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Surgical Anatomy & Approaches MCQs

Practice Set 18 of 102

This practice set contains high-yield board review questions covering key concepts in Surgical Anatomy & Approaches. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 341

Topic: Surgical Anatomy & Approaches

Figures A-C are images of a 37-year-old man who presents with isolated muscle atrophy due to a compressed nerve. Which of the following sequences correctly describes the pathway of this nerve through the brachial plexus, before it innervates the affected muscles?

. C5-C7 nerve roots; upper/middle trunks; anterior division; lateral cord
. C5-C6 nerve roots; upper trunk; posterior division; posterior cord
. C5-C6 nerve roots; upper trunk
. C5-C7 nerve roots
. C8-T1 nerve root; lower trunk; anterior division; medial cord

Correct Answer & Explanation

. C5-C6 nerve roots; upper trunk; posterior division; posterior cord

Explanation

Figures A-C shows atrophy of teres minor and deltoid due to compression of the axillary nerve. The correct pathway of the axillary nerve within the brachial plexus is, C5-C6 nerve roots; upper trunk, posterior division, posterior cord.Quadrilateral space syndrome is a condition defined by axillary nerve, +/- posterior humeral circumflex artery compression in the quadrilateral space. It most commonly affects the dominant shoulder in overhead movement athletes (e.g. basketball players) or other throwing athletes. Physical examination may reveal weakness with the arm positioned in abduction and external rotation. In situations of long-standing compression, there may also be atrophy of the teres minor and deltoid muscle.Chafik et al. dissected thirty-one cadaveric human shoulders to describe the neuromuscular anatomy of teres minor. They showed that the primary nerve branch to teres minor travelled in a fascial sling 44 mm medial to the muscular insertion. Thisarea may be the potential site of greatest compression and tethering of this nerve in patients with isolated teres minor atrophy.Friend et al. performed a cadaveric dissection of nine shoulder specimens to look at the anatomical variability in course, length and branching pattern of both the teres minor nerve and the axillary nerve. These were compared to a case-based study of these two male patients with isolated atrophy of teres minor. They concluded that there is no good anatomical predictor of nerve compression outside the quadrilateral space as there is considerable anatomical variation in its origin and course, as well as potential site of compression.Figure A-C are MRI images that show atrophy of the teres minor muscle and possibly deltoid muscle. The rotator cuff muscles are labeled in Illustration A. The teres minor muscle is labeled in Illustration B. Illustration C shows a diagram of the brachial plexus.Incorrect1:Thisdescribesthemusculocutaneousnerve.3:Thisdescribesthesuprascapularnerve.4:Thisdescribesthelong thoracicnerve.

Question 342

Topic: Surgical Anatomy & Approaches
A 32-year-old man presents to the emergency department with a humeral shaft fracture. He has wrist drop as well as impaired finger and thumb extension. Which motor function would be expected to recover last?
. Elbow extension
. Forearm supination
. Wrist extension in radial deviation
. Middle finger MCP extension
. Index finger MCP hyperextension

Correct Answer & Explanation

. Index finger MCP hyperextension

Explanation

DISCUSSION: The patient is presenting with radial nerve palsy secondary to his humerus fracture. Motor recovery proceeds in a proximal to distal direction. Abrams et al detailed the order of innervation of the radial nerve and found the following order (proximal to distal): brachioradialis, extensor carpi radialis longus, supinator, extensor carpi radialis brevis, extensor digitorum communis, extensor carpi ulnaris, extensor digiti quinti, abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis, and extensor indicis proprius. Branovacki et al found a slightly different pattern: brachioradialis, extensor carpi radialis longus, superficial sensory, extensor carpi radialis brevis, supinator, extensor digitorum/extensor carpi ulnaris, extensor digiti minimi, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus and extensor indicis proprius. While both extensor digitorum and extensor indicis proprius extend the index finger MCP joint, only extensor indicis proprius hyperextends the index finger past neutral.

