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CO MLO practice questions

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Question 1Medical legal fundamentals and legal process

Under the standard model of the physician-patient relationship, which element is required for a valid implied consent to a routine physical examination when the patient voluntarily presents at the clinic and cooperates?

  1. The presence of a family member as a witness
  2. A signed written authorization executed before the examination begins
  3. The patient's informed understanding of the nature of the touching and voluntary submission to it Correct answer.
  4. A court order authorizing the examination

Explanation

Implied consent rests on the patient's conduct: voluntarily presenting and cooperating signals understanding of, and agreement to, the touching involved in a routine examination. It does not require writing, judicial authorization, or a witness, which are requirements attached to other legal mechanisms such as formal written consent or court-ordered evaluations.

Question 2Medical legal fundamentals and legal process

A physician performs a procedure without any consent and without any emergency. In a subsequent tort action, which cause of action most directly addresses the unauthorized touching itself?

  1. Defamation
  2. Negligence
  3. Breach of fiduciary duty
  4. Battery Correct answer.

Explanation

Performing a procedure without consent is an intentional, unpermitted touching, which is the essence of battery. Negligence addresses a failure to meet the standard of care in a consented-to treatment, while fiduciary duty and defamation concern different interests entirely.

Question 3Medical legal fundamentals and legal process

Which standard governs whether a physician's disclosure of risks before obtaining informed consent was adequate in most jurisdictions?

  1. What the patient's insurer requires to be documented
  2. What the treating physician personally considers important to disclose
  3. What the physician's professional association recommends as a minimum
  4. What a reasonable patient in similar circumstances would consider material to the decision Correct answer.

Explanation

The prevailing materiality standard asks what a reasonable person in the patient's position would want to know when deciding whether to accept the proposed treatment. The physician-oriented standard, by contrast, measures disclosure against customary professional practice in the relevant community.

Question 4Medical legal fundamentals and legal process

A patient signs a consent form that includes a broad clause waiving all claims for any future negligent care. A court later considers the clause. What is the most likely treatment of such a prospective waiver?

  1. It is enforceable only if witnessed by a nurse
  2. It is generally unenforceable as against public policy Correct answer.
  3. It transfers liability to the patient's insurer
  4. It is fully enforceable because the patient signed it

Explanation

Prospective releases of liability for a provider's own negligence in medical care are generally void as against public policy, because patients cannot be asked to bargain away the standard of care in advance. Signature on a form does not cure that defect, and witnessing or insurance arrangements do not change the analysis.

Question 5Medical legal fundamentals and legal process

In a malpractice action, the plaintiff must generally establish which four elements?

  1. Duty, breach, causation, and damages Correct answer.
  2. Duty, intent, malice, and damages
  3. Consent, disclosure, documentation, and injury
  4. Standard of care, licensure, insurance, and harm

Explanation

Negligence requires proof of a duty owed, a breach of the applicable standard of care, causation linking the breach to the harm, and actual damages. Intent, malice, licensure status, and insurance are not elements of the cause of action.

Question 6Medical legal fundamentals and legal process

A specialist in a small community argues that the local standard of care should apply because few practitioners in the area perform the procedure. How do most modern courts approach this argument?

  1. They apply a national standard for specialists, since competence does not vary by geography Correct answer.
  2. They apply a strict local standard limited to the same county
  3. They apply the standard of the nearest teaching hospital
  4. They defer entirely to the defendant's own customary practice

Explanation

The locality rule has largely given way to a national standard of care for specialists, reflecting uniform training, certification, and access to literature. Geographic location may still matter for general practitioners in some jurisdictions, but it does not lower the specialist's expected competence.

Question 7Medical legal fundamentals and legal process

Which doctrine allows a plaintiff to prove negligence by showing that the injury would not ordinarily occur absent negligence, shifting the burden of explanation to the defendant?

  1. Stare decisis
  2. Caveat emptor
  3. Res ipsa loquitur Correct answer.
  4. Res judicata

Explanation

Res ipsa loquitur permits an inference of negligence where the injury is of a kind that ordinarily does not happen without negligence and was caused by something within the defendant's exclusive control. The other doctrines concern precedent, finality of judgments, and buyer risk, respectively.

Question 8Medical legal fundamentals and legal process

A surgeon leaves a surgical sponge inside a patient despite counting protocols. The patient sues. Which doctrine most strongly supports an inference of negligence without expert testimony on the precise misstep?

