterior two layers of the optic cup (neuroectoderm), in association with choroidal mesoderm, give rise to the ciliary body and the iris. The optic cup also gives rise to the neural and pigment layers of the retina.
Retinal ganglion cells axons, run in the optic stalk, become the nerve fibers of the optic nerve. Closure of the choroid fissure in the optic stalk occurs during the seventh week of development. The former optic stalk is then called the optic nerve.
Mesoderm surrounding the optic cup becomes the sclera and choroid of the eye.
Mesoderm surrounding the optic stalk gives rise to the meninges surrounding the optic nerve.
15
Q
Neuroscientist perform study requires him increase the concentration of norepinepinephrine in the cortex of an animal subject. Does so by electrically stimulating a nucleus in the brain. Which nuclei is most imortant source of noradrenergic innervation to the cerebral cortex?
A
Locus Caeruleus
Locus caeruleus is a dense collection of neuromelanin-containing cells in the rostral pons, near the lateral edge of the floor of the fourth ventricle. Appears blue-black in unstained brain tissue is where it gets its name which means “blue spot”. These cells, which contain norepinephrine, provide the majority of noradrenergic innervation to the forebrain, including the cerebral cortex.
16
Q
A surgeon tells a medical student to tap the side of the face of a ptient who just had thyroid surgery. The surgeon is ost worried about damage to which of the following Vessels?
A
Superior and Inferior Thyroid Arteries
The surgeon has asked the student to test for tetany, which can occur if the blood supply to the parathyroid glands (through the superior and inferior thyroid arteries) is disrupted during thyroid surgery. Specifically the medical student is being asked to tap with his fingers the muscles of mastication, notably the masseter, which because of its strength is a sensitive indicator of tetany. Tetany will be seen as an abnormally strong jerk or contraction related to the hypocalcemia that can develop if scretion of parathyroid hormone is inadequate.
17
Q
45 y/o abdominal pain that has progressively worseened since the previous night. Nausea and vomiting, but is afebrile. Upper gastrointestinal radiographic studies reveal that a loop of small intestine has pass through the epiploic foramen into the omental bursa and is contricted by the margins of the foramen as the intestine fills. The constriction should not be surgically relived by opening the epiploic foramen because this procedure woudl risk cutting the?
A
Hepatic Artery
The hepatic artery is one commponent of the portal triad: the hepatic artery, common bile dict, and the portal vein. These structures constitute the porta hepatis and lie in the free edge of the lesser omentum as it forms the epiploic foramen. Opening the epiploic foramen would therefore involve cutting the porta hepatis and, possibly, the hepatic artery and other components of the portal triad.
18
Q
26 y/o stabbed left chest. several days later returns complaining of decreased function in his left arm. Examination reveals winged left scapula and an inability to raise his left arm above the horizontal which nerves is most likely affected?
A
Long Thoracic
The serratus anterior, innervated by the long thoracic nerve, is responsible for stabilization of the scapula during abduction of the arm from 90 to 180 degrees. When the long thoracic nerve is damaged, it is difficult to elevate the arm above the horizontal. This nerve arises from C5, 6 and 7. Remember: Winged scapula is a classic clue for long thoracic nerve injury.
19
Q
Patient transported to the emergency department with a knife wound to the right fifth intercostal space at the midaxillary line. Which of the following structures is likely to have been damaged?
A
Liver
Any perforating wound occuring below the level of the fourth intercostal space on the right side may damage the liver, which is protected by the rib cage, although it is an abdominal organ lying inferior to the diaphragm.
20
Q
where is the mid axillary line?
A
21
Q
where is the midclavicular line
A
22
Q
At what stage of embryonic development does an embryo normally begin to implant in the endometrium?
A
Blastocyst
After fertilization, the fertilized ovum begins to divide as it migrates through the uterine tube. It reaches the blastocyst stage (approximately 110 cells) at about day 5, and it enters the uterus at about day 6. Implantation normally begins on day 6 with the syncytiotrophoblast of the embryonic pole of the blastocyst eroding into the endometrium.
23
Q
A newborn male is found to have urethral openings along the ventral surface of the penis. The physician explains to the parents that the bilateral structures that should have fused in the midline failed to fuse completely, and this resulted in the defect. The parents are very concerned, but the physician reassures them that this can easily be surgically corrected. Which of the following structures in a female normally develop from the same structures that failed to fuse in this boy?
A
Labia Minora
The urethral folds in the female to not fuse, and they develop into the labia minora. The space between the folds becomes the vestibule of the vagina. In the male, the urethral folds normally fuse to become the ventral surface of the penis. A failure of these folds to fuse normally in the male results in hypospadia, the presence of openings of the urethra along the ventral surface of the penis.
24
Q
19 y/o falling on roller blades. 3cm laceration over the lateral aspect of the knee penetrating so deep that the head of the fibula is apparent. Radiograph negative for fractures. Noticeable foot-drop occurs while the patient walks. Inability to dorsiflex or evert the foot. What best explains her injury.
A
The common peroneal nerve was severed.
The common peroneal nerve wraps around the lateral aspect of the head of the fibula and is highly susceptible to damage during lacerations or blunt injuries to the lateral knee. Foot-drop with loss of dorsiflexion or eversion is characteristic.
25
Resident physician performing pelvic exam, on woman fingers of one hand are in the vagina, palpating the cervix. The other hand is pressing on the abdomen. With the palm of his hand, the physician feels a bony structure in the lower midline. This structure is mostly likely the .
Pubis
The resident is feeling the two pubic bones, which are joined at the midline by the symphysis pubis. Experienced obstetrician/gyn, can often perceived the softening of the symphysis pubis that occurs during late pregnancy as a "springiness" of the pubic bones during palpation.
26
45 y/o with history of stable angina presents emerg with episode of chest pain tha tis not relieved by rest or nitroglycerin. After stabilization in the telemetry unit for 2 days, he undergoes a thallium stress test. The results show reduced perfusion of the lateral wall of the left ventricle. Which artery is most like occluded?
Left Circumflex
In some patients with coronary artery disease, thallium stress tests may be performed instead of cardiac catheterization to determine the vessels involved and the extent of occlusion. The left circumflex (LCx) branch supplies the lateral wall of the left venricle, in 10% of the population, it also supplies the posterior wall and AV node.
27
41 y/o man motorcycle accident. treated for abdominal, spinal and head injuries. Neurologists examines and notices the patient has left-sided facial swelling and discoloration, slight drooping of the left eyelid, and a constricted pupil on the left side. There are no other motor or sensory abnormalities. Which of the following is the most likely cause of this patients ocular disorder?
A lesion of the thoracic spinal cord
The pupillary dialator muscle is innervated by the sympathetic nervous system. Preganglionic fibers originating at the spinal cord levels T1 through T5 ascend to the superior cervical ganglion, from which postganglionic fibers travel to the eye. Muellers muscle in the upper eyelid is also innervated by sympathetic fibers originating in the upper thoracic spinal cor. Disruption of the sympathetic supply to the eye, as has apparently occurred in this patient, causes ptosis and miosis due to unopposed action of the pupillary constrictor muscle. Interruption of the sympathetic supply to the eye is known as horners syndrome.
