Radiologic landmarks

Radiologic landmarks US Medical PG Question 1: A 27-year-old male presents to the Emergency Room as a code trauma after being shot in the neck. En route, the patient's blood pressure is 127/73 mmHg, pulse is 91/min, respirations are 14/min, and oxygen saturation is 100% on room air with GCS of 15. On physical exam, the patient is in no acute distress; however, there is an obvious entry point with oozing blood near the left lateral neck above the cricoid cartilage with a small hematoma that is non-pulsatile and stable since arrival. The rest of the physical exam is unremarkable. Rapid hemoglobin returns back at 14.1 g/dL. After initial resuscitation, what is the next best step in management?

• A. Bedside neck exploration
• B. Conventional angiography
• C. MRI
• D. Plain radiography films
• E. CT angiography (Correct Answer)

Radiologic landmarks Explanation: ***CT angiography*** - **CT angiography** is the most appropriate next step for **stable patients** with penetrating neck trauma, like this patient, to evaluate for vascular and airway injuries. - It offers **rapid, non-invasive assessment** of the extent of injury and helps guide further management. *Bedside neck exploration* - **Bedside neck exploration** is typically reserved for patients with **hard signs** of vascular injury (e.g., active hemorrhage, expanding hematoma, pulsatile hematoma) or **signs of airway compromise**, which are absent here. - This patient is **hemodynamically stable** and has a non-expanding hematoma. *Conventional angiography* - **Conventional angiography** is more **invasive** and time-consuming than CTA, carrying risks such as arterial dissection or stroke. - It is usually reserved for **diagnostic confirmation** or **therapeutic intervention** (e.g., embolization) after initial imaging, especially when CTA findings are equivocal or reveal treatable lesions. *MRI* - **MRI** is generally **contraindicated** in acute trauma situations, especially when the presence of metallic foreign bodies (e.g., bullet fragments) is a concern. - Its **longer acquisition time** and **lack of immediate availability** in the emergency setting make it less suitable for initial evaluation of penetrating neck trauma. *Plain radiography films* - **Plain radiographs** can identify **bony fractures** and the general location of foreign bodies, but they offer **limited information** regarding soft tissue and vascular structures. - They are insufficient for comprehensively evaluating potential vascular or airway injuries in penetrating neck trauma.

Radiologic landmarks US Medical PG Question 2: A 36-year-old male is taken to the emergency room after jumping from a building. Bilateral fractures to the femur were stabilized at the scene by emergency medical technicians. The patient is lucid upon questioning and his vitals are stable. Pain only at his hips was elicited. Cervical exam was not performed. What is the best imaging study for this patient?

• A. AP and lateral radiographs of hips
• B. Lateral radiograph (x-ray) of hips
• C. Magnetic resonance imaging (MRI) of hips, knees, lumbar, and cervical area
• D. Anterior-posterior (AP) and lateral radiographs of hips, knees, lumbar, and cervical area
• E. Computed tomography (CT) scan of cervical spine, hips, and lumbar area (Correct Answer)