  1. Informed consent
  2. Res ipsa loquitur Correct answer.
  3. Good Samaritan immunity
  4. Statute of limitations

Explanation

A retained foreign body is a classic res ipsa situation: the event does not ordinarily occur without negligence and the instrumentalities were under the surgical team's control. This permits the jury to infer negligence even without pinpointing which team member erred.

Question 9Medical legal fundamentals and legal process

What is the primary purpose of a statute of limitations in medical malpractice litigation?

  1. To limit expert witnesses to board-certified physicians
  2. To cap the amount of damages a jury may award
  3. To require pre-suit review by a licensing board
  4. To require plaintiffs to bring claims within a defined period after accrual Correct answer.

Explanation

A statute of limitations sets the time within which a claim must be filed after it accrues, promoting timely investigation and finality. Damage caps and expert-witness rules come from separate statutes or procedural rules, not from the limitations period.

Question 10Medical legal fundamentals and legal process

A jurisdiction follows the discovery rule for malpractice claims. A patient underwent a procedure in 2020, but a retained clip causing symptoms was only identified in 2024. When does the claim generally accrue?

  1. On the date the patient first consulted any physician
  2. When the patient knew or reasonably should have known of the injury and its cause Correct answer.
  3. On the date the medical record was requested
  4. On the date of the procedure regardless of later discovery

Explanation

Under the discovery rule, accrual is postponed until the patient knows or reasonably should know of the injury and that it was caused by the provider's conduct. This prevents claims from expiring before the harm is even detectable.

Question 11Medical legal fundamentals and legal process

A statute of repose differs from a statute of limitations in which key respect?

  1. It applies only to criminal prosecutions
  2. It can be extended indefinitely by the plaintiff's request
  3. It applies only to claims against hospitals
  4. It sets an outer time limit from a defined event regardless of when the injury is discovered Correct answer.

Explanation

A statute of repose bars claims after a fixed period measured from a specified event, such as the act of treatment, even if the injury has not yet been discovered. A statute of limitations, by contrast, generally runs from accrual, which may be delayed by the discovery rule.

Question 12Medical legal fundamentals and legal process

Which of the following best describes the doctrine of respondeat superior in a hospital setting?

  1. An employer is liable for the negligent acts of employees committed within the scope of employment Correct answer.
  2. A hospital is immune from suit for emergency care
  3. A patient assumes the risks of treatment by seeking care
  4. A physician is liable only for acts personally performed

Explanation

Respondeat superior makes an employer vicariously liable for negligence by employees acting within the scope of their employment. It does not require the employer's personal fault, and it does not shield the employee from individual liability.

Question 13Medical legal fundamentals and legal process

A hospital contracts with an independent group to staff its emergency department. Under the apparent agency doctrine, when may the hospital be held liable for the group physician's negligence?

  1. Only when the patient signs a form acknowledging independent status
  2. When the hospital held itself out in a way that led the patient to reasonably believe the physician was its employee Correct answer.
  3. Whenever the physician is board certified
  4. Only when the physician is a direct employee

Explanation

Apparent agency attaches when the hospital's representations, such as signage, uniforms, or billing practices, lead a reasonable patient to believe the treating clinician is the hospital's agent. A disclaimer form may be considered but is not automatically controlling if the overall presentation is misleading.

Question 14Medical legal fundamentals and legal process

What is the function of a Good Samaritan statute in the medical context?

  1. To immunize hospitals from all malpractice claims
  2. To limit liability for providers who render emergency care without expectation of compensation Correct answer.
  3. To create a duty to rescue for bystanders
  4. To require providers to render aid in all circumstances

Explanation

Good Samaritan statutes generally protect clinicians who voluntarily render emergency assistance outside their normal duty, often conditioned on acting in good faith and without gross negligence. They do not create an affirmative duty to rescue, and the protection is narrower than blanket hospital immunity.

Question 15Medical legal fundamentals and legal process

A clinician terminates care of an established patient who still requires treatment, without notice or an opportunity to find a successor. Which claim is most likely implicated?

  1. Defamation
  2. Abandonment Correct answer.
  3. Battery
  4. Invasion of privacy

Explanation

Abandonment occurs when a provider unilaterally ends a professional relationship while the patient still needs care, without reasonable notice and a chance to arrange alternative treatment. Proper termination requires notice, records access, and continuity planning.

