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1. General Principles & Basic Science MCQs

Practice Set 626 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 12501

Topic: 1. General Principles & Basic Science

A 29-year-old bodybuilder feels a pop in his anterior axilla while bench pressing. Examination reveals a loss of the anterior axillary fold. MRI confirms a rupture of the pectoralis major at the sternocostal head insertion. Where does the sternocostal head insert relative to the clavicular head on the humerus?

. Proximal and anterior
. Proximal and posterior
. Distal and anterior
. Distal and posterior
. Directly medial

Correct Answer & Explanation

. Distal and posterior

Explanation

The pectoralis major tendon twists 180 degrees before inserting on the lateral lip of the bicipital groove. The sternocostal head inserts deep (posterior) and distal to the clavicular head, making it the most vulnerable during eccentric loading.

Question 12502

Topic: Surgical Anatomy & Approaches

During an anterior intrapelvic (ilioinguinal or Stoppa) approach to the acetabulum, the surgeon encounters significant bleeding over the superior pubic ramus. This bleeding is most likely originating from an anastomosis between which two vessels?

. External iliac artery and internal pudendal artery
. Internal iliac artery and superior gluteal artery
. Inferior epigastric artery and obturator artery
. Pudendal artery and inferior epigastric artery
. External iliac vein and internal pudendal vein

Correct Answer & Explanation

. Inferior epigastric artery and obturator artery

Explanation

The corona mortis is a critical vascular anastomosis between the external iliac system (inferior epigastric vessels) and the internal iliac system (obturator vessels) located over the superior pubic ramus, approximately 5-7 cm from the pubic symphysis. It can cause severe bleeding if lacerated during pelvic surgery.

Question 12503

Topic: Surgical Anatomy & Approaches

The anterior (Henry) approach to the radius utilizes an internervous plane. Proximally, this plane runs between muscles supplied by which two nerves?

. Median nerve and Radial nerve
. Median nerve and Ulnar nerve
. Radial nerve and Musculocutaneous nerve
. Axillary nerve and Radial nerve
. Ulnar nerve and Radial nerve

Correct Answer & Explanation

. Median nerve and Ulnar nerve

Explanation

The volar (Henry) approach to the radius utilizes the internervous plane between the brachioradialis (innervated by the radial nerve) and the pronator teres (proximally) or flexor carpi radialis (distally), both of which are innervated by the median nerve.

Question 12504

Topic: Surgical Anatomy & Approaches

The axillary nerve and posterior circumflex humeral artery exit the axilla through the quadrangular space. What forms the inferior border of this space?

. Teres minor
. Teres major
. Long head of the triceps
. Surgical neck of the humerus
. Subscapularis

Correct Answer & Explanation

. Surgical neck of the humerus

Explanation

The borders of the quadrangular space are: superiorly the teres minor (or subscapularis when viewed anteriorly), inferiorly the teres major, medially the long head of the triceps, and laterally the surgical neck of the humerus. It transmits the axillary nerve and posterior circumflex humeral artery.

Question 12505

Topic: Surgical Anatomy & Approaches

In piriformis syndrome, variations in the relationship between the sciatic nerve and the piriformis muscle are often cited. What is the most common anatomical relationship between these two structures?

. The entire nerve passes deep (anterior) to the piriformis.
. The common peroneal nerve pierces the piriformis while the tibial nerve passes deep.
. The entire nerve pierces the piriformis.
. The common peroneal nerve passes superficial to the piriformis while the tibial nerve passes deep.
. The entire nerve passes superficial (posterior) to the piriformis.

Correct Answer & Explanation

. The entire nerve passes deep (anterior) to the piriformis.

Explanation

In the most common anatomical configuration (Beaton and Anson Type 1, present in ~80-85% of people), the undivided sciatic nerve passes deep (anterior and inferior) to the piriformis muscle. The second most common variant involves the common peroneal division piercing the muscle.

Question 12506

Topic: 1. General Principles & Basic Science

The medial and lateral menisci have distinct anatomical characteristics. Which of the following statements correctly differentiates them?

