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Question 1

A 55-year-old man with severe coughing is admittedto the hospital. Radiographic examination revealstuberculosis of the right lung, with extension tothe thoracic vertebral bodies of T6 and T7, producinga “gibbus deformity.” Which of the following conditionsis most likely also to be confi rmed by radiographicexamination?⃣ A. Lordosis⃣ B. Kyphosis⃣ C. Scoliosis⃣ D. Spina bifi da⃣ E. Osteoarthritis

Answer 1

B. Kyphosis is characterized by a “hunchback”due to an abnormal increase in curvature of the thoracicregion of the vertebral column. Lordosis, or“swayback,” is an increase in lumbar curvature of thespine. Lordosis can be physiologic, such as seen in apregnant woman. Scoliosis is a lateral curvature ofthe spine with rotation of the vertebrae. Spina bifi dais a neural tube defect characterized by failure of closureof the vertebral arch. Osteoarthritis is a degenerativedisorder that affects the articular cartilage ofjoints and is not specifi cally related to the thoracicregion of the spine.GAS 77; GA 2, 26

Question 2

A 68-year-old man is admitted to the hospital dueto severe back pain. Radiographic examination revealssevere osteoporosis of the vertebral column, with crushfractures of vertebrae L4 and L5. Which of the followingparts of the vertebrae are most likely to be fracturedin this patient?⃣ A. Spinal process⃣ B. Vertebral bodies⃣ C. Transverse process⃣ D. Superior articular process⃣ E. Intervertebral disk

Answer 2

B. A crush fracture is characterized by compressionof the entire vertebral body. The wedge fractureis similar in that it affects the vertebral bodies, but itinvolves small fractures around the perimeter of thevertebral body. Both of these fractures cause reductionsin overall height. Fracture of the spinal, transverse,or superior articular processes can be due to anoblique, transverse, or comminuted fracture. Intervertebraldisks are associated with disk herniation, notcompression fractures.GAS 84; GA 21-30

Question 3

A 45-year-old man is admitted to the hospitalbecause of severe pain in the back and lower limb.Radiographic examination reveals spinal stenosis syndrome.Which of the following conditions is most likelyto be confi rmed by MRI examination?⃣ A. Hypertrophy of supraspinous ligament⃣ B. Hypertrophy of interspinous ligament⃣ C. Hypertrophy of ligamentum fl avum⃣ D. Hypertrophy of anterior longitudinal ligament⃣ E. Hypertrophy of nuchal ligament

Answer 3

C. The ligamentum fl avum connects the laminaof two adjacent vertebrae and forms the posteriorwall of the vertebral canal. It is the only answerchoice that is in direct contact with the vertebral foramen.Therefore, hypertrophy of only the ligamentumfl avum would present as spinal stenosis. The supraspinousand interspinous ligaments connect spinousprocesses. The anterior longitudinal ligament connectsthe anterior portion of the vertebral bodies andintervertebral disks. Finally, the nuchal ligament is athickened extension of the supraspinous ligamentabove the level of C7.GAS 84; GA35

Question 4

A 35-year-old man is admitted to the hospital aftera severe car crash. Radiographic examination revealsan injury to the dorsal surface of the neck and afracture in the medial border of the right scapula. Duringphysical examination the patient presents with thescapula retracted laterally on the affected side. Whichof the following nerves has most likely been injured onthat side?⃣ A. Axillary⃣ B. Long thoracic⃣ C. Dorsal scapular⃣ D. Greater occipital⃣ E. Suprascapular

Answer 4

C. The dorsal scapular nerve (from the ventralramus of C5) is responsible for innervating rhomboidsmajor and minor. The rhomboids are responsible formedial retraction (adduction) of the scapula. Therefore,if this nerve is damaged, individuals present witha laterally displaced (abducted) scapula. In this casethe levator scapular remains functional due to additionalinnervation provided by C3-4 spinal nerves. Theaxillary nerve innervates the deltoid and teres minormuscles. The deltoid muscle abducts the humerus, andthe teres minor laterally rotates the humerus. The longthoracic nerve innervates the serratus anterior, whichfunctions to abduct and upwardly rotate the scapula.The greater occipital nerve is mainly sensory and isalso contributing to the innervation of the semispinaliscapitis. In addition, greater occipital nerve is implicatedin occipital neuralgias. The suprascapular nerve innervatesthe supraspinatus and infraspinatus muscles. Thesupraspinatus abducts the humerus, and the infraspinatusmuscles laterally rotate the humerus. Injury toany of these other nerves would not present with alaterally retracted scapula.GAS 89, 110-111; GA 37, GA 369-371

Question 5

A 64-year-old man arrived at the clinic with aseverely painful rash and skin eruptions that are localizedentirely on one side of his body, closely followingthe dermatome level of spinal nerve C7. The patientwas diagnosed with herpes zoster virus. In what structurehas the virus most likely proliferated to cause thepatient’s current condition?⃣ A. The sympathetic chain⃣ B. The dorsal root ganglion of the C7 spinalnerve⃣ C. The lateral horn of the C7 spinal cordsegment⃣ D. The posterior cutaneous branch of the dorsalprimary ramus of C7⃣ E. The ventral horn of the C7 spinal cordsegment

Answer 5

B. Herpes zoster is a viral disease that remains latentin the dorsal root ganglia of sensory nerves andpresents as a painful skin lesion. It is associated onlywith sensory nerve fi bers and has no motor involvement.The only answer choice that is solely responsiblefor sensory innervation is the dorsal root ganglion.GAS 110; GA 45-49

Question 6

A 45-year-old woman states that she has experiencedmoderate pain for 2 years over her left lowerback, pain that radiates to her left lower limb. Shestates that after lifting a case of soft drinks, the painbecame intense. She was admitted to the emergencydepartment. Radiographic examination revealed diskherniation between vertebral levels L4 and L5. Whichof the following nerves was most likely affected by thedisk herniation?⃣ A. L1⃣ B. L2⃣ C. L3⃣ D. L4⃣ E. L5

Answer 6

E. Disk herniation in the lumbar region betweenL4 and L5 affects the L5 spinal nerve roots. Eventhough the L4 spinal nerve root lies directly betweenthe L4 and L5 vertebrae, it exits from the spinal canalsuperior to the intervertebral disk, whereas the L5spinal nerve root lies directly posterior to the disk.GAS 81; GA 32-34

Question 7

A 3-year-old child is admitted to the emergencydepartment with severe headache, high fever, malaise,and confusion. Radiographic and physical examinationsreveal that the patient suffers from meningitis.A lumbar puncture is ordered. Which vertebrallevel is the most appropriate location for the lumbarpuncture?⃣ A. T12-L1⃣ B. L1-2⃣ C. L2-3⃣ D. L4-5⃣ E. L5-S1

Answer 7

D. A lumbar puncture is performed by taking asample of CSF from the lumbar cistern (the subarachnoidspace below the spinal cord) between vertebraeL4 and L5 or sometimes between L3 and L4. It is donein this region because the spinal cord ends at the levelof L1 to L2 and the dural sac ends at the level of S2.Therefore it is the safest place to do the procedurebecause it lies between these areas and the risk ofinjuring the spinal cord is avoided.GAS 108; GA 34, 44-49

Question 8

When a lumbar puncture is performed to samplecerebrospinal fl uid, which of the following externallandmarks is the most reliable to determine the positionof the L4 vertebral spine?⃣ A. The inferior angles of the scapulae⃣ B. The iliac crests⃣ C. The lowest pair of ribs bilaterally⃣ D. The posterior superior iliac spines⃣ E. The posterior inferior iliac spines

Answer 8

B. The iliac crests are used as a landmark for locatingthe position of L4 to L5 for a lumbar puncture;they are identifi ed and traced medially toward thevertebral column. The inferior angles of the scapulaelie at vertebral level T7; the lowest ribs lead one toT12; a line between the posterior superior iliac spinescrosses vertebral level S2; the posterior inferior iliacspines lie below S2.GAS 101, 106-109; GA 34, 44-49

Question 9

A 39-year-old male presents with severe neckpain after a whiplash injury, sustained when his carwas struck from behind. Radiographic studies revealtrauma to the ligament lying on the anterior surface ofthe cervical vertebral bodies. Which ligament is this?⃣ A. Anterior longitudinal ligament⃣ B. Ligamentum fl avum⃣ C. Nuchal ligament⃣ D. Posterior longitudinal ligament⃣ E. Transverse cervical ligament