28
4 day old brought to pediatric clinic for breathing difficulties and poor feeding. Coughs, chokes, and spits up milk very soon after beginning to suckle. Physical exam and radiographs reveal presence of the most common type of tracheoesophageal fistula. The infants defect is likely resulted from?
Failure of the tracheoesophageal ridges to fuse
The tracheoesophageal ridges are two longitudinal ridges that separate the respiratory diverticulum from the foregut. Eventually, they fuse to form a septum separating the esophagus (dorsal) from the trachea (ventral) and lung buds, maintaining a communication only rostrally at the pharynx. Incomplete formation of the tracheoesophageal septum (by fusion of ridges) results in the most common type of tracheoesophageal fistula, whereby the proximal part of the esophagus ends as a blind sac (esophageal atresia), while the distal part is connected to the trachea by a narrow canal just above the bifurcation. This defect occurs in approximately 1 in 2500 births.
29
40 y/o complains loss of sensation over right scrotum and on the medial right thigh. Damage to which of the following nerves would result in such symptoms?
Ilioinguinal
Question involves sensory innervation of the perineum and vicinity. The ilioinguinal nerve supplies the skin of the scrotum and the medial thigh with sensory fibers.
30
A neonate has a prominent defect at the base of his spine through which his meninges and spinal cord protrude. A failure of which of the following processes is the most common cause of this type of defect?
Fusion of the vertebral arches.
The condition described is spina bifida with myelomeningocele. A failure of the posteriorly located vertebral arches to fuse posteriorly causes spina bifida, which can vary in severity from a completely asymptomatic minor abnormality to protrusion of the spinal cord and roots through an open skin defect with a very real risk of minor trauma or infection causing paralysis.
31
Passenger bleeding profusely from neck and surmises bleeding from carotid artery. To conrol bleeding, the surgeon can compress the carotid artery against the anterior tubercle of which of the following vertebrae?
Sixth Cervical
The sixth cervical vertebra is a critical boundary of the root of the neck. To enter the neck from the chest, the vascular structures pass through a ringlike opening bounded by the scalene musslces laterally, the sternum and the first ribs anteriorly, and the vertebrae (notably C6)
32
An intravenous pyelogram is performed on a patient to evaluate the function and structure of her kidneys. Examination of the resulting radiographs reveals that the left kidney is normal but that there is a duplication of the ureter and renal pelvis on the right side. Further testing reveals kidney function is normal. This variation is a result of abnormal development of which of the following structures?
Ureteric Bud
The ureteric bud forms the ureter, renal pelvis, major and minor calyces, and collecting tubules of the kidney. The ureteric bud is an outgrowth of the mesonephric duct that grows toward the metanephric blastema and induces the metanephric blastema to develop into the nephrons of the kidney. The caudal end of the mesonephric duct becomes incorporated into the trigone of the urinary bladder. Thus, the ureteric bud drains urine from the filtration portion of the kidney into the bladder.
33
62 y/o man brain tumor growing in his interhemispheric fissure at the level of the central sulcus. The tumor produces neurologic dysfunction of the cerebral cortex on either side of the tumor. A neurologic examination of this patient would most likely reveal?
Paraplegia
Knowledge of the motor homunculus of the precentral gyrus (primary motor cortex) is necessary to answer this question. The parts of the cortex that control the legs are burried within the interhemispheric fissure. Paraplegia indicates weakness of both legs.
34
Brunners glands secrete an alkaline product that helps achieve optimal PH for the activity of pancreatic enzymes. Where are the glands located?
In the submucosa of the duodenum
Brunners glands are located in the submucosa of the duodenum. These glands are connected to the intestinal lumen by ducts that open into certain crypts. They secrete an alkaline product that protects the duodenal mucosa from the acidic chyme and helps achieve optimal PH for pancreatic enzymes.
35
A 24 y/o man presents with pain in his right wrist that resulted when he fell hard on his outstretched hand. Radiographic studies indicate an anterior dislocation of a proximal row carpal bone that articulates with the most lateral proximal row carpal bone. Which bone was dislocated?
Lunate
The lunate is in the proximal row and articulates with the scaphoid laterally (this being the most lateral of the proximal row). The lunate is the most commonly dislocated carpal bone. It is usually displaced anteriorly by rotation on his proximal, convex surface (where it articulates with the radius). The displaced bone may compress the median nerve in the carpal tunnel, leading to pain, sensory loss, and or paralysis.
36
The femoral triangle is bounded superiorly by the inguinal ligament. Which of the following structures from the lateral and medial borders of the femoral triangle?
Adductor longus and sartorius
You should know the boundaries of the femoral triangle: the inguinal ligament above, the medial border of the sartorius laterally, and the medial border of the adductor longus on the inner aspect of the thigh.
37
43 y/o woman diagnosed wtih condition that causes excruciating pain near her nose adn mouth. The involved nerve innervates which of the following branchial arches?
First
The clinical history suggests trigeminal neuralgia, which is characterized by extreme pain along the distributions of the maxillary and mandibular subdivisions of the fifth cranial nerve. The trigeminal nerve innervates the first branchial arch.
38
Infant born with abnormally developed falci-form ligament. The hepatogastric and hepatoduodenal ligaments are also malformed. These developmental anomalies are most likely due to abnormal development of the?
Ventral mesentery
The ventral mesentery forms the falciform ligament and lesser omentum, which can be divided into the hepatogastric and hepatoduodenal ligament.
39
Man died, pathologist discovers that the man has a small atrial septal defect. The defect is seen in the portion of the atrial septum near the upper border of the fossa ovalis. Which of the following was the likely functional manifestation of this defect during life?
No cyanosis occured prenatally or postnatally
Atrial septal defect is a non-cyanotic defect. This defect will result in postnatal shunting of blood from the left to the right atrium. Because the left atrium contains oxygenated blood, this shunt results in oxygenated blood being sent back to the pulmonary circuit. Cyanosis is the result of deoxygenated blood being sent to the systemic circuit. Heart deects that result in postnatal shunts from right to left are cyanotic defects because deoxygenated blood on the right side of the heart is shunted to the left side of the heart, which sends blood into the systemic circulation.
40
6 y/o neck mass. mother reports that first developed mass 3 days ago and not resolved. Questioning reveals recently recovered from a viral upper respiratory infection. He is otherwise healthy and is up to date on all recommended vaccinations. Physical examination shows a 2cm neck mass in the midline immediately above the thyroid cartilage notch. The mass elevates when he sticks his tongue out of his mouth. What is the most likely diagnosis?
Thyroglossal duct cyst
Thyroglossal duct cysts are derived from the remnant of the thyroglossal duct. The thyroglossal duct extends from the foramen cecum of the tongue base to the thyroid gland during the embryologic development of the thyroid gland, and it typically degenerates completely. If a portion of the duct remains, it can develop into a cyst and enlarge, presenting as a midline neck mass. The pathognomonic finding of a thyroglossal duct is elevation during protrusion of the tongue, which is true in this case.
41
When removing an impacted mandibular third molar, the oral surgeon must warn the patient of possible lasting numbness of the tip of the tongue. The loss of general sensation is due to damage of the?
Lingual nerve
The lingual nerve is a branch of the mandibular division of the trigeminal nerve that conveys general sensation from the anterior two-thirds of the tongue. It enters the oral cavity by passing just under the mandibular third molar between the medial pterygoid muscle and the mandibular ramus.
