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Physiology & Rehabilitation MCQs

Practice Set 6 of 26

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

Question 101

Topic: Physiology & Rehabilitation

A 45-year-old male presents with chronic knee pain and a noticeable gait abnormality characterized by severe knee hyperextension during the stance phase. He reports a history of an anterior physeal arrest in his distal femur during childhood. Physical examination reveals a fixed hyperextension deformity of the knee. Given the clinical presentation and the principles outlined in the case, which of the following is the most likely underlying biomechanical issue?

. A. Proximal femoral procurvatum, leading to compensatory knee flexion.
. B. Distal femoral varus, causing medial compartment overload.
. C. Distal femoral recurvatum, positioning the knee posterior to the sagittal mechanical axis.
. D. Tibial procurvatum, resulting in an anterior shift of the knee joint center.
. E. Patella alta, predisposing to patellofemoral instability.

Correct Answer & Explanation

. C. Distal femoral recurvatum, positioning the knee posterior to the sagittal mechanical axis.

Explanation

Correct Answer: CThe patient's presentation of severe knee hyperextension during gait, coupled with a history of anterior physeal arrest in the distal femur, is highly indicative of distal femoral recurvatum. As detailed in the case, distal femoral recurvatum is an apex posterior deformity where the knee joint is positioned posterior to the sagittal mechanical plumb line. This pathologic alignment forces the patient into compensatory postures, most notably severe knee hyperextension, to maintain their center of gravity during the stance phase. The image provided also depicts a patient with severe knee hyperextension, consistent with this diagnosis.Option A (Proximal femoral procurvatum)would typically lead to a flexion deformity of the hip or knee, not hyperextension.Option B (Distal femoral varus)is a frontal plane deformity, primarily affecting medial compartment loading and causing a bow-legged appearance, not directly causing sagittal plane hyperextension.Option D (Tibial procurvatum)would result in an apex anterior deformity of the tibia, which would tend to cause a fixed flexion deformity of the knee, not hyperextension.Option E (Patella alta)is a patellofemoral tracking issue, which can lead to instability and pain, but is not the primary biomechanical cause of a global knee hyperextension deformity originating from a distal femoral angular deformity.

Question 102

Topic: Physiology & Rehabilitation

A 28-year-old patient with uncorrected severe distal femoral recurvatum presents with worsening knee pain. Which of the following long-term biomechanical consequences is most likely to develop due to the chronic abnormal loading associated with this deformity?

. A. Medial collateral ligament laxity and valgus instability.
. B. Severe anterior compartment compression and early patellofemoral arthritis.
. C. Posterior cruciate ligament rupture and posterior sag of the tibia.
. D. Lateral compartment overload and varus deformity progression.
. E. Fixed flexion contracture of the knee and quadriceps weakness.

Correct Answer & Explanation

. B. Severe anterior compartment compression and early patellofemoral arthritis.

Explanation

Correct Answer: BThe case specifically details the predictable cascade of biomechanical failures resulting from uncorrected distal femoral recurvatum. This 25-degree apex posterior deformity forces the knee into severe, damaging hyperextension during the stance phase. This chronic abnormal loading leads to 'severe anterior compartment compression, relentless posterior capsular and ligamentous stretching, and the early onset of debilitating patellofemoral arthritis due to altered extensor mechanism tracking.' Therefore, severe anterior compartment compression and early patellofemoral arthritis are direct and highly likely long-term consequences.Option A (Medial collateral ligament laxity and valgus instability)is typically associated with valgus deformities, not recurvatum.Option C (Posterior cruciate ligament rupture and posterior sag of the tibia)is a result of posterior instability, which is not the primary consequence of recurvatum, although posterior capsular stretching does occur.Option D (Lateral compartment overload and varus deformity progression)is associated with valgus deformities, not recurvatum.Option E (Fixed flexion contracture of the knee and quadriceps weakness)is characteristic of procurvatum or other conditions causing knee flexion, not hyperextension (recurvatum).