Question 343

Topic: Surgical Anatomy & Approaches
Which nerve root contributes to both the sciatic and femoral nerves?
. L2
. L3
. L4
. L5

Correct Answer & Explanation

. L4

Explanation

DISCUSSION: The lumbosacral plexus is formed from the lumbar and sacral roots that are redistributed into the obturator, femoral, and sciatic nerves. The obturator nerve is composed of the L1, L2, and L3 roots. The femoral nerve has contributions from the L3 and L4 roots. The sciatic nerve contains the L4, L5, S1, and lower sacral roots. Therefore, only the L4 root contributes to the femoral and sciatic (via the lumbosacral trunk) nerves, which allows it to innervate the quadriceps and the anterior tibialis muscles.

Question 344

Topic: Surgical Anatomy & Approaches
Which structure is indicated by the arrow in Figure 33?
. Corona mortis
. Tibial division, sciatic nerve
. Sciatic nerve, peroneal division
. Fifth lumbar nerve root
. Kocher-Langenbeck approach
. Stoppa approach
. Obturator vessels
. L4 nerve root

Correct Answer & Explanation

. Fifth lumbar nerve root

Explanation

The L5 nerve root is located on the anterior sacrum and is indicated by the arrow. The position of this neural structure must be considered whether the surgeon is stabilizing the sacroiliac (SI) joint with percutaneous iliosacral screws or with anterior SI plating through the lateral window of the ilioinguinal approach. The posterior position of the sciatic nerve in relation to the acetabulum and the lateral peroneal division makes the peroneal division of the sciatic nerve the portion of the nerve that is most likely to be injured in a posterior traumatic hip dislocation.

Question 345

Topic: Surgical Anatomy & Approaches
Spontaneous entrapment of the posterior interosseous nerve most commonly occurs in which of the following locations?
. Lateral intermuscular septum
. Extensor carpi radialis brevis
. Arcade of Frohse
. Midsubstance of the supinator
. Leash of Henry

Correct Answer & Explanation

. Arcade of Frohse

Explanation

The extensor carpi radialis brevis, supinator muscle, arcade of Frohse, and leash of Henry are potential sites of compression for the posterior interosseous nerve. The most common location of spontaneous entrapment is the arcade of Frohse. The lateral intermuscular septum is a site of compression for the radial nerve.

Question 346

Topic: Surgical Anatomy & Approaches

A 65-year-old woman with rheumatoid arthritis is unable to actively extend her index, middle, ring, and little fingers secondary to tendon rupture. In performing a flexor digitorum sublimis (FDS) of the middle/ring finger to extensor digitorum communis (EDC) transfer to restore active metacarpophalangeal (MCP) joint extension, the FDS should be passed

. ulnarly, around the ulna in a dorsal direction.
. radially, around the radius in a dorsal direction.
. through the interosseous membrane.
. through the intermetacarpal spaces between the index, middle, ring, and little fingers.
. through the lumbrical canals of the index, middle, ring, and little fingers.

Correct Answer & Explanation

. ulnarly, around the ulna in a dorsal direction.

Explanation

Although the early use of FDS as a transfer to restore finger extension in patients with radial nerve palsy was performed by passing the tendon through the interosseous membrane, Nalebuff and Patel later modified this procedure for the rheumatoid arthritis patient by passing the FDS radially, around the radius in a dorsal direction. They felt that this provided a number of advantages, including: 1. technical ease, 2. avoidance of synovial disease on the dorsum of the wrist, and 3. correction of ulnar deviation of the fingers through the line of pull from the radial side of the forearm.

Question 347

Topic: Surgical Anatomy & Approaches
Which of the following drawbacks is associated with the Ganz periacetabular osteotomy?
. The tendency to anterior displacement of the hip joint
. The need for two incisions
. Limited potential for acetabular reorientation
. Posterior column disruption
. Devascularization of the acetabulum

Correct Answer & Explanation

. The tendency to anterior displacement of the hip joint

Explanation

Although technically challenging, the Ganz periacetabular osteotomy offers advantages over other rotational pelvic osteotomies. Posterior column integrity is maintained, as is the acetabular vascular supply. Free mobility of the fragment makes large corrections in the center edge angle possible. Because of the asymmetric cuts and the need to restore anterior coverage, there is a tendency to anterior displacement of the joint while flexing the acetabulum. The procedure is commonly performed through a Smith-Petersen incision.