Question 16Medical legal fundamentals and legal process

Which statement correctly describes the physician's duty when a patient refuses a recommended life-sustaining treatment but has decision-making capacity?

  1. The physician may treat over the refusal to preserve life
  2. The family must consent to the refusal before it is valid
  3. The refusal must be respected after informed discussion and documentation Correct answer.
  4. The physician must obtain a court order in every case

Explanation

A patient with capacity may refuse any treatment, including life-sustaining measures, after an informed discussion, and the decision should be documented. Courts generally require clear and convincing evidence only when a surrogate is deciding for an incapacitated patient, not when the capable patient refuses directly.

Question 17Medical legal fundamentals and legal process

A patient lacks decision-making capacity and has no advance directive. Which approach is generally preferred for making treatment decisions?

  1. Automatic consent by the attending physician alone
  2. A decision by the hospital's finance department
  3. Random selection among family members
  4. Substituted judgment based on the patient's known values, or best interests if values are unknown Correct answer.

Explanation

Surrogates are expected to use substituted judgment, deciding as the patient would have decided based on known values and preferences. Where those are unknown, the best-interests standard considers what a reasonable person would choose in the circumstances.

Question 18Medical legal fundamentals and legal process

What legal effect does a properly executed durable power of attorney for health care have?

  1. It transfers ownership of the patient's medical records to the agent
  2. It overrides the patient's own decisions while the patient still has capacity
  3. It designates an agent to make health care decisions when the patient lacks capacity Correct answer.
  4. It authorizes the agent to practice medicine on the patient's behalf

Explanation

A health care power of attorney appoints a surrogate who acts only when the patient cannot decide, and the agent's authority is bounded by the patient's expressed wishes. It does not transfer records ownership, confer clinical authority, or displace a capable patient's decisions.

Question 19Medical legal fundamentals and legal process

A 15-year-old seeks treatment for a sexually transmitted infection in a jurisdiction with a minor-consent statute covering such care. What is the most likely legal position?

  1. The physician must notify police before treating
  2. The minor may consent only if accompanied by a guardian
  3. The minor may consent independently, and confidentiality protections generally apply Correct answer.
  4. Parental consent is always required regardless of statute

Explanation

Many jurisdictions allow minors to consent independently to specified services, commonly including testing and treatment for sexually transmitted infections, and confidentiality is generally preserved. Statutory exceptions displace the general rule requiring parental consent for minors.

Question 20Medical legal fundamentals and legal process

Which of the following is the most accurate description of the physician's duty regarding disclosure of a medical error that caused harm?

  1. Disclosure is required only if the patient asks directly
  2. Disclosure may be delegated to the billing office
  3. Ethical guidance and growing legal requirements favor prompt disclosure to the patient Correct answer.
  4. Disclosure is prohibited because it creates liability

Explanation

Professional ethics and many jurisdictions now require or encourage prompt disclosure of harmful errors, coupled with an apology and explanation. Some statutes protect expressions of apology from use as admissions, but concealment is neither ethically nor legally sound.

Question 21Medical legal fundamentals and legal process

A plaintiff in a malpractice case offers testimony from a physician in a different specialty who is familiar with the relevant standard through training and experience. What is the most likely ruling on admissibility?

  1. Admissible if the witness demonstrates sufficient knowledge of the applicable standard of care Correct answer.
  2. Admissible only if the expert treated the plaintiff
  3. Inadmissible because experts may not testify about standards
  4. Inadmissible because only same-specialty experts may testify

Explanation

Expert qualification turns on knowledge of the relevant standard, which may be shown through training, experience, or practice in a related field. Same-specialty matching is not universally required, and treating the plaintiff is not a condition of expert testimony.

Question 22Medical legal fundamentals and legal process

Which statement best describes the collateral source rule in malpractice litigation?

  1. Benefits the plaintiff received from a source independent of the defendant generally do not reduce the defendant's liability Correct answer.
  2. The defendant may always offset jury awards with the plaintiff's sick leave
  3. The rule limits damages to out-of-pocket expenses only
  4. Any insurance payment automatically bars the claim

Explanation

The collateral source rule prevents a tortfeasor from benefiting from compensation the plaintiff obtained from an independent source such as health insurance. Many jurisdictions have modified the rule by statute, but the traditional principle remains the starting point.