Question 103

Topic: Physiology & Rehabilitation

According to the principles of deformity correction outlined by Paley, what is the ultimate goal of surgical realignment in the lower extremity?

. To achieve a cosmetically straight limb on plain radiographs.
. To simply reduce the Mechanical Axis Deviation (MAD) to zero, regardless of joint line orientation.
. To restore the intricate biomechanical relationship between the joint surfaces and the limb's physiological load-bearing axis, ensuring joint lines are parallel to the ground.
. To fuse the affected joint to eliminate pain and instability.
. To primarily address soft tissue contractures before any bone cuts.

Correct Answer & Explanation

. To restore the intricate biomechanical relationship between the joint surfaces and the limb's physiological load-bearing axis, ensuring joint lines are parallel to the ground.

Explanation

Correct Answer: CThe text emphasizes this point: "The ultimate goal of deformity correction is not simply to create a bone that appears straight on an X-ray, but to perfectly restore the intricate biomechanical relationship between the joint surfaces and the limb's physiological load-bearing axis." It further states, "If the joint lines of the knee and ankle are not parallel to the ground during the stance phase of gait, the limb remains biomechanically dysfunctional, leading to shear forces that destroy cartilage." This highlights the importance of both mechanical axis correction and proper joint line orientation.Option A is insufficient as cosmetic straightness does not guarantee biomechanical function. Option B is incomplete; while reducing MAD to zero is crucial, it must be done while maintaining parallel joint lines to avoid shear forces. Option D describes arthrodesis, which is a salvage procedure, not the primary goal of deformity correction. Option E misrepresents the primary focus of osteotomy, which is bone correction, although soft tissue balance is also important.

Question 104

Topic: Physiology & Rehabilitation

Which of the following terms describe a rehabilitative exercise in which the foot is mobile and the motion of the knee is independent of hip and ankle motion?

. Isotonic
. Isokinetic
. Isometric
. Open kinetic chain
. Dynamic variable resistance

Correct Answer & Explanation

. Open kinetic chain

Explanation

Open chain exercises of the lower extremity are defined as "The foot is mobile, and motion at the knee joint occurs independent of motion at the hip and ankle joints, as opposed to closed chain exercises in which the foot is fixed and motion at the knee joint is accompanied by motion at the hip and ankle joints in a predictable manner.

Question 105

Topic: Physiology & Rehabilitation
What type of muscle contraction occurs while the muscle is lengthening?
. Isometric
. Isotonic
. Concentric
. Isokinetic
. Eccentric

Correct Answer & Explanation

. Eccentric

Explanation

A muscle that lengthens as it is activated is an eccentric contraction. Isometric contraction involves no change in length. Concentric contraction occurs while the muscle is shortening. In isotonic contraction, the force remains constant through the contraction range. Isokinetic muscle contraction occurs at a constant rate of angular change of the involved joint.

Question 106

Topic: Physiology & Rehabilitation
Which of the following rehabilitation methods should be used for the first 24 hours following a blunt injury to the quadriceps musculature to avoid short-term stiffness?
. Heat
. Gentle active flexion-extension exercises
. Isokinetic strengthening
. Electrical muscle stimulation
. Immobilization of the limb with the knee in full flexion

Correct Answer & Explanation

. Gentle active flexion-extension exercises

Explanation

A West Point study utilizing a three-phase protocol after quads contusion was cited. Phase I was to limit hemorrhage. Rest, ice, compression and elevation were used for 24 to 48 hours depending on the severity of the contusion. Rest involved ace wrap to entire leg and hip and knee flexed to tolerance. When the patient was pain free at rest and thigh girth had stabilized Phase II had begun. The purpose of this phase was to restore ROM. Ice and cool whirlpool were continued, gravity assisted motion and active flexion and extension exercises are started. Weightbearing to tolerance is continued and crutches are discontinued when 90 degrees of motion, no limp and good quad control is attained. Phase III starts when there is 120 degrees of pain free active motion and participation in noncontact sports is allowed, when full strength, motion and endurance is achieved contact sports can be resumed. A thigh pad is worn for 3-6 months. In the past immobilization in full extension was recommended, but it was noticed that the lack of flexion prolonged disability. Flexion of the knee during the first 24 hours also aids in limiting the extent of intramuscular hematoma. Myositis ossificans is higher in any patient presenting after a quad contusion and has active knee ROM of less than 120 degrees and delay in treatment greater than 3 days.