Question 348

Topic: Surgical Anatomy & Approaches
The anterolateral (Watson-Jones) approach to the hip exploits the intermuscular interval between the
. gluteus medius and tensor fascia lata.
. gluteus medius and minimus.
. gluteus medius and maximus.
. gluteus minimus and piriformis.
. tensor fascia lata and sartorius.

Correct Answer & Explanation

. gluteus medius and tensor fascia lata.

Explanation

The Watson-Jones approach to the hip uses the intermuscular interval between the gluteus medius and the tensor fascia lata. This is not a true internervous plane, as both muscles are supplied by the superior gluteal nerve.

Question 349

Topic: Surgical Anatomy & Approaches
A 25-year-old woman undergoes surgical treatment of a displaced proximal humeral fracture via a deltopectoral approach. At the first postoperative visit, she reports a tingling numbness along the anterolateral aspect of the forearm. What structure is most likely injured?
. Medial cord of the brachial plexus
. Radial nerve
. Median nerve
. Axillary nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Musculocutaneous nerve

Explanation

DISCUSSION: Sensation along the anterolateral aspect of the forearm is supplied by the lateral antebrachial cutaneous nerve, the terminal branch of the musculocutaneous nerve. The musculocutaneous nerve can be injured by proximal humeral fractures or dislocations, and is also at risk during surgical exposure if excessive retraction is placed on the conjoint tendon.

Question 350

Topic: Surgical Anatomy & Approaches

A 35-year-old male sustains a posterior hip dislocation with an associated Pipkin type II femoral head fracture. Following an urgent closed reduction, a post-reduction CT scan demonstrates a 3 mm step-off of the femoral head fragment without intra-articular loose bodies in the acetabular fossa. Which of the following is the most appropriate surgical approach for open reduction and internal fixation of this fracture?

. Kocher-Langenbeck approach
. Smith-Petersen (anterior) approach or surgical hip dislocation
. Ilioinguinal approach
. Stoppa approach
. Direct lateral (Hardinge) approach

Correct Answer & Explanation

. Smith-Petersen (anterior) approach or surgical hip dislocation

Explanation

A Pipkin type II fracture is a femoral head fracture extending superior to the fovea capitis (weight-bearing portion). Because the posterior blood supply (medial circumflex femoral artery) is already at risk from the posterior dislocation, an anterior approach (Smith-Petersen) or a trochanteric flip / surgical hip dislocation is preferred. A Kocher-Langenbeck (posterior) approach requires further dissection of the critical posterior soft tissues and jeopardizes the remaining blood supply to the femoral head.

Question 351

Topic: Surgical Anatomy & Approaches

During an ilioinguinal approach for the internal fixation of an anterior column acetabular fracture, massive hemorrhage occurs upon dissection over the superior pubic ramus, approximately 5 cm lateral to the pubic symphysis. This bleeding is most likely originating from the 'corona mortis'. What two vascular systems does this structure anastomose?

. Internal pudendal artery and the superficial epigastric artery
. Obturator system and the external iliac or inferior epigastric system
. Superior gluteal artery and the internal iliac artery
. Inferior gluteal artery and the lateral sacral artery
. Deep circumflex iliac artery and the femoral artery

Correct Answer & Explanation

. Internal pudendal artery and the superficial epigastric artery

Explanation

The 'corona mortis' (crown of death) is an anatomical variant defined as a vascular anastomosis between the obturator vessels (branching from the internal iliac system) and the external iliac or inferior epigastric vessels. It lies on the posterior aspect of the superior pubic ramus, typically 4 to 6 cm from the symphysis pubis, and is at high risk of iatrogenic injury during anterior pelvic approaches.

Question 352

Topic: Surgical Anatomy & Approaches

A 28-year-old patient sustains a posterior fracture-dislocation of the hip in a high-speed motor vehicle collision. Following closed reduction, neurologic examination reveals an inability to actively dorsiflex the ankle or extend the great toe, while plantar flexion remains fully intact. Which specific nerve structure has been injured?

. Femoral nerve
. Tibial division of the sciatic nerve
. Peroneal division of the sciatic nerve
. Superior gluteal nerve
. Obturator nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

The peroneal (fibular) division of the sciatic nerve is located laterally and is more securely tethered than the tibial division. This anatomy makes it highly susceptible to stretch or contusion injuries during a posterior dislocation of the hip, manifesting as a foot drop.

