Chapter: Heart – Surface Anatomy & Venous Drainage; Topic: Cardiac Veins and Coronary Sinus; Subtopic: Great Cardiac Vein Course and Clinical Relevance
Keyword Definitions:
Great cardiac vein: Main vein of the anterior interventricular (IV) groove that drains much of the left ventricle.
Anterior interventricular sulcus: Groove on the anterior surface of the heart containing the left anterior descending artery and great cardiac vein.
Coronary sinus: Large venous channel on the posterior atrioventricular groove that collects most cardiac venous blood.
Small cardiac vein: Vein that runs in the right AV groove draining right ventricle into the coronary sinus.
Cardiac venous drainage: Network of veins that return deoxygenated blood from myocardium to right atrium via coronary sinus.
1) Lead Question – 2016
Great cardiac vein lies in ?
a) Tricuspid valve
b) Anterior interventricular sulcus
c) Posterior interventricular sulcus
d) None
Answer: b) Anterior interventricular sulcus
Explanation (≈100 words): The great cardiac vein runs in the anterior interventricular sulcus alongside the left anterior descending (LAD) artery, collecting venous blood from the anterior aspects of both ventricles and the interventricular septum. It ascends the sulcus to the left atrioventricular groove where it curves posteriorly to become the coronary sinus, which empties into the right atrium. Its anatomical association with the LAD makes it a consistent landmark in surgical and imaging procedures. Knowledge of this relationship is crucial during bypass grafting and coronary sinus cannulation for retrograde cardioplegia, as accidental injury may compromise myocardial venous drainage and complicate interventions.
2) The coronary sinus opens into the right atrium near the–
a) Interatrial septum
b) Tricuspid valve orifice
c) Aortic orifice
d) Pulmonary vein ostia
Answer: a) Interatrial septum
Explanation (≈100 words): The coronary sinus terminates in the right atrium in the posterior part of the atrioventricular (AV) groove, opening into the right atrium on the posterior inferior aspect of the atrial wall, close to the interatrial septum and just anterior to the inferior vena cava opening. The ostium is guarded by the Thebesian valve in many hearts. Its location near the septum and AV node region is clinically important for procedures like retrograde cardioplegia cannulation and electrophysiology interventions; inadvertent damage or misplacement here risks inadequate myocardial protection or arrhythmogenic complications. Recognising the sinus ostium landmarks ensures safe cardiac interventions.
3) The small cardiac vein typically runs in the–
a) Anterior IV sulcus
b) Posterior IV sulcus
c) Right AV groove (coronary sulcus)
d) Left AV groove
Answer: c) Right AV groove (coronary sulcus)
Explanation (≈100 words): The small cardiac vein courses in the right atrioventricular groove (coronary sulcus) along with the right coronary artery, collecting blood mainly from the right ventricle and right atrium before draining into the coronary sinus. Its position parallel to the right coronary artery makes it relevant during right-sided coronary interventions and valve surgery. Anatomical variations exist: the small cardiac vein may be absent or replaced by alternative drainage paths. Surgeons must account for this when dissecting the right AV groove to avoid unexpected bleeding or compromise of venous return, especially during coronary artery bypass or tricuspid valve procedures.
4) The posterior interventricular (middle cardiac) vein lies in the–
a) Anterior IV sulcus
b) Posterior IV sulcus
c) Right AV groove
d) Left atrioventricular groove
Answer: b) Posterior IV sulcus
Explanation (≈100 words): The posterior interventricular, or middle cardiac, vein travels in the posterior interventricular sulcus parallel to the posterior descending artery (PDA). It drains the posterior aspects of both ventricles and empties into the coronary sinus near its termination. This anatomical pairing mirrors the great cardiac vein–LAD relationship on the anterior surface but on the inferior posterior aspect. During posterior ventricular repairs, occlusion, or ablation procedures, recognition of the middle cardiac vein’s course is essential to avoid venous injury. Its consistent location also aids radiologic interpretation of posterior myocardial perfusion and venous anatomy in invasive cardiology.
5) Retrograde cardioplegia is delivered via–
a) Pulmonary veins
b) Coronary sinus
c) Aortic root only
d) Superior vena cava
Answer: b) Coronary sinus
Explanation (≈100 words): Retrograde cardioplegia is administered into the coronary sinus to perfuse the coronary venous system in a direction opposite to normal blood flow, allowing myocardial protection in cases of proximal coronary occlusion or poor antegrade distribution. Cannulation of the coronary sinus requires knowledge of its size, Thebesian valve, and relationship to adjacent structures to avoid perforation. This technique supplements antegrade cardioplegia via the aortic root and is invaluable when coronary ostia are diseased or inaccessible. Effective retrograde delivery hinges on intact venous channels like the great cardiac and middle cardiac veins, which distribute the cardioplegic solution to myocardial territories.
6) In coronary artery bypass grafting (CABG), the great cardiac vein is important because–
a) It is used as a graft conduit
b) It indicates the location of the LAD artery
c) It supplies arterial blood to myocardium
d) It drains directly into the right ventricle
Answer: b) It indicates the location of the LAD artery
Explanation (≈100 words): The great cardiac vein’s consistent parallel course with the left anterior descending artery makes it a reliable surface landmark for identifying the LAD during CABG or epicardial procedures. Surgeons use this venous groove to localise the artery for graft anastomosis or to plan approaches for ventricular repairs. The great cardiac vein itself is not suitable as an arterial graft and does not supply arterial blood. Careful dissection around this vein is required to avoid bleeding and to preserve venous drainage. Thus, its chief surgical significance lies in guiding access to the LAD and adjacent anterior wall territories.
7) Anomalous drainage of the coronary sinus into the left atrium causes–
a) Left-to-right shunt
b) Right-to-left shunt and systemic desaturation
c) No physiological effect
d) Increased coronary perfusion pressure
Answer: b) Right-to-left shunt and systemic desaturation
Explanation (≈100 words): If the coronary sinus drains into the left atrium instead of the right atrium, deoxygenated venous blood from the myocardium mixes with oxygenated systemic arterial blood, creating a right-to-left shunt. This can produce systemic arterial desaturation and cyanosis, especially if large. Such anomalous venous return may be associated with congenital defects like unroofed coronary sinus or persistent left superior vena cava. Clinically, unexplained hypoxemia, paradoxical embolism, or atypical echocardiographic findings prompt investigation for venous drainage anomalies. Surgical correction may be required depending on symptom severity and associated anomalies.