42
A resident physician is demonstrating the correct technique for inserting a subclavian central venous line. He has a medical student palpate the clavicle, then the chest wall below it. The first bony structure that can be palpated below the inferior margin of the medial portion of the clavicle is the?
second rib
the palpable space immediately inferior to the clavicle is the first intercostal space, and the bone below it is the second rib.
the first rib is hidden under the clavicle
43
34 y/o female, straining to take a breath but can only mouth "i cant br..." before collapsing. Tongue is swollen and protruding from her mouth. Patient has only minimal air movement with bag-mask ventilation. Oxygen saturation is approximately 80%. Attempts at oral intubation are unsuccessful due to massive soft tissie edema of her pharynx. A decision is made to perform a cricothyrotomy. The necessary instrument tray is collected, and the patients neck is quickly prepped. After palpating the neck to identify the appropriate landmarks, an incision should be made at which of the following locations?
The cricothyroid membrane, which is located between the thyroid cartilage and the cricoid cartilage below.
A cricothyrotomy is performed at the cricothyroid membrane, which is correctly located between the thyroid cartilage (adams apple) and the cricoid cartilage below.
44
Infant born to an alcoholic mother had microcephaly and cardiac abnormalities and died despite resucitative efforts. During which of the following periods of pregnancy is alcohol most teratogenic?
Third through ninth weeks
Embryonic tissue is most susceptible to teratogens during the third through ninth weeks of pregnancy. This is when organogenesis, as well as most major congenital anomalies, occurs. Because brain development occurs throughout pregnancy, however, it is wisest for a pregnant woman to avoid alcohol for all 9 months of gestation.
Teratogenic - Teratogenic drugs: A teratogen is an agent that can disturb the development of the embryo or fetus. Teratogens halt the pregnancy or produce a congenital malformation (a birth defect). Classes of teratogens include radiation, maternal infections, chemicals, and drugs.
45
15 y/o with a history of chronic rhinitis, allergy, asthma, and nasal polyposis presents with fever and dental pain. She is diagnosed with maxillary sinusitis. Mucopurulent exudate would be most likely to drain through an ostium in the?
Hiatus semilunaris
The patient has two risk factors for sinusitis: chronic rhinitis and allergy. She probably also has aspirin allergy, which is associated with the triad of nasal polyps, asthma, and sinusitis. In maxillary sinusitis, exudate may drain into the middle meatus through an ostium in the hiatus semilunaris, which contains openings to the frontal and maxillary sinuses and anterior ethmoidal cells.
The hiatus semilunaris (or semilunar hiatus) is a crescent-shaped groove in the lateral wall of the nasal cavity just inferior to the ethmoidal bulla. It is the location of the openings for the frontal sinus, maxillary sinus, and anterior ethmoidal sinus.
46
A patient presents to the physician complaining of "something wrong with her foot" that causes her to trip and fall. Physical examination reveals an inability to dorsiflex (extend) the foot and a loss of sensation between the first and second toes. There is no other motor or sensory loss. Which of the following nerves was most likely injured?
Deep peroneal
The deep peroneal nerve arises from the common peroneal nerve (L4-S2). It innervates the muscles of the anterior compartment of the leg, which dorsiflex (extend) the foot. Damage to the nerve therefore produces "foot-drop". A classic clue to deep peroneal nerve pathology. The nerve gives rise to many branches, one of which inervates the skin between the first and second toes.
47
71 y/o routine physical eexamination found to have 7cm pulsatile mass deep in the abdomen, between the xiphoid and the umbilicus. He has a history of untreated hypertension. The endothelial lining of the affected structure is composed of which of the following tissue?
Simple squamous epithelium
Endothelium lines the cardiovascular and lymphatic vessels and is composed of simple squamous epithelium. The mesothelium that lines the pleural, pericardial, and peritoneal cavities is also composed of a single layer of simple squamous epithelium.
48
week after sexual encounter a young woman develops a painful, swollen knee joint. The emergency department suspects gonococcal arthritis and wants to confirm this by sending joint fluid for bacterial culture. He uses the standard suprapatellar approach and passes a needle from the lateral aspect of the thigh into the region immediately proximal to the patella Through which of the following muscles does the needle pass?
Vastus lateralis
This route passes through the vastus lateralis to penetrate the knee joint via the suprapatellar bursa, allowing aspiration of joint fluid for culture. The vastus lateralis, together with the vastus medialis, vastus intermedius, and rectus femoris, forms the quadriceps muscle.
49
67 y/o man abnormal neurologic exam. An electroencephalogram is subsequently performed and reveals delta waves over his left frontal lobe. Which of the following was the most likely abnormal finding on his neurologic exam?
Right hemiparesis
A normal waking adult characteristically shows alpha activity over the posterior regions of the head, some beta activity in the frontocentral regions, and few (if any) theta waves over the temporal areas. Delta waves are not present in normal adults during wakefullness. The delta waves over his left frontal lobe indicate a lesion in this area. The left primary motor cortex resides in this region and would produce a right hemiparesis if damaged.
50
23 y/o wearing high-heel shoes inverts and sprains her ankle while running. Which of the following ligaments did she most likely injured?
Calcaneofibular
The most common type of ankle sprain is lateral, which occurs as a result of excessive inversion of the foot and plantar flexion of the ankle. The calcaneofibular and anterior talofibular ligaments may tear. Producing marked swelling and pain. These two ligaments cobined with the posterior talofibular ligament constitute the lateral ligament of the ankle.
51
A surgeon performing an appendectomy makes an incision through the ventrolateral abdominal wall. The layers of the abdominal wall are shown below.
1. Internal oblique
2. external oblique
3. peritoneum
4. transversus abdominis
What is the order of penetration of the layers of the abdominal wall?
2, 1, 4, 3
external oblique, internal oblique, transversus abdominis, peritoneum.
52
A 49 y/o woman has right upper quadrant pain, nausea, vomiting, and fever. She also complains of pain in her right shoulder. A right upper quadrant ultrasound reveals multiple gallstones and pericholecystic fluid. Which of the following dermatomes is most likely involved in her shoulder pain?
C3 - C5
Pain in the liver and gallbladder can be referred to C3-C5 dermatomes of the right shoulder. Many people are familiar with the projection of cardiac pain to the left shoulder, which is a similar phenomenon. Pancreatic disease can also produce left shoulder pain. On physical examination, refered pain can usually be distinguished from pain truly originating in the perceived area by palpation and manipulation of the area. Local physical manipulation does not usually alter the character or intensity of referred pain, but it does alter those features of skin, joint, or muscle pain truly localized to the region.
53
54
57 y/o man has hematuria and left-sided flank pain. Diagnostic studies show a left-sided renal mass with extension into the renal vein. A radical nephrectomy is performed, and the specimen is sent for pathologic evaluation. Which of the following structures present in this patients specimen is lined with epithelium derived from mesoderm of the ureteric bud?
bowman capsule
distal convoluted tubule
loop of henle
proximal convoluted tubule
ureter
Ureter
The transitional epitheium that lines the ureter, the renal pelvis, and the major and minor calyces is derived from the mesoderm of the ureteric bud. Similarly, the cuboidal epithelium of the collecting tubules derives from the ureteric bud mesoderm.