. The medial meniscus is more circular and covers more of the articular surface than the lateral meniscus.
. The lateral meniscus is firmly attached to the LCL, whereas the medial meniscus is not attached to the MCL.
. The medial meniscus is wider posteriorly than anteriorly, while the lateral meniscus is relatively uniform in width.
. The lateral meniscus is less mobile than the medial meniscus.
. The meniscofemoral ligaments (Humphry and Wrisberg) typically attach to the posterior horn of the medial meniscus.

Correct Answer & Explanation

. The medial meniscus is wider posteriorly than anteriorly, while the lateral meniscus is relatively uniform in width.

Explanation

The medial meniscus is C-shaped, wider posteriorly than anteriorly, less mobile, and is attached to the deep MCL. The lateral meniscus is more circular, more uniform in width, more mobile, unattached to the LCL (separated by the popliteus), and serves as the attachment site for the meniscofemoral ligaments (Humphry and Wrisberg).

Question 12507

Topic: 1. General Principles & Basic Science

The gluteus medius has multiple footprint insertions on the greater trochanter. Which facet of the greater trochanter serves as the primary, largest broad insertion site for the gluteus medius?

. Anterior facet
. Lateral facet
. Posterior facet
. Superoposterior facet
. Lesser trochanter

Correct Answer & Explanation

. Lateral facet

Explanation

The gluteus medius inserts primarily onto the lateral and superoposterior facets of the greater trochanter. The lateral facet is the largest footprint for the gluteus medius. The gluteus minimus inserts on the anterior facet.

Question 12508

Topic: Surgical Anatomy & Approaches

A patient presents with isolated weakness of the teres minor and deltoid following a posterior shoulder dislocation. The injured nerve passes through a quadrilateral space in the posterior shoulder. Which of the following muscles forms the inferior border of this anatomical space?

. Teres major
. Long head of the triceps
. Lateral head of the triceps
. Subscapularis
. Infraspinatus

Correct Answer & Explanation

. Subscapularis

Explanation

The axillary nerve and posterior circumflex humeral artery pass through the quadrangular space. The borders of the quadrangular space are: superiorly the teres minor (and inferior capsule), inferiorly the teres major, medially the long head of the triceps, and laterally the surgical neck of the humerus.

Question 12509

Topic: Surgical Anatomy & Approaches

During an ilioinguinal approach to the acetabulum, severe hemorrhage is encountered dissecting over the superior pubic ramus near the symphysis. This is most likely due to an inadvertent injury to the 'corona mortis'. This structure represents an anastomosis between which two vascular systems?

. External iliac artery and internal pudendal artery
. External iliac artery and obturator artery
. Internal iliac artery and inferior epigastric artery
. Obturator artery and internal pudendal artery
. Obturator artery and inferior epigastric artery

Correct Answer & Explanation

. External iliac artery and internal pudendal artery

Explanation

The corona mortis ('crown of death') is a vascular anastomosis between the external iliac system (inferior epigastric artery/vein) and the internal iliac system (obturator artery/vein). It crosses the superior pubic ramus and is highly susceptible to injury during the ilioinguinal or Stoppa approaches.

Question 12510

Topic: 1. General Principles & Basic Science

The 'Master Knot of Henry' is a key anatomical landmark in the plantar aspect of the midfoot where two tendons cross. Which of the following accurately describes their spatial relationship at this intersection?

. Flexor hallucis longus crosses dorsal (deep) to the flexor digitorum longus
. Flexor digitorum longus crosses dorsal (deep) to the flexor hallucis longus
. Tibialis posterior crosses dorsal (deep) to the flexor hallucis longus
. Flexor hallucis longus crosses dorsal (deep) to the tibialis posterior
. Flexor digitorum longus crosses dorsal (deep) to the tibialis anterior

Correct Answer & Explanation

. Flexor hallucis longus crosses dorsal (deep) to the flexor digitorum longus

Explanation

At the Master Knot of Henry, located under the navicular/medial cuneiform, the flexor digitorum longus (FDL) tendon crosses superficial (plantar) to the flexor hallucis longus (FHL) tendon. Therefore, the FHL is positioned dorsal (deep) to the FDL at this crossing.