8) During electrophysiological ablation for atrial fibrillation, why is knowledge of coronary venous anatomy useful?
a) It helps locate pulmonary veins only
b) Coronary veins serve as landmarks and potential ablation routes
c) Coronary veins carry electrical impulses only
d) They are not relevant
Answer: b) Coronary veins serve as landmarks and potential ablation routes
Explanation (≈100 words): Coronary venous anatomy is useful during electrophysiology because veins such as the great cardiac vein and the coronary sinus provide stable landmarks for catheter navigation and positioning. The coronary sinus itself is commonly cannulated to access left atrial and left ventricular regions, and adjacent veins can be used to deliver energy for epicardial ablation or mapping of arrhythmogenic foci. Misunderstanding venous paths risks coronary injury or ineffective lesion placement. Therefore, precise venous mapping optimises ablation strategies and minimises complications like coronary vein perforation or inadvertent damage to nearby coronary arteries.
9) Thebesian veins are–
a) Large veins collecting into the coronary sinus only
b) Minute intramyocardial veins draining directly into cardiac chambers
c) Veins supplying arterial blood
d) Branches of the pulmonary veins
Answer: b) Minute intramyocardial veins draining directly into cardiac chambers
Explanation (≈100 words): Thebesian veins are tiny valveless venous channels within the myocardium that drain directly into all four cardiac chambers, predominately the right atrium and right ventricle. They provide a minor but direct route for myocardial venous blood to enter the cardiac chambers, bypassing the coronary sinus. While individually small, their collective effect contributes to physiologic shunting and influences oxygen tension gradients within the heart. They are distinct from the larger epicardial cardiac veins that converge into the coronary sinus. Recognising Thebesian drainage is relevant in interpreting intracardiac oxygen measurements and in certain rare pathological conditions.
10) Occlusion of the coronary sinus would most likely cause–
a) Increased arterial inflow to myocardium
b) Impaired venous drainage of the heart and potential myocardial edema/ischemia
c) Immediate myocardial infarction due to arterial occlusion
d) No clinical consequence
Answer: b) Impaired venous drainage of the heart and potential myocardial edema/ischemia
Explanation (≈100 words): Thrombosis or surgical ligation of the coronary sinus impedes major myocardial venous outflow, leading to venous congestion, elevated myocardial interstitial pressure, reduced perfusion gradients, and potential subendocardial ischemia or edema. Although arterial flow remains, compromised venous return can impair oxygen delivery and waste removal, worsening myocardial function. Clinically, coronary sinus obstruction may present with myocardial dysfunction, arrhythmias, or chest pain and requires prompt recognition and management. This underscores the importance of preserving coronary sinus patency during cardiac procedures and of monitoring venous drainage integrity in postoperative patients.
Chapter: Lungs & Pleura; Topic: Apex & Cervical Pleura (Cupula)
Keyword Definitions:
Lung apex: Superior-most part of the lung projecting above the clavicle into the neck.
Cupula (cervical pleura): Parietal pleura covering the lung apex and extending into the neck above the clavicle.
Sibson’s fascia: Suprapleural membrane reinforcing the thoracic inlet over the cupula.
Clavicle: Anterior bony landmark used to estimate the apex position; apex commonly projects 2–3 cm above its medial third.
Pancoast (superior sulcus) tumor: Apical lung tumor that invades local structures producing shoulder/arm symptoms.
1) Lead Question – 2016
Apex of the lung lies at what level?
a) Above the clavicle
b) Below the clavicle
c) At the level of the clavicle
d) None
Explanation (includes answer): The lung apex projects into the root of the neck and extends above the medial part of the clavicle; classically it reaches about 2–3 cm superior to the medial third of the clavicle. This superior extension is covered by the cervical pleura (cupula) and is reinforced externally by Sibson’s fascia (suprapleural membrane). Clinically the apical lung position is important because penetrating neck injuries or apical tumours may involve pleura, subclavian vessels, brachial plexus roots or sympathetic chain. Therefore the correct answer is (a) Above the clavicle.
2) The cervical pleura (cupula) is reinforced by which structure?
a) Sibson’s fascia (suprapleural membrane)
b) Prevertebral fascia
c) Thoracoabdominal diaphragm
d) Scalenus posterior
Explanation (includes answer): The cervical pleura (cupula) is reinforced by Sibson’s fascia, also called the suprapleural membrane, which is a thickening of the prevertebral fascia attaching to the inner border of the first rib and the transverse process of C7. This membrane stabilizes the cupula against intrathoracic pressure changes and protects the thoracic inlet contents. It is clinically relevant in high neck injuries and in surgical approaches to the thoracic inlet. Thus the correct answer is (a) Sibson’s fascia (suprapleural membrane).
3) A Pancoast (superior sulcus) tumour typically produces which clinical sign?
a) Horner’s syndrome
b) Dysphagia only
c) Wrist drop
d) Loss of knee jerk
Explanation (includes answer): A Pancoast tumour at the lung apex invades nearby structures including the stellate (cervicothoracic) ganglion and lower cervical sympathetic chain, producing Horner’s syndrome—ptosis, miosis, and anhidrosis on the affected side. It may also involve brachial plexus roots causing shoulder/arm pain and muscle weakness, but the classic apical tumour sign is Horner’s syndrome. Dysphagia, wrist drop, or knee reflex loss are not characteristic primary signs. Therefore the correct answer is (a) Horner’s syndrome.
4) The apex of the lung is most closely related posteriorly to which vertebral level approximately?
a) C7–T1 region
b) T4–T5 region
c) T10 region
d) L1 region
Explanation (includes answer): The lung apex lies at the thoracic inlet around the root of the neck, roughly opposite the C7–T1 vertebral level posteriorly. This region corresponds to the upper thoracic inlet and explains why apical processes can affect lower cervical structures. Mid and lower thoracic vertebral levels (T4–T5 and below) are far inferior. Clinically, this relation matters for imaging and for understanding spread of apical tumours to adjacent vertebral or neural structures. Hence the correct answer is (a) C7–T1 region.