55
Woman prenatal visit. Examination reveals that her uterus is considerably larger than her gestational age would predict. Ultrasound examination reveals that she has polyhydraminios. Which of the following congenital defects of the fetus would be most likely to be associated with this abnormality?
Esophageal atresia
polyhydraminios is the presence of excess amniotic fluid. Because amniotic fluid is normally swalled by the fetus, esophageal atresia, an obstruction of the esophagus that prevents the fetus from swallowing the amniotic fluid, an excess of fluid is retained in the amniotic cavity.
56
Gastric biopsy perfromed. Pathologists inspects and finds numerous normal cuboidal to columnar cells with apical membrane bound secretion granules in the gastric glands. From which area of the stomach was the biopsy specimen most likely taken?
Fundic Region
The pathologist saw normal chief cells, which are abundant in the body and fundus of the stomach. Chief cells secrete pepsinogen, which is stored in apical membrane-bound granules. The body and fundus of the stomach contain high concentrations of four other types of cells in the epithelium. The parietal (oxyntic) cells are large, pyramidal, and acidophilic with central nuclei (like a fried egg). They make and secrete HCl. The Mucous neck cells secrete mucus and apppear clea. The enteroendocrine cells have affinity for silver stains and exhibit a positive chromaffin reaction, these cells synthesize amines, polypeptides, or proteins.
57
During a football game player sustains powerful blow to the lateral side of his weight bearing leg. Experiences excruciating knee pain and is unable to walk. The three structures most likely to be injured are the?
Anterior cruciate and medial collateral ligaments and the medial meniscus
The anterior cruciate and medial collateral ligaments and the medial meniscus are sometimes called the "unhappy triad", because they are commony injured in lateral blows to the knee that forcefully abduct the tibia. A good mnemonic is MAMM (for medial collateral, anterior cruciate, and medial meniscus. Damage to the anterior cruciate ligament is characterized by the ability to push the tibia too far forward on the femur.
58
5 y/o female to physician complaining that child still seems to regularly wet herself despite having been toilet-trained. Physician orders an IV pyelogram, which emonstrates a complete duplication of the ureter on the right side. Although one ureter opens normally into the bladder, the other opens ectopically into the vagina. This congenital anomaly is caused by ?
early division of the ureteric bud
The collecting system of the kidney, including the ureters, develops from an outgrowth of the distal mesonephric duct called the ureteric bud. The ureteric bud grows into the metanephros and induces the formation of the excretory system (nephrons). Early splitting of the ureteric bud may result in partial or complete duplication of the ureter. One of the buds typically opens into the bladder. The lower, abnormal bud usually opens more inferiorly and may communicate with the vagina or urethra in females.
59
Newborn observed to be cyanotic imediately after birth. Diagnostic studies, including an ultrasound, reveal that the baby has persistent truncus arteriosus. Which of the following additional defects is this baby most likely to have?
membraneous ventricular septal defect
Persistent truncus arteriosus results from failure of the aorticopulmonary septum to form. Normally, the aorticopulmonary septum divides the truncus arteriosus into the ascending aorta nd the pulmonary trunk. The aorticopulmonary septum also contributes to the formation of the membranous portion of the interventricular septum. Wen the aorticopulmonary septum does not form., the truncus arteriosus persists rather than being divided, and the membranous interventricular septum is incomplete. Because neural crest cells contribute to the formation of the aorticopulmonary septum it is beleived that this defect may result from a defect in migration of neural crest cells.
Perimembranous ventricular septal defects (also called membranous VSD'S) are located in the membranous septum, a relatively small portion of the septum located near the heart valves. Ventricular septal defects may also be described as inlet or outlet VSDs. These terms further describe where the defect is located.
60
61 y/o, surgery remove solitary painless mass anterior to the tragus of her left ear. Pathologic examination shows a well-circumscribed yallowish white tumor with a rpoliferation of epithelial and myoepithelial cells in duct formations within a background of loose myxoid tissue. During the surgery, particular attention is paid to the nerve that exists the skull via the stylomastoid foramen, passes lateral to the styloid process, and then enters this affected structure. Injury to the lower division of this nerve during surgery will most likely result in?
Weakness of the lower lip on the same side
The motor component (special visceral efferent) of the facial nerve (CN VII) exits the skull via the stylomastoid foramen, passes lateral to the styloid process, and then enters the parotid gland. Within the gland, two divisions can usually be identified (upper and lower), which in turn give off five named branches that innervate the muscles of the face. The upper division gives rise to the temporal and zygomatic branches, which collectively innervate the frontalis, corrugator, and orbicularis oculi muscles. The lower division gives off the buccal, mandibular, and cervical branches. The largest, the buccal, innervates the muscles ataching to the upper lip, including the orbicularis oris and the levators, as well as the buccinator and the muscles of the nose. The mandibular branches innervate the muscles of the lower lip and of the chin, whereas the cervical branch innervates the platysma muscle. There are usually communicating branches between the named terminal nerves so that overlappping innervation of the muscles occurs. If the lower division is injured, there will be weakness (not frank paralysis because of the innervation overlap) of the muscles that attach to the lower lip.
61
An arteriogram is performed on a patient with atherosclerosis. Luminal narrowing of which of the following vessels would compromise blood flow through the renal arteries?
Abdominal Aorta
The renal arteries emerge from the abdominal aorta at about the level of the L1/L2 intervertebral disk and travel at nearly right angles to it (on the right, passing posterior to the inferior vena cava) to enter the hilum of the kidney.
Renal Hilum - The renal hilum (Latin: hilum renale) or renal pedicle is the hilum of the kidney, that is, its recessed central fissure where its vessels, nerves and ureter pass. The medial border of the kidney is concave in the center and convex toward either extremity; it is directed forward and a little downward.
62
Nissl bodies correspond to which of the following cytoplasmic organelles?
Rough endoplasmic reticulum
Rough endoplasmic reticulum present in neurons is called Nissl substance, or Nissl bodies. Nissl bodies stain intensely with basic dyes and are found in the cell body and proximal dendrites, but not in the axon hillock or axon.
A Nissl body, also known as Nissl substance and Nissl material, is a large granular body found in neurons. These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis.
63
42 y/o undergoes surgery for medullary carcinoma of the thyroid. After the surgery, he complains of a noisy quality to his voice. This condition was most likely caused by damage to the ?
recurrent laryngeal nerve
The recurrent laryngeal nerves are branches of the vagus (CN X), and supply all intrinsic muscles of the larynx except the cricothyroid. The right recurrent laryngeal nerve recurs around the right subclavian artery. The left recurrent laryngeal nerve recurs in the thorax around the arch of the aorta and ligamentum arteriosum. Both nerves ascend to the larynx by passing between the trachea and esophagus, close to the thyroid gland.
64
After an amniocentesis, a 29 y/o woman carrying twins learns tha tone fetus has XY and other has XX. At 37 weeks gestation, the woman delivers two healthy babies. Which of th following structures is likely to be present in the baby with th XY chromosomes but not in the one with the XX chromosomes?