Radiologic landmarks Explanation: ***Computed tomography (CT) scan of cervical spine, hips, and lumbar area*** - In **high-energy trauma** (fall from height), a CT scan is the **gold standard** for evaluating the **spine and pelvis**, providing detailed cross-sectional images superior to plain radiographs. - Since the **cervical exam was not performed**, cervical spine imaging is **mandatory** per ATLS (Advanced Trauma Life Support) protocols. High-energy falls carry significant risk of **cervical spine injury** even without obvious neurological symptoms. - CT allows comprehensive assessment of **hip fractures, pelvic injuries, and the entire spine** (cervical, thoracic, lumbar), identifying both obvious and **subtle fractures** that may be missed on plain films. - This approach provides the most **efficient and thorough evaluation** in the acute trauma setting, allowing for appropriate surgical planning and ruling out life-threatening spinal instability. *AP and lateral radiographs of hips* - Plain radiographs provide **limited detail** and may **miss subtle fractures**, particularly in complex areas like the pelvis and acetabulum. - This option **fails to address cervical spine clearance**, which is essential in all high-energy trauma patients, especially when cervical exam has not been performed. - Radiographs are insufficient for **comprehensive trauma evaluation** after a fall from height. *Lateral radiograph (x-ray) of hips* - A single lateral view is **grossly insufficient** for evaluating hip and pelvic fractures, providing only a **two-dimensional perspective** that can miss significant injuries. - This option **completely neglects spinal evaluation**, which is dangerous in an uncleared trauma patient with a high-energy mechanism. *Magnetic resonance imaging (MRI) of hips, knees, lumbar, and cervical area* - While MRI excels at evaluating **soft tissues, ligaments, and bone marrow**, it is **not the initial imaging modality** for acute bony trauma due to longer scan times and lower sensitivity for acute fractures compared to CT. - MRI is **time-consuming and impractical** in the emergency setting for initial fracture assessment, potentially delaying definitive treatment. - CT is superior for evaluating **acute skeletal injuries** in the trauma bay. *Anterior-posterior (AP) and lateral radiographs of hips, knees, lumbar, and cervical area* - Multiple plain radiographs have **limited sensitivity** for complex or non-displaced fractures, particularly in the **spine and pelvis**, making them inadequate for high-energy trauma evaluation. - Obtaining multiple radiographic views requires **numerous patient repositionings**, which risks further injury if **spinal instability** is present. - Plain films provide significantly **less diagnostic information** than CT scanning for trauma assessment.

Radiologic landmarks US Medical PG Question 3: A 36-year-old woman comes to the physician for a 2-month history of urinary incontinence and a vaginal mass. She has a history of five full-term normal vaginal deliveries. She gave birth to a healthy newborn 2-months ago. Since then she has felt a sensation of vaginal fullness and a firm mass in the lower vagina. She has loss of urine when she coughs, sneezes, or exercises. Pelvic examination shows an irreducible pink globular mass protruding out of the vagina. A loss of integrity of which of the following ligaments is most likely involved in this patient's condition?

• A. Infundibulopelvic ligament
• B. Broad ligament of the uterus
• C. Cardinal ligament of the uterus (Correct Answer)
• D. Round ligament of uterus
• E. Uterosacral ligament

Radiologic landmarks Explanation: ***Cardinal ligament of the uterus*** - The patient's symptoms, including **vaginal mass**, **urinary incontinence** with coughing/sneezing, and history of **multiple vaginal deliveries**, strongly suggest **uterine prolapse**. - The cardinal ligaments are crucial in providing **lateral cervical support** and are often damaged during childbirth, leading to uterine descent. *Infundibulopelvic ligament* - This ligament primarily supports the **ovaries** and contains the **ovarian artery** and vein. - Damage to this ligament is associated with ovarian prolapse or complications during oophorectomy, not uterine prolapse. *Broad ligament of the uterus* - The broad ligament is a **peritoneal fold** that drapes over the uterus, fallopian tubes, and ovaries. - While it helps to hold these structures in place, its primary role is not in preventing uterine prolapse; it mainly provides a medium for neurovascular structures. *Round ligament of uterus* - The round ligament extends from the uterus to the **labia majora** and primarily helps maintain **anteversion** of the uterus. - It plays a minor role in uterine support and its laxity is not a primary cause of uterine prolapse. *Uterosacral ligament* - The uterosacral ligaments provide **posterior support** to the uterus, particularly by anchoring the cervix to the sacrum. - While damage to these ligaments contributes to **apical prolapse**, the cardinal ligaments are more critical for lateral support and more commonly implicated in overall uterine prolapse following childbirth.

Radiologic landmarks US Medical PG Question 4: A 42-year-old woman comes to the physician because of a 12 month history of progressive fatigue and shortness of breath with exertion. Five years ago, she emigrated from Eastern Europe. She has smoked one pack of cigarettes daily for 20 years. She has a history of using methamphetamines and cocaine but quit 5 years ago. Vital signs are within normal limits. Physical examination shows jugular venous pulsations 9 cm above the sternal angle. The lungs are clear to auscultation. There is a normal S1 and a loud, split S2. An impulse can be felt with the fingers left of the sternum. The abdomen is soft and nontender. The fingertips are enlarged and the nails are curved. There is pitting edema around the ankles bilaterally. An x-ray of the chest shows pronounced central pulmonary arteries and a prominent right heart border. Which of the following is most likely to confirm the diagnosis?