5) During central line insertion, an inadvertent puncture of the lung apex is most likely when placing which line?
a) Subclavian central venous catheter (infraclavicular approach)
b) Internal jugular central line
c) Femoral central line
d) Transfemoral arterial line
Explanation (includes answer): The subclavian (infraclavicular) approach to central venous catheterisation carries a risk of pneumothorax because the lung apex and cervical pleura extend above the clavicle and lie close to the subclavian vein. A misplaced needle or dilator can puncture the cupula causing apical pneumothorax. Internal jugular, femoral, and transfemoral approaches pose different complications but are less likely to puncture the lung apex. Thus the correct answer is (a) Subclavian central venous catheter (infraclavicular approach).
6) The apex beat of the heart is normally felt in which intercostal space at the midclavicular line?
a) 5th intercostal space
b) 2nd intercostal space
c) 8th intercostal space
d) 1st intercostal space
Explanation (includes answer): Although not directly about the lung apex, knowledge of thoracic surface anatomy is essential. The cardiac apex beat is normally palpated in the left 5th intercostal space at the midclavicular line, corresponding to the left ventricle apex. This contrasts with the lung apex which is high in the neck. Clinically, displacement of the apex beat indicates cardiomegaly or chest wall shift. Therefore the correct answer is (a) 5th intercostal space.
7) Excision of the apex of the lung (apical resection) risks injury to which important neural structure located nearby?
a) Brachial plexus roots (lower trunks)
b) Phrenic nerve in the neck only
c) Hypoglossal nerve
d) Recurrent laryngeal nerve
Explanation (includes answer): The lung apex lies adjacent to the lower roots/trunks of the brachial plexus (C8–T1 region) and the stellate ganglion; apical lung surgery (e.g., for Pancoast tumours) risks damage to these neural structures causing upper limb sensory/motor deficits and sympathetic dysfunction. While the phrenic nerve runs more anteriorly and recurrent laryngeal nerves are more medial, the most at-risk neural elements for apical procedures are the lower brachial plexus components and stellate ganglion. Thus the correct answer is (a) Brachial plexus roots (lower trunks).
8) On a chest radiograph, the cervical pleura (cupula) may be visible above the clavicle; which projection best demonstrates a pneumothorax at the lung apex?
a) Upright inspiratory chest radiograph with inspiration-expiration views
b) Supine AP film only
c) Lateral decubitus with patient lying on affected side
d) Prone film
Explanation (includes answer): An upright inspiratory chest radiograph with an additional expiratory or inspiratory–expiratory comparison increases sensitivity for detecting small apical pneumothoraces because free air rises to the apex and is best seen with the patient erect. Supine films are less sensitive for apical air, and lateral decubitus techniques are used for pleural effusions rather than apical pneumothorax. Therefore the correct answer is (a) Upright inspiratory chest radiograph with inspiration-expiration views.
9) The subclavian artery crosses relative to the lung apex; injury to the lung apex may cause which vascular complication?
a) Hemothorax from subclavian vessel injury
b) Leg ischemia
c) Mesenteric infarction
d) Portal vein thrombosis
Explanation (includes answer): Because the subclavian vessels and the apex of the lung are in close proximity at the thoracic inlet, penetrating trauma or iatrogenic injury at the apex can lacerate the subclavian artery or vein producing a hemothorax (blood in pleural cavity). This is an important and potentially life-threatening complication. The other options (leg ischemia, mesenteric infarction, portal vein thrombosis) are unrelated to apical thoracic injury. Therefore the correct answer is (a) Hemothorax from subclavian vessel injury.
10) In ultrasound-guided regional anaesthesia for brachial plexus block at the supraclavicular level, knowledge of lung apex position is important to avoid–
a) Pneumothorax
b) Phlebitis only
c) Retroperitoneal hemorrhage
d) Deep vein thrombosis
Explanation (includes answer): During supraclavicular brachial plexus block, the needle is placed near the subclavian artery and the lung apex (cupula) lies immediately posterior and inferior; inadvertent pleural puncture can produce pneumothorax. Hence ultrasound guidance and awareness of the lung apex location reduce this risk. Phlebitis, retroperitoneal hemorrhage, and DVT are not typical direct complications of this procedure. Thus the correct answer is (a) Pneumothorax.
Chapter: Thorax; Topic: Diaphragm; Subtopic: Nerve Supply, Openings & Clinical Anatomy
Keyword Definitions:
Phrenic nerve: Main motor nerve of the diaphragm arising from C3–C5 spinal roots.
Cervical roots (C3–C5): Roots contributing to phrenic nerve; “C3,4,5 keep the diaphragm alive.”
Crura of diaphragm: Musculotendinous pillars attaching diaphragm to lumbar vertebrae.
Hiatuses: Three major openings—T8 IVC, T10 esophagus, T12 aorta.
Central tendon: Strong aponeurotic part of diaphragm receiving phrenic nerve sensory fibres.
1) Lead Question – 2016
Diaphragm is supplied by ?
a) Phrenic nerve
b) C2, C3, C4 roots
c) Thoracodorsal nerve
d) Long thoracic nerve
Answer: a) Phrenic nerve
Explanation: The diaphragm receives its entire motor supply from the **phrenic nerve**, arising from cervical roots C3, C4, and C5. Although the roots are C3–C5, the nerve itself is the functional motor supply, making option (a) correct. The phrenic nerve also carries central sensory fibres supplying the central tendon, mediastinal pleura, and diaphragmatic pleura. The thoracodorsal and long thoracic nerves supply muscles of the upper limb and thorax, not the diaphragm. Damage to the phrenic nerve results in diaphragmatic paralysis and paradoxical movement, clinically important during neck trauma or thoracic surgery.
2) The sensory supply of the peripheral diaphragm is via–
a) Vagus nerve
b) Intercostal nerves
c) Glossopharyngeal nerve
d) Long thoracic nerve
Answer: b) Intercostal nerves
Explanation: Peripheral parts of the diaphragm receive sensory supply from intercostal nerves (T5–T11). This explains referred pain to the thoracic wall.