Bulbourethral gland
The bulbourethral glands are paired structures located within the deep perineal pouch, embedded within the sphincter urethrae. Their ducts pass to the spongy urethra. The homologous female structures are the greater vestibular (Bartholins) glands. Which are located in the superficial perineal pouch.
Bulbourethral gland, also called Cowper's Gland, either of two pea-shaped glands in the male, located beneath the prostate gland at the beginning of the internal portion of the penis; they add fluids to semen during the process of ejaculation
65
During an automobile accident, a person sustains a broken neck and dies after a small bony fragment is driven into his spinal cord. From which bones was this fragment most likely derived?
Axis
The odontoid process is the part of the axis (second cervical vertebrae) that fits into and articulates with the atlas (first cervical vertebrae). It is susceptible to traumatic fracture, and bony fragments can injure the spinal cord. The scenario presented is unfortunately realistic, and a similar mechanism is thought to cause deaths by execution-style hanging.
66
Patient complaining of dificulty swallowing. Barium contrast x-ray shows a constriction of the esophagus at the level of the third thoracic vertebra. An aortogram shows that the patient has a double aortic arch. Which of the following developmental abnormalities explains this finding?
aBNORMAL PERSISTENCE OF THE RIGHT DORSAL AORTA
Each pharyngeal arch has a aortic arch that passes through it. The aortic arches connect the aortic sac with the right and left dorsal aortas. Normally, the left fourth aortic arch is retained as the definitive aortic arch. the right fourth aortic arch normally forms the proximal part of the right subclavian artery. the distal part of this artery is formed by the right seventh intersegmental artery. Normally, most of the right dorsal aorta between these two vessels disappears. The presence of a right aortic arch in addition to the normal left aortic arch indicates that the portion of the right dorsal aorta that should have disappeared did not.
67
93 y/o weak, liquid diet is fed in bed. Refuses to sit up, so fed while lying on back. Halfway through feeding patient aspirates the liquid and subsequently develops pneumonia. Most likely site of this pneumonia?
Apical segment of the right lower lobe
Aspiration pneumonia is a common complication observed in nursing home patients. The most probable site of the pneumonia can be anticipated by knowing the anatomy of the bronchial tree, since the aspirated fluid usually flows downhill. IN a supine or nearly supine patient, the fluid flows into the trachea and then into either the (typically the right) main bronchi. The first posteriorly located branch is the one leading to the apical aspect of (either) lower lobe. The lateral and posterior segments of the lower lobes are also supplied by posteriorly branching segemental bronchi. In contrast, the posterior aspects of the upper lobes are somewhat protected by an initial anteriorly directed bifurcation before their segmental bronchi arise. All other segments of the bronchial tree and their corresponding portions of the lung are more anterior.
68
patient has tiny .2cm but exquisitely painful tumor under the nail of her index finger. local anesthetic block to a branch of which of the following nerves would be most likely to provide adequate anesthesia for the surgical removal of the mass?
MEDIAN
The tumor in question is probably a benign glomus tumor, which is notorious for producing pain far out of proportion to its small size. The question is a little tricky but important clinically for obvious reasons, because the most distal aspect of the dorsal skin of the fingers, including the nail beds, is innervated by the palmar digital nerves rather than the dorsal digital nerves. Specifically, the median nerve, through its palmar digital nerves, supplies teh nail beds of the thumb, index finger, middle finger, and half the ring finger.
69
3 y/o boy repeated episodes of sore throat and fever. Undergoes surgery to remove collections of lymphoid tissue tha tlie on each side of the oropharynx between the pataoglossal and palatopharyngeal arches. The removed structures developed from which of the following pharyngeal pouches?
Second
Epithelial lining of the second pharyngeal pouch buds into the mesenchye to form the palatine tonsil. part of the pouch remains in the adult as the tonsillar fossa.
Important to review the other choices since pharyngeal pouch derivatives are typically tested on the Step 1.
The first pharyngeal pouch develops into the middle ear cavity and the eustachian tube.
the third pharyngeal pouch develops into the thymus and the inferior parathyroid glands.
The fourth pharyngeal pouch gives rise to the superior parathyroid glands. Recall that abnormal development of the third and fourth pouches leads to DiGeorge syndrome and results in hypocalcemia, as well as abnormal cellular immunity and consequent susceptibility to viral and fungal illnesses.
70
35 y/o woman with severe dysmenorrhea and prolonged menstrual periods due to large uterine fibroids undergoes a hysterectomy. which of the following structures is the gynecologist most likely to inadvertently ligate during surgery?
Ureter
The ureter passes directly inferior to the uterine artery, lateral to the body of the uterus near its junction with the cervix ( water flows under the bridge) During a hysterectomy, therefore, the ureter (instead of the uterine artery) may be inadvertently ligated.
71
Pregnant woman comes to physician with questions about the effect that ingested substances ma have on her unborn child. Physician explains that large molecules do not pass between the mother and fetus because of the placental barrier. The phhysician adds that fetal blood is in the fetal blood vessels of the villi of the placenta and the mothers blood is in the maternal blood vessels, and that these blood vessels do not connect. The placental villi are formed from which of the following cells.?
Syncytiotrophoblast
The syncytiotrophoblasts are cells that form a syncytium and invade the endometrium. These cells form the placental villi. The syncytiotrophoblast arises from cells of the cytotrophobast. The trophoblasts are the outer cells of the blastocyst. Fetal blood and fetal blood vessels develop within the placental villi. These blood vessels later communicate with intraembryonic blood vessels and thereby provide communication between the emryo and the placenta. Maternal blood is found in the intervillous spaces of the placenta. The cells and extracellular matrix of the placental villi form the placental barrier.
Syncytiotrophoblast (from the Greek 'syn'- "together"; 'cytio'- "of cells"; 'tropho'- "nutrition"; 'blast'- "bud") is the epithelial covering of the highly vascular embryonic placental villi, which invades the wall of the uterus to establish nutrient circulation between the embryo and the mother.
72
32 y/o complains of progressive, severe, generalized headaches that began 3 months ago, are worse in the mornings and lately have been accompanies by projectile vomiting. Also has lost his upper gaze, and on physical examination the upper part of the sclera is visible above the downward looking irises. Which of the following is the most likely diagnoses.
Tumor in the area of the pineal gland.
The first two lines of the question clearly suggest a brain tumor. The additional ocular findings (loss of upper gaze and "sunset eyes" the upper part of the sclera is visible above the downward looking irises) locate it to the pineal gland area.
The setting sun sign (also known as the sunset eye sign or setting sun phenomenon) is a clinical phenomenon encountered in infants and young children with raised intracranial pressure.
73
A prostate specific antigen (PSA) level is drawn from a 54 y/o man as part of a routine health evaluation. Which of the following embryonic structures gives rise to the organ being screened for carcinoma?
Urogenital sinus
It is recommended that PSA (prostate specific antigen) levels be measured annually in men older than 50 to screen for prostatic carcinoma (and to record the baseline level) The prostate is immediately derived from the prostatic urethra, which is derived from the urogenital sinus.
Prostatic urethra. The prostatic urethra is the part of the urethra that passes through the prostate. It is about 3-4 cm long and extends from the base of the bladder, just below the pre-prostatic urethra, to the membranous part of the urethra.