Question 23Medical legal fundamentals and legal process

What is the principal role of a state medical board in the legal process affecting physicians?

  1. Setting hospital reimbursement rates
  2. Prosecuting criminal cases against physicians
  3. Licensing and disciplining physicians for violations of practice standards Correct answer.
  4. Adjudicating malpractice damages awards

Explanation

State medical boards grant licenses and impose discipline for misconduct, incompetence, or statutory violations. They do not award tort damages, prosecute crimes, or set reimbursement, which belong to courts, prosecutors, and payers respectively.

Question 24Medical legal fundamentals and legal process

During a malpractice trial, the plaintiff's attorney seeks to introduce evidence of a similar prior malpractice judgment against the same physician. What is the most likely basis for the court's ruling?

  1. It must be admitted because it proves the physician's character
  2. It must be admitted because judgments are self-authenticating
  3. It may be admitted only if the physician consented to the prior judgment
  4. It may be excluded because prior judgments are generally inadmissible to show conduct on a particular occasion Correct answer.

Explanation

Evidence of prior acts or judgments is generally excluded to prove that a person acted in conformity with a character trait on a particular occasion. Such evidence may be relevant to other issues, such as notice or bias, but its admissibility is limited and subject to balancing.

Question 25Orthopaedic anatomy, biomechanics, and injury mechanisms

A 25-year-old basketball player lands on an inverted foot and sustains an ankle injury. Which structure is most commonly injured in this mechanism?

  1. Anterior talofibular ligament Correct answer.
  2. Posterior cruciate ligament
  3. Deltoid ligament
  4. Anterior cruciate ligament

Explanation

Inversion ankle sprains are the most common athletic injury, and the anterior talofibular ligament (ATFL) is the first and most frequently torn structure on the lateral side. The deltoid is injured with eversion, while the cruciate ligaments are injured by knee mechanisms.

Question 26Orthopaedic anatomy, biomechanics, and injury mechanisms

Which nerve is most at risk during a direct lateral approach to the hip?

  1. Sciatic nerve
  2. Superior gluteal nerve Correct answer.
  3. Obturator nerve
  4. Femoral nerve

Explanation

The superior gluteal nerve runs between the gluteus medius and minimus and is vulnerable during the lateral approach, especially if the split is carried too far proximally. Injury causes a Trendelenburg gait from gluteus medius weakness.

Question 27Orthopaedic anatomy, biomechanics, and injury mechanisms

The ligamentum teres of the hip is attached to which structure?

  1. Transverse acetabular ligament
  2. Fovea capitis Correct answer.
  3. Ischial spine
  4. Acetabular notch

Explanation

The ligamentum teres (round ligament) runs from the fovea capitis on the femoral head to the acetabular notch and transverse ligament. It carries a small artery but is not a major stabilizer.

Question 28Orthopaedic anatomy, biomechanics, and injury mechanisms

A patient sustains a blow to the lateral knee. Which structure is most likely injured?

  1. Posterior cruciate ligament
  2. Anterior cruciate ligament
  3. Lateral collateral ligament
  4. Medial collateral ligament Correct answer.

Explanation

A valgus force to the lateral knee stresses the medial side, injuring the medial collateral ligament. The lateral collateral ligament is injured by varus stress.

Question 29Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure forms the medial border of the femoral triangle?

  1. Sartorius
  2. Adductor longus Correct answer.
  3. Inguinal ligament
  4. Iliopsoas

Explanation

The femoral triangle is bounded by the inguinal ligament superiorly, the sartorius laterally, and the adductor longus medially. Its floor is formed by the iliopsoas, pectineus, and adductor longus.

Question 30Orthopaedic anatomy, biomechanics, and injury mechanisms

Which muscle is the primary flexor of the hip?

  1. Iliopsoas Correct answer.
  2. Rectus femoris
  3. Gluteus maximus
  4. Biceps femoris

Explanation

The iliopsoas is the main hip flexor, formed by the iliacus and psoas major. Rectus femoris also flexes the hip but is a secondary flexor.

Question 31Orthopaedic anatomy, biomechanics, and injury mechanisms

The anterior cruciate ligament prevents which motion of the tibia?

