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1. General Principles & Basic Science MCQs

Practice Set 7 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 121

Topic: Physiology & Rehabilitation

Peak patellofemoral joint reaction forces during normal gait occur at which phase?

. Initial contact
. Mid-stance
. Terminal stance
. Pre-swing
. Initial swing

Correct Answer & Explanation

. Mid-stance

Explanation

Peak patellofemoral joint reaction forces occur during the early mid-stance phase of gait. This correlates with the point of maximum knee flexion (around 15-20 degrees) during the weight-bearing phase.

Question 122

Topic: 1. General Principles & Basic Science

Which of the following arteries is considered the principal blood supply to the articular segment of the humeral head?

. Posterior humeral circumflex artery
. Anterior humeral circumflex artery
. Suprascapular artery
. Thoracoacromial artery
. Subscapular artery

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

Recent microvascular studies demonstrate that the posterior humeral circumflex artery provides approximately 64% of the blood supply to the humeral head. This contradicts older literature that primarily credited the anterior humeral circumflex artery.

Question 123

Topic: 1. General Principles & Basic Science

What is the primary difference in the vascularity of the medial and lateral menisci in an adult?

. The medial meniscus is fully vascularized while the lateral is avascular
. The lateral meniscus receives its blood supply from the popliteal artery while the medial from the femoral artery
. The peripheral 10-30% of both menisci are vascularized via the perimeniscal capillary plexus
. The inner third of both menisci has the richest blood supply
. There is no difference as both are completely avascular in adults

Correct Answer & Explanation

. The peripheral 10-30% of both menisci are vascularized via the perimeniscal capillary plexus

Explanation

In adults, only the peripheral 10% to 30% of both menisci (the red-red zone) receives vascularity. This supply comes from the perimeniscal capillary plexus derived from the medial and lateral genicular arteries.

Question 124

Topic: 1. General Principles & Basic Science

The artery of the ligamentum teres is a branch of which of the following arteries?

. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Obturator artery
. Superior gluteal artery
. Inferior gluteal artery

Correct Answer & Explanation

. Obturator artery

Explanation

The artery of the ligamentum teres is typically a branch of the posterior division of the obturator artery. Its contribution to the femoral head blood supply is minimal in adults but can be important in children.

Question 125

Topic: 1. General Principles & Basic Science

Which annular pulleys are most critical to preserve during flexor tendon surgery to prevent bowstringing?

. A1 and A3
. A2 and A4
. A1 and A5
. A3 and A5
. A2 and A3

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 and A4 pulleys arise directly from the periosteum of the proximal and middle phalanges, respectively. They are the most biomechanically crucial pulleys for preventing flexor tendon bowstringing.

Question 126

Topic: 1. General Principles & Basic Science

According to static biomechanical models of the hip during single-leg stance, the ratio of the force generated by the hip abductors to body weight is approximately:

. 0.5 to 1
. 1 to 1
. 2.5 to 1
. 4 to 1
. 6 to 1

Correct Answer & Explanation

. 2.5 to 1

Explanation

During single-leg stance, the hip abductors must generate a force approximately 2.5 times body weight to balance the pelvis. This results in a total joint reaction force across the hip of about 3 to 4 times body weight.

Question 127

Topic: 1. General Principles & Basic Science

Tendons are primarily composed of type I collagen. Which of the following proteoglycans is most abundant in the tensile-bearing regions of normal tendons?

. Aggrecan
. Decorin
. Biglycan
. Versican
. Lumican

Correct Answer & Explanation

. Decorin

Explanation

Decorin is the predominant small leucine-rich proteoglycan (SLRP) found in the tensile-bearing regions of normal tendons. It plays a key role in regulating collagen fibrillogenesis and directly binds to type I collagen.

Question 128

Topic: 1. General Principles & Basic Science
The medial plantar nerve provides motor innervation to all of the following muscles EXCEPT the:
. Abductor hallucis
. Flexor digitorum brevis
. Flexor hallucis brevis
. First lumbrical
. Adductor hallucis

Correct Answer & Explanation

. Adductor hallucis

Explanation

The adductor hallucis is innervated by the deep branch of the lateral plantar nerve. The medial plantar nerve reliably innervates the abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, and the first lumbrical.