74
Football player examined by team physician following a shoulder injury during a game. Preliminary xray films show an inferior dislocation of the humerus. Further examination, there is weakness in lateral rotation and abduction of the arm. The nerve most likely affected is the?
Axillary
Because of the proximity of the axillary nerve to the glenohumeral joint, a fractur3e of the surgical neck of the humerus or an inferior dislocation of the humerus could damage the nerve. The axillary nerve innervates the deltoid muscle. The deltoid abducts, adducts, flexes, extends, and rotates the arm medially. The axillary nerve also innervates the teres minor, which rotates the arm laterally..
The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus (upper trunk, posterior division, posterior cord) at the level of the axilla (armpit) and carries nerve fibers from C5 and C6.
75
Dissecting atrial chambers of the heart. At upper border of the fossa ovalis, discover small opening through which the tip of her probe can be passed from the right into the left atrium. The laboratory instructor identifies this as a probe patency of the atrial septum. This probe patency resulted from which of the following developmental events?
failure of postnatal fusion of septum primum and septum secundum
The normal atrial septum is formed from the septum primum and septum secundum. The septum secundum covers the foramen secundum within the septum primum. Normally, the prenatal pressure gradient in the atria is from right to left, resulting in a patent foramen ovale. Normally, at birth the pressure gradient reverses and becomes a left to right gradient. This causes the septum primum to be pressed against the septum secundum, thus closing the foramen ovale. Fusion of the two septa does not immediately occur. In most people, the two septa eventually fuse, however, the foramen ovale is functionally closed regardless of whether there is fusion or not. When fusion does not occur completely (approximately 10 to 15% of the population), a probe patency of the atrial septum can be found. There is normally no functional significance to this finding inasmuch as there is no shunting of blood across the septum.
76
20 y/o man stabbed immediately to the left of the body of the sternum at the fifth intercostal space. The knife most likely penetrated the ?
RIGHT VENTRICLE
the right ventricle comprises the most of the anterior surface of the heart.
The left atrium and the left ventricle are located more posteriorly.
the right atrium is located more to the right of the sternum.
the stomach is located more inferiorly and to the left.
77
5 month old girl has fatigue on exetion. Was born at full term with a birth weight of 9lb and had an uncomplicated perinatal period. bottle fed and no feeding problems. Alert and appears well. Examination reveals loud holosystolic murmur in the left parasternal region with an associated systolic thrill. The first and second heart sounds are normal. There is no gallop or diastolic murmur. Her blood pressure is normal in all four extremities, and she has palpable peripheral pulses. There is no peripheral edema or cyanosis. Which of the follwoing is the most likely diagnosis?
Ventricular septal defect
A ventricular septal defect is the most common congenital cardiac defect and is associated with a loud, holosystolic murmur and is often associated with a thrill.
78
elderly woman with osteoporosis is taken to the emergency department following a fall. One of her legs appears shortened and is externally rotated. A fracture of which part of the femur is suggested by these findings?
Neck
This is the classic presentation of a fracture o the neck of the femur. This type of fracture typicallly occurs in postmenopausal women with significant bone resorption due to osteoporosis.. Dislocation of the head of the femur can produce a similar effect. The change in the position of the leg is due to the action of the gluteal muscles, particularly the gluteus maximus.
79
Healthy medical student concerned he has several painless uniform large bumps at the back of his tongue. These are most likely?
circumvallate papillae
Medical student has apparently not yet studied the anatomy of the tongue. Otherwise he would have recognized the large bumps at the back of his tongue as circumvallate papillae. These are large circular structures surrounded by moatlike depressions. The lateral surfaces of these papillae contain taste buds.
80
oblique xray view of patient with right middle lobar pneumonia demonstrates an area of consolidation bounded by sharp, intersecting, relatively straight lines above and below. These lines correspond to which of the following?
transverse fissure above the oblique fissure below
The transverse fissure above (between teh right upper and right middle lobes) and the oblique fissure below (between the right middle and right lower lobes) are often strikingly visible on the oblique view in patients with right middle lobar pneumonia. The diaphragm and the breast may also be seen but do not overlap the middle lobe on the oblique view.
Chest xray. there is a consolidation that obscures the right obrder of the heart. This finding is consistent with a right middle lobe pneumonia.
the lateral view shows this opacity over the region of the heart, supporting the diagnosis of a right middle lobe pneumonia.
81
during interview a 34 y/o psychiatric patient suddenly becomes aggressive. Patient is quickly taken to a quiet, private room and given an intramuscular injection of haloperidol in the upper outer quadrant of the buttock. The injection is given at this specific location to prevent damage to which of the following nerves?
sciatic
Injections are given in the upper, outer quadrant of the buttocks to prevent damage to the sciatic nerve, which is present in the lower quadrant. The other nerves listed are not particularly vulnerable to injections into the buttocks.
82
21 y/o man brought hospital after car accident. Examination reveals clear fluid draining from his left ear. Laboratory results confirm fluid is cerebrospinal fluid. Which is the most likely site of trauma that has resulted in the leakage of this fluid?
fracture of the floor of the middle cranial fossa, along with rupture of the tympanic membrane.
The leakage of cerebrospinal fluid is called otorrhea. This patients fluid leaked from the subarachnoid space of the middle cranial fossa into the middle ear cavity. From the middle ear cavity, it passed through the ruptured tympanic membrane into the external ear canal. The roof of the middle ear cavity (tegmen tympani) is the floor of the middle cranial fossa along the anterior surface of the petrous portion of the temporal bone. Along with the bony fracture, the dura and underlying arachnoid are torn, providing a direct communicaiton between the subarachnoid space, where the cerebrospinal fluid is found. and the middle ear cavity. The rupture of the tympanic membrane provided access to the outside body. Because of this open communication there is risk of infection in the cranial cavity.
83
20 y/o stabbed with ice pick. weapon passes through the superior orbital fissure. which of the following is the most likely to be severed as the ice pick passes through this fissure. Choices are nerves and arteries.
Abducens nerve.
a good way to remember what goes through the superior orbital fissure is that every thing that innervates orbital structures, other than the opitic nerve, passes, through this fissure. This includes the oculomotor nerve (CN III), the trochlear nerve (CN IV), the ophthalmic nerve (VI) and the abducens nerve (CN VI)
84
patient emergency after sustaining laceration of the first web space of his hand in a rock climbing accident. Which structures is also likely to be injured?
radial artery
after crossing the floor of the anatomic snuff box, the radial artery passes deep to the tendon of the extensor pollicis longus to enter the palm deeply in the space between the first and second metacarpals (first web space). Within this space, it contributes to the formation of the deep palmar arterial arch.
85
Motor vehicle accident patient is brought to the emergency room. xray reveal that she has fractures of her left ninth and tenth ribs. She has a rapid heart rate and low blood pressure. Peritoneal lavage reveals free blood in the peritoneal cavity. A surgeon is able to stop the bleeding by placing a clamp across which of the following strutures?
splenorenal ligament
this patient has a ruptured spleen. the splenic artery and vein reach the spleen by passing through the splenorenal ligament. A clamp across this ligament will stop the flow of blood to the spleen. The spleen lies under cover of the left ninth, tenth, and eleventh ribs. Fractures of these ribs may cause laceration of the spleen and bleeding into the peritoneal cavity.
