hllj/quesmed huggingface dataset:
During a randomised controlled trial (RCT), the people analysing the data and performing the experiment are blinded so they are unaware of who is in which group.

How does this affect the study?

Options:
explanation: Blinding would reduce bias, thereby increasing internal validity.
name: Reduces internal validity
label: d
answer: no
explanation: This reduces the observer bias in a study. This ensures the outcomes of each group are managed in the same way, which reduces bias.
name: Reduces bias
label: a
answer: yes
explanation: RCTs have high efficacy and internal validity. Efficacy can be defined as the performance of an intervention under ideal and controlled circumstances, whereas effectiveness refers to its performance under 'real-world' conditions. RCTs often lack effectiveness.
name: Increases effectiveness
label: e
answer: no
explanation: Blinding does not affect confounding. Randomisation of the groups reduces confounding.
name: Reduces confounding
label: c
answer: no
explanation: RCTs have low external validity. External validity is the extent to which the outcomes observed in the study apply to the people outside the sample included in the trial. RCTs may not be generalisable outside of the study group for many reasons, e.g. inclusion criteria for the study may not be representative of the general population.
name: Increases external validity
label: b
answer: no

Correct answer: a
Which type of study provides lower-quality evidence than a case-control study?

Options:
explanation: Cohort studies provide some evidence for causal association. However, they are vulnerable to confounding.
name: Cohort study
label: c
answer: no
explanation: These provide the highest quality of evidence and have the lowest risk of bias.
name: Meta-analysis
label: d
answer: no
explanation: These studies can be descriptive or analytic, whereas the other studies are all analytic. Cross-sectional studies are also very vulnerable to confounding.
name: Cross-sectional study
label: a
answer: yes
explanation: These provide the highest quality of evidence and have the lowest risk of bias.
name: Systematic review
label: e
answer: no
explanation: RCTs have high-quality evidence for causal association. Randomisation of groups reduces the chances of confounding. They are experimental analytical studies.
name: Randomised control trial
label: b
answer: no

Correct answer: a
The cerebellum is key to motor learning in the brain.

Error signals come from which structure in the brain?

Options:
explanation: Other inputs to the cerebellum come from the spinal cord through mossy fibres. However, these carry proprioceptive information.
name: Spinal cord
label: b
answer: no
explanation: This is the output centre of the cerebellum. From here, signals will be sent to other structures.
name: Deep cerebellar nuclei
label: c
answer: no
explanation: Other inputs to the cerebellum come from the pons through mossy fibres. However, these carry information from the cortex.
name: Pons
label: e
answer: no
explanation: Purkinje cells in the cerebellum inhibit the deep cerebellar nuclei. They are involved in controlling output signals of the cerebellum
name: Purkinje cells
label: d
answer: no
explanation: Climbing fibres from the inferior olive in the brainstem carry error signals. These signals are thought to correct future movement.
name: Inferior olive
label: a
answer: yes

Correct answer: a
The prime supinator of the forearm when the elbow is flexed is innervated by which branch of the brachial plexus?

Options:
explanation: The musculocutaneous nerve innervates the biceps brachii which is the prime supinator of the flexed elbow.
name: Musculocutaneous nerve
label: a
answer: yes
explanation: The axillary nerve innervates the deltoid but does not innervate any supinating muscles.

<br>
name: Axillary nerve
label: e
answer: no
explanation: The radial nerve does innervate the supinator muscle but it is the prime mover of the extended elbow, not the flexed elbow.
name: Radial nerve
label: d
answer: no
explanation: The median nerve innervates most of the muscles in the anterior compartment of the forearm and hand, but no supinating muscles.
name: Median nerve
label: b
answer: no
explanation: The ulnar nerve innervates the flexor carpi ulnaris, medial interossei, lumbricals, hypothenar muscles and medial heads of the flexor digitorum profundus, but no supinating muscles.
name: Ulnar nerve
label: c
answer: no

Correct answer: a
After a fall on an outstretched hand, which carpal bone is most at risk of proximal avascular necrosis?