Question 129

Topic: Biology, Genetics & Bone Healing

Following a diaphyseal fracture treated with rigid plate fixation (absolute stability), healing primarily occurs via which of the following mechanisms?

. Endochondral ossification
. Intramembranous ossification
. Haversian remodeling (cutting cones)
. Callus formation
. Fibrous tissue differentiation

Correct Answer & Explanation

. Haversian remodeling (cutting cones)

Explanation

Rigid plate fixation provides absolute stability, minimizing interfragmentary strain to near zero. This leads to primary bone healing via direct Haversian remodeling (cutting cones) without an intermediate cartilage phase or visible callus.

Question 130

Topic: Surgical Anatomy & Approaches

Which of the following structures forms the superior border of the quadrangular space, through which the axillary nerve and posterior circumflex humeral artery pass?

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

Correct Answer & Explanation

. Teres minor

Explanation

The quadrangular space is bordered superiorly by the teres minor, inferiorly by the teres major, medially by the long head of the triceps, and laterally by the surgical neck of the humerus.

Question 131

Topic: 1. General Principles & Basic Science

Regarding the menisci of the knee, which of the following statements most accurately describes their vascular supply and intrinsic healing potential?

. The entire meniscus receives blood supply from the middle genicular artery
. Only the inner avascular zone is capable of robust healing after surgical repair
. The peripheral 10-30% is vascularized by branches of the superior and inferior genicular arteries
. The lateral meniscus has a greater blood supply than the medial meniscus
. The popliteal artery directly supplies the anterior horns of both menisci

Correct Answer & Explanation

. The entire meniscus receives blood supply from the middle genicular artery

Explanation

The peripheral 10-30% of the menisci (red-red zone) is vascularized by the perimeniscal capillary plexus originating from the medial and lateral genicular arteries. This zone has the greatest potential for healing following a meniscal repair.

Question 132

Topic: Infection, Pharmacology & VTE

The medial collateral ligament (MCL) of the knee consists of superficial and deep layers. The superficial MCL is the primary restraint to valgus stress. Where is its primary tibial insertion?

. Immediately distal to the joint line, deep to the pes anserinus
. Approximately 4-5 cm distal to the joint line, deep to the pes anserinus
. Approximately 4-5 cm distal to the joint line, superficial to the pes anserinus
. On the anterior medial tibial crest
. Directly on the medial meniscus

Correct Answer & Explanation

. Immediately distal to the joint line, deep to the pes anserinus

Explanation

The superficial MCL has a broad tibial insertion located approximately 4.5 cm distal to the joint line. It sits deep to the pes anserinus tendons, separated from them by a bursa.

Question 133

Topic: 1. General Principles & Basic Science

The "screw-home" mechanism of the knee provides terminal extension stability, locking the joint. This mechanism is primarily driven by which inherent anatomical feature?

. Increased tension in the posterior cruciate ligament
. Asymmetry between the medial and lateral femoral condyles
. Active contraction of the popliteus muscle
. Engagement of the patella within the trochlear groove
. Tightening of the iliotibial band during extension

Correct Answer & Explanation

. Asymmetry between the medial and lateral femoral condyles

Explanation

The screw-home mechanism involves obligatory external rotation of the tibia during terminal knee extension. It is dictated mechanically by the larger articular surface area and geometric asymmetry of the medial femoral condyle compared to the lateral condyle.

Question 134

Topic: Surgical Anatomy & Approaches

Which of the following capsular ligaments is considered the thickest and strongest in the human body, serving as the primary restraint against hyperextension of the hip joint?

. Pubofemoral ligament
. Ischiofemoral ligament
. Iliofemoral ligament
. Ligamentum teres
. Transverse acetabular ligament

Correct Answer & Explanation

. Iliofemoral ligament

Explanation

The iliofemoral ligament, also known as the Y ligament of Bigelow, is the strongest ligament in the human body. It spans the anterior aspect of the hip joint capsule and tightly winds during extension to potently resist hip hyperextension.