Answer 9

A. The anterior longitudinal ligament lies anteriorto the vertebral bodies along the vertebral column.The ligamentum fl avum connects the lamina of twoadjacent vertebrae. The nuchal ligament is a continuationof the supraspinous ligament above C7, whichconnects spinous processes. The posterior longitudinalligament lies on the posterior edge of the vertebralbodies. The transverse cervical (cardinal) ligament isassociated with the pelvic region of the body and notthe spinal column.GAS 82-84; GA 35

Question 10

A 65-year-old male complains of severe back painand inability to move his left lower limb. Radiographicstudies demonstrate the compression of nerve elementsat the intervertebral foramen between vertebrae L5 andS1. Which structure is most likely responsible for thisspace-occupying lesion?⃣ A. Anulus fi brosus⃣ B. Nucleus pulposus⃣ C. Posterior longitudinal ligament⃣ D. Anterior longitudinal ligament⃣ E. Ligamentum flavum

Answer 10

B. Compression of nerves at the intervertebralforamen indicates a disk herniation. A disk herniationis characterized by protrusion of the nucleuspulposus from the anulus fi brosus posterolaterallyinto the spinal canal or intervertebral foramen. Theligaments may be affected by the herniation but arenot responsible for the compression of the spinalnerve roots.GAS 79-81; GA 32-35

Question 11

A 27-year-old man is admitted to the emergencydepartment after a car crash. Physical examination revealsweakness in medial rotation and adduction of thehumerus. Which of the following nerves was mostprobably injured?⃣ A. Thoracodorsal⃣ B. Axillary⃣ C. Dorsal scapular⃣ D. Spinal accessory⃣ E. Radial

Answer 11

A. The thoracodorsal nerve innervates the latissimusdorsi, one of three major muscles that adductand medially rotate the humerus. The axillary nervesupplies the deltoid muscle, the dorsal scapular suppliesthe rhomboids and levator scapulae, whereasthe spinal accessory innervates the trapezius. Noneof these nerves medially rotates or adducts the humerus.The radial nerve is responsible for the innervationon the posterior aspect of the arm. The medialand lateral pectoral nerves and the lower subscapularnerve supply the other two medial rotators of thehumerus.GAS 89-90; GA 371

Question 12

A 39-year-old woman complains of an inability toreach the top of her head to brush her hair. Historyreveals that she had undergone a bilateral mastectomyprocedure 2 months earlier. Physical examination demonstrateswinging of both of her scapulae. Whichnerves were most likely damaged during surgery?⃣ A. Axillary⃣ B. Spinal accessory⃣ C. Long thoracic⃣ D. Dorsal scapular⃣ E. Thoracodorsa

Answer 12

C. The long thoracic nerve innervates the serratusanterior, which is responsible for elevation andabduction of the scapula beyond the horizontal levelwhile maintaining its position against the thoracicwall. Along with the thoracodorsal nerve, the longthoracic nerve runs superfi cially along the thoracicwall and is commonly subject to injury during mastectomyprocedures. The axillary nerve, the spinalaccessory nerve, and the thoracodorsal nerve supplythe deltoid muscle, trapezius muscle, and latissimusdorsi muscles, respectively. The dorsal scapular nerveis responsible for innervation of the rhomboids andlevator scapulae. Aside from the long thoracic andthoracodorsal nerves, the remaining nerves do notcourse along the lateral thoracic wall.GAS 89-90, 139, 688-690; GA 371

Question 13

A 19-year-old man is brought to the emergencydepartment after dislocating his shoulder while playingfootball. Following treatment of the dislocation, he cannotinitiate abduction of his arm. An MRI of the shouldershows a torn muscle. Which muscle was mostlikely damaged by the injury?⃣ A. Coracobrachialis⃣ B. Long head of the triceps⃣ C. Pectoralis minor⃣ D. Supraspinatus⃣ E. Teres major

Answer 13

D. The rotator cuff muscles are common sites ofdamage during shoulder injuries. These muscles includethe supraspinatus, infraspinatus, teres minor,and subscapularis (SITS). Initiation of abduction ofthe humerus (the fi rst 15 ° ) is performed by the supraspinatus,followed by the deltoid from 15 ° to 90 ° .Above the horizontal, the humerus is abducted by thetrapezius and serratus anterior. The teres major andthe pectoralis major are responsible for medial rotationand adduction of the humerus. These musclesare therefore not involved in abduction at the glenohumeraljoint.GAS 674-678; GA 356-358, 362-366

Question 14

A 1-year-old girl is brought to the clinic for a routinecheckup. The child appears normal except for adimpling of the skin in the lumbar region with a tuft ofhair growing over the dimple. You reassure the motherthat this condition is seen in 10% to 25% of births andnormally has no ill effects. What is this relatively commoncondition that results from incomplete embryologicdevelopment?⃣ A. Meningomyelocele⃣ B. Meningocele⃣ C. Spina bifi da occulta⃣ D. Spina bifi da cystica⃣ E. Rachischisis

Answer 14

C. Spina bifi da is a developmental condition resultingfrom incomplete fusion of the vertebral archeswithin the lumbar region. Spina bifi da occulta commonlypresents asymptomatically with a tuft of hairand a small dimple in the overlying skin. More severeforms (spina bifi da cystica) are categorized into threetypes: Spina bifi da cystica with meningocele presentswith protrusion of the meninges through the unfusedvertebral arches. Spina bifi da with meningomyeloceleis characterized by protrusion both of the meningesand CNS tissues and is often associated with neurologicdefi cits. Rachischisis, also known as spina bifi dacystica with myeloschisis, results from a failure ofneural folds to fuse and is characterized by protrusionof the spinal cord or spinal nerves and meninges.GAS 76; GA 21-35

Question 15

Which nerve fi bers carry the sensation of a mosquitobite on the back, just lateral to the spinous processof the T4 vertebra?⃣ A. Somatic afferent⃣ B. Somatic efferent⃣ C. Visceral afferent⃣ D. Visceral efferent⃣ E. Somatic efferent and visceral afferent

Answer 15

A. Somatic afferents are responsible for conveyingpain, pressure, touch, temperature, and proprioceptionto the CNS. Afferent fi bers carry only sensorystimuli, whereas efferent fi bers convey motor information.Visceral innervation is associated with theautonomic nervous system. Visceral afferents generallycarry information regarding the physiologicchanges of the internal viscera whereas visceral efferentsdeliver autonomic motor function to threetypes of tissue: smooth muscle, cardiac muscle, andglandular epithelium.GAS 35-42, 40-41; GA 44-45

Question 16

A 15-year-old female was suspected to have meningitis.To obtain a sample of cerebrospinal fl uid byspinal tap in the lumbar region (lumbar puncture), thetip of the needle must be placed in which of the followinglocations?⃣ A. In the epidural space⃣ B. Between anterior and posterior longitudinalligaments⃣ C. Superfi cial to the ligamentum fl avum⃣ D. Between arachnoid mater and dura mater⃣ E. In the subarachnoid space

Answer 16

E. Cerebrospinal fl uid is found within the subarachnoidspace and is continuous with the ventriclesof the brain (CSF fl ows from the ventricles to the subarachnoidspace). The epidural space, positioned betweenthe dura mater and periosteum, is characterizedby fat deposits and contains the internal vertebral venousplexus (of Batson). The subdural space, betweenthe arachnoid mater and dura mater, exists only as apotential space and does not contain cerebrospinalfl uid. The anterior and posterior longitudinal ligamentstraverse the length of the vertebral body.GAS 106-108; GA 47-51

Question 17

In the event of intervertebral disk herniation inthe cervical region, which of the following ligaments isin an anatomic position to protect the spinal cord fromdirect compression?⃣ A. Supraspinous⃣ B. Posterior longitudinal⃣ C. Anterior longitudinal⃣ D. Ligamentum fl avum⃣ E. Nuchal ligament

Answer 17

B. The posterior longitudinal ligament is theonly ligament spanning the posterior aspect of thevertebral bodies and intervertebral disks. With intervertebraldisk herniation, the nucleus pulposus of theintervertebral disk protrudes posterolaterally. The anteriorlongitudinal ligament traverses the anterior sideof the vertebral bodies and thus would not protect thespinal cord from direct compression. The supraspinousand ligamentum fl avum ligaments connect thespinous processes and the laminae of adjacent vertebrae,respectively. The nuchal ligament is a continuationof the supraspinous ligaments near the C7 vertebraeand runs to the occipital protuberance.GAS 82-84; GA 35