Question 107

Topic: Physiology & Rehabilitation

Which of the following changes is seen with age and degeneration in the intervertebral disk? Review Topic

. Increased number of blood vessels in the outer annulus fibrosus
. Increased number of notochordal cells in the nucleus pulposus
. Increase of diffusion gradient between the annulus fibrosus and the nucleus pulposus
. Decreased type 1 collagen
. Decreased water content of the nucleus pulposus

Correct Answer & Explanation

. Decreased water content of the nucleus pulposus

Explanation

The intervertebral disk consists of annulus fibrosus, nucleus pulposus, and endplate. Nucleus cells have a critical need for glucose because they obtain their energy primarily by glycolysis, even in the presence of oxygen. Disk cells do not require oxygen to remain alive, but they die at low glucose levels or acidic pH. Nutrients are supplied from the blood vessels at the margins of the disk and have to traverse the cartilaginous endplate and the fibrous annulus in order to reach the disk cells. The loss of the nutrient supply through the vertebral body will starve the cells in the disk center and may be a major factor in disk degeneration. The gross appearance of the nucleus pulposus is clear watery gelatinous matrix in the very young disk, but with age the nucleus pulposus becomes more opaque, and less hydrated and firm. The cellular composition of the young disk consists of many notochordal cells, but after 10 years of age, notochordal cells are not seen in the disk. Notochordal cells are the remnant of embryonal cells in the nucleus pulposus.

Question 108

Topic: Physiology & Rehabilitation

ACL rehabilitation often includes exercises with the distal end of the extremity fixed in place with axial loading and co-contracture of muscle groups to help stabilize the joint. This type of exercise is more commonly referred to as: Review Topic

. Eccentric contraction
. Closed chain exercise
. Open chain exercise
. Proprioceptive neuromuscular facilitation
. Isometric contraction

Correct Answer & Explanation

. Closed chain exercise

Explanation

A "closed chain exercise" is one in which the distal end of the extremity is fixed, allowing axial loading of the extremity with co-contracture of muscles decreasing stress across that joint.Closed chain exercises are preferred for any rehabilitation protocol that wants to minimize stress across a potentially unstable joint. After ACL reconstruction it is important to begin motion and strengthening but not stress the reconstructed ligament which may lead to loss of stability or failure.An example of a closed chain exercise of the quadriceps is a squat or leg press in which the foot is fixed against the floor/plate and both the quadriceps and hamstrings can contract together keeping the knee joint stable and preventing excess stress across the reconstructed ACL. An example of an open chain exercise of the quadriceps is a seated leg extension in which the foot is not fixed and the quadriceps contract in isolation. This creates a strong anterior pull on the tibia which can lead to excess stress on the ACL graft.Beynnon et al. present a review on the behavior of ACL grafts during rehabilitation. They found that exercises that produce the least amount of stress across an ACL graft are either dominated by hamstring muscle contraction, involve quadriceps muscle activity with the knee flexed at 60° or greater, or involve active knee motion between35°and90°offlexion.Illustration A is an example of a squat, which is a closed chain exercise. Notice the feet are fixed in place against the floor. Illustration B is an example of a seated leg extension, which is an open chain exercise. Notice the feet are not fixed in place and no axial loading or co-contracture can occur.Incorrect