3) The diaphragm develops from all except–
a) Septum transversum
b) Pleuroperitoneal membranes
c) Dorsal mesentery of esophagus
d) Somites of cervical region (C3–C5)
Answer: d) Somites of cervical region (C3–C5)
Explanation: Cervical somites do not form diaphragm tissue; they only contribute phrenic nerve fibres.
4) A penetrating injury at the neck near the anterior scalene risks paralysis of–
a) Diaphragm
b) Deltoid
c) Pectoralis major
d) Wrist extensors
Answer: a) Diaphragm
Explanation: The phrenic nerve runs on the anterior scalene; injury causes diaphragmatic paralysis.
5) The aortic hiatus is located at–
a) T8
b) T10
c) T12
d) L1
Answer: c) T12
Explanation: Aortic hiatus at T12 transmits aorta, thoracic duct, and azygous vein.
6) The IVC passes through the diaphragm at which part?
a) Muscular portion
b) Central tendon
c) Right crus
d) Left crus
Answer: b) Central tendon
Explanation: IVC passes through the central tendon at T8, preventing compression during respiration.
7) Left phrenic nerve palsy results in–
a) Elevated left dome of diaphragm
b) Elevated right dome
c) Bilateral elevation
d) No change
Answer: a) Elevated left dome of diaphragm
Explanation: Paralysis causes paradoxical upward movement on inspiration and elevation on imaging.
8) Herniation through the esophageal hiatus most commonly leads to–
a) Sliding hiatal hernia
b) Morgagni hernia
c) Lumbar hernia
d) Umbilical hernia
Answer: a) Sliding hiatal hernia
Explanation: The esophageal hiatus enlargement leads to sliding gastroesophageal herniation.
9) The structure passing anterior to the root of the lung and close to the diaphragm is–
a) Phrenic nerve
b) Vagus nerve
c) Recurrent laryngeal nerve
d) Sympathetic chain
Answer: a) Phrenic nerve
Explanation: Phrenic nerve passes anterior to the lung root and descends to the diaphragm.
10) The right crus of diaphragm gives fibers forming the–
a) Aortic sphincter
b) Esophageal sphincter
c) Pulmonary sphincter
d) IVC sphincter
Answer: b) Esophageal sphincter
Explanation: Right crus fibers contribute to lower esophageal sphincter function.
11) Complete failure of pleuroperitoneal membrane fusion results in–
a) Bochdalek hernia
b) Sliding hernia
c) Incisional hernia
d) Paraumbilical hernia
Answer: a) Bochdalek hernia
Explanation: Posterolateral congenital diaphragmatic hernia (Bochdalek) arises from membrane fusion failure.
Chapter: Abdomen; Topic: Surface Anatomy; Subtopic: Anatomical Planes & Landmarks
Keyword Definitions:
Suprasternal notch: Superior border of manubrium, palpable central depression.
Pubic symphysis: Midline fibrocartilaginous joint uniting pubic bones.
Transpyloric plane: Horizontal plane at L1, midway between suprasternal notch and pubic symphysis.
Transtubercular plane: Horizontal plane through iliac tubercles at L5.
Xiphisternal plane: Transverse plane through xiphisternal joint at T9.
1) Lead Question – 2016
Midpoint between suprasternal notch and pubic symphyses passes through which plane?
a) Transpyloric plane
b) Transtubercular plane
c) Trnasxiphoid plane
d) None
Answer: a) Transpyloric plane
Explanation: The **transpyloric plane** lies at the midpoint between the suprasternal notch and the pubic symphysis. It crosses the L1 vertebra and is an important landmark because it corresponds to structures such as the pylorus of the stomach, neck of pancreas, origin of the superior mesenteric artery, and the hila of kidneys. The transtuberular plane lies much lower at L5, and the transxiphoid plane is higher near the diaphragm. Thus, only the transpyloric plane represents this anatomical midway line, making option (a) the correct choice.
2) The transpyloric plane passes through which vertebral level?
a) T12
b) L1
c) L3
d) L4
Answer: b) L1
Explanation: The transpyloric plane classically lies at the level of **L1**, crossing key abdominal structures.
3) Which structure is located on the transpyloric plane?
a) IVC bifurcation
b) Pylorus
c) Aortic bifurcation
d) Iliac crest
Answer: b) Pylorus
Explanation: The pylorus of the stomach corresponds to the transpyloric plane.
4) A stab wound at L1 level in midline may damage which structure?
a) Pancreatic neck
b) Rectum
c) Spleen
d) Cecum
Answer: a) Pancreatic neck
Explanation: The neck of the pancreas lies along the transpyloric plane.
5) Which of the following is NOT crossed by the transpyloric plane?
a) Origin of SMA
b) Fundus of stomach
c) Renal hili
d) Portal vein formation
Answer: b) Fundus of stomach
Explanation: Fundus lies higher under left dome of diaphragm.
6) The xiphisternal joint corresponds to which vertebral level?
a) T7
b) T8
c) T9
d) T10
Answer: c) T9
Explanation: Xiphisternal joint marks inferior limit of thoracic cavity.
7) The intertubercular plane passes through–
a) L1
b) L2
c) L4
d) L5
Answer: d) L5
Explanation: It acts as a lower abdominal landmark through iliac tubercles.
8) Surface marking of SMA origin is at–
a) T12
b) L1
c) L2
d) L3
Answer: b) L1
Explanation: SMA originates at the transpyloric plane.
9) The gallbladder fundus lies at intersection of transpyloric plane and–
a) Midclavicular line
b) Midaxillary line
c) Midsternal line
d) Anterior axillary line
Answer: a) Midclavicular line
Explanation: This corresponds to the surface landmark of the gallbladder.
10) Pain referred to the shoulder from diaphragm irritation occurs due to involvement of–
a) T7
b) T10
c) C3–C5
d) L1
Answer: c) C3–C5
Explanation: Phrenic nerve supplies diaphragm; shoulder pain follows C4 dermatome.
11) Which plane divides the abdomen into upper and lower halves?
a) Subcostal plane
b) Transpyloric plane
c) Transtubercular plane
d) Iliac crest plane
Answer: c) Transtubercular plane
Explanation: The transtubercular plane at L5 is a major horizontal dividing plane.