Question 18

In spinal anesthesia the needle is often insertedbetween the spinous processes of the L4 and L5 vertebraeto ensure that the spinal cord is not injured. Thislevel is safe because in the adult the spinal cord usuallyterminates at the disk between which of the followingvertebral levels?⃣ A. T11 and T12⃣ B. T12 and L1⃣ C. L1 and L2⃣ D. L2 and L3⃣ E. L3 and L4

Answer 18

C. L1 and L2. This is the location of the conusmedullaris, a tapered conical projection of the spinalcord at its inferior termination. Although the conusmedullaris rests at the level of L1 and L2 in adults,it is often situated at L3 in newborns. The caudaequina and fi lium terminale extend beyond the conusmedullaris.GAS 101-102; GA 44-51

Question 19

A 22-year-old female is diagnosed with Raynaud’sdisease. In such a case the patient suffers chronic vasospasmin response to cold. This can lead to arterialconstriction and painful ischemia, especially in thefi ngers or toes. Relief from the symptoms in the handswould require surgical division of which of the followingneural elements?⃣ A. Lower cervical and upper thoracic sympatheticfi bers⃣ B. Lower cervical and upper thoracic ventralroots⃣ C. Lower cervical and upper thoracic dorsalroots⃣ D. Lower cervical and upper thoracic spinalnerves⃣ E. Bilateral spinal accessory nerves

Answer 19

A. Lower cervical and upper thoracic sympatheticfi bers. The sympathetic division of the autonomicnervous system is primarily responsible forvasoconstriction. Separation of ventral or dorsal rootswould lead to undesired consequences, such as a lossof motor or sensory activity. Similarly, surgical divisionof spinal nerves would also have unwanted consequences,but such are not related to the increasedarterial constriction and the painful ischemia in thedigits. Division of selected sympathetic chain ganglia,however, would decrease the sympathetic outfl ow tothe upper limbs.GAS 41-42; GA 44-45

Question 20

A 69-year-old female visits her physician due tosevere neck pain. Radiographic studies reveal bonygrowths (osteophytes) in the intervertebral foramenbetween vertebrae C2 and C3. Which of the followingmuscles would be most likely affected by thiscondition?⃣ A. Rhomboid⃣ B. Serratus anterior⃣ C. Supraspinatus⃣ D. Diaphragm⃣ E. Latissimus dorsi

Answer 20

D. The diaphragm is innervated by the phrenicnerve, which arises from C3 to C5. The rhomboid,serratus anterior, supraspinatus, and latissimus dorsiare innervated by the ventral rami of the brachialplexus (C5 to T1).GAS 157-158; GA 110

Question 21

A 42-year-old female is diagnosed with constrictionof the cervical vertebral canal. A laminectomy oftwo vertebrae is performed. Which of the followingligaments will most likely also be removed?⃣ A. Anterior longitudinal⃣ B. Denticulate⃣ C. Ligamentum fl avum⃣ D. Nuchal⃣ E. Cruciate

Answer 21

C. The anterior longitudinal ligament runs alongthe anterior-most aspect of the vertebral column fromC1 to the sacrum and would therefore be unaffected bylaminectomy. Denticulate ligaments extend laterallyfrom the pia mater to the arachnoid mater along thelength of the spinal cord. The ligamentum fl avum isone of the two ligaments found in the vertebral canaland is adherent to the anterior aspect of the vertebralarches. It is thus simultaneously removed upon excisionof the lamina. The nuchal ligament is a thicklongitudinal extension continuing from the supraspinousligament at the level of C6 to the external occipitalprotuberance. The cruciate ligament is an incorrectanswer because it is located anterior to the spinal cord,and thus would not be involved in laminectomy.GAS 82-84; GA 21-27

Question 22

A 28-year-old pregnant woman is admitted to theobstetrics department for delivery. In the fi nal stages oflabor a caudal anesthetic is administered via the sacralhiatus. Into which of the following spaces in the sacralcanal is the anesthetic placed?⃣ A. Vertebral canal⃣ B. Vertebral venous plexus⃣ C. Epidural space⃣ D. Subarachnoid space⃣ E. Subdural space

Answer 22

C. The vertebral canal is the longitudinal canalthat extends through the vertebrae, containing themeninges, spinal cord, and associated ligaments. The vertebral venous plexus is the valveless network ofveins extending longitudinally along the vertebralcanal. Neither of these answer choices describes aspecifi c space. The epidural space is found superfi -cially to the dura mater. It is a fat-fi lled space extendingfrom C1 to the coccyx. The subarachnoid space isa true space containing CSF. It is found within theCNS and extends to the level of S2. The subduralspace is a potential space between the dura and thearachnoid mater. Normally these two layers are fuseddue to the pressure of CSF in the subarachnoidspace.GAS 106-109; GA 44-49

Question 23

A 12-year-old child was brought to the emergencydepartment by his parents because he has been sufferingfrom a very high fever and severe stiffness in hisback. The initial diagnosis is meningitis. The attendingphysician orders a lumbar puncture to confi rm the diagnosis.Upon microscopic examination of the cerebrospinalfl uid, hematopoetic cells are seen. Which of thefollowing ligaments is most likely to be penetrated bythe needle?⃣ A. Supraspinous⃣ B. Denticulate⃣ C. Anterior longitudinal⃣ D. Posterior longitudinal⃣ E. Nuchal ligament

Answer 23

D. Lumbar puncture is generally performed atthe level of L4, L5. The supraspinous ligament extendsbetween spinous processes on the dorsal aspectof the vertebrae. The needle would bypass this structure.The denticulate ligaments are not correct becausethey terminate with the conus medullaris at thelevel of L2 and are located laterally. The anterior longitudinalligament extends along the most anterioraspect of the vertebral bodies and can be reachedonly ventrally. The posterior longitudinal ligament ispresent at the correct vertebral level but will be puncturedonly if the procedure is performed incorrectly asin this case, where hematopoetic cells were aspiratedfrom the vertebral body anterior to the ligament. Thenuchal ligament extends cranially from the supraspinousligament in the lower cervical region to theskull.GAS 106-109; GA 44-51

Question 24

A 25-year-old male race car driver is admitted tothe emergency department after a severe car crash.Radiographic studies reveal damage to the tip of thetransverse process of the third cervical vertebra, with asignifi cantly large pulsating hematoma. What artery isthe most likely to have been damaged?⃣ A. Anterior spinal artery⃣ B. Vertebral artery⃣ C. Ascending cervical artery⃣ D. Deep cervical artery⃣ E. Posterior spinal arteries

Answer 24

B. The anterior spinal artery is located anteriorlyalong the spinal cord and is not directly associatedwith the vertebrae. The vertebral arteries run throughthe transverse foramina of cervical vertebrae C6through C1 and are therefore most closely associatedwith injury to the transverse processes. The ascendingcervical artery is a very small branch from the thyrocervicaltrunk of the subclavian artery, running on theanterior aspect of the vertebrae. The deep cervicalartery arises from the costocervical trunk is also avery small artery and courses along the posterior aspectof the cervical vertebrae. The posterior spinalarteries are adherent to the posterior aspect of thespinal cord.GAS 102-103; GA 41

Question 25

A 79-year-old male retired military veteran presentsto the outpatient clinic with an abnormal curvatureof the vertebral column. He complains that it hasbecome increasingly painful to walk around town.Upon physical examination he has an abnormally increasedthoracic curvature resulting from osteoporosis.Which of the following is the most likely clinical conditionof this patient’s spine?⃣ A. Scoliosis⃣ B. Kyphosis⃣ C. Spinal stenosis⃣ D. Lordosis⃣ E. Herniated disk

Answer 25

B. Scoliosis is defi ned as a lateral deviation ofthe spinal column to either side. Kyphosis is an increasedprimary curvature of the spinal column. Thiscurvature is associated with thoracic and sacral regionsand is most likely this patient’s clinical condition.Spinal stenosis is a narrowing of the vertebralcanal and is not directly associated with a displacementof the spinal column. Lordosis is the increasedsecondary curvature affecting the cervical and lumbarregions. A herniated disk is a rupture of the anulusfi brosus of the intervertebral disk, commonly causinga posterolateral displacement of the nucleus pulposusinto the vertebral canal.GAS 77; GA 21

Question 26

A 42-year-old woman complains of pain and stiffnessin her neck. She was injured sliding into secondbase headfi rst during her company softball game. Radiographsreveal no fractures of her spine. However,upon physical examination her right shoulder is droopingand she has diffi culty in elevating that shoulder. Ifyou ordered an MRI, it would most likely reveal softtissue damage to which of the following nerves?⃣ A. Thoracodorsal nerve⃣ B. Spinal accessory nerve⃣ C. Dorsal scapular nerve⃣ D. Greater occipital nerve⃣ E. Axillary nerve