Options:
explanation: The lunate is supplied by the branches of the deep palmar arch between the radial and ulnar arteries. Although it can undergo avascular necrosis (Kienbock's disease), proximal avascular necrosis of the lunate bone is not associated with a fall on the outstretched hand.
name: Lunate
label: c
answer: no
explanation: The pisiform is supplied by the dorsal carpal, lateral pedicle and lower pedical branches of the ulnar artery. Pisiform fractures are typically associated with direct trauma, however, avascular necrosis is very rare.

<br>
name: Pisiform
label: e
answer: no
explanation: The hamate is supplied by the branches of the deep palmar arch between the radial and ulnar arteries. Although the hook of the hamate is at risk of avascular necrosis after fracture, the proximal aspect of the hamate is not.
name: Hamate
label: b
answer: no
explanation: The trapezoid is supplied by numerous branches of the deep palmar arch between the radial and ulnar arteries. Avascular necrosis of the trapezoid is rare and is known to spontaneously resolve.
name: Trapezoid
label: d
answer: no
explanation: The scaphoid bone has a retrograde arterial supply from the radial artery as it passes through the anatomical snuffbox, around the thumb, and back towards the wrist. This retrograde supply means a break can compromise the vascular supply to the proximal fragment, leading to avascular necrosis.
name: Scaphoid
label: a
answer: yes

Correct answer: a
Which of the following describes the motor signs seen upon lower ulnar nerve severance?

Options:
explanation: This is a description of the ulnar claw hand. Froment's sign will also be positive as a patient with ulnar nerve damage has to use flexor pollicis longus and brevis to grip a piece of paper between their thumb and index finger due to paralysis of the adductor pollicis.
name: Extension of the metacarpophalangeal joint with flexion of the interphalangeal joints in the ring and little finger
label: a
answer: yes
explanation: This is a description of wrist drop, the result of radial nerve injury in which muscles of the extensor compartment of the forearm are paralysed, often as a result of compression or penetrating trauma.
name: Inability to extend carpometacarpal, metacarpophalangeal or interphalangeal joints in each finger
label: c
answer: no
explanation: This is a description of Klumpke's palsy, the result of inferior brachial plexus root T1 and C8 avulsion when the arm is abducted and pulled superiorly, which sometimes occurs during childbirth.
name: Extension of the metacarpophalangeal joint with flexion of the interphalangeal joints in each finger
label: b
answer: no
explanation: This is a description of Erb's palsy, the result of superior brachial plexus root C5 and C6 avulsion when the arm is adducted and pushed inferiorly. This typically occurs in babies who have difficult deliveries (usually due to shoulder dystocia or fetal macrosomia).

<br>
name: Adduction and internal rotation of the shoulder, extension of the elbow, pronation of the forearm and flexion of the wrist
label: e
answer: no
explanation: This is a description of the sign of Benediction which is a result of median nerve injury. It is usually accompanied by thenar muscle wasting.
name: Inability to flex the thumb, index or middle finger
label: d
answer: no

Correct answer: a
What is the anti-natal function of the ligament found in adults at the same spinal level as the sternal angle?

Options:
explanation: The foramen ovale allows the shunting of oxygenated blood from the inferior vena cava and right atrium to the left atrium. Once a baby takes its first breaths and the pulmonary circulation opens, the decrease in pulmonary resistance causes the left atrial pressure to exceed the right atrial pressure, forcing the foramen ovale to close. It then fuses shut, becoming the fossa ovalis.
name: To shunt oxygenated blood from the right side of the heart to the left side of the heart
label: c
answer: no
explanation: The ductus arteriosus shunts blood from the left pulmonary artery to the arch of the aorta, bypassing the foetal lungs. This blood comes from 2 places: the deoxygenated superior vena cava and the oxygenated inferior vena cava (this blood has picked up oxygen from the maternal circulation in the placenta). In actuality, only some blood passes through the ductus arteriosum, with most of it passing through the foramen ovale. Within hours of birth, the withdrawal of maternal prostaglandins causes closure and eventual fibrosis of the ductus arteriosus, resulting in the ligamentum arteriosum.
name: To shunt partially oxygenated blood from the pulmonary circulation to the systemic circulation
label: a
answer: yes
explanation: Although the formation of the recurrent laryngeal nerve does occur inferior to the ductus arteriosus, and the descent of the fetal heart does necessitate the long path of the recurrent laryngeal nerve so it can return to its innervation targets in the 6th pharyngeal arch, this is not the function of the ductus arteriosus.
name: To guide the recurrent laryngeal nerve to its adult position
label: d
answer: no
explanation: The ductus venosus shunts blood from the umbilical vein to the inferior vena cava, and is inferior to the liver. This closes within 2-18 days of birth and fibroses to become ligamentum venosum.
name: To shunt oxygenated blood from the placental circulation to the inferior vena cava
label: b
answer: no
explanation: Although the ductus arteriosus does physically join the left pulmonary artery and arch of the aorta, its main role is to shunt blood from the pulmonary circulation to the systemic circulation.