Question 12511

Topic: Surgical Anatomy & Approaches

The Smith-Petersen (anterior) approach to the hip utilizes a true internervous plane. Which of the following describes the innervation of the muscles forming the superficial boundary of this approach?

. Femoral nerve and Superior gluteal nerve
. Femoral nerve and Obturator nerve
. Superior gluteal nerve and Inferior gluteal nerve
. Sciatic nerve and Superior gluteal nerve
. Femoral nerve and Sciatic nerve

Correct Answer & Explanation

. Femoral nerve and Superior gluteal nerve

Explanation

The superficial plane of the Smith-Petersen approach lies between the sartorius (innervated by the femoral nerve) and the tensor fasciae latae (TFL, innervated by the superior gluteal nerve).

Question 12512

Topic: 1. General Principles & Basic Science

The medial femoral circumflex artery (MFCA) provides the predominant blood supply to the adult femoral head. Which specific branch of the MFCA is considered the most critical for the perfusion of the superolateral aspect of the femoral head?

. Ascending branch
. Descending branch
. Transverse branch
. Deep branch (lateral epiphyseal artery)
. Acetabular branch

Correct Answer & Explanation

. Deep branch (lateral epiphyseal artery)

Explanation

The deep branch of the MFCA (which gives rise to the posterosuperior retinacular vessels, also known as the lateral epiphyseal artery) provides the majority of the blood supply to the weight-bearing superolateral dome of the femoral head.

Question 12513

Topic: Surgical Anatomy & Approaches

According to the Beaton and Anson classification of sciatic nerve variants, the normal anatomy (Type A) involves the undivided sciatic nerve exiting below the piriformis muscle. What describes the second most common variant (Type B)?

. Common peroneal nerve passes through the piriformis, while the tibial nerve passes below it
. Common peroneal nerve passes above the piriformis, while the tibial nerve passes below it
. The entire sciatic nerve passes directly through the piriformis belly
. The entire sciatic nerve passes above the piriformis
. The tibial nerve passes through the piriformis, while the common peroneal passes below it

Correct Answer & Explanation

. Common peroneal nerve passes through the piriformis, while the tibial nerve passes below it

Explanation

Type B is the most frequent variant (~10-15% of people), in which the sciatic nerve divides early; the common peroneal branch pierces the piriformis muscle, while the tibial branch exits inferior to the piriformis.

Question 12514

Topic: Surgical Anatomy & Approaches

The anterior (Smith-Petersen) approach to the hip utilizes a true internervous plane. During the deep dissection of this approach, a specific vessel is routinely identified crossing the surgical field and must often be ligated. This vessel is a branch of which of the following arteries?

. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Inferior gluteal artery
. First perforating artery
. Obturator artery

Correct Answer & Explanation

. Lateral femoral circumflex artery

Explanation

The deep internervous plane of the anterior approach to the hip (Smith-Petersen) lies between the rectus femoris (femoral nerve) and the gluteus medius (superior gluteal nerve). The ascending branch of the lateral femoral circumflex artery transverses this plane and must be identified and ligated to prevent excessive hemorrhage.

Question 12515

Topic: Surgical Anatomy & Approaches

During an ilioinguinal approach for an anterior column acetabular fracture, the middle window is accessed. What are the respective lateral and medial borders of this specific surgical window?

. Lateral: Iliopsoas muscle; Medial: External iliac vessels
. Lateral: Iliopectineal fascia; Medial: Rectus abdominis
. Lateral: External iliac vessels; Medial: Spermatic cord
. Lateral: Anterior superior iliac spine; Medial: Iliopsoas muscle
. Lateral: Femoral nerve; Medial: External iliac vessels

Correct Answer & Explanation

. Lateral: Femoral nerve; Medial: External iliac vessels

Explanation

The ilioinguinal approach features three main windows. The lateral window is lateral to the iliopsoas. The middle window is bound laterally by the iliopsoas/femoral nerve and medially by the external iliac vessels. The medial window is bound laterally by the external iliac vessels and medially by the rectus abdominis/spermatic cord.