Answer 26

B. The thoracodorsal nerve innervates the latissimusdorsi, which has no action on the shouldergirdle. The spinal accessory nerve is the eleventh cranialnerve (CN XI) and innervates both the trapeziusand sternocleidomastoid muscles. The loss of CN XIresults in drooping of the shoulder due to paralysis ofthe trapezius. In addition to the clinical fi ndings ofthe MRI, one can test the innervation of this nerve byasking the patient to shrug his or her shouldersagainst resistance (testing the trapezius), as well asturning his or her head against resistance (testing thesternocleidomastoid). The dorsal scapular nerve innervatesthe levator scapulae muscle, as well as therhomboids. The greater occipital nerve is a sensorynerve innervating the posterolateral aspect of thescalp. The axillary nerve is a branch of the brachialplexus and innervates the deltoid and teres minor. Itis not involved in shoulder elevation.GAS 89-90; GA 371

Question 27

A 53-year-old male was in a head-on vehicle collisionthat resulted in compression of the spinal cord bythe dens of the axis, with resulting quadriplegia. Whichof the following ligaments was most probably torn?⃣ A. Anterior longitudinal ligament⃣ B. Transverse ligament of the atlas⃣ C. Ligamentum fl avum⃣ D. Supraspinous ligament⃣ E. Nuchal ligament

Answer 27

B. The anterior longitudinal ligament runs on theanterior aspect of the vertebrae and is not affected. Thetransverse ligament of the atlas anchors the dens laterallyto prevent posterior displacement of the dens. Thisligament has been torn in this injury. The ligamentumfl avum is found on the posterior aspect of the vertebralcanal and does not contact the anteriorly placed dens.The supraspinous ligament is located along the spinousprocesses of the vertebrae. The nuchal ligamentis a longitudinal extension of the supraspinous ligamentabove the level of C7.GAS 82-84; GA 35

Question 28

An 18-year-old female passenger injured in a rollovercar crash was rushed to the emergency department.After the patient is stabilized she undergoesphysical examination. She demonstrates considerableweakness in her ability to fl ex her neck, associatedwith injury to CN XI. Which of the following musclesis most probably affected by nerve trauma?⃣ A. Iliocostalis thoracis⃣ B. Sternocleidomastoid⃣ C. Rhomboid major⃣ D. Rhomboid minor⃣ E. Teres major

Answer 28

B. The iliocostalis thoracis muscle is found inthe deep back and functions to maintain posture. It isnot associated with neck fl exion. The sternocleidomastoidmuscle is innervated by CN XI and functionsin contralateral rotation and bilateral fl exion of theneck. Rhomboid major and minor are both innervatedby the dorsal scapular nerve and serve to adduct thescapulae. Teres major is innervated by the lower subscapularnerve and serves to medially rotate and adductthe humerus.GAS 95-97; GA 40-41

Question 29

A 23-year-old male was killed in a high-speed motorvehicle collision after racing his friend on a localhighway. When the medical examiner arrives upon the BACK5scene, it is determined that the most likely cause ofdeath was a spinal cord injury. Upon confi rmation bythe autopsy, the medical examiner offi cially reportsthat the patient’s cause of death was a fracture of thepedicles of the axis (C2). Breaking of which of the followingligaments would be most likely implicated inthis fatal injury?⃣ A. Ligamentum fl avum⃣ B. Nuchal ligament⃣ C. Cruciform ligament⃣ D. Posterior longitudinal ligament⃣ E. Supraspinous ligament

Answer 29

C. The pedicles are bony structures connectingthe vertebral arches to the vertebral body. The ligamentumfl avum runs on the posterior aspect of thevertebral canal and is more closely associated withthe lamina than to the pedicles of the vertebrae. Thenuchal ligament is a longitudinal extension of thesupraspinous ligament from C7 to the occiput, bothrunning on the most posterior aspect of the vertebraealong the spinous processes. The cruciform (alsocalled cruciate) ligament is a stabilizing ligamentfound in C1/C2. It attaches to the pedicles and helpsanchor the dens in situ, but it has been broken in thiscase. The posterior longitudinal ligament extends thelength of the anterior aspect of the vertebral canal andis anterior to the pedicles.GAS 72-73; GA 35

Question 30

A 65-year-old male is injured when a vehicle travelingat a high rate of speed hits his car from behind.Radiographic examination reveals that two of his articularprocesses are now locked together, a conditionknown as “facet jumping.” In which region of the spineis this injury most likely to occur?⃣ A. Cervical⃣ B. Thoracic⃣ C. Lumbar⃣ D. Lumbosacral⃣ E. Sacral

Answer 30

A. Spondylolysis, also known as “facet jumping,”is the anterior displacement of one or morevertebrae. This is most commonly seen with the cervicalvertebrae because of their small size and structureand the oblique angle of the articular facets. Lumbarvertebrae are somewhat susceptible to this problembecause of the pressures at lower levels of the spineand the sagittal angles of the articular facets. It ismuch less common in the thoracic vertebrae due tothe stabilizing factor of the ribs. It is never seen in thesacral vertebrae because they are fused together.GAS 85-86; GA 21-29

Question 31

Following a car crash a 47-year-old female complainsof severe headache and back pain. Radiographicexamination reveals bleeding of the internalvertebral venous plexus (of Batson), resulting in alarge hematoma. In what space has the blood mostlikely accumulated?⃣ A. Subarachnoid space⃣ B. Subdural space⃣ C. Central canal⃣ D. Epidural space⃣ E. Lumbar cistern

Answer 31

D. The internal vertebral plexus (of Batson) surroundsthe dura mater in the epidural space; hence,the bleeding would cause the hematoma in thatspace. The subarachnoid space, containing the CSF, islocated between pia and arachnoid mater. A subarachnoidbleed would most likely result from a rupturedintercerebral aneurysm. A subdural hematomawould result most likely from a venous bleed from atorn cerebral vein as it enters the superior sagittalvenous sinus within the skull. The central canal islocated within the gray matter of the spinal cord. Thelumbar cistern is an enlargement of the subarachnoidspace between the conus medullaris of the spinal cordand the inferior end of the subarachnoid space.GAS 106-108; GA 47

Question 32

A 32-year-old male elite athlete was lifting heavyweights during an intense training session. The athletefelt severe pain radiating to the posterior aspect of hisright thigh and leg. The patient was taken to the hospitalwhere MRI revealed a ruptured L4/L5 intervertebraldisk. Which nerve is most probably affected?⃣ A. L3⃣ B. L4⃣ C. L2⃣ D. L5⃣ E. S1

Answer 32

D. In the lumbar region spinal nerves exit thevertebral column below their named vertebrae. In anL4, L5 intervertebral disk herniation, the L5 spinalnerve would be affected as it descends between L4,L5 vertebrae to exit below the L5 level. L2, L3, and L4spinal nerves have already exited above the level ofherniation; therefore, they would not be affected bythis herniation. An “L6” spinal nerve normally doesnot exist. (The NBME does not allow “made up”structures, but in cases of lumbarization of S1, somepeople recognize an L6 nerve.)GAS 107-109; GA 44-45

Question 33

A 24-year-old patient suffered a lower back strainafter a severe fall while snow skiing. MRI studies revealinjury to the muscles responsible for extending andlaterally bending the trunk. What arteries provideblood supply for these muscles?⃣ A. Subscapular⃣ B. Thoracodorsal⃣ C. Anterior intercostal⃣ D. Suprascapular⃣ E. Posterior intercostal

Answer 33

E. Posterior intercostal arteries supply the deepback muscles that are responsible for extending andlaterally bending the trunk. The subscapular suppliessubscapularis muscle, the thoracodorsal supplies latissimusdorsi, the anterior intercostal supplies theupper nine intercostal spaces, and the suprascapularsupplies supraspinatus and infraspinatus muscles.These muscles are not responsible for extension andlateral fl exion of the trunk.GAS 102-103; GA 46, 68

Question 34

A 22-year-old male soccer player is forced toleave the game following a head-to-head collisionwith another player. He is admitted to the hospital,and radiographic examination reveals slight dislocationof the atlantoaxial joint. As a result, he experiencesdecreased range of motion at that joint. Whatmovement of the head would most likely be severelyaffected?⃣ A. Rotation⃣ B. Flexion⃣ C. Abduction⃣ D. Extension⃣ E. Adduction

Answer 34

A. The atlantoaxial joint is a synovial joint responsiblefor rotation of the head, not fl exion, abduction,extension, or adduction. The atlanto-occipitaljoint is primarily involved in fl exion and extension ofthe head on the neck.GAS 102-103; GA 46, 68