Question 135

Topic: 1. General Principles & Basic Science

The anterolateral ligament (ALL) of the knee has been identified as a secondary restraint to internal tibial rotation. What is the typical anatomic insertion site of this ligament?

. Fibular head
. Gerdy's tubercle
. Proximal tibia, midway between Gerdy's tubercle and the fibular head
. Anterior horn of the lateral meniscus
. Anterior tibial tuberosity

Correct Answer & Explanation

. Proximal tibia, midway between Gerdy's tubercle and the fibular head

Explanation

The anterolateral ligament (ALL) originates near the lateral femoral epicondyle and takes an oblique course to insert on the anterolateral tibia, approximately midway between Gerdy's tubercle and the fibular head.

Question 136

Topic: Physiology & Rehabilitation

During a closed kinetic chain lower extremity exercise, such as a deep squat, patellofemoral joint reaction forces reach their peak at approximately which range of knee flexion?

. 0 to 30 degrees
. 30 to 60 degrees
. 60 to 90 degrees
. 90 to 120 degrees
. Forces remain constant throughout the arc of flexion

Correct Answer & Explanation

. 90 to 120 degrees

Explanation

Patellofemoral joint reaction forces increase substantially with deeper flexion during closed kinetic chain activities. These forces typically peak around 90 to 120 degrees of knee flexion due to the increased quadriceps force required and the smaller contact area.

Question 137

Topic: Surgical Anatomy & Approaches

During an arthroscopic inside-out repair of a posterior horn tear of the medial meniscus, aberrant suture passage poses the greatest iatrogenic risk to which of the following nerves?

. Common peroneal nerve
. Saphenous nerve
. Tibial nerve
. Sural nerve
. Sciatic nerve

Correct Answer & Explanation

. Saphenous nerve

Explanation

Inside-out meniscal repair of the medial meniscus places the saphenous nerve and its infrapatellar branches at significant risk during suture passage. By contrast, the common peroneal nerve is at risk during lateral inside-out meniscal repairs.

Question 138

Topic: 1. General Principles & Basic Science

In an adult patient, the intrinsic blood supply to the menisci of the knee is physiologically restricted to which anatomical zone?

. Peripheral 10-30%
. Central 50%
. Inner 10-30%
. Anterior horns only
. Posterior horns only

Correct Answer & Explanation

. Peripheral 10-30%

Explanation

The vascular supply to the menisci originates from the perimeniscal capillary plexus supplied by the genicular arteries. In adults, this vascularity recedes and is strictly limited to the peripheral 10% to 30% (the "red-red" zone), severely limiting the healing potential of central tears.

Question 139

Topic: 1. General Principles & Basic Science

Which of the following is not a cause of failure following arthroscopic subacromial decompression:

. Error in diagnosis
. Detachment of the deltoid
. Reconstitution of bursal tissue
. Inadequate bone resection
. Retained coracoacromial (C A) ligament

Correct Answer & Explanation

. Detachment of the deltoid

Explanation

Causes of failure following arthroscopic decompression are similar to the causes of failure following open acromioplasty. Numerous studies have documented errors in diagnosis as the most common cause of failure. Inadequate bone resection can also cause continued pain and dysfunction. A retained coracoacromial ligament attachment can decrease the volume in the subacromial space and lead to recurrent impingement. Although bursal tissue can reconstitute following partial excision, this has not been shown as a common cause of failure following decompression. Deltoid detachment may cause weakness and pain.

Question 140

Topic: 1. General Principles & Basic Science

Which of the following statements is true concerning the bands of the posterior cruciate ligament:

. The anterolateral band is tightest in flexion.
. The posterolateral band is tightest in flexion.
. The posteromedial band is tightest in flexion.
. The anteromedial band is tightest in flexion.
. The anteromedial band is tightest in extension.

Correct Answer & Explanation

. The anterolateral band is tightest in flexion.

Explanation

The posterior cruciate ligament is composed of two functional bands. The larger anterolateral band is tightest in flexion and loosest in extension. The smaller posteromedial band is tightest in extension and loosest in flexion. Conventional posterior cruciate ligament reconstruction replaces only the anterolateral band.

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