Question 109

Topic: Physiology & Rehabilitation
An 18-year-old high school basketball player is being treated for Achilles tendinitis. What type of strengthening exercise has been shown to be helpful in the later phases of rehabilitation?
. Eccentric
. Isokinetic
. Concentric
. Isometric
. Isotonic

Correct Answer & Explanation

. Eccentric

Explanation

Eccentric strengthening for tendinopathies has proved most helpful in the later stages of rehabilitation. Although the exact mechanism of the effect of eccentric exercises is not known, the most widely accepted theory is that the absence of concentric stretching disrupts the normal lengthening/shortening cycle which may cause shearing in the tendon and injury to the collagen.

Question 110

Topic: Physiology & Rehabilitation
  • What is the primary immediate source of energy for muscle?
. Glycolytic pathway
. Oxidative phosphorylation
. Breakdown of fat
. Breakdown of protein
. Breakdown of adenosine triphosphate

Correct Answer & Explanation

. Glycolytic pathway

Explanation

The basic source of energy for muscle contraction is ATP. ATP is also the immediate energy source for muscle. The body then utilizes glucose to produce ATP. Glycolysis splits glucose to form two molecules of pyruvic acid and two ATP.Almost 90% of the total ATP formed by glucose metabolism is formed during oxidative phosphorylation. This is accomplished by a series of enzymatically catalyzed reactions in the mitochondria. When the body’s stores of carbohydrates decrease below normal, glucose can be formed from the breakdown of protein and fat via gluconeogenesis to yield more ATP.

Question 111

Topic: Physiology & Rehabilitation

Which of the following types of exercise used to increase flexibility is considered most beneficial in increasing joint range of motion?

. Ballistic stretching
. Static stretching
. Proprioceptive neuromuscular facilitation (PNF)
. Isokinetic
. Eccentric

Correct Answer & Explanation

. Ballistic stretching

Explanation

DISCUSSION: Evidence has shown that PNF is the treatment of choice to increase joint range of motion and flexibility.  PNF has the advantage of pushing the patient to stretch a little further when the muscle tendon unit is relaxed by a partner.  While isokinetic and eccentric exercises can improve flexibility, and therefore increase range of motion, their main purpose is to increase strength and endurance.  Ballistic stretching involves a large load applied rapidly; however, evidence has shown that static stretching, where a low load is applied for a long duration, offers a more significant benefit.REFERENCES: Sady SP, Wortman M, Blanke D: Flexibility training: Ballistic, static or proprioceptive neuromuscular facilitation?  Arch Phys Med Rehabil 1982;63:261-263.Tanigawa MC: Comparison of the hold-relax procedure and passive mobilization on increasing muscle length.  Phys Ther 1972;52:725-735.Wallin D, Ekblom B, Grahn R, Nordenberg T: Improvement of muscle flexibility: A comparison between two techniques.  Am J Sports Med 1985;13:263-268.

Question 112

Topic: Physiology & Rehabilitation

During the early swing phase of the normal gait cycle, what lower extremity muscle is primarily contracting?

. Tibialis posterior
. Tibialis anterior
. Vastus medialis
. Adductor longus
. Gastrocnemius

Correct Answer & Explanation

. Tibialis posterior

Explanation

DISCUSSION: Electromyography during walking reveals the tibialis anterior muscle is active during early swing, allowing the foot to clear the ground.  All of the other muscles are quiet, as the limb moves forward through space with minimal muscular effort.  The other muscles are primarily active during weight acceptance or push-off.REFERENCES: Gage JR: An overview of normal walking.  Instr Course Lect 1990;39:291-303.Wootten ME, Kadaba MP, Cochran GV: Dynamic electromyography II:  Normal patterns during gait.  J Orthop Res 1990;8:259-265.