Question 35

A 42-year-old male is struck in the back, rupturingthe internal vertebral venous plexus (of Batson).Radiographic studies reveal a hematoma causing compressionof the spinal cord. When aspirating the excessblood, the physician performing the procedure muststop the needle just before puncturing which of the followingstructures?⃣ A. Spinal cord⃣ B. Pia mater⃣ C. Arachnoid mater⃣ D. Dura mater⃣ E. Ligamentum fl avum

Answer 35

D. The internal vertebral plexus (of Batson) liesexternal to the dura mater in the epidural space. Toaspirate excess blood, the physician must pass theneedle through the ligamentum fl avum to reach theepidural space wherein the blood would accumulate.The spinal cord, pia mater, and arachnoid mater arelocated deep to the epidural space.GAS 103-108; GA 47

Question 36

A 35-year-old male pedestrian is crossing a busyintersection and is hit by a truck. He is admitted to theemergency department, and a CT scan reveals a dislocationof the fourth thoracic vertebra. Which of thefollowing costal structures is most likely also involvedin the injury?⃣ A. Head of the fourth rib⃣ B. Neck of the fourth rib⃣ C. Head of the third rib⃣ D. Tubercle of the third rib⃣ E. Head of the fifth rib

Answer 36

E. The T4 thoracic vertebra articulates with thehead of the fi fth rib. The head of the rib has two facets.The rib articulates with the superior facet on thebody of its own vertebra (fourth rib articulates withthe superior facet T4 vertebra) and with the inferiorfacet on the body of the vertebra above (fourth ribarticulates with the inferior facet of T3 vertebra). Takingthe T4 vertebra into consideration, the superiorfacet of this vertebra articulates with the head of thefourth rib and the inferior facet articulates with thehead of the fi fth rib. The head of the fourth rib hastwo points of articulation (a joint with the vertebralbody and costotransverse joint) on T4, so when it isinjured it moves as a unit, whereas the fi fth rib hasonly one articulation with T4.GAS 125-126; GA 57-61

Question 37

A 20-year-old hiker suffers a deep puncture betweenthe trapezius and latissimus dorsi muscles onthe right lateral side of his back. Upon admission to the BACK6hospital, physical examination reveals weak adductionand medial rotation of his arm. Which of the followingmuscles is most probably injured?⃣ A. Teres minor⃣ B. Triceps brachii⃣ C. Supraspinatus⃣ D. Infraspinatus⃣ E. Teres major

Answer 37

E. Teres major is responsible for adduction andmedial rotation of the humerus. Teres minor is responsiblefor lateral rotation of the humerus. Tricepsbrachii is responsible for extension of the forearm.Supraspinatus is responsible for the 0 ° to 15 ° of BACK15abduction, and infraspinatus is a lateral rotator.GAS 89-91; GA 364-365

Question 38

A 22-year-old male is thrown through a plateglass wall in a fi ght. Radiologic examination revealsthat the lateral border of his right scapula is shattered.He is admitted to the emergency department, andphysical examination reveals diffi culty laterally rotatinghis arm. Which of the following muscles is most probablyinjured?⃣ A. Teres major⃣ B. Infraspinatus⃣ C. Latissimus dorsi⃣ D. Trapezius⃣ E. Supraspinatus

Answer 38

B. Infraspinatus is responsible for lateral rotation(along with the teres minor, not a choice here).Teres major is responsible for adduction and medialrotation of the humerus. Latissimus dorsi is responsiblefor adduction, extension, and medial rotation ofthe humerus. Trapezius is an elevator of the scapulaand rotates the scapula during abduction of the humerusabove the horizontal plane. Supraspinatus isresponsible for the 0 ° to 15 ° of abduction.GAS 89-91; GA 364-365

Question 39

A 24-year-old female presents with severe headache,photophobia, and stiffness of her back. Physicalexamination reveals positive signs for meningitis. Theattending physician decides to perform a lumbar punctureto determine if a pathogen is in the CSF. What isthe last structure the needle will penetrate beforereaching the lumbar cistern?⃣ A. Arachnoid mater⃣ B. Dura mater⃣ C. Pia mater⃣ D. Ligamentum fl avum⃣ E. Posterior longitudinal ligament

Answer 39

A. When a lumbar puncture is performed, theneedle must penetrate the ligamentum fl avum, thedura mater, and fi nally the arachnoid mater to reachthe subarachnoid space where the CSF is located. Thelumbar cistern is a continuation of the subarachnoidspace below the conus medullaris. The pia mater isadherent to the spinal cord, and the posterior longitudinalligament is attached to the posterior aspect ofthe vertebral bodies.GAS 106-108; GA 44-49

Question 40

A 19-year-old presents at the emergency departmentwith high fever, severe headache, nausea, andstiff neck for 3 days. The attending physician suspectsmeningitis and obtains a sample of CSF using a lumbarpuncture. From which of the following spaces was theCSF collected?⃣ A. Epidural space⃣ B. Subdural space⃣ C. Subarachnoid space⃣ D. Pretracheal space⃣ E. Central canal of the spinal cord

Answer 40

C. The subarachnoid space, containing the CSF,is located between the pia and the arachnoid mater.Neither the epidural space, the subdural space, northe pretracheal space contains CSF. Although the centralcanal, contained within the substance of the spinalcord, does contain CSF, extraction of CSF fromthis region would result in spinal cord injury. CSFcirculates in the area of the subarachnoid space andcan be aspirated only from that location. The subduralspace is only a potential space between the duraand arachnoid mater. The epidural space contains theepidural fat and Batson’s venous plexus and is thepreferred site for aspirating CSF for diagnostic purposes(and epidural anesthesia). CSF is not located inthe pretracheal space.GAS 103-108; GA 44-49

Question 41

A 38-year-old male is admitted to the emergencydepartment after a car collision. During physical examinationseveral lacerations in the back are discovered.Pain from lacerations or irritations of the skin ofthe back is conveyed to the central nervous system bywhich of the following?⃣ A. Dorsal primary rami⃣ B. Communicating rami⃣ C. Ventral primary rami⃣ D. Ventral roots⃣ E. Intercostal nerves

Answer 41

A. General somatic afferent fi bers are conveyedfrom the skin of the back via the dorsal primary rami.Communicating rami contain general visceral efferent(sympathetic) fi bers and general visceral afferent fi -bers of the autonomic nervous system. Ventral primaryrami convey mixed spinal nerves to/from allother parts of the body excluding the back, and partsof the head innervated by cranial nerves. The ventralroots contain only efferent (motor) fi bers. Intercostalnerves are the ventral rami of T1 to T11. The ventralramus of T12 is the subcostal nerve.GAS 39-49; GA 14-15

Question 42

A 66-year-old female had been diagnosed with atumor on her spine. She has started to retain urine andis experiencing decreased anal and rectal tone. Both ofthese symptoms are signs of conus medullaris syndrome.At which of the following vertebral levels is thetumor probably located?⃣ A. L3/L4⃣ B. L3⃣ C. L4⃣ D. T12 to L2⃣ E. T11

Answer 42

D. The conus medullaris is located at the L1-2vertebral level; therefore, any choice that containsthat region is the correct answer. L3-4 is a commonlocation to perform lumbar puncture, but it is caudalto the apex of the conus medullaris. L3 and L4 arecaudal to the conus medullaris. T11 is superior to theconus medullaris.GAS 101-108; GA 44-49

Question 43

Examination of a 3-day-old male infant revealsprotrusion of his spinal cord and meninges from a defectin the lower back. Which of the following describesthis congenital anomaly?⃣ A. Avulsion of meninges⃣ B. Meningitis⃣ C. Spina bifi da occulta⃣ D. Spina bifi da with meningomyelocele⃣ E. Spina bifida with meningocele

Answer 43

D. Because the meninges and spinal cord areincluded in the protrusion, the patient’s condition is aclassic presentation of spina bifi da with meningomyelocele.If the protrusion contains only meninges butno CNS tissue, it is known as spina bifi da with meningocele.Meningitis is an infl ammation of the meningescaused by bacteria, viral, or numerous other irritants.It does not cause deformation of vertebrae or result inprotrusion of spinal cord contents. Spina bifi da occultais a normally asymptomatic condition in whichthe vertebral lamina fail to fuse completely duringembryologic development. A tuft of hair is commonlyseen growing over the affected region (usually lumbarin position).GAS 76; GA 44-49