Chapter: Back & Thorax; Topic: Thoracolumbar Fascia; Subtopic: Muscular Relations
Keyword Definitions:
Thoracolumbar fascia: A multilayered fascial complex in the lumbar region enclosing deep back and abdominal wall muscles.
Anterior layer: The deepest layer, covering quadratus lumborum anteriorly.
Middle layer: Lies posterior to quadratus lumborum, separating it from erector spinae.
Quadratus lumborum: Muscle extending from iliac crest to 12th rib, stabilizing the spine.
Psoas major: Hip flexor lying more medially, not between the TL fascia layers.
1) Lead Question – 2016
Muscle lying between anterior and middle layer of thoracolumbar fascia is ?
a) Psoas major
b) Quadratus Lumborum
c) Obdurator internus
d) External oblique
Answer: b) Quadratus lumborum
Explanation: The thoracolumbar fascia has three layers: anterior, middle, and posterior. The **quadratus lumborum** is located between the anterior and middle layers. The anterior layer covers the muscle from the front, while the middle layer lies posterior to it and separates it from the erector spinae group. Psoas major lies medial to these layers, and external oblique is superficial and not part of the fascial compartment. Thus, only quadratus lumborum fits the anatomical location precisely.
2) Which layer of thoracolumbar fascia forms the lateral raphe?
a) Anterior
b) Middle
c) Posterior
d) Deep investing fascia
Answer: c) Posterior
Explanation: The posterior layer thickens laterally to form the lateral raphe where abdominal wall muscles attach.
3) Quadratus lumborum receives nerve supply from–
a) Subcostal nerve
b) Ilioinguinal nerve
c) Genitofemoral nerve
d) L5 root
Answer: a) Subcostal nerve
Explanation: QL is supplied by T12 (subcostal nerve) and L1–L4 branches of lumbar plexus.
4) A patient with lateral bending weakness likely has injury to:
a) Quadratus lumborum
b) Psoas minor
c) Piriformis
d) Gluteus minimus
Answer: a) Quadratus lumborum
Explanation: QL is the primary lumbar lateral flexor.
5) Middle layer of thoracolumbar fascia attaches to:
a) Spinous processes
b) Transverse processes
c) Iliac crest only
d) Coccyx
Answer: b) Transverse processes
Explanation: The middle layer attaches to lumbar transverse processes and separates deep muscle groups.
6) Posterior layer of thoracolumbar fascia encloses:
a) Psoas major
b) Erector spinae
c) Quadratus lumborum
d) Rectus abdominis
Answer: b) Erector spinae
Explanation: The posterior layer surrounds the erector spinae mass completely.
7) Which muscle stabilizes 12th rib during inspiration?
a) External oblique
b) Quadratus lumborum
c) Transversus abdominis
d) Internal oblique
Answer: b) Quadratus lumborum
Explanation: QL fixes the 12th rib allowing diaphragm to act efficiently.
8) Thoracolumbar fascia contributes to origin of:
a) External oblique
b) Internal oblique
c) Rectus abdominis
d) Quadratus lumborum
Answer: b) Internal oblique
Explanation: Internal oblique and transversus abdominis partly arise from thoracolumbar fascia.
9) Psoas major lies anterior to which fascial layer?
a) Anterior
b) Middle
c) Posterior
d) Transversalis fascia
Answer: a) Anterior
Explanation: Psoas major is medial and anterior to the TL fascia system.
10) Injury to thoracolumbar fascia commonly presents with:
a) Pain on shoulder abduction
b) Low-back pain
c) Knee instability
d) Ankle inversion weakness
Answer: b) Low-back pain
Explanation: TL fascia stabilizes lumbar spine; damage causes chronic low-back strain.
11) Which muscle does *not* attach to thoracolumbar fascia?
a) Latissimus dorsi
b) Internal oblique
c) Transversus abdominis
d) Pectoralis minor
Answer: d) Pectoralis minor
Explanation: Pectoralis minor is a thoracic muscle unrelated to TL fascia.
Chapter: Anterior Abdominal Wall; Topic: Rectus Sheath; Subtopic: Anatomy & Applied Anatomy
Keyword Definitions:
Rectus sheath: Fibrous sheath enclosing rectus abdominis formed by abdominal muscle aponeuroses.
Arcuate line: A landmark below which all three aponeuroses pass anterior to rectus abdominis.
External oblique aponeurosis: Most superficial contributor to the anterior sheath throughout.
Internal oblique aponeurosis: Splits above arcuate line but passes fully anterior below it.
Transversus abdominis aponeurosis: Contributes posteriorly above arcuate line but fully anterior below it.
1) Lead Question – 2016
Anterior Rectus Sheath just above pubic symphysis is formed by ?
a) External Oblique Aponeurosis
b) The aponeurosis of three muscles including External Oblique, Internal Oblique, and Transversus Abdominis
c) Linea Alba
d) Internal Oblique only
Answer: b) The aponeurosis of three muscles including External Oblique, Internal Oblique, and Transversus Abdominis
Explanation: Below the arcuate line and particularly just above the pubic symphysis, the **anterior rectus sheath is formed by the aponeuroses of all three lateral abdominal muscles**—external oblique, internal oblique, and transversus abdominis. These fuse anteriorly, leaving no posterior sheath in this region. The linea alba is a midline fibrous structure, not the sheath itself. Internal oblique alone never forms the complete anterior sheath here. Therefore, the correct answer is the contribution of all three aponeuroses.
2) Above the arcuate line, the posterior rectus sheath is formed by:
a) External oblique only
b) Internal oblique and transversus abdominis
c) Transversus abdominis only
d) No muscle aponeurosis
Answer: b) Internal oblique and transversus abdominis
Explanation: Above the arcuate line, the internal oblique splits into anterior and posterior laminae; the posterior lamina combines with the aponeurosis of transversus abdominis to form the posterior rectus sheath.
3) Below the arcuate line, the posterior rectus sheath:
a) Becomes thicker
b) Is absent
c) Is formed by external oblique
d) Contains transversalis fascia
Answer: b) Is absent
Explanation: All three aponeuroses pass anteriorly below the arcuate line, so only transversalis fascia lies posterior to rectus abdominis.