<br>
name: To maintain the relative positions of the vessels within the mediastinum
label: e
answer: no

Correct answer: a
The thoracic duct passes from the abdomen to the thorax at which spinal level?

Options:
explanation: T8 is the level at which the inferior vena cava passes through the diaphragm.
name: T8
label: c
answer: no
explanation: T10 is the level at which the oesophagus passes behind the right crux of the diaphragm before joining the stomach at T11.
name: T10
label: d
answer: no
explanation: L1 is the transpyloric plane, containing the pylorus, duodenojejunal flexure, pancreatic neck, fundus of the gallbladder, splenic hilum, renal hila, portal vein origin, 2nd part of the duodenum, origin of the superior mesenteric artery, 9th costal cartilages and the termination of the spinal cord.

<br>
name: L1
label: e
answer: no
explanation: The thoracic duct arises from the upper extremity of the cisterna chyli in the abdomen at T12 and immediately passes through the aortic hiatus of the diaphragm (also at T12) into the posterior mediastinum.
name: T12
label: a
answer: yes
explanation: The sternal angle (T4/5) contains the structures denoted by the acronym RATPLANT:

* Rib 2,
* Aortic arch,
* Tracheal bifurcation
* Pulmonary trunk bifurcation
* Ligamentum arteriosum (and left recurrent laryngeal nerve)
* Azygos vein
* Nerves (cardiac plexus)
* Thoracic duct switch from right to left.
name: T4/5
label: b
answer: no

Correct answer: a
Which dermatomes may pain refer to if the diaphragm is irritated?

Options:
explanation: The least splanchnic nerve with roots from T12 supplies the hindgut and can cause suprapubic pain in pathologies such as diverticulitis.
name: T12
label: d
answer: no
explanation: The sympathetic nerves with roots from T2-4 supply the heart. Pain can be referred to these dermatomes during angina, causing chest pain.
name: T2-4
label: b
answer: no
explanation: The greater splanchnic nerve with roots from T7-9 supplies the foregut and can cause epigastric pain in pathologies such as gastric ulcers.

<br>
name: T7-9
label: e
answer: no
explanation: The lesser splanchnic nerve with roots from T10-11 supplies the midgut and can cause periumbilical pain in pathologies such as early appendicitis.
name: T10-11
label: c
answer: no
explanation: The phrenic nerve originates from C3-5, innervates the diaphragm, and may be irritated by stimuli such as blood from ruptured ectopic pregnancy. Irritation of the phrenic nerve can cause shoulder pain.
name: C3-5
label: a
answer: yes

Correct answer: a
Which two structures join at the same spinal level as the hila of the kidneys?

Options:
explanation: The right and left main bronchi join at T4/5 to form the trachea.
name: The right and left main bronchi
label: c
answer: no
explanation: The left and right common iliac veins join at T5 to form the inferior vena cava.
name: The left and right common iliac veins
label: b
answer: no
explanation: The portal vein is formed at the transpyloric plane of L1 from the junction of the splenic vein and the superior mesenteric vein.
name: The splenic vein and the superior mesenteric vein
label: a
answer: yes
explanation: The ileocaecal junction is typically found in the right iliac fossa at more inferior lumbar levels than L1.
name: The ileum and the caecum
label: d
answer: no
explanation: The thoracic duct arises from the upper extremity of the cisterna chyli at T12, superior to the hila of the kidneys at L1.

<br>
name: Cisterna chyli and the thoracic duct
label: e
answer: no

Correct answer: a
Which of these statements about the greater omentum is true?