Question 44

A 32-year-old mother complains of serious painin the coccygeal area some days after giving birth. Todetermine whether the coccyx is involved, a localanesthetic is fi rst injected in the region of the coccyxand then dynamic MRI studies are performed. TheMRI reveals coccydynia, which confi rms that hercoccyx dislocates upon sitting. The local anestheticis used to interrupt which of the following nervepathways?⃣ A. Visceral afferents⃣ B. Somatic efferent⃣ C. Somatic afferent⃣ D. Sympathetic preganglionic⃣ E. Parasympathetic preganglionic

Answer 44

C. Somatic afferent fi bers convey localized pain,typically from the body wall and limbs. Visceral afferentsconvey autonomic nervous system sensoryinformation. Pain from these fi bers will present asdull and diffuse. Somatic efferent fi bers convey motorinformation to skeletal muscle. Sympathetic preganglionicfi bers are visceral efferent fi bers and do notcontain sensory information. Parasympathetic preganglionicfi bers are also visceral efferents and do notcontain sensory information.GAS 39-49; GA 14-19

Question 45

During a routine physical examination a 65-yearoldmale patient is tested for ease and fl exibility of themovements of his lumbar region. Which of the following BACK7movements is most characteristic of the intervertebraljoints in the lumbar region?⃣ A. Circumduction⃣ B. Lateral fl exion⃣ C. Abduction⃣ D. Adduction⃣ E. Inversion

Answer 45

B. Lateral fl exion is the best answer becauseother movements of the lumbar portion of the vertebralcolumn are very limited due to the orientation ofthe articular facets.GAS 67-75, 41; GA 21-24, 35

Question 46

A 72-year-old man with cancer of the prostategland presents with loss of consciousness and seizures.A CT scan is performed and a brain tumor is diagnosed.The tumor spread to the brain from the abdomen via theinternal vertebral venous plexus (of Batson). What featureof the plexus allows this to happen?⃣ A. They are the longest veins in the body.⃣ B. They have valves that ensure one-way movementof blood.⃣ C. They are located in the subarachnoid space.⃣ D. They are valveless.⃣ E. They are located in the subdural space.

Answer 46

D. Batson’s venous plexus is a valveless networkof veins located in the epidural space of thevertebral canal. The lack of valves can provide a routefor the metastasis of cancer (i.e., from prostate orbreast to brain) because the fl ow of blood is not unidirectional.The length of Batson’s plexus is irrelevantto the question. B is incorrect because Batson’s plexusdoes not have valves or one-way movement of blood.Batson’s plexus is located within the epidural space,not the subarachnoid or subdural spaces.GAS 102-106; GA 47

Question 47

A 26-year-old man painting his house slipped andfell from the ladder, landing on the pavement below.After initial examination in the emergency department,the patient is sent to the radiology department. Radiographsreveal that the portion of his left scapula thatforms the tip, or point, of the shoulder has been fractured.Which part of the bone was fractured?⃣ A. Coracoid process⃣ B. Superior angle of the scapula⃣ C. Glenoid⃣ D. Spine of the scapula⃣ E. Acromion

Answer 47

E. The acromion (the highest point of the shoulder)is the part of the scapula that forms the “point”of the shoulder. The coracoid process is located moremedially. The superior angle of the scapula is locatednear the midline of the back. The glenoid of thescapula articulates with the head of the humerus toform the glenohumeral joint. The spine of the scapulais located posteriorly and separates supraspinous andinfraspinous fossae.GAS 665-673; GA 354-358

Question 48

A 43-year-old male construction worker surviveda fall from a two-story building but lost all sensationfrom his lower limbs and was admitted to the hospitalfor examination and treatment. Radiographic studiesrevealed that he crushed his spinal cord at vertebrallevel C6. Which of the following muscles will mostlikely be paralyzed?⃣ A. Supraspinatus⃣ B. Trapezius⃣ C. Rhomboid muscles⃣ D. Latissimus dorsi⃣ E. Deltoid

Answer 48

D. All of the spinal nerves below the C7 vertebrallevel will be affected. This includes the C7 spinalnerve because it exits the vertebral column above theC7 vertebra. The trapezius would be intact because itis innervated by the spinal accessory nerve. The deltoidmuscles and supraspinatus muscles will be unaffectedbecause they receive motor supply from C5 andC6. The rhomboid muscles should function normallybecause they are innervated by the dorsal scapularnerve (C5). The latissimus dorsi muscles would notfunction normally because they are innervated by thethoracodorsal nerves, which receive contributionsespecially from the C7 spinal nerves.GAS 89-92; GA 34

Question 49

A maternal serum sample with high alphafetoproteinalerted the obstetrician to a possible neuraltube defect. Ultrasound diagnosis revealed a meningoceleprotruding from the back of the child. Which ofthe following is the most likely diagnosis of this congenitalanomaly?⃣ A. Cranium bifi da⃣ B. Spina bifi da occulta⃣ C. Spina bifi da cystica⃣ D. Hemothorax⃣ E. Arnold-Chiari malformation

Answer 49

C. Spina bifi da cystica refers to spina bifi dawith meningocele and is the correct answer. Craniumbifi da could present with meningocele in theskull, but it would not be located in the lower back.Spina bifi da occulta is a defect in the formation ofthe vertebral arches and does not present with meningocele.Hemothorax refers to blood accumulationin the pleural space surrounding the lungs. ArnoldChiarimalformation is a herniation of the medullaoblongata and cerebellum through the foramen magnumand would not present with pathologies in thelower back.GAS 76; GA 21-27

Question 50

A 7-year-old female who is somewhat obese isbrought to the emergency department because of a softlump above the buttocks. Upon physical examinationyou note the lump is located just superior to the iliaccrest unilaterally on the left side. The protrusion isdeep to the skin and pliable to the touch. Which of thefollowing is the most probable diagnosis?⃣ A. Tumor of the external abdominal obliquemuscle⃣ B. Herniation at the lumbar triangle (of Petit)⃣ C. Indirect inguinal hernia⃣ D. Direct inguinal hernia⃣ E. Femoral hernia

Answer 50

B. The lumbar triangle (of Petit) is bordered mediallyby the latissimus dorsi, laterally by the externalabdominal oblique, and inferiorly by the iliac crest.The fl oor of Petit’s triangle is formed by the internalabdominal oblique, and this is a possible site of herniation.An indirect inguinal hernia is located in theinguinal canal of the anterior abdominal wall. A directinguinal hernia is located in the Hesselbach triangleof the anterior abdominal wall. A femoral hernia occursbelow the inguinal ligament. Answer A is not thebest answer because this lump is described as softand pliable, which would not likely indicate a tumor,as tumors tend to be hard masses.GAS 91-94; GA 37

Question 51

A 54-year-old woman is admitted to the emergencydepartment due to increasing back pain over thepreceding year. MRI reveals that her intervertebral diskshave been compressed. It is common for the disks toshrink in people older than 40, and it can result in spinalstenosis and disk herniation. At which locations arethe spinal nerves most likely to be compressed?⃣ A. Between the denticulate ligaments⃣ B. As they pass through the vertebral foramen⃣ C. Between the superior and inferior articularfacets⃣ D. Between inferior and superior vertebralnotches⃣ E. Between the superior and inferior intercostovertebraljoints

Answer 51

D. This question tests anatomic knowledge relatingto typical vertebrae and the spinal cord. Intervertebraldisk herniations occur when the nucleuspulposus of the intervertebral disk protrudes throughthe anulus fi brosus into the intervertebral foramen orvertebral canal. The most common protrusion is posterolaterally,where the anulus fi brosus is not reinforcedby the posterior longitudinal ligament. Theinferior and superior vertebral notches frame the intervertebralforamen, so this is the most likely locationof compression. The denticulate ligaments arelateral extensions of pia mater that anchor to the duramater, and they hold the spinal cord in positionwithin the subarachnoid space. The vertebral foramenis the canal through which the spinal cord passes;while this may also be a place of compression, it isnot the most likely site of herniation. Articular facetsare the locations where vertebral bodies articulatewith each other. Intercostovertebral joints are locationswhere vertebral bodies articulate with ribs.GAS 80-86; GA 32-35

Question 52

A 37-year-old pregnant woman is administered acaudal epidural block to alleviate pain during delivery.Caudal epidural block involves injection of local anestheticinto the sacral canal. Which of the followinglandmarks is most commonly used for the caudal epiduralblock?⃣ A. Anterior sacral foramina⃣ B. Posterior sacral foramina⃣ C. Cornua of the sacral hiatus⃣ D. Intervertebral foramina⃣ E. Medial sacral crest