• A. CT angiography
• B. Serologic testing
• C. Doppler echocardiography
• D. High-resolution CT of the lung
• E. Right-heart catheterization (Correct Answer)

Radiologic landmarks Explanation: ***Right-heart catheterization*** - This is the **gold standard** for diagnosing **pulmonary hypertension** by directly measuring pulmonary artery pressure, pulmonary wedge pressure, and cardiac output. The patient's symptoms (fatigue, shortness of breath, loud split S2, prominent right heart border, JVP elevation, peripheral edema, digital clubbing) strongly suggest pulmonary hypertension. - It helps classify the type of pulmonary hypertension and guides treatment strategies, as **mean pulmonary artery pressure (mPAP) > 20 mmHg** at rest is diagnostic. *CT angiography* - Primarily used to diagnose **pulmonary embolism** or to evaluate for chronic thromboembolic pulmonary hypertension (CTEPH). While helpful in some cases of pulmonary hypertension, it does not directly measure pressures. - It would show emboli or chronic organized thrombi if present but doesn't provide the hemodynamic data needed to confirm the severity and type of pulmonary hypertension. *Serologic testing* - Used to identify underlying systemic diseases (e.g., **autoimmune conditions like scleroderma**) that can cause pulmonary hypertension. However, it does not directly confirm the diagnosis of pulmonary hypertension itself. - While it may uncover **etiological factors**, serological markers are not diagnostic for the presence or severity of pulmonary hypertension. *Doppler echocardiography* - A crucial initial screening tool that **estimates pulmonary artery pressure** and assesses right ventricular function, often prompting further investigation for pulmonary hypertension. - While highly suggestive, it is **indirect and an estimation**, and thus not considered definitive for confirming the diagnosis or for precise hemodynamic measurements. *High-resolution CT of the lung* - Used to evaluate for **interstitial lung disease** or other parenchymal lung conditions that can cause secondary pulmonary hypertension. - It provides detailed images of the lung parenchyma but does not directly measure pulmonary pressures or confirm the diagnosis of pulmonary hypertension.

Radiologic landmarks US Medical PG Question 5: A 65-year-old man with a 40-pack-year smoking history presents with hemoptysis and a persistent cough. Chest CT shows a 3.5 cm centrally located mass in the right main bronchus. Positron emission tomography confirms a malignant nodule. Bronchoscopy with transbronchial biopsy is performed and a specimen sample of the nodule is sent for frozen section analysis. The tissue sample is most likely to show which of the following tumor types?

• A. Carcinoid tumor
• B. Metastasis of colorectal cancer
• C. Small cell lung carcinoma
• D. Large cell carcinoma
• E. Squamous cell carcinoma (Correct Answer)

Radiologic landmarks Explanation: ***Squamous cell carcinoma*** - This is the most likely diagnosis given the **central location** in the main bronchus, **heavy smoking history**, and presentation with **hemoptysis**. - **Squamous cell carcinoma** accounts for 25-30% of lung cancers and characteristically arises in **central/proximal airways**, making it readily accessible by **bronchoscopy**. - Histologically, it shows **keratin pearls** and **intercellular bridges** on biopsy. - The **central endobronchial location** and ability to obtain tissue via transbronchial biopsy strongly favor squamous cell over peripheral tumors. *Carcinoid tumor* - **Carcinoid tumors** are **neuroendocrine tumors** that can present as central endobronchial masses and cause hemoptysis. - However, they are typically **slow-growing** with more indolent presentation, and PET scans show **variable uptake** (often less intense than aggressive carcinomas). - They represent only **1-2% of lung tumors** and occur more commonly in **younger, non-smoking patients**. *Metastasis of colorectal cancer* - While lung is a common site for **colorectal metastases**, these typically present as **multiple peripheral nodules** rather than a solitary central endobronchial mass. - The clinical presentation strongly suggests **primary lung cancer** rather than metastatic disease. - Without history of colorectal cancer, this is unlikely. *Small cell lung carcinoma* - **Small cell lung carcinoma** (SCLC) represents 15% of lung cancers and typically presents as a **large central mass** with early mediastinal involvement. - However, SCLC is usually **too extensive at presentation** for transbronchial biopsy alone and often requires mediastinoscopy or CT-guided biopsy. - Histology shows **small cells with scant cytoplasm**, **salt-and-pepper chromatin**, and **oat-cell morphology**. - While possible, the single accessible endobronchial mass is more characteristic of squamous cell. *Large cell carcinoma* - **Large cell carcinoma** is a **diagnosis of exclusion** made when tumors lack features of adenocarcinoma, squamous cell, or small cell differentiation. - It typically presents as **large peripheral masses** rather than central endobronchial lesions. - It represents only **10% of lung cancers** and is less common than squamous cell carcinoma in this clinical scenario.