4) A patient has a Spigelian hernia. Which layer is primarily defective?
a) External oblique
b) Internal oblique
c) Transversus abdominis
d) Transversalis fascia
Answer: c) Transversus abdominis
Explanation: Spigelian hernias occur along the semilunar line where transversus abdominis aponeurosis is weak or deficient.
5) The arcuate line corresponds to which vertebral level approximately?
a) L1
b) L2
c) S1
d) T12
Answer: a) L1
Explanation: The arcuate line is usually at the level of L1, marking the transition in sheath composition.
6) Which muscle lies inside the rectus sheath?
a) Pyramidalis
b) Transversus abdominis
c) Internal oblique
d) External oblique
Answer: a) Pyramidalis
Explanation: Pyramidalis lies anterior to rectus abdominis and inside the rectus sheath, inserting into linea alba.
7) A penetrating injury below the arcuate line risks damage to:
a) Superior epigastric artery
b) Inferior epigastric artery
c) Musculophrenic artery
d) Intercostal arteries
Answer: b) Inferior epigastric artery
Explanation: Inferior epigastric vessels ascend posterior to rectus until below the arcuate line where the sheath changes.
8) Linea alba is formed by fusion of:
a) Only external oblique
b) All three abdominal muscle aponeuroses
c) Rectus abdominis
d) Transversalis fascia
Answer: b) All three abdominal muscle aponeuroses
Explanation: The linea alba results from midline fusion of aponeuroses of external oblique, internal oblique, and transversus abdominis.
9) Rectus abdominis originates from:
a) Pubic crest
b) Xiphoid process
c) Costal margin
d) Iliac crest
Answer: a) Pubic crest
Explanation: Rectus abdominis arises from the pubic crest and symphysis and inserts into the 5th–7th costal cartilages.
10) Which structure passes between the layers of the rectus sheath?
a) Thoracodorsal vessels
b) Superior epigastric vessels
c) Short gastric arteries
d) Pudendal nerve
Answer: b) Superior epigastric vessels
Explanation: Superior epigastric artery descends within the sheath supplying the upper rectus region.
11) The semilunar line marks the lateral border of:
a) Transversus abdominis
b) External oblique
c) Rectus abdominis
d) Psoas major
Answer: c) Rectus abdominis
Explanation: The semilunar line is a curved tendinous margin forming the lateral border of the rectus abdominis muscle.
Chapter: Abdomen; Topic: Suprarenal Gland Anatomy; Subtopic: Venous Drainage
Keyword Definitions:
Suprarenal gland: Endocrine gland located above kidneys, divided into cortex and medulla.
Suprarenal vein: Main venous channel draining each adrenal gland.
Inferior vena cava: Major vessel on the right side receiving direct tributaries.
Renal vein: Large venous drainage vessel from kidney; receives left suprarenal vein.
Adrenal drainage asymmetry: Right drains to IVC, left drains to left renal vein.
1) Lead Question – 2016
Right suprarenal vein drains into ?
a) Inferior vena cava
b) Right renal vein
c) Left renal vein
d) Accessory Hemiazygous vein
Answer: a) Inferior vena cava
Explanation: The venous drainage of the suprarenal glands is asymmetric. The **right suprarenal vein drains directly into the inferior vena cava**, owing to its short course and proximity to the IVC. The left suprarenal vein drains instead into the left renal vein because of anatomical positioning near the left kidney. Neither gland drains into accessory hemiazygos or directly into the right renal vein. Understanding this anatomical asymmetry is important for surgical approaches, trauma evaluation, and preventing intraoperative venous injury. Thus, the correct drainage of the right suprarenal vein is into the IVC.
2) Left suprarenal vein drains into:
a) IVC
b) Left renal vein
c) Right renal vein
d) Azygos vein
Answer: b) Left renal vein
Explanation: The left suprarenal vein empties into the left renal vein before reaching the IVC because of the left-sided anatomical relationships.
3) Which artery supplies the suprarenal cortex?
a) Superior suprarenal artery
b) Middle suprarenal artery
c) Inferior suprarenal artery
d) All of the above
Answer: d) All of the above
Explanation: Three sets of arteries supply the adrenal gland: superior (from inferior phrenic), middle (from aorta), and inferior (from renal artery).
4) A patient undergoing right adrenalectomy is at highest risk of bleeding from:
a) Left suprarenal vein
b) Right suprarenal vein
c) Inferior phrenic artery
d) Azygos vein
Answer: b) Right suprarenal vein
Explanation: The right suprarenal vein is short and drains directly into the IVC, making surgical manipulation risky.
5) Suprarenal medulla is derived from:
a) Mesoderm
b) Ectoderm
c) Neural crest
d) Endoderm
Answer: c) Neural crest
Explanation: Chromaffin cells originate from neural crest tissue and produce catecholamines.
6) Which hormone is NOT produced by adrenal cortex?
a) Cortisol
b) Aldosterone
c) Androgens
d) Adrenaline
Answer: d) Adrenaline
Explanation: Adrenaline is produced by the medulla, not the cortex.
7) A tumor compressing the left renal vein may cause engorgement of:
a) Right suprarenal vein
b) Left suprarenal vein
c) Azygos vein
d) SVC
Answer: b) Left suprarenal vein
Explanation: Because the left suprarenal vein directly drains into the left renal vein, any obstruction elevates its pressure.
8) Venous drainage of adrenal gland ultimately reaches:
a) Portal vein
b) IVC
c) Hepatic vein
d) Splenic vein
Answer: b) IVC
Explanation: Both sides eventually reach the IVC—right directly and left via the left renal vein.
9) Zona glomerulosa secretes:
a) Cortisol
b) Aldosterone
c) Androgens
d) Adrenaline
Answer: b) Aldosterone
Explanation: Aldosterone is produced in the outer zona glomerulosa under renin–angiotensin control.
10) The adrenal gland is located in which space?
a) Peritoneal
b) Retroperitoneal
c) Subserosal
d) Intrathoracic
Answer: b) Retroperitoneal
Explanation: Adrenal glands lie in the retroperitoneum superior to kidneys.