Question 12516

Topic: Surgical Anatomy & Approaches

The 'corona mortis' is a vascular anastomosis of significant importance during anterior approaches to the pelvis. It connects the obturator vessels with which of the following vascular systems?

. Internal pudendal vessels
. External iliac or inferior epigastric vessels
. Internal iliac vessels
. Superior gluteal vessels
. Deep circumflex iliac vessels

Correct Answer & Explanation

. External iliac or inferior epigastric vessels

Explanation

The corona mortis (crown of death) is an important vascular variant consisting of an anastomosis between the obturator vessels and the external iliac or inferior epigastric vessels. It crosses the superior pubic ramus and must be carefully identified and ligated during pelvic surgery (e.g., ilioinguinal approach) to prevent severe hemorrhage.

Question 12517

Topic: 1. General Principles & Basic Science

Which of the following accurately describes the normal vascular supply of the menisci in the adult human knee?

. The entire meniscus is avascular and receives nutrition purely from synovial fluid
. Only the inner 10-25% (white-white zone) is vascularized by the genicular arteries
. Only the peripheral 10-30% (red-red zone) is vascularized by the superior and inferior genicular arteries
. The middle 50% (red-white zone) contains the highest density of vascularity
. The entire meniscus is richly vascularized directly from the middle genicular artery

Correct Answer & Explanation

. Only the peripheral 10-30% (red-red zone) is vascularized by the superior and inferior genicular arteries

Explanation

In the adult knee, only the peripheral 10% to 30% of the medial and lateral menisci (the 'red-red' zone) is vascularized by a perimeniscal capillary plexus originating from the medial and lateral superior and inferior genicular arteries. The inner portions are avascular and rely entirely on diffusion from synovial fluid for nutrition.

Question 12518

Topic: 1. General Principles & Basic Science

In approximately 10-15% of the general population, an anatomical variant exists wherein a portion of the sciatic nerve pierces the piriformis muscle. Which division of the sciatic nerve is most commonly involved in this piercing variation?

. Tibial division
. Common peroneal division
. Sural division
. Posterior femoral cutaneous division
. Pudendal division

Correct Answer & Explanation

. Common peroneal division

Explanation

According to the Beaton and Anson classification of sciatic nerve variants, the most common variation (aside from the normal anatomy where the entire nerve passes below the piriformis) occurs when the common peroneal division pieces the piriformis muscle, while the tibial division passes underneath it.

Question 12519

Topic: Surgical Anatomy & Approaches

During a deltopectoral approach to the shoulder, the axillary nerve is at risk as it exits the axilla. What is its correct anatomical course relative to the quadrangular space?

. It runs anterior to the subscapularis muscle.
. It exits posteriorly accompanied by the posterior circumflex humeral artery.
. It pierces the clavipectoral fascia medial to the short head of the biceps.
. It passes through the triangular interval with the profunda brachii artery.
. It travels superior to the teres minor muscle.

Correct Answer & Explanation

. It exits posteriorly accompanied by the posterior circumflex humeral artery.

Explanation

The axillary nerve exits the axilla posteriorly via the quadrangular space. It courses inferior to the capsule of the shoulder joint and posterior to the surgical neck of the humerus, accompanied by the posterior circumflex humeral artery.

Question 12520

Topic: Surgical Anatomy & Approaches

A surgeon is performing a posterior approach to the humeral shaft for open reduction internal fixation. On average, at what distance proximal to the radiocapitellar joint does the radial nerve cross the lateral intermuscular septum to enter the anterior compartment?

. 5 cm
. 10 cm
. 15 cm
. 20 cm
. 25 cm

Correct Answer & Explanation

. 10 cm

Explanation

The radial nerve travels in the spiral groove and pierces the lateral intermuscular septum to enter the anterior compartment approximately 10 cm proximal to the radiocapitellar joint (or lateral epicondyle).

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