Answer 52

C. Caudal anesthesia is used to block the spinalnerves that carry sensation from the perineum. Thisprocedure is commonly used by obstetricians to relievepain during labor and childbirth. Administrationof local anesthetic to the epidural space is via thesacral hiatus, which opens between the sacral cornua.The anterior sacral foramina are located on the pelvicsurface of the sacrum and are not palpable from adorsal approach. The posterior sacral foramina andintervertebral foramina are the openings throughwhich sacral nerves exit and are not palpable landmarks.The medial sacral crest is cranial to the injectionsite.GAS 106-110; GA 44-48

Question 53

A 34-year-old pregnant woman in the maternityward was experiencing considerable pain during labor.Her obstetrician decided to perform a caudal epiduralblock within the sacral canal. What are the most importantbony landmarks used for the administration ofsuch anesthesia?⃣ A. Ischial tuberosities⃣ B. Ischial spines⃣ C. Posterior superior iliac spines⃣ D. Sacral cornua⃣ E. Coccyx

Answer 53

D. The sacral cornua lie on either side of thesacral hiatus, from which one can gain access to thesacral canal. This is the best landmark for administrationof anesthesia. The ischial tuberosities are morecommonly used as landmarks for a pudendal nerveblock. The ischial spines cannot be palpated. Theposterior superior iliac spines, though palpable, arenot proximal enough for an epidural block withinthe sacral canal. The coccyx is not part of the sacralcanal.GAS 106-110; GA 44-48

Question 54

A 22-year-old man is brought into the emergencydepartment following a brawl in a tavern. He has severepain radiating across his back and down his leftupper limb. He supports his left upper limb with hisright, holding it close to his body. Any attempt to movethe left upper limb greatly increases the pain. A radiographis ordered and reveals an unusual sagittal fracturethrough the spine of the left scapula. The fractureextends superiorly toward the suprascapular notch.Which nerve is most likely affected?⃣ A. Suprascapular nerve⃣ B. Thoracodorsal nerve⃣ C. Axillary nerve⃣ D. Subscapular nerve⃣ E. Suprascapular nerve and thoracodorsal nerve

Answer 54

A. The suprascapular nerve passes through thesuprascapular notch, deep to the superior transversescapular ligament. This nerve is most likely affected ina fracture of the scapula as described in the question.The thoracodorsal nerve runs behind the axillary artery BACK17and lies superfi cial to the subscapularis muscle andwould therefore be protected. The axillary nerve passesposteriorly through the quadrangular space, which isdistal to the suprascapular notch. The subscapularnerve originates from the posterior cord of the brachialplexus, which is distal to the site of fracture.GAS 680-683; GA 366, 370

Question 55

A 5-year-old boy is admitted to the hospital becauseof pain in the upper back. Radiographic examinationreveals abnormal fusion of the C5 and C6 vertebraeand a high-riding scapula. Which of the followingconditions is characteristic of his symptoms?⃣ A. Lordosis⃣ B. Kyphosis⃣ C. Scoliosis⃣ D. Spina bifi da⃣ E. Klippel-Feil syndrome

Answer 55

E. Klippel-Feil syndrome is a congenital defect inwhich there is a reduction, or extensive fusion, in thenumber of cervical vertebrae. It often manifests as ashort, stiff neck with limited motion. Lordosis is anabnormal increase in lumbar curvature. Kyphosis(“hunchback”) is an abnormal increase in thoraciccurvature. Scoliosis is a lateral curvature. Spina bifi daoften presents with deformities in the lumbar region.GAS 76-79; GA 21-33

Question 56

A 53-year-old male is admitted to the emergencydepartment due to severe back pain. MRI examinationreveals anterior dislocation of the body of the L5 vertebraupon the sacrum. Which of the following is themost likely diagnosis?⃣ A. Spondylolysis⃣ B. Spondylolisthesis⃣ C. Herniation of intervertebral disk⃣ D. Lordosis⃣ E. Scoliosis

Answer 56

B. Spondylolisthesis is an anterior vertebral displacementcreated by an irregularity in the anteriormargin of the vertebral column such that L5 and theoverlying L4 (and sometimes L3) protrude forwardrather than being restrained by S1. Spondylolysis is acondition in which the region between the superiorand inferior articular facets (on the posterior arch ofthe L5 vertebra) is damaged or missing, which is notthe case in this example. Herniation is a protrusion ofthe nucleus pulposus through the anulus fi brosus,and this is not associated with vertebral dislocation.Lordosis and scoliosis are excessive curvatures thatdo not involve dislocations.GAS 85-86; GA 21-33

Question 57

A male newborn infant is brought to the clinic byhis mother and diagnosed with a congenital malformation.MRI studies reveal that the cerebellum and medullaoblongata are protruding inferiorly through theforamen magnum into the vertebral canal. What is thisclinical condition called?⃣ A. Meningocele⃣ B. Klippel-Feil syndrome⃣ C. Arnold-Chiari malformation⃣ D. Hydrocephalus⃣ E. Tethered cord syndrome

Answer 57

C. Arnold-Chiari malformation results from herniationof the medulla and cerebellum into the foramenmagnum. Meningocele is a small defect in the craniumin which only the meninges herniate. Klippel-Feil syndromeresults from an abnormal number of cervicalvertebral bodies. Hydrocephalus results from an overproductionof cerebrospinal fl uid, obstruction of itsfl ow, or interference with CSF absorption. Tetheredcord syndrome is a congenital anomaly caused by adefective closure of the neural tube. This syndrome ischaracterized by a low conus medullaris and a thickfi lum terminale.GAS 76, 294, 834; GA 21-33

Question 58

A 62-year-old woman is admitted to the hospitalbecause of her severe back pain. Radiographic examinationreveals that the L4 vertebral body has slippedanteriorly, with fracture of the zygapophysial joint( Fig. 1-1 ). What is the proper name of this condition?⃣ A. Spondylolysis and spondylolisthesis⃣ B. Spondylolisthesis⃣ C. Crush vertebral fracture⃣ D. Intervertebral disk herniation⃣ E. Klippel-Feil syndrome

Answer 58

A. Spondylolisthesis is an anterior displacementcreated by an irregularity in the anterior marginof the vertebral column such that L5 and theoverlying L4 (and sometimes L3) protrude forward.Spondylolysis is a condition in which the region betweenthe superior and inferior articular facets (onthe posterior arch of the L5 vertebra) is damaged ormissing, which is not the case in this example. Crushvertebral fracture is a collapse of vertebral bodies asa result of trauma. Intervertebral disk herniationsoccur when the nucleus pulposus protrudes throughthe anulus fi brosus into the intervertebral foramenor vertebral canal. The most common protrusion isposterolaterally, where the anulus fi brosus is notreinforced by the posterior longitudinal ligament.Klippel-Feil syndrome results from an abnormalnumber of cervical vertebral bodies.GAS 85-86; GA 21-33

Question 59

A 40-year-old woman survived a car crash inwhich her neck was hyperextended when her vehiclewas struck from behind. At the emergency depart-BACK9ment a plain radiograph of her cervical spine revealeda fracture of the odontoid process (dens). Which ofthe following was most likely injured?⃣ A. Anterior arch of the atlas⃣ B. Posterior tubercle of the atlas⃣ C. Atlanto-occipital joint⃣ D. Inferior articular process of the axis⃣ E. Anterior tubercle of the atlas

Answer 59

A. The odontoid process, or the dens, projectssuperiorly from the body of the axis and articulateswith the anterior arch of the atlas. The posterior andanterior tubercles of the atlas are bony eminences onthe outer surface. The inferior articular facet is wherethe axis joins to the C3 vertebra.GAS 67-74; GA 21-33

Question 60

A 34-year-old woman is admitted to the emergencydepartment after a car crash. Radiographic examinationreveals a whiplash injury in addition tohyperextension of her cervical spine. Which of thefollowing ligaments will most likely be injured?⃣ A. Ligamentum fl avum⃣ B. Anterior longitudinal ligament⃣ C. Posterior longitudinal ligament⃣ D. Anulus fi brosus⃣ E. Interspinous ligament

Answer 60

B. The anterior longitudinal ligament is a strongfi brous band that covers and connects the anterolateralaspect of the vertebrae and intervertebral disks; itmaintains stability and prevents hyperextension. It canbe torn by cervical hyperextension. The ligamentumfl avum helps maintain upright posture by connectingthe laminae of two adjacent vertebrae. The posteriorlongitudinal ligament runs within the vertebral canalsupporting the posterior aspect of the vertebrae andprevents hyperfl exion. The anulus fi brosus is the outerfi brous part of an intervertebral disk. The interspinousligament connects adjacent spinous processes.GAS 82-86; GA 35