11) Adrenal cortex arises from:
a) Ectoderm
b) Mesoderm
c) Neural crest
d) Endoderm
Answer: b) Mesoderm
Explanation: The cortex develops from mesodermal coelomic epithelium, unlike the neural crest–derived medulla.
Chapter: Anterior Abdominal Wall; Topic: External Oblique Aponeurosis; Subtopic: Derivatives & Applied Anatomy
Keyword Definitions:
External oblique aponeurosis: Flat tendinous sheet contributing to the anterior abdominal wall and inguinal structures.
Inguinal ligament: Inferior thickened rolled-up border of the external oblique aponeurosis.
Lacunar ligament: Medial expansion of the inguinal ligament attaching to pectineal line.
Pectineal ligament (Cooper’s ligament): Thickened periosteum of pectineal line; not derived from external oblique.
Linea semilunaris: Lateral curved margin of rectus abdominis formed by aponeuroses.
1) Lead Question – 2016
Which of the following is not derived from the external oblique aponeurosis?
a) Inguinal Ligament
b) Lacunar ligament
c) Line Semilunaris
d) Pectineal Ligament
Answer: d) Pectineal ligament
Explanation: The **inguinal ligament** and **lacunar ligament** are direct specializations of the external oblique aponeurosis. The **linea semilunaris** is a landmark formed partly by the fusion of aponeuroses including external oblique. However, the **pectineal ligament (Cooper’s ligament)** is a dense thickening of the periosteum along the pectineal line of the pubis and does **not** arise from the external oblique. This ligament is important in hernia repairs, especially in femoral hernia surgery.
2) The superficial inguinal ring is a defect in:
a) Internal oblique
b) Transversus abdominis
c) External oblique aponeurosis
d) Rectus sheath
Answer: c) External oblique aponeurosis
Explanation: The superficial ring is an opening in external oblique aponeurosis allowing spermatic cord or round ligament to exit.
3) The conjoint tendon is formed by:
a) External and internal oblique
b) Internal oblique and transversus abdominis
c) All three muscles
d) Transversus abdominis only
Answer: b) Internal oblique and transversus abdominis
Explanation: Their aponeuroses fuse to strengthen the posterior wall of the inguinal canal.
4) A direct inguinal hernia passes through:
a) Deep ring
b) Hesselbach’s triangle
c) Femoral ring
d) Obturator canal
Answer: b) Hesselbach’s triangle
Explanation: Direct hernias protrude medial to inferior epigastric vessels through the weakened triangle.
5) Cremasteric muscle is derived from:
a) External oblique
b) Internal oblique
c) Transversus abdominis
d) Rectus abdominis
Answer: b) Internal oblique
Explanation: Internal oblique fibers descend into scrotum forming the cremaster.
6) External oblique is innervated by:
a) T6–T12
b) L1–L2
c) T1–T5
d) T12 only
Answer: a) T6–T12
Explanation: Thoracoabdominal nerves supply the external oblique muscle.
7) A femoral hernia lies ______ to the lacunar ligament.
a) Medial
b) Lateral
c) Anterior
d) Posterior
Answer: a) Medial
Explanation: Femoral hernia extends medial to femoral vein, and lacunar ligament forms its medial boundary.
8) Contents of inguinal canal include:
a) Femoral artery
b) Round ligament
c) Pudendal nerve
d) Ilioinguinal nerve only
Answer: b) Round ligament
Explanation: In females, the round ligament traverses the canal along with the ilioinguinal nerve.
9) Internal oblique contributes to which wall of the inguinal canal?
a) Anterior
b) Posterior
c) Roof
d) Floor
Answer: c) Roof
Explanation: Arched fibers of internal oblique and transversus form the superior wall.
10) External spermatic fascia is derived from:
a) Internal oblique
b) Transversus abdominis
c) External oblique aponeurosis
d) Cremaster muscle
Answer: c) External oblique aponeurosis
Explanation: The external spermatic fascia forms from the external oblique as the testis descends.
11) Which structure lies in the floor of the inguinal canal?
a) Inguinal ligament
b) Transversus abdominis
c) Conjoint tendon
d) Cremaster muscle
Answer: a) Inguinal ligament
Explanation: The floor is formed mainly by the inguinal ligament and lacunar ligament medially.
Chapter: Abdomen; Topic: Stomach Blood Supply; Subtopic: Arterial Anatomy
Keyword Definitions:
Coeliac trunk: First major anterior branch of abdominal aorta supplying foregut structures.
Splenic artery: Branch of coeliac trunk that supplies spleen and part of stomach.
Gastroduodenal artery: Branch of common hepatic artery supplying pylorus and duodenum.
Left gastric artery: Primary artery supplying lesser curvature of stomach.
Right gastroepiploic artery: Supplies greater curvature of stomach via gastroduodenal system.
1) Lead Question – 2016
Stomach is supplied by ?
a) Coeliac trunk
b) Splenic artery
c) Gastroduodenal artery
d) All of the above
Answer: d) All of the above
Explanation: The **stomach receives arterial supply from multiple branches of the coeliac trunk**. The coeliac trunk directly gives the left gastric artery and indirectly gives the splenic artery (which gives short gastric and left gastroepiploic arteries). The gastroduodenal artery, a branch of the common hepatic artery, supplies the right gastroepiploic artery supplying the greater curvature. Thus, all listed arteries contribute to gastric vascularization. This rich collateral supply is essential for maintaining gastric perfusion even during vascular compromise or surgical ligations.
2) The left gastric artery supplies which part of the stomach?
a) Fundus
b) Pylorus
c) Lesser curvature
d) Greater curvature
Answer: c) Lesser curvature
Explanation: The left gastric artery ascends and runs along the lesser curvature of the stomach, supplying its medial border.
3) Short gastric arteries arise from:
a) Left gastric artery
b) Splenic artery
c) Common hepatic artery
d) Gastroduodenal artery
Answer: b) Splenic artery
Explanation: Short gastric arteries originate from the splenic artery and supply the gastric fundus.