Radiologic landmarks US Medical PG Question 6: A 72-year-old man presents to his physician’s office with complaints of a cough and painful breathing for the last 2 months. He says that he has also observed a 5 kg (11 lb) weight loss during the past month. He is relatively healthy but the sudden change in his health worries him. Another problem that he has been facing is the swelling of his face and arms at unusual times of the day. He says that the swelling is more prominent when he is supine. He has also lately been experiencing difficulty with his vision. He consumes alcohol occasionally and quit smoking last year following a 25-year history of smoking. On examination, the patient is noted to have distended veins in the chest and arms. His jugular veins are distended. Physical examination shows ptosis of the right eye and miosis of the right pupil. His lungs are clear to auscultation. He is sent for an X-ray for further evaluation of his condition. Which of the following is the most likely site for the detection of the nodule on CT scan?

• A. Right upper lobe (Correct Answer)
• B. Brain stem metastasis
• C. Left upper lobe
• D. Central hilar region
• E. Peripheral bronchial region

Radiologic landmarks Explanation: ***Right upper lobe*** - The patient's symptoms, including **Ptosis**, **Miosis**, and **Anhidrosis** of the right side of the face, are indicative of **Horner's syndrome**. - **Horner's syndrome** in a patient with a smoking history, cough, weight loss, and edema of the face and arms (suggesting **SVC syndrome**) points strongly to a **Pancoast tumor** (superior sulcus tumor). - The tumor is located in the **right upper lobe** specifically because the **Horner's syndrome is right-sided** (right ptosis, right miosis). Pancoast tumors cause **ipsilateral** Horner's syndrome by invading the sympathetic chain on the same side as the tumor. *Brain stem metastasis* - While a brain stem lesion could cause vision difficulties and neurological deficits, it does not explain the **SVC syndrome** (facial/arm swelling, distended veins) or the pulmonary symptoms like cough and weight loss. - **Pancoast tumors** can cause vision changes due to **Horner's syndrome**, not necessarily brain metastasis. *Left upper lobe* - Although a tumor in the left upper lobe could cause similar symptoms to a right upper lobe tumor, the examination findings of **ptosis** and **miosis** on the **right side** localize the lesion to the **right apex**. - **Horner's syndrome** develops on the **ipsilateral side** of the sympathetic chain disruption. *Central hilar region* - A tumor in the central hilar region would typically cause symptoms related to bronchial obstruction or compression of central structures, such as a persistent cough, hemoptysis, or SVC syndrome if it's large enough. - However, it is less likely to directly cause **Horner's syndrome** with ptosis and miosis localized to one eye, which is a hallmark of an apical (Pancoast) tumor affecting the sympathetic chain. *Peripheral bronchial region* - A peripheral bronchial nodule would usually present with a cough, possibly hemoptysis, or be asymptomatic until it grows large enough to cause obstructive symptoms or pleural involvement. - It is unlikely to cause both **SVC syndrome** and **Horner's syndrome** simultaneously, which are characteristic of an apical lung tumor.

Radiologic landmarks US Medical PG Question 7: A 40-year-old woman is brought to the emergency department by a paramedic team from the scene of a motor vehicle accident where she was the driver. The patient was restrained by a seat belt and was unconscious at the scene. On physical examination, the patient appears to have multiple injuries involving the trunk and extremities. There are no penetrating injuries to the chest. As part of her trauma workup, a CT scan of the chest is ordered. At what vertebral level of the thorax is this image from?