Question 113

Topic: Physiology & Rehabilitation

The findings in Brown-Sequard syndrome include loss of which of the following? Review Topic

. Greater loss of upper extremity motor function than lower extremity function
. Ipsilateral motor function and ipsilateral pain and temperature sensation
. Ipsilateral motor function and contralateral pain and temperature sensation
. Contralateral motor function and ipsilateral pain and temperature sensation
. Lower of extremity proprioception and balance

Correct Answer & Explanation

. Greater loss of upper extremity motor function than lower extremity function

Explanation

Brown-Séquard syndrome is most commonly seen after penetrating injuries to the spinal cord and results in ipsilateral loss of motor function and contralateral loss of pain and temperature sensation. Patients with central cord syndrome have greater weakness in the upper extremities than in the lower extremities. Loss of proprioception is typically seen in patients with posterior cord syndrome.

Question 114

Topic: Physiology & Rehabilitation

ofhat parameter is most commonly used to estimate the maximum tension a muscle can generating?

. Length
. Moment arm
. Total volume
. Physiologic cross-sectional area
. Distribution of slow and fast twitch fibers

Correct Answer & Explanation

. Length

Explanation

The mass or volume of a muscle is proportional to its work capacity, and the fiber length of a muscle is proportional to its potential excursion. By dividing the fiber length into the volume of each muscle, the cross-sectional area of the muscle is determined.The concept of physiologic cross section of a muscle from Weber and Fick, identifies the critical importance of the cross sectional area of all the fibers of a muscle as proportional to maximum tension. (Relationship between muscle size and muscle strength).

Question 115

Topic: Physiology & Rehabilitation

The skeletal muscle length-tension relationship for voluntary force generation is observed with which of the following biomechanical paradigms? Review Topic

. Isometric
. Isotonic
. Isokinetic
. Concentric
. Eccentric

Correct Answer & Explanation

. Isometric

Explanation

Muscle force during isometric contractions (muscle not allowed to shorten) varies with starting length. If the length is too long, the sarcomeres generate little or no active tension. If a muscle is overstretched during certain surgical procedures, then the patient may generate less than 30% maximal force. The force-velocity relationship describes isotonic (constant load) conditions.

Question 116

Topic: Physiology & Rehabilitation

A 17-year-old boy is shot in the left side of the neck at the C5-6 level and sustains an incomplete spinal cord injury that is called a Brown-Sequard syndrome. Which of the following best describes the expected deficits? Review Topic

. Profound bilateral wrist extensor, finger flexor, and intrinsic weakness with good preservation of lower extremity motor function
. Severe bilateral upper and lower extremity weakness, pain and temperature sensory deficit but preservation of deep pressure and proprioception
. Weakness of the right upper and lower extremity with diminished pain and temperature sensation on the left side of the body
. Left wrist extensor weakness and numbness along the radial border of the left forearm extending into the thumb and index finger
. Weakness of the left upper and lower extremity with diminished pain and temperature sensation on the right side of the body

Correct Answer & Explanation

. Profound bilateral wrist extensor, finger flexor, and intrinsic weakness with good preservation of lower extremity motor function

Explanation

Brown-Sequard syndrome is an incomplete spinal cord injury that involves damage unilaterally to the cord, most commonly from penetrating trauma. The motors fibers of the cord decussate within the brainstem so the motor deficit is ipsilateral to the injury; whereas, the pain and temperature fibers cross midline immediately on entering the cord so that the sensory deficit is contralateral to the injury. This patient was shot in the left side, thus he would have weakness of the left upper and lower extremity with diminished pain and temperature sensation on the right side of the body. Response 3 describes opposite symptoms that would result from a right-sided injury. Response 1 describes a central syndrome with greater upper than lower extremity involvement. Response 2 is an anterior cord syndrome with only preservation of the posterior columns of the cord. Response 4 describes a C6 root injury.

Question 117

Topic: Physiology & Rehabilitation

The nucleus pulposus of the intervertebral disk consists of chondrocyte-like cells that have a limited vascular supply and generate energy through which of the following?