4) A patient undergoing splenectomy is at risk of ischemia of:
a) Lesser curvature
b) Fundus
c) Pylorus
d) Cardia
Answer: b) Fundus
Explanation: The gastric fundus depends on short gastric arteries, which are ligated during splenectomy.
5) Right gastroepiploic artery is a branch of:
a) Left gastric artery
b) Splenic artery
c) Gastroduodenal artery
d) Inferior phrenic artery
Answer: c) Gastroduodenal artery
Explanation: It arises from the gastroduodenal artery and supplies the greater curvature.
6) Venous drainage of the stomach ultimately drains into:
a) IVC
b) Portal vein
c) Renal vein
d) Azygos system
Answer: b) Portal vein
Explanation: All gastric veins drain into the portal circulation, mainly via left gastric and splenic veins.
7) The gastroepiploic arcade lies along the:
a) Lesser curvature
b) Greater curvature
c) Cardiac notch
d) Pyloric canal
Answer: b) Greater curvature
Explanation: Right and left gastroepiploic arteries form an anastomotic arcade along the greater curvature.
8) Left gastroepiploic artery is a branch of:
a) Splenic artery
b) Gastroduodenal artery
c) Left gastric artery
d) Common hepatic artery
Answer: a) Splenic artery
Explanation: It arises from the splenic artery and supplies the greater curvature.
9) Which artery supplies the pylorus?
a) Left gastric artery
b) Right gastric artery
c) Gastroduodenal artery
d) Superior mesenteric artery
Answer: c) Gastroduodenal artery
Explanation: The gastroduodenal artery plays a major role in supplying the pyloric region.
10) The arterial supply of the stomach belongs to which embryological division?
a) Foregut
b) Midgut
c) Hindgut
d) Cloaca
Answer: a) Foregut
Explanation: Stomach develops from the foregut and is supplied by branches of the coeliac trunk.
11) Which artery forms an anastomosis along the lesser curvature with the left gastric artery?
a) Right gastric artery
b) Right gastroepiploic artery
c) Superior mesenteric artery
d) Left inferior phrenic artery
Answer: a) Right gastric artery
Explanation: Right and left gastric arteries form a continuous arcade along the lesser curvature.
Chapter: Abdomen; Topic: Peritoneum; Subtopic: Omenta
Keyword Definitions:
Greater omentum: Large peritoneal fold hanging from the stomach and covering intestines.
Peritoneum: Serous membrane lining the abdominal cavity and covering its organs.
Gastrocolic ligament: Portion of greater omentum connecting stomach to transverse colon.
Omental layers: Multiple peritoneal reflections forming sheet-like folds.
Mesentery: Double layer of peritoneum anchoring intestines to the posterior abdominal wall.
1) Lead Question – 2016
What is the number of layers in greater omentum?
a) 1
b) 2
c) 3
d) 4
Answer: d) 4
Explanation: The **greater omentum is formed by four layers of peritoneum**, created when two double layers (derived from dorsal mesogastrium) fuse during development. Initially, the dorsal mesentery elongates and hangs over the transverse colon; later, its adjacent layers fuse to form a four-layered peritoneal sheet. Despite fusion, anatomically it is still considered a four-layered fold. It contains fat, vessels (especially gastroepiploic arteries), and has protective, immune, and insulation functions. It also limits the spread of infection by adhering to inflamed organs such as the appendix.
2) Which ligament is part of the greater omentum?
a) Falciform ligament
b) Gastrosplenic ligament
c) Coronary ligament
d) Ligamentum teres
Answer: b) Gastrosplenic ligament
Explanation: The gastrosplenic ligament connects the stomach to the spleen and is derived from the dorsal mesogastrium, forming a component of the greater omentum.
3) The greater omentum is derived embryologically from:
a) Ventral mesogastrium
b) Dorsal mesogastrium
c) Vitelline duct
d) Septum transversum
Answer: b) Dorsal mesogastrium
Explanation: Elongation of the dorsal mesogastrium during development gives rise to the greater omentum.
4) Which artery runs within the greater omentum?
a) Inferior mesenteric artery
b) Right gastroepiploic artery
c) Right gastric artery
d) Left gastric artery
Answer: b) Right gastroepiploic artery
Explanation: The gastroepiploic arcade runs within the greater omentum, supplying the greater curvature of the stomach.
5) A patient with generalized peritonitis is found to have omental adhesions around the inflamed appendix. This phenomenon is called:
a) Omental caking
b) Omental patching
c) Omental wrap
d) Abdominal cocoon
Answer: b) Omental patching
Explanation: The greater omentum often migrates to sites of inflammation to wall off infection, known as omental patching.
6) Which of the following structures lies immediately posterior to the greater omentum?
a) Liver
b) Transverse colon
c) Spleen
d) Sigmoid colon
Answer: b) Transverse colon
Explanation: The greater omentum drapes over the transverse colon, which lies behind it.
7) Which recess is associated with the greater omentum?
a) Lesser sac
b) Hepatorenal recess
c) Subphrenic recess
d) Rectovesical pouch
Answer: a) Lesser sac
Explanation: The greater omentum forms the anterior boundary of the lesser sac (omental bursa).
8) Which of the following best describes the vascular function of the greater omentum?
a) Storage of bile
b) Rich anastomotic arcade
c) Venous drainage to IVC
d) No vascular significance
Answer: b) Rich anastomotic arcade
Explanation: The omentum houses the gastroepiploic vessels, forming extensive anastomoses.
9) In gastric surgery, the gastrocolic ligament is divided to expose:
a) Portal vein
b) Lesser sac
c) Esophageal hiatus
d) Duodenal bulb
Answer: b) Lesser sac
Explanation: Dividing the gastrocolic ligament opens the lesser sac for posterior gastric access.
10) Greater omentum is commonly referred to as:
a) Abdominal curtain
b) Fatty apron
c) Mesenteric sheath
d) Hepatic veil
Answer: b) Fatty apron
Explanation: The greater omentum hangs like a fatty apron over the intestines.
11) Greater omentum has a role in immunity because it contains:
a) Kupffer cells
b) Peyer's patches
c) Milky spots
d) Hassall's corpuscles
Answer: c) Milky spots
Explanation: Milky spots are immune cell clusters within the omentum that help fight infection.