  1. Varus angulation
  2. Posterior translation
  3. External rotation
  4. Anterior translation Correct answer.

Explanation

The ACL resists anterior translation of the tibia on the femur and limits internal rotation. The PCL resists posterior translation.

Question 32Orthopaedic anatomy, biomechanics, and injury mechanisms

A 20-year-old sustains a shoulder dislocation during a football tackle. Which direction is most common?

  1. Anterior Correct answer.
  2. Superior
  3. Inferior
  4. Posterior

Explanation

Anterior dislocation accounts for about 95% of shoulder dislocations, usually from an abduction and external rotation force. Posterior dislocations are less common and often associated with seizures or electric shock.

Question 33Orthopaedic anatomy, biomechanics, and injury mechanisms

The radial nerve is most at risk in which humeral fracture location?

  1. Surgical neck
  2. Supracondylar
  3. Midshaft Correct answer.
  4. Greater tuberosity

Explanation

The radial nerve runs in the spiral groove on the posterior midshaft of the humerus, where it is vulnerable in midshaft fractures. This causes wrist drop.

Question 34Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure is located in the carpal tunnel?

  1. Flexor carpi ulnaris tendon
  2. Ulnar nerve
  3. Radial artery
  4. Median nerve Correct answer.

Explanation

The carpal tunnel contains the median nerve and the flexor tendons of the fingers and thumb. The ulnar nerve and artery pass through Guyon's canal, not the carpal tunnel.

Question 35Orthopaedic anatomy, biomechanics, and injury mechanisms

A patient has a positive Trendelenburg sign. Which muscle group is most likely weak?

  1. Hip extensors
  2. Hip abductors Correct answer.
  3. Hip adductors
  4. Hip flexors

Explanation

The Trendelenburg sign indicates weakness of the hip abductors, primarily gluteus medius and minimus. When standing on the affected leg, the pelvis drops on the opposite side.

Question 36Orthopaedic anatomy, biomechanics, and injury mechanisms

Which ligament prevents excessive anterior translation of the atlas on the axis?

  1. Ligamentum flavum
  2. Alar ligament
  3. Posterior longitudinal ligament
  4. Transverse ligament of the atlas Correct answer.

Explanation

The transverse ligament of the atlas holds the dens against the anterior arch of C1 and prevents anterior translation of the atlas. Its rupture can cause spinal cord compression.

Question 37Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure is most commonly injured in a hyperextension injury of the knee?

  1. Posterior cruciate ligament Correct answer.
  2. Medial collateral ligament
  3. Anterior cruciate ligament
  4. Lateral meniscus

Explanation

Hyperextension of the knee primarily stresses the posterior cruciate ligament and posterior capsule. The ACL is more commonly injured by rotational or valgus forces.

Question 38Orthopaedic anatomy, biomechanics, and injury mechanisms

The blood supply to the femoral head in adults is primarily from which artery?

  1. Obturator artery
  2. Lateral circumflex femoral artery
  3. Superior gluteal artery
  4. Medial circumflex femoral artery Correct answer.

Explanation

The medial circumflex femoral artery provides most of the blood supply to the adult femoral head via the retinacular vessels. Disruption in femoral neck fractures can lead to avascular necrosis.

Question 39Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure forms the lateral border of the anatomical snuffbox?

  1. Abductor pollicis longus tendon
  2. Flexor carpi radialis tendon
  3. Extensor pollicis longus tendon
  4. Extensor pollicis brevis tendon Correct answer.

Explanation

The anatomical snuffbox is bounded laterally by the extensor pollicis brevis and abductor pollicis longus tendons, and medially by the extensor pollicis longus tendon. The scaphoid and trapezium form its floor.

Question 40Orthopaedic anatomy, biomechanics, and injury mechanisms

A patient sustains a posterior hip dislocation. Which nerve is most at risk?

  1. Obturator nerve
  2. Femoral nerve
  3. Superior gluteal nerve
  4. Sciatic nerve Correct answer.

Explanation

Posterior hip dislocation is frequently associated with sciatic nerve injury, often presenting with foot drop. The femoral nerve is at risk in anterior dislocation.

Question 41Orthopaedic anatomy, biomechanics, and injury mechanisms

Which muscle tendon passes through the tarsal tunnel?