86
Football player experiences an anterior dislocation of the shoulder. Cutaneous sensation over the lower half of the deltoid muscle is impaired. These findings suggest damage to which of the following nerves?
Axillary
the axillary nerve can be damaged during anterior dislocation of the shoulder, causing loss of sensation in the skin overlying the lower half of the deltoid muscle.
87
45 y/o garbage collector has severe neck pain and weakness in his left upper extremity. Gotten no relief from over counter meds. No trauma. Examination patient is thin and walks with his neck tilted to the left side. The patient has limited neck flexion and extension secondary to pain. The patient has a normal motor and sensory examination of all extremities, with the exception of the left upper extremety. His left radial forearm and thumb are numb to the touch (decreased sensation to light touch). The patient has a decreased brachioradialis reflex and slight weakness of his wrist extensors. Plain radiographs appear normal. Which of the following is the most likely diagnosis.
Compression of his left C6 nerve root
This anatomy question demonstrates the importance of knowing a basic neurologic examination and appropriate sensory dermatomes. This patient has decreased sensation in his C6 deratome and an asymmetric brachioradialis reflex (C6). Although the C6 root contributes to many different motor functions, wrist extension and elbow flexion are included among them. Motor findings are unilateral for this patient, so only the left C6 root is being compressed. There are other causes of radicular findings, but compression by a cervical disc is by far the most common.
88
A patient with a left adrenal mass is scheduled for surgery. The surgeon is planning to approach the suprarenal area by removing the twelfth rib. With this approach, the surgeon should take care to avoid damaging which of the following structures?
Diaphragm
The diaphragm is at particular risk because it is closely related to both the 12th rib and the suprarenal area. Surgeons sometimes call this the perilous pleura because of the care they must exercise with this approach. The close physical relationship also accounts for the pleural effusions seen in some patients with kidney infections. The other structures listed in the answers are not particularly vulnerable.
89
45 y/o mass on right side of face. determined that he has a benign tumor of the parotid gland. the tumor is excised. After surgical excision of the tumor it is noted that the patients mouth droops on the right side and when asked to smile his smile is asymmetrical. The patient is able to open and close both eyes normally and can wrinkle his forehead symmetrically and raise both eyebrows. Sensation is normal on both sides of his face. What is the most likely cause of the findings.
Damage to branches of the facial nerve
The facial nerve passes through the parotid gland and may be injured during the parotidectomy. the facial nerve divides into branches as it passes through the gland. The branches innervate the muscles of facial expression. The branches innured in this patient are likely the buccal and mandibular branches because of the abnormalities seen in the region of the mouth. The zygomatic and temporal branches are probably intact because the patient has normal function in the muscles around the eye and forehead.
90
during anatomy lab a medical student notes a fibrous band that runs on the visceral surface of the liver. It is attached on one end to the inferior vena cava and on the other end to the left branch of the portal vein. In the embryo, this structure corresponds to?
Ductus venosus
This question could have tricked you if you didn't cach the key words, "in the embryo" If you read the question too quickly and thought you were going to be asked to identify the structure described you probably chose choice C (ligamentum venosum) since that is indeed the structure in the question. In the embryo, however, this fibrous band is actually the ductus venosus. The ductus venosus is an embryonic vessel that allows blood to bypass the fetal liver, this prevents the depletion of oxygen and nutrient rich blood in the hepatic sinusoids.
91
While examining a newborn baby in the nursery, a physician notes that urine is draining from the umbilicus. Contrast dye is introduced into the bladder through the urethra, and it is confirmed radiologically that dye is passing to the umbilicus. Which of the following embryonic structures has abnorally persisted?
Allantoic Duct
The allantoic duct or (allantois) is an evagination of the caudal end of the gut tube. This part of the gut tube becomes the cloaca. The allantoic duct extends into the umbilical cord and in lower species, serves as a pathway for waste. In humans, it does not serve this function and is vestigial. The anterior portion of the cloaca forms the urinary bladder, and the allantoic duct passes from the bladder into the umbilical cord. Normally, this duct becomes a fibrous cord calld the urachus and persists in the adult as the median umbilical ligament. If it remains patent as a duct, urine ay pass from the urinary bladder through the duct to the umbilicus. This is called a urachal fistula.
The navel is a protruding, flat or hollowed scar left after the umbilical cord detaches. The navel (clinically known as the umbilicus, colloquially known as the belly button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord.
92
4 y/o with recurrent urinary tract infections is evaluated fro renal/urinary tract abnormalities with voiding cystourethrogram (VCUG). Reflux is discovered, so an intravenous pyelogram (IVP) is performed. The renal anatomy appears normal. On the IVP, which of the following structures would have been seen emptying into the renal pelvis?
Major Calyx
Children with recurrent urinary tract infections should be further evaluated for renal/urinary tract abnormalities with a voiding cystourethrogram (VCUG). If the VCUG shows no urinary reflux, an ultrasound should be performed to evaluate the upper urinary tract and kidney. If reflux is present, an intravenous pyelogram (IVP) or radionuclide scan may be performed to detect renal scarring. (Note, that the number one cause of urinary reflux in children is posterior urethral valves\>) A normal IVP would be expected to display normal renal anatomy, in which two cup shaped major calyces unite to form the renal pelvis.
Urine formed in the kidney passes through a renal papilla at the apex into the minor calyx; two or three minor calyces converge to form a major calyx, through which urine passes before continuing through the renal pelvis into the ureter.
93
A neonate is observed to have a small notch in the transitional zone and a vermillion border of the lip. which of the following is the most likely etiology of this mal-formation?
Failure of the maxillary processes and medial nasal swellings to fuse
Cleft lip is caused by the failure of the maxillary processes to fuse with the medial nasal swellings.
94
A patients left hypoglossal nerve (CN XII) is injured during a carotid endarterectomy. Which of the following would most likely result form this injury?
deviation of the tongue to the left on the protrusion
The hypoglossal nerve is a pure motor nerve (general somatic efferent) to the intrinsic muscles of the tongue. If the nerve is damaged, denervation atrophy of the affected side will permit the intact musculature of the opposite side to operate unopposed, thereby protruding the tongue to the side fo the injury.
The hypoglossal nerve is the twelfth cranial nerve, and innervates all the extrinsic and intrinsic muscles of the tongue, except for the palatoglossus which is innervated by the vagus nerve.[a] It is a nerve with a solely motor function. The nerve arises from the hypoglossal nucleus in the medulla as a number of small rootlets, passes through the hypoglossal canal and down through the neck, and eventually passes up again over the tongue muscles it supplies into the tongue.
The nerve is involved in controlling tongue movements required for speech and swallowing, including sticking out the tongue and moving it from side to side. Damage to the nerve or the neural pathways which control it can affect the ability of the tongue to move and its appearance, with the most common sources of damage being injury from trauma or surgery, and motor neuron disease
95
During a physical examination a physician elicits a pu;illary light reflex by shining a light into a patients eye. The iris conracts, thereby constricting the pupil. Where are the cell bodies of the preganglionic neurons found that are responsible for this response?