Question 353

Topic: Surgical Anatomy & Approaches
In a retroperitoneal approach to the lumbar spine, what structure runs along the medial aspect of the psoas and along the lateral border of the spine?
. Ilioinguinal nerve
. Genitofemoral nerve
. Sympathetic trunk
. Ureter
. Aorta

Correct Answer & Explanation

. Sympathetic trunk

Explanation

The sympathetic trunk runs longitudinally along the medial border of the psoas. The ilioinguinal nerve emerges along the upper lateral border of the psoas and travels to the quadratus lumborum, and the genitofemoral nerve lies more laterally on the psoas. The ureter is adherent to the posterior peritoneum and falls away from the psoas and the spine in the dissection, as does the aorta.

Question 354

Topic: Surgical Anatomy & Approaches

A 25-year old right-hand dominant professional baseball pitcher complains of posteromedial right elbow pain that is worsened by throwing. He also reports occasional paresthesias in his small and ring finger after lengthy bullpen sessions. On examination, he is tender along the medial olecranon and complains of pain when extending the elbow >- 20° of extension. He has negative valgus stress, moving valgus stress, and milking maneuver tests. He is stable to varus stress, chair rise, and lateral pivot shift tests. Radiographs reveal a small osteophyte along the posteromedial  border  of   the   olecranon.  What   is   the   most   likely diagnosis?

. Valgus extension overload
. Varus posteromedial rotatory instability (VPMRI) C. Valgus posterolateral rotatory instability (VPLRI) D. Olecranon bursitisThe patient has valgus extension overload. This is a spectrum of pathologies, often seen in pitchers, that begins with posteromedial impingement between the medial olecranon and posterior trochlea during forceful elbow extension. As a result, a medial olecranon osteophyte is typically the first notable imaging finding. As pathology increases, there can be progressive damage to the medial collateral ligament (MCL), degeneration of the radiocapitellar articulation, and neuritis of the ulnar nerve. VPMRI is often associated with a large anteromedial coronoid fracture and posterior band MCL rupture. VPLRI occurs when the lateral collateral ligament complex is ruptured. Olecranon bursitis presents with focal swelling or a fluid collection over the posterior aspect of the olecranon.

Correct Answer & Explanation

. Valgus extension overload

Explanation

A patient sustains a displaced diaphyseal humerus fracture following a motor vehicle accident. Open reduction internal fixation is indicated due to concomitant lower extremity trauma and is planned through an anterior approach. Which intramuscular interval is exploited during the deep dissection of the mid-humerus in this approach?A.   Lateral head of triceps (radial nerve) and brachialis(musculocutaneous nerve)B.   Lateral head of the triceps (radial nerve) and biceps brachii(musculocutaneous nerve)C.   Lateral brachialis (radial nerve) and medial brachialis(musculocutaneous nerve)D.   Brachialis (musculocutaneous nerve) and coracobrachialis(musculocutaneous nerve)

Question 355

Topic: Surgical Anatomy & Approaches
  • Figures 42a and 42b show the sagittal and axial MRI scans of a 24-year-old patient who has sciatia. Which of the following combinations of physical findings is most consistent wit the MRI studies?
. Decreased ankle jerk and positive femoral nerve stretch test
. Decreased knee jerk and positive straight-leg raising sign
. Gastrocnemius-soleus complex weakness and positive straight-leg raising sign
. Weakness of the extensor hallucis longus and positive straight-leg raising sign
. Weakness of the extensor hallucis longus and positive femoral nerve stretch test

Correct Answer & Explanation

. Decreased ankle jerk and positive femoral nerve stretch test

Explanation

Figures 42a and 42b show a posterocentral disc herniation between L5 and S1 and will affect the S1 nerve root. This will cause sensory changes in the posterior calf and plantar foot, motor loss in the gastrocnemius/soleus complex, reflex changes in the ankle jerk, and a positive straight leg raise sign. A positive femoral nerve stretch test may indicate L2, L3, or L4 nerve root irritation. EHL function is mainly L5.