  1. Tibialis anterior
  2. Tibialis posterior Correct answer.
  3. Peroneus longus
  4. Extensor hallucis longus

Explanation

The tarsal tunnel contains the tibialis posterior, flexor digitorum longus, and flexor hallucis longus tendons, along with the posterior tibial nerve and vessels. Tibialis anterior passes anteriorly.

Question 42Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure is the primary stabilizer against anterior translation of the knee?

  1. Medial collateral ligament
  2. Anterior cruciate ligament Correct answer.
  3. Posterior cruciate ligament
  4. Lateral collateral ligament

Explanation

The ACL is the primary restraint to anterior tibial translation. The PCL restrains posterior translation, and the collateral ligaments restrain varus and valgus.

Question 43Orthopaedic anatomy, biomechanics, and injury mechanisms

A patient has a positive Froment sign. Which nerve is most likely injured?

  1. Median nerve
  2. Musculocutaneous nerve
  3. Ulnar nerve Correct answer.
  4. Radial nerve

Explanation

The Froment sign tests for ulnar nerve weakness of the adductor pollicis. When pinching paper, the patient compensates with the flexor pollicis longus (median nerve), causing thumb IP flexion.

Question 44Orthopaedic anatomy, biomechanics, and injury mechanisms

Which ligament is the primary restraint to anterior translation of the talus in the ankle?

  1. Deltoid ligament
  2. Posterior talofibular ligament
  3. Anterior talofibular ligament Correct answer.
  4. Calcaneofibular ligament

Explanation

The anterior talofibular ligament (ATFL) is the primary restraint to anterior translation of the talus and is the most commonly injured ankle ligament. The calcaneofibular ligament restrains inversion.

Question 45Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure is at risk during a supracondylar humeral fracture in a child?

  1. Radial nerve
  2. Median nerve
  3. Ulnar nerve
  4. Brachial artery Correct answer.

Explanation

Supracondylar fractures of the humerus in children can injure the brachial artery, leading to Volkmann ischemic contracture. The median nerve is also at risk, but the arterial injury is the classic concern.

Question 46Orthopaedic anatomy, biomechanics, and injury mechanisms

The glenohumeral joint is stabilized anteriorly by which structure?

  1. Transverse humeral ligament
  2. Coracoacromial ligament
  3. Inferior glenohumeral ligament Correct answer.
  4. Coracohumeral ligament

Explanation

The inferior glenohumeral ligament is the primary anterior stabilizer of the shoulder, especially in abduction and external rotation. The coracoacromial ligament forms the coracoacromial arch.

Question 47Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure is most commonly injured in a dashboard injury to the knee?

  1. Medial collateral ligament
  2. Lateral meniscus
  3. Anterior cruciate ligament
  4. Posterior cruciate ligament Correct answer.

Explanation

A dashboard injury drives the tibia posteriorly, rupturing the posterior cruciate ligament. This is a classic mechanism for PCL injury.

Question 48Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure forms the roof of the popliteal fossa?

  1. Gastrocnemius
  2. Adductor magnus
  3. Popliteal fascia Correct answer.
  4. Biceps femoris

Explanation

The popliteal fossa is covered by the popliteal fascia, which forms its roof. Its boundaries include the biceps femoris, semimembranosus, and heads of the gastrocnemius.

Question 49Orthopaedic anatomy, biomechanics, and injury mechanisms

Which structure is most at risk in a posterior sternoclavicular dislocation?

  1. Esophagus
  2. Trachea
  3. Subclavian artery
  4. Brachiocephalic vein Correct answer.

Explanation

Posterior sternoclavicular dislocation can compress the brachiocephalic vein and other mediastinal structures. The subclavian artery is also at risk but less commonly injured than the vein.

Question 50Orthopaedic anatomy, biomechanics, and injury mechanisms

A 45-year-old cyclist falls onto an outstretched hand with the elbow fully extended. According to the mechanism of injury, which structure is most likely to be injured?

  1. The radial head
  2. The distal radius Correct answer.
  3. The ulnar collateral ligament of the elbow
  4. The scaphoid bone

Explanation

A fall onto an outstretched hand with the elbow extended transmits axial load through the wrist to the distal radius, which is the most common fracture site in this mechanism. The distal radius fails in bending and compression before the load reaches the elbow or carpus. Scaphoid and radial head injuries occur with different wrist positions or elbow flexion.