Question 61

A 23-year-old college student is admitted to theemergency department after jumping from a 50-footwaterfall. The MRI of his back reveals a lateral shiftof the spinal cord to the left. Which of the followingstructures has most likely been torn to cause thedeviation?⃣ A. Posterior longitudinal ligament⃣ B. Tentorium cerebelli⃣ C. Denticulate ligaments⃣ D. Ligamentum fl avum⃣ E. Nuchal ligament

Answer 61

C. The denticulate ligaments are lateral extensionsof pia mater between the dorsal and ventralroots of the spinal nerves that attach to the dura mater.These ligaments function to keep the spinal cordin the midline position. The posterior longitudinalligament supports the posterior aspect of the vertebraewithin the vertebral canal. The tentorium cerebelliis a layer of dura mater that supports the occipitallobes of the cerebral hemispheres and covers thecerebellum. The ligamentum fl avum helps maintainupright posture by connecting the laminae of twoadjacent vertebrae. The nuchal ligament is a thickeningof the supraspinous ligaments extending from theC7 vertebra to the external occipital protuberance.GAS 101-110; GA 48-49

Question 62

A 6-year-old boy is admitted to the hospital withcoughing and dyspnea. During taking of the history hecomplains that it feels like there is glass in his lungs.Auscultation reveals abnormal lung sounds. The abnormallung sounds are heard most clearly during inhalationwith the scapulae abducted. Which of the followingform the borders of a triangular space where oneshould place the stethoscope in order to best hear thelung sounds?⃣ A. Latissimus dorsi, trapezius, medial border ofscapula⃣ B. Deltoid, levator scapulae, trapezius⃣ C. Latissimus dorsi, external abdominal oblique,iliac crest⃣ D. Quadratus lumborum, internal abdominaloblique, inferior border of the twelfth⃣ E. Rectus abdominis, inguinal ligament, inferiorepigastric vessels

Answer 62

A. The region bounded by the upper border ofthe latissimus dorsi, the lateral border of the trapezius,and the medial border of the scapula is knownas the triangle of auscultation. Lung sounds can be heard most clearly from this location because minimaltissue intervenes between the skin of the backand the lungs. The deltoid, levator scapulae, andtrapezius do not form the borders of the “triangleof auscultation.” The latissimus dorsi, externalabdominal oblique, and iliac crest form the borderof Petit’s inferior lumbar triangle. The quadratuslumborum, internal abdominal oblique, and inferiorborder of the twelfth rib form the border of theGrynfeltt’s superior lumbar triangle. The rectus abdominis,inguinal ligament, and inferior epigastricvessels form the border of the Hesselbach triangle.Petit, Grynfeltt, and Hesselbach triangles are commonsites for hernias.GAS 80-94; GA 37, 141

Question 63

A 45-year-old woman is admitted to the outpatientclinic for shoulder pain. During physical examinationshe presents with weakened shoulder movements.Radiographic examination reveals quadrangular spacesyndrome, causing weakened shoulder movements.Which of the following nerves is most likely affected?⃣ A. Suprascapular⃣ B. Subscapular⃣ C. Axillary⃣ D. Radial⃣ E. Ulnar

Answer 63

C. The weakness in shoulder movement resultsfrom denervation of the teres minor and deltoid bythe axillary nerve, which passes through the quadrangularspace. Quadrangular space syndrome happenswhen there is hypertrophy of the muscles that borderthe quadrangular space or fi brosis of portions of themuscles that are in contact with the nerve.GAS 680-682; GA 362-366, 378

Question 64

A 29-year-old female elite athlete was liftingheavy weights during an intense training session. Theathlete felt severe pain radiate suddenly to the posterioraspect of her right thigh and leg. The patient was takento the hospital where an MRI was performed ( Fig. 1-2 ).Which nerve was most probably affected?⃣ A. L3⃣ B. L4⃣ C. L2⃣ D. L5⃣ E. S1

Answer 64

D. In this MRI a posterolateral herniation betweenL4/L5 exists. In the lumbar region, spinalnerves exit the vertebral column below their namedvertebrae. In an L4/L5 intervertebral disk herniation,the L5 spinal nerve would be affected as it descendsbetween L4/L5 vertebrae to exit below the L5 level.GAS 108-110; GA 32-33, 44

Question 65

A 58-year-old male in the intensive care wardexhibited little voluntary control of urinary or fecalactivity following a transplant procedure of his leftkidney. In addition, physical examination revealedwidespread paralysis of his lower limbs. These functionswere essentially normal prior to admission toFig. 1-2BACK10the hospital. The most likely cause of this patient’sproblems is which of the following?⃣ A. Injury to the left vertebral artery⃣ B. Injury of the great radicular artery(of Adamkiewicz)⃣ C. Ligation of the posterior spinal artery⃣ D. Transection of the conal segment of the spinalcord⃣ E. Division of the thoracic sympathetic chain

Answer 65

B. The (great radicular) artery of Adamkiewicz isimportant for blood supply to anterior and posteriorspinal arteries. The location of this artery should benoted during surgery because damage to it can resultin dire consequences, including loss of all sensationand voluntary movement inferior and at the level ofthe injury. Injury to the left vertebral artery would notbe likely due its superior location to the surgical site.Ligation of the posterior spinal artery would not occurbecause of its protected location inside the spinal column.Transection of the conus medullaris of the spinalcord would not occur as this structure is located at L1,L2 levels and is, again, protected inside the spinal column.Division of the thoracic sympathetic chain wouldnot be likely as the symptoms described include limbparalysis, which would not be a consequence of sympatheticdisruption.GAS 102-103; GA 46

Question 66

A 23-year-old woman is admitted to the hospitaldue to back pain. Radiographic examination revealsthat she suffers from a clinical condition affecting hervertebral column. Physical examination and historytaking reveals that she suffered from polio and a musculardystrophy. Which of the following conditions ofthe vertebral column will most likely be present in thispatient?⃣ A. Lordosis⃣ B. Kyphosis⃣ C. Scoliosis⃣ D. Spina bifi da⃣ E. Osteoarthritis

Answer 66

C. Scoliosis can be a secondary condition insuch disorders as muscular dystrophy and polio inwhich abnormal muscle does not keep the vertebralcolumn’s normal alignment and results in a lateralcurvature. Lordosis is increased secondary curvatureof the lumbar region. It can be caused by stress on thelower back and is quite common in pregnancy. Kyphosisis increased primary curvature of the thoracicregions and produces a hunchback deformity. It canbe secondary to tuberculosis, producing a “gibbusdeformity,” which results in angulated kyphosis at thelesion site. Spina bifi da is a congenital defect andwould not present as a result of muscular dystrophyor polio. Osteoarthritis most commonly presents withage from normal “wear and tear.” It is not likely in a23-year-old woman.GAS 77-79; GA 21-30

Question 67

A 65-year-old patient complains of severe, chronicpain from the region of her right hip. The patient isadmitted to the hospital and a decision is made to performsurgery to avoid prescribing excessive pain medication.In such a case, which would the surgeon mostlikely choose to perform?⃣ A. Division of the ventral primary rami of nervessupplying the affected region⃣ B. Transection of all dorsal primary rami ofnerves from the hip area⃣ C. Removal of abdominal sympathetic chain gangliaon the right side⃣ D. Transection of the dorsal rootlets of spinalnerves supplying the right hip⃣ E. Division of lower lumbar and sacral ventralrootlets

Answer 67

B. Transection of all dorsal rootlets of the nervesfrom the hip area is also known as a dorsal rhizotomy.This type of surgical procedure is performed to eliminatepain sensation from whichever dermatome levelis transected. Because dorsal rootlets contain generalsensory afferent fi bers, cutting these would eliminatesensation and thus pain. Division of the ventral primaryrami might result in pain elimination; however,because the fi bers in ventral rootlets are mixed, therewould also be adverse consequences such as motorand sympathetic and even parasympathetic defi citsdepending on the level. Removal of abdominal sympatheticchain ganglia on the right side would noteliminate pain in the hip area since the fi bers for thissensation are general somatic afferents and the sympatheticchain contains general visceral efferents andafferents. Transection of dorsal primary rami of spinalnerves would not eliminate pain in the hip becausethe dorsal rootlets contain mixed fi bers that supplyonly a limited area on the back. Division of lowerlumbar and sacral ventral rootlets would not eliminatepain sensation since these rootlets contain efferentmotor fi bers and no afferents.GAS 36-39, 107-110; GA 45