• A. T1
• B. T6
• C. T4
• D. T5
• E. T8 (Correct Answer)

Radiologic landmarks Explanation: ***T8*** - The CT image shows the **inferior vena cava (IVC)** located anterior and to the right of the aorta, and the **esophagus** located posterior to the aorta and slightly to the left. The **azygos vein** is seen to the right of the vertebral body and posterior to the esophagus. - The **mainstem bronchi** are no longer visible, indicating a level below the carina. The presence of the IVC, aorta, esophagus, and azygos vein with the absence of mainstem bronchi is characteristic of the **T8 vertebral level**. *T1* - At the T1 level, the structures would primarily be the **trachea** anterior to the esophagus, with the main great vessels (e.g., brachiocephalic veins and arteries) visible, not the IVC. - The mainstem bronchi would not yet be visualized at this higher level. *T6* - At the T6 level, the **trachea would have already bifurcated into the mainstem bronchi**, which would be prominent structures visible on the CT scan. - While the aorta and esophagus would be present, the specific arrangement relative to the mainstem bronchi would differentiate it from T8. *T4* - The T4 level is typically associated with the **carina**, where the trachea bifurcates into the mainstem bronchi. - The great vessels would be prominent, but the IVC in its more inferior course would not be as distinctly visualized in this configuration compared to T8. *T5* - At the T5 level, the **mainstem bronchi** would still be clearly visible, having just diverged from the trachea. - While vessels like the aorta are present, the key differentiating factor from T8 is the presence of the mainstem bronchi.

Radiologic landmarks US Medical PG Question 8: A 60-year-old post-menopausal female presents to her gynecologist with vaginal bleeding. Her last period was over 10 years ago. Dilation and curettage reveals endometrial carcinoma so she is scheduled to undergo a total abdominal hysterectomy and bilateral salpingo-oophorectomy. During surgery, the gynecologist visualizes paired fibrous structures arising from the cervix and attaching to the lateral pelvic walls at the level of the ischial spines. Which of the following vessels is found within each of the paired visualized structure?

• A. Vaginal artery
• B. Superior vesical artery
• C. Uterine artery (Correct Answer)
• D. Artery of Sampson
• E. Ovarian artery

Radiologic landmarks Explanation: ***Uterine artery*** - The paired fibrous structures described are the **cardinal ligaments (transverse cervical ligaments)**, which contain the **uterine arteries** as they course towards the uterus. - The uterine artery, a branch of the **internal iliac artery**, crosses over the **ureter** within the cardinal ligament—a critical anatomical relationship during gynecological surgery ("water under the bridge"). - This is the primary vessel within the cardinal ligament and the key vascular structure at risk during hysterectomy. *Vaginal artery* - The vaginal artery typically branches from the **uterine artery** or directly from the **internal iliac artery**, but it is not the main vessel found within the cardinal ligament. - It primarily supplies the **vagina**, not contained within the cardinal ligament support structure. *Superior vesical artery* - The superior vesical artery supplies the **upper part of the bladder** and originates from the **umbilical artery** (a branch of the internal iliac artery). - It is not anatomically associated with the cardinal ligament or uterine support structures. *Artery of Sampson* - The Artery of Sampson is a branch of the **uterine artery** that anastomoses with the **ovarian artery** within the **broad ligament**, not the cardinal ligament. - It is a minor vessel involved in the dual blood supply to the ovaries and uterus, not a primary structure within the cardinal ligament. *Ovarian artery* - The ovarian artery originates directly from the **abdominal aorta** and travels within the **suspensory ligament of the ovary (infundibulopelvic ligament)**, not the cardinal ligament. - It supplies the **ovaries and fallopian tubes**, with a trajectory that is anatomically distinct from structures within the cardinal ligament.

Radiologic landmarks US Medical PG Question 9: A 21-year-old man comes to the physician for a follow-up examination. Four days ago, he injured his right knee while playing soccer. Increased laxity of the right knee joint is noted when the knee is flexed to 30° and an abducting force is applied to the lower leg. The examination finding in this patient is most likely caused by damage to which of the following structures?