. Anaerobic glycolysis
. Kreb's cycle
. Ketosis
. Gluconeogenesis
. Lipogenesis

Correct Answer & Explanation

. Anaerobic glycolysis

Explanation

The intervertebral disk is an avascular structure in the adult. Nucleus pulposus cells have a critical need for glucose because they obtain their energy primarily by glycolysis, even in the absence of oxygen. Disk cells do not require oxygen to remain alive but they die at low glucose levels or acidic pH. Nutrients are supplied from the blood vessels at the margins of the disk and have to traverse the cartilaginous end plate to reach the disk cells. The loss of the nutrient supply through the vertebral body will starve the cells in the disk center and may be a major factor in disk degeneration.

Question 118

Topic: Physiology & Rehabilitation
Which of the following activities can improve posterior capsular contractures?
. Theraband exercises to strengthen the external rotator
. Latissimus pull-down exercises to the chest
. Seated rows
. Internal rotation stretch at 90 degrees abduction with scapular stabilization
. Bench press with wide grip

Correct Answer & Explanation

. Internal rotation stretch at 90 degrees abduction with scapular stabilization

Explanation

Posterior capsule stretching is performed in the cross-chest and behind the back positions. Stretching in internal rotation in the abducted shoulder will further stretch the posterior capsule. Wide grip stretch, and anterior capsule and strengthening exercises will not necessarily stretch the capsule.

Question 119

Topic: Physiology & Rehabilitation

Which of the following activities produces greater hip joint contact pressures than full weight bearing during normal gait?

. Performing isometric hip exercises
. Getting on a bed pan
. Ambulating with a cane
. Rising from a chair using the affected leg
. Toe-touch weight bearing with passive hip abduction

Correct Answer & Explanation

. Performing isometric hip exercises

Explanation

Rising from a seated position on a chair on the affected leg has been shown to create the highest contact pressure within the hip, even higher than full weight-bearing during walking.Limiting activities that create high contact pressures is important in situations such as after internal fixation of an acetabular fracture. Full weight bearing during a normal gait cycle is often considered too much contact pressure and considered a risk for early failure of fixation. During the postoperative period weight bearing and activities are limited to prevent this. It has been shown that the highest contact pressures, even higher than normal walking, are seen when rising from a chair on the affected leg.Brand et al. analyzed joint reactive forces in patients walking with and without a cane. Compared to age matched controls they estimate that using a cane decreases the contact pressure in the hip to about 60% of normal.Hodge et al. looked at data from an implanted hip prosthesis with pressure sensors. They found that some activities common to the early rehabilitative period, such as using a bed pan and performing isometric exercises about the hip, can create pressure approaching those of normal walking. The highest pressures recorded were when rising from a chair.Incorrect answers:

Question 120

Topic: Physiology & Rehabilitation

What type of exercise is used early in the rehabilitation process to safely stimulate co-contraction of the scapular and rotator cuff muscles? Review Topic

. Resistive active motion
. Facilitated active motion
. Plyometrics
. Open kinetic chain
. Closed kinetic chain

Correct Answer & Explanation

. Resistive active motion

Explanation

Closed kinetic chain exercises are used early in the rehabilitation process. The distal segment is fixed, and an axial load is applied which provides glenohumeral compression and reduces the demand on the rotator cuff. These exercises stimulate co-contractions of the scapular and rotator cuff muscles, load scapular stabilizers, and facilitate active motion. Facilitated active motion exercises use proximal segment motion to stimulate and facilitate motion in the target tissue. These exercises are often performed in diagonal movements. Resistive active motion exercises are used later in the rehabilitation process. These are typically open kinetic chain exercises that involve active glenohumeral motion with extrinsic loads such as weights or exercise tubing. During the later stages of upper extremity rehabilitation, plyometrics are added. These exercises help to prepare the athlete for return to sport. When performed at slower speeds, these exercises emphasize stabilization and control. As the speeds increase, muscles begin to work in the stretch-shortening sequence associated with sports participation.

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