Options:
explanation: The greater omentum, although lacking muscular tissue, moves to sites of infection within the peritoneum to reduce spread and prevent extensive peritonitis.
name: The position of the greater omentum is fixed
label: c
answer: no
explanation: The posterior mesentery suspends the alimentary canal from the peritoneum. Both structures are derived from peritoneal folds, the mesentery from 2 layers and the greater omentum from 4.
name: The greater omentum suspends the alimentary canal from the peritoneum
label: d
answer: no
explanation: The greater omentum is supplied by the left and right epiploic arteries, arising from the anastomotic right and left gastro-epiploic arteries, each derived from branches of the coeliac trunk.
name: The greater omentum is avascular
label: b
answer: no
explanation: One function of the greater omentum is the storage of visceral fat, which can be mobilised in catabolic states and deposited during caloric excess. This fat contributes more significantly to the development of metabolic syndrome and its complications than subcutaneous fat.

<br>
name: The greater omentum has no metabolic function
label: e
answer: no
explanation: The greater omentum is formed embryonically from 4 layers of peritoneum folded inferiorly from the bilayer between the greater curve of the stomach and the transverse colon.
name: The greater omentum is a peritoneal structure
label: a
answer: yes

Correct answer: a
Through which of these structures must the descending testicle pass last to reach its adult position?

Options:
explanation: The gubernaculum is the hyaluronic acid-rich column of extracellular matrix which spans between the inferior pole of the gonad and the scrotum. Its non-contractile shortening is what 'pulls' the testis to its adult position.
name: Gubernaculum
label: c
answer: no
explanation: When passing through the abdominal wall, the testis descends laterally to the rectus abdominis. This occurs through the deep and superficial inguinal rings, the latter of which is found in the inguinal (Hesselbach's) triangle, the medial border of which is the rectus abdominis (the inferior border is the inguinal ligament, and the lateral border is the inferior epigastric vessels).
name: Rectus abdominis
label: b
answer: no
explanation: The Foramen magnum is found at the base of the skull. It is the foramen through which structures including the conversion of the medulla oblongata to the spinal cord, the meninges, the spinal root of cranial nerve 11, the anterior and posterior spinal arteries and the vertebral arteries pass.

<br>
name: Foramen magnum
label: e
answer: no
explanation: The descending testis must pass through the parietal peritoneum. This results in a connection known as processus vaginalis. This connection closes, seals and disintegrates during development, leaving the tunica vaginalis covering the testis in the adult scrotum.
name: Parietal peritoneum
label: a
answer: yes
explanation: The epiploic foramen (the foramen of Winslow) is a connection between the greater and lesser sacs of the peritoneum found inferiorly to the caudate lobe of the liver and bounded by the free edge of the lesser omentum (containing the hepatic artery, portal vein and common bile duct) anteriorly, the inferior vena cava posteriorly and the 1st part of the duodenum inferiorly.
name: Epiploic foramen
label: d
answer: no

Correct answer: a
A student trips and everts their ankle.

To which bony structure do their sprained ligaments most likely attach?

Options:
explanation: The deltoid ligament is comprised of 4 components, each of which attaches to the medial malleolus of the tibia:

1. The posterior tibiotalar ligament connects the medial malleolus to the posterosuperior aspect of the talus.
2. The tibiocalcaneal ligament connects the medial malleolus to the sustenaculum tali of the calcaneus/
3. The tibionavicular ligament connects the medial malleolus to the medial aspect of the navicular bone
4. The anterior tibiotalar ligament connects the tip of the medial malleolus to the anterosuperior aspect of the talus.

Eversion stretches these ligaments, leading to sprain or tear.
name: Medial malleolus
label: a
answer: yes
explanation: The lateral malleolus connects to 3 main lateral ligaments: the posterior talofibular ligament, the calcaneofibular ligament and the anterior talofibular ligament. These are stretched upon inversion of the ankle.
name: Lateral malleolus
label: b
answer: no
explanation: The 2 most relevant structures which attach to the 5th metatarsal are the fibularis brevis and fibularis tertius tendons. These are responsible for some of the dorsiflexion and eversion of the ankle and are shortened, rather than stretched, upon ankle inversion and are therefore not vulnerable to injury by this mechanism.
name: 5th metatarsal
label: c
answer: no
explanation: The most significant ligaments joining to the cuboid are the plantar calcaneocuboid ligament (short plantar ligament) and the long plantar ligament. These are at risk of injury from mechanisms causing excessive stress on the arch of the foot rather than eversion.
name: Cuboid
label: d
answer: no
explanation: The lateral cuneiform has short, strong, fibrous attachments to each of its surrounding bones such as the cuboid, middle cuneiform and navicular bone. None of these are particularly at risk in ankle eversion injuries.