• A. Medial collateral ligament (Correct Answer)
• B. Anterior cruciate ligament
• C. Posterior cruciate ligament
• D. Lateral collateral ligament
• E. Lateral meniscus

Radiologic landmarks Explanation: ***Medial collateral ligament*** - An abducting force applied to the lower leg (a **valgus stress**) when the knee is flexed to 30° tests the integrity of the MCL. Increased laxity indicates damage to this ligament. - The MCL resists **valgus stress** and is commonly injured in contact sports, especially when a force is applied to the outside of the knee. *Anterior cruciate ligament* - The **anterior drawer test** and **Lachman test** (anterior translation of the tibia with the knee flexed) are used to assess ACL integrity. - ACL injuries usually result from hyperextension, sudden stopping, or pivoting movements, leading to **anterior instability**. *Posterior cruciate ligament* - The **posterior drawer test** (posterior translation of the tibia with the knee flexed) is used to assess PCL integrity. - PCL injuries typically occur from a direct blow to the tibia or an anterior force on the tibia, indicating **posterior instability**. *Lateral collateral ligament* - The LCL is assessed by applying an **adducting force** to the lower leg (a **varus stress**). - Increased laxity during **varus stress** would indicate damage to the LCL. *Lateral meniscus* - Meniscal injuries are usually associated with clicking, locking, or catching sensations within the joint, and pain during twisting motions. - Meniscal tears are primarily diagnosed using specific provocative tests like **McMurray's test** or **Apley's grind test**, not by assessing ligamentous laxity with abducting forces.

Radiologic landmarks US Medical PG Question 10: A 72-year-old male presents to a cardiac surgeon for evaluation of severe aortic stenosis. He has experienced worsening dyspnea with exertion over the past year. The patient also has a history of poorly controlled hypertension, diabetes mellitus, and hyperlipidemia. An echocardiogram revealed a thickened calcified aortic valve. The surgeon is worried that the patient will be a poor candidate for open heart surgery and decides to perform a less invasive transcatheter aortic valve replacement. In order to perform this procedure, the surgeon must first identify the femoral pulse just inferior to the inguinal ligament and insert a catheter into the vessel in order to gain access to the arterial system. Which of the following structures is immediately lateral to this structure?

• A. Lymphatic vessels
• B. Femoral vein
• C. Sartorius muscle
• D. Pectineus muscle
• E. Femoral nerve (Correct Answer)

Radiologic landmarks Explanation: ***Femoral nerve*** - The **femoral nerve** lies lateral to the **femoral artery** within the **femoral triangle**. - The order of structures from **lateral to medial** under the inguinal ligament is remembered by the mnemonic **NAVEL**: **N**erve, **A**rtery, **V**ein, **E**mpty space, **L**ymphatics. *Lymphatic vessels* - **Lymphatic vessels** and nodes are located most medially within the femoral triangle, medial to the femoral vein. - This position is not immediately lateral to the femoral artery. *Femoral vein* - The **femoral vein** is located immediately medial to the **femoral artery**. - It would not be found immediately lateral to the femoral artery. *Sartorius muscle* - The **sartorius muscle** forms the lateral boundary of the **femoral triangle** but is not immediately adjacent and lateral to the femoral artery within the triangle itself. - The femoral nerve is enclosed within the iliopsoas fascial compartment, which runs deep to the sartorius. *Pectineus muscle* - The **pectineus muscle** forms part of the floor of the **femoral triangle**, but it is deep to the neurovascular structures. - It is not immediately lateral to the femoral artery.

Radiologic landmarks Flashcard 1 of 4

Question: The normal neonatal thymus appears "_____-shaped" on a Chest X-Ray

Answer: sail

Radiologic landmarks Flashcard 2 of 4

Question: What vertebral level does the renal artery branch off the aorta? _____

Answer: L1/L2

Radiologic landmarks Flashcard 3 of 4

Question: On an abdominal CT scan, the pancreas can be identified by: - its head in close association with the _____ part of the duodenum - its body overlying the _____

Answer: 2nd

Extra Information: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/gross-anatomy/videos/hepatoduodenal-ligament-celiac-trunk-stomach-spleen-liver-and-gallbladder?index=4] https://onlinemeded.org?ref=anki 

Radiologic landmarks Flashcard 4 of 4

Question: On a CT of the thorax, the _____ is a good landmark to localize the esophagus (located posteriorly) and the great vessels (located anteriorly)

Answer: trachea

Extra Information: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/gross-anatomy/videos/mediastinum?index=2] https://onlinemeded.org/spa/cardiac/anatomy-of-the-heart/acquire?ref=anki