Question 356

Topic: Surgical Anatomy & Approaches

Figure 25 shows an arthroscopic thermal capsular shrinkage device being used in the anterior inferior quadrant of a patient with a subluxating shoulder. Which of the following neurologic complications is most frequently reported with this technique?

. Axillary nerve dysesthesia
. Axillary nerve motor partial paralysis
. Suprascapular nerve neurapraxia
. Musculocutaneous nerve neurapraxia
. Radial nerve sensory dysesthesia

Correct Answer & Explanation

. Axillary nerve dysesthesia

Explanation

DISCUSSION: The axillary nerve lies within millimeters of the anterior inferior capsule.  The inferior capsule is of varying thickness, and thermal energy used in shortening the ligament can cause damage to the sensory fibers of the axillary nerve.  Clinically, this is manifested as a burnt skin sensation in the axillary nerve distribution area.  The motor branch of the axillary nerve is usually spared.  The suprascapular nerve and the radial nerve are far from the shrinkage zone.  The musculocutaneous nerve, frequently at risk with open procedures, lies well anterior.REFERENCES: Fanton GS: Arthroscopic electrothermal surgery of the shoulder.  Op Tech Sports Med  1998;6:157-160.David TS, Drez DJ Jr: Electrothermally-assisted capsular shift.  IEEE Eng Med Biol Mag 1998;17:102-104.

Question 357

Topic: Surgical Anatomy & Approaches

-Which treatment approach for acetabular fractures carries the highest risk for heterotopic ossification?

. Ilioinguinal
. Watson-Jones
. Extended iliofemoral
. Extended ilioinguinal
. Modified Rives-Stoppa

Correct Answer & Explanation

. Ilioinguinal

Explanation

Question 358

Topic: Surgical Anatomy & Approaches

A 35-year-old man has a brachial plexus injury affecting the lateral cord. He partially improves with observation and now has complete return of median nerve function and pectoral muscle function. What nerve transfer is most likely to restore the motor function he is lacking?

. Median and ulnar fascicles to musculocutaneous nerve transfer
. Medial triceps branch to axillary nerve transfer
. ntercostal nerve to triceps branch of radial nerve transfer
. Anterior interosseous nerve (AIN) to ulnar motor transfer

Correct Answer & Explanation

. Median and ulnar fascicles to musculocutaneous nerve transfer

Explanation

EXPLANATION:The lateral cord of the brachial plexus gives off the lateral pectoral nerve, the musculocutaneous nerve, and then contributes to the median nerve. The patient has had recovery of function of these components except for the musculocutaneous nerve. The musculocutaneous nerve innervates the biceps and the brachialis, which provide elbow flexion. To restore motor function, a nerve transfer would have to providereinnervation of the biceps and brachialis.

Question 359

Topic: Surgical Anatomy & Approaches

The most appropriate surgical approach includes which of the following? Review Topic

. Anterior approach of Henry
. Lateral Kocher approach
. Medial column approach
. Posterior extensile elbow approach with olecranon chevron osteotomy
. Closed reduction and percutaneous screw fixation

Correct Answer & Explanation

. Posterior extensile elbow approach with olecranon chevron osteotomy

Explanation

Intra-articular distal humerus fractures are best approached through a posterior elbow approach, including an olecranon chevron osteotomy to clearly visualize the reduction of the articular surface. The other stated approaches will not provide sufficient visualization of the joint surface to allow stable reduction. A closed reduction and screw fixation will not offer optimal fracture stability.

Question 360

Topic: Surgical Anatomy & Approaches

Which of the following is associated with increased fetal morbidity and mortality in acetabular fractures during pregnancy?

. Fetal position
. Surgical approach
. Mechanism of injury
. Fracture classification
. Trimester of pregnancy

Correct Answer & Explanation

. Mechanism of injury

Explanation

Fixation of pelvic and acetabular fractures in pregnancy is not contraindicated. However, both maternal and fetal morbidity and mortality is increased in this patient subset. Factors shown to be associated with increased fetal mortality include: injury severity, mechanism of injury, and maternal hemorrhage. Surgical approach, fracture classification, fetal position, and the trimester of pregnancy have not been shown to affect fetal morbidity or mortality.

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