<br>
name: Lateral cuneiform
label: e
answer: no

Correct answer: a
During a bike accident, a student lacerates the proximal lateral aspect of their leg below the knee.

Which of the following describes their most likely peripheral nerve injury?

Options:
explanation: Plantarflexion of the foot is performed by the gastrocnemius, soleus, flexor hallucis longus, flexor digitorum and tibialis posterior. The tibial nerve provides the motor component to each of these, not the fibular nerve.
name: Inability to plantarflex their foot
label: b
answer: no
explanation: Active inversion and plantarflexion of the ankle are performed by the tibialis posterior which is innervated by the tibial nerve. This is opposed to the tibialis anterior which actively inverts and dorsiflexes the ankle and is innervated by the deep branch of the fibular nerve - this would be affected by severance of the common fibular nerve.
name: Inability to actively invert and plantarflex their ankle
label: c
answer: no
explanation: Sensation of the skin in the popliteus is supplied by the posterior femoral nerve's cutaneous branch, which arises from the tibial portion of the sciatic nerve rather than the common fibular nerve. In a fibular nerve injury, sensation to the lower limb would be affected in the distribution of the sural (skin on the lower posterior leg and small toe), superficial fibular (skin on the lower lateral leg and the medial 4 toes) and deep fibular nerves (small triangle on the superior aspect of the skin between the hallux and second toe).
name: Inability to feel touch sensation in their popliteus
label: d
answer: no
explanation: The common fibular nerve passes superficially around the neck of the fibula below the knee and is at risk of injury in this case. This results in foot drop whereby the muscles of the anterior and lateral compartments of the leg, which dorsiflex the ankle and are innervated by the deep and superficial branches of the fibular nerve respectively, are paralysed.
name: Inability to dorsiflex their foot
label: a
answer: yes
explanation: The extension of the knee is mediated by the 4 components of the quadriceps: vastus medialis, vastus lateralis, vastus intermedius and rectus femoris. Each of these are innervated by the femoral nerve which has no branches that reach below the knee.

<br>
name: Inability to extend the knee
label: e
answer: no

Correct answer: a
The unhappy triad of O'Donoghue occurs upon valgus (inward) stress on the knees. It most commonly occurs when the foot is planted on the ground.

Which of the following describes one of the findings upon examination?

Options:
explanation: A positive posterior drawer test indicates posterior cruciate ligament (PCL) rupture which is not part of the unhappy triad of O'Donoghue. The PCL spans from the posterior intercondylar area to the posterolateral aspect of the medial femoral condyle and stops the femur from slipping forwards on the tibia.
name: Positive posterior drawer test
label: d
answer: no
explanation: Foot drop is the result of paralysis of the anterior compartment of the leg, and is most commonly due to common fibular nerve lesions. Although associated with trauma, it is not part of the unhappy triad of O'Donoghue.

<br>
name: Foot drop
label: e
answer: no
explanation: A positive anterior drawer test indicates an anterior cruciate ligament (ACL) rupture which is part of the unhappy triad of O'Donoghue, alongside a medial meniscus tear and medial collateral ligament tear. The ACL spans from the anterior intercondylar area to the posteromedial aspect of the lateral femoral condyle and stops the femur from slipping backwards on the tibia.
name: Positive anterior drawer test
label: a
answer: yes
explanation: This is McMurray's test for lateral meniscus tears. These tears are not part of the unhappy triad of O'Donoghue which consists of a medial meniscus tear, medial collateral ligament tear and anterior cruciate ligament (ACL) rupture.
name: Click and discomfort upon varus stress, internal rotation and extension of the knee
label: b
answer: no
explanation: Tenderness over the lateral joint line is indicative of a lateral meniscus tear or lateral collateral ligament tear, neither of which are part of the unhappy triad of O'Donoghue. These tears would be produced upon varus stress to the leg such as when running and stopping suddenly by bracing against a planted foot with the foot internally rotated.
name: Tenderness over the lateral joint line
label: c
answer: no

Correct answer: a