Edinger-Westphal nucleus
The Edinger-Westphal nucleus is found in the midbrain and contains preganglionic parasympathetic cell bodies. The axons of these neurons leave the brain stem with the oculomotor nerve and travel with this nerve through the cavernous sinus to the superior orbital fissure. At the fissure, the ocuomotor nerve divides into a superior and inferior division. The preganglionic parasympathetic axons continue with the inferior division. They enter the ciliary ganglion through the motor root fo the ganglion and the synapse on the postganglionic parasympathetic neurons. These postganglionic parasympathetic neurons innervate the smooth muscle of the sphincter pupillae found in the iris.
96
69 y/o fractures her humerus during a motor vehicle accident. Which of these types of bone will most likely be seen in a biopsy taken from the healing area?
Woven
Bone is formed by type I collagen fibers, ground substance, and hydroxyapatite crystals. The collagen is oriented in a layered or lamellar fashion. It can be parallel (trabecular bone and periosteum) or concentric (Haversian system). When bone is formed quickly, as in a healing fracture site, metabolic bone disease, or tumor, the collagen is randomly oriented and is called woven bone.
97
58 y/o man with lymphoma has shortness of breath and chest pain. Xray shows bilateral blunting of the costophrenic angle. A thoracocentesis is performed. During this procedure it is important to pass the needle immediately above the rib to prevent damage to which of the following structures in the subcostal groove
Intercostal nerve, artery and vein
All three structures lie in the subcostal groove below a rib. Third and fourth year students are sometimes offered the chance to help tap a patients pleural effusion, and can look a little foolish if the resident has to stop them because they have forgotten this basic anatomic point and have entered the intercostal space in the middle or upper region.
98
Newborn boy does not pass meconium until 48 hours after his birth. Several weeks later his mother complains that he has not been passing stool regularly. Anorectal manometry reveals increased internal anal sphincter pressure on rectal distention with a balloon. The patients disorder may be attributed to.
failure of neural crest cells to migrate into the colonic wall
The infant has Hirschsprung disease (more common in males) a diagnosis that should spring to mind in an infant who fails to pass meconium soon after birth and presents with chronic constipation. Diagnosis is made most easily and most reliably by anal manometry and or rectal biopsy. On manometry, internal anal sphincter spressure increases on rectal balloon distention in patients with Hirschsprung disease (normally, pressure decreases with distention) Rectal biopsy reveals an abbsence of ganglion cells (which are derived from neural crest cells) in a portion of the colonic wall. Barium enema would show a transition zone between the aganglionic area of bowel (narrow) and the region of normal bowel proximal to it (dilated).
Neural crest cells (NCC) are multipotent cells induced at the border of the neural plate that subsequently migrate throughout the embryo and later differentiate into multiple cell types contributing to most of the peripheral nervous system and the cranio-facial cartilage and bones, as well as pigment and endocrine
99
38 y/o woman slips on an icy sidewalk and falls hitting her right elbow. Reports experiencing severe pain in her upper limb. Examination reveals cannot extend hand at wrist. Diminished sensation on the lateral portion of the dorsum of her hand. Which of the following is most likely site of her fracture?
mid portion of the shaft of the humerus
The clinical findings indicate that the radial nerve has been injured. The radial nerve innervates all of the posterior muscles of the forearm. The paralysis of these muscles prevents the patient from extending the hand at the wrist. The radial nerve also provides sensory innervation to the skin of the dorsum of the hand in the region of the lateral three and one half digits. The radial nerve injury results int he diminished sensation in this region. The radial nerve passes through the arm in close proximith to the midshaft of the radius. The musculospiral groove of the radius has the radial nerve and the deep brachial artery lying in it. Fracture of the midshaft of the humerus endangers the radial nerve.
100
Infant temperature of 40C (104F). Physician notes that the infant has a bulging anterior fontanelle. The third year med student reads physicians note and wants to evaluate this finding, but forgot where anterior fontanelle is. Evaluating this finding the med student should look for which of the following anatomic landmarks.
Bregma
Bregma represents the point where the coronal and sagittal sutures interesect, it is the site of the anterior fontanelle.
101
63 y/o man has blood streaked stools and constipation. Barium enema shows a right sided obstructing lesion. Surgery is perfromed and pathologic evaluation reveals a well-differentiated, colonic adenocarcinoma. Observation of a hematoxylin and eosin-stained microscopic slide from the specimen reveals that the nuclei of the cells are blue. What is the basis for this observation.
Hematoxylin binds to nucleic acids
Blue hematoxylin binds to polyanions such as RNA and DNA. Nuclei contain large amounts of DNA and RNA, and they are consequently almost always blue. The nuclei of dysplastic and cancerous cells are often enlarged and hyperchromatic (i.e. darker blue) compared with normal cells of similar cell lines, because these altered cells often have extra DNA (are aneuploid) and/or RNA (are metabolically active).
Pink Eosin binds relatively nonselectively to cellular components, particularly proteins. Cytoplasm of different cell lines can be pink, purple, or blue, depending on principally on the number of ribosomes in the cytoplasm. Consequently, blue-tinged cytoplasm tends to suggest high synthetic activity (abundant ribosomes)
102
7 y/o appears much more developed in his lower body than his upper body. Blood pressure in the upper extremities exceeds that of the lower extremities. On cardiac examination, there is a midsystolic murmur over the anterior chest and back. The childs lower extremities are cold, and femoral pulses are absent. The part of the vascular system that is affected in this disorder is derived from which of the following embryologic structures.?
third, fourth, and sixth aortic arches.
This patient has coarctation of the aorta. (Constriction of the ascending aorta) which is suggested by a midsystolic murmur over the anterior part of the chest and back, hypertension in the upper extremities, and absent or delayed pulsations in the femoral arteries. The upper extremities and thorax may be more developed than the lower extremities. Patients with coarctation of the aorta may experience symptoms such as cold extremities as a result of tissue ischemia. The truncus arteriosus gives rise to the proximal portions of the ascending aorta and the pulmonary trunk. The third, fourth, and sixth aortic arches and the right and left dorsal aortae conribute to the remainder of the aorta.
103
Urologist performs a cystoscopy to examine the bladder and the openings of the ureters into the bladder. After distention of the bladder iwth air, the physician slowly passes the cystoscope up the urethra into the bladder. In which directioin should she turn the head of the cytoscope to see the ureteric orifices and examine for blockage?
Posterior and inferior
The submucosa and mucosa lining the inside of the bladder are highly folded when the bladder is empty, but are loosely adherent to the underlying muscle and move against each other, smoothing the folds of the bladder wall as it fills. The only site where the attachment of mucosa to muscle is tight is the traingularly shaped trigone othe bladder, located onthe posterior bladder floor (i.e posterior and inferior). The internal wall here is smooth even when the bladder is empty. All ducts that open into the lbadder including the internal ureteric orifices ) do so at the angles of the trigone, hence they are not stretched or pulled by the movement of the bladder wall as the bladder fills. In the distended bladder, the internal ureteric openings are approximately 5cm apart.
104
After receiving a punch to the left eye a 16 y/o boy complains of double vision. has difficulty when looking medially, inferolaterally, superolaterally, and superomedially, the affected muscles are derived from which of the following structures?
Somitomeres
The somitomeres are specialized masses of mesoderm found int he head region that give rise to the muscles of the head. The extraocular muscles are derived from somitomeres 1,2,3, and 5.
