Anatomical terminology and positions US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Anatomical terminology and positions. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Anatomical terminology and positions US Medical PG Question 1: A 17-year-old boy comes to the physician because of a 3-month history of pain in his right shoulder. He reports that he has stopped playing for his high school football team because of persistent difficulty lifting his right arm. Physical examination shows impaired active abduction of the right arm from 0 to 15 degrees. After passive abduction of the right arm to 15 degrees, the patient is able to raise his arm above his head. The dysfunctional muscle in this patient is most likely to be innervated by which of the following nerves?
- A. Long thoracic nerve
- B. Suprascapular nerve (Correct Answer)
- C. Upper subscapular nerve
- D. Accessory nerve
- E. Axillary nerve
Anatomical terminology and positions Explanation: ***Suprascapular nerve***
- The patient exhibits impaired active abduction from 0 to 15 degrees but normal abduction after passive assistance, indicating dysfunction of the **supraspinatus muscle**.
- The **supraspinatus muscle** is responsible for **initiating shoulder abduction** from 0 to 15 degrees, after which the deltoid muscle takes over for continued abduction.
- The **suprascapular nerve** innervates both the **supraspinatus** and **infraspinatus muscles**, with the supraspinatus being crucial for the initial phase of abduction.
*Long thoracic nerve*
- This nerve innervates the **serratus anterior muscle**, which is responsible for **scapular protraction** and upward rotation.
- Damage to the long thoracic nerve would typically result in **winged scapula**, not difficulty in initiating abduction.
*Upper subscapular nerve*
- The upper subscapular nerve innervates the **subscapularis muscle**, part of the rotator cuff.
- This muscle is primarily involved in **internal rotation** of the shoulder and contributes to adduction, not abduction.
*Accessory nerve*
- The accessory nerve (cranial nerve XI) innervates the **sternocleidomastoid** and **trapezius muscles**.
- Damage to this nerve would most likely present with weakness in **shrugging the shoulders** or turning the head, not difficulty with shoulder abduction.
*Axillary nerve*
- This nerve innervates the **deltoid muscle** and the **teres minor muscle**, and provides sensory input from the shoulder joint and lateral arm.
- The deltoid is responsible for **shoulder abduction** from 15 to 90 degrees; a deficit here would affect a different range of motion than what is described.
Anatomical terminology and positions US Medical PG Question 2: A neurology resident sees a stroke patient on the wards. This 57-year-old man presented to the emergency department after sudden paralysis of his right side. He was started on tissue plasminogen activator within 4 hours, as his wife noticed the symptoms and immediately called 911. When the resident asks the patient how he is doing, he replies by saying that his apartment is on Main St. He does not seem to appropriately answer the questions being asked, but rather speaks off topic. He is able to repeat the word "fan." His consciousness is intact, and his muscle tone and reflexes are normal. Upon striking the lateral part of his sole, his big toe extends upward and the other toes fan out. Which of the following is the area most likely affected in his condition?
- A. Caudate nucleus
- B. Broca’s area
- C. Arcuate fasciculus
- D. Temporal lobe (Correct Answer)
- E. Cuneus gyrus
Anatomical terminology and positions Explanation: ***Temporal lobe***
- The patient exhibits features of **Wernicke's aphasia**, characterized by **fluent but nonsensical speech** ("apartment is on Main St." when asked how he is), poor comprehension, and the ability to repeat words. **Wernicke's area**, responsible for language comprehension, is located in the **posterior part of the superior temporal gyrus**.
- **Sudden paralysis of the right side** indicates involvement of the left cerebral hemisphere (**contralateral motor cortex** lesion), while speech disturbances point to the dominant hemisphere, which is typically the **left temporal lobe**.
*Caudate nucleus*
- Lesions of the **caudate nucleus** are primarily associated with **movement disorders** (e.g., chorea) and **behavioral changes**, not typically with fluent aphasia as described.
- While it plays a role in cognitive functions, its direct involvement in the specific language deficits presented is less likely.
*Broca’s area*
- Damage to **Broca's area**, located in the **frontal lobe**, causes **Broca's aphasia**, characterized by **non-fluent, halting speech** with good comprehension and poor repetition.
- The patient's speech is **fluent**, though off-topic, which contrasts with the typical presentation of Broca's aphasia.
*Arcuate fasciculus*
- The **arcuate fasciculus** connects Broca's and Wernicke's areas, and damage to it typically causes **conduction aphasia**, characterized by **impaired repetition** despite fluent speech and good comprehension.
- While the patient has impaired comprehension, his ability to repeat "fan" makes conduction aphasia less likely than Wernicke's aphasia, where repetition can vary but comprehension is profoundly affected.
*Cuneus gyrus*
- The **cuneus gyrus** is located in the **occipital lobe** and is primarily involved in **visual processing**.
- Damage to this area would lead to **visual field deficits** (e.g., hemianopia) rather than the language and comprehension problems described.
Anatomical terminology and positions US Medical PG Question 3: A patient undergoes spinal surgery at the L4-L5 level. During the procedure, which of the following ligaments must be divided first to access the spinal canal?
- A. Nuchal ligament
- B. Anterior longitudinal ligament
- C. Supraspinous ligament
- D. Ligamentum flavum (Correct Answer)
Anatomical terminology and positions Explanation: ***Ligamentum flavum***
- The **ligamentum flavum** connects the laminae of adjacent vertebrae and forms the posterior boundary of the spinal canal, making it the first ligament encountered anteriorly after removing the lamina.
- While performing a posterior approach **laminectomy**, the ligamentum flavum is typically divided or removed to gain access to the neural structures within the spinal canal.
*Nuchal ligament*
- The **nuchal ligament** is located in the cervical spine and provides attachment for muscles, extending from the external occipital protuberance to the spinous process of C7.
- It is not present at the **L4-L5 level** and therefore plays no role in lumbar spinal surgery.
*Anterior longitudinal ligament*
- The **anterior longitudinal ligament** runs along the anterior surfaces of the vertebral bodies and intervertebral discs.
- It would be encountered during an **anterior surgical approach** to the spine, not a posterior approach to access the spinal canal.
*Supraspinous ligament*
- The **supraspinous ligament** connects the tips of the spinous processes and is the most superficial ligament posteriorly.
- While it is incised during a posterior approach, it is **superficial to the lamina** and ligamentum flavum; therefore, the lamina and ligamentum flavum must be removed or divided first to access the canal.
Anatomical terminology and positions US Medical PG Question 4: A 40-year-old male presents to the physician's office complaining of an inability to push doors open. He has had this problem since he was playing football with his children and was tackled underneath his right arm on his lateral chest. On examination, he has a winged scapula on the right side. Which of the following nerves is most likely the cause of this presentation?
- A. Phrenic nerve
- B. Spinal accessory nerve
- C. Long thoracic nerve (Correct Answer)
- D. Greater auricular nerve
- E. Musculocutaneous nerve
Anatomical terminology and positions Explanation: ***Long thoracic nerve***
- The **long thoracic nerve** innervates the **serratus anterior muscle**, which is responsible for scapular protraction and upward rotation.
- Damage to this nerve, often from trauma to the lateral chest wall (tackled underneath the arm), leads to paralysis of the serratus anterior and a characteristic **winged scapula** with lateral and inferior prominence.
- Patients have difficulty with **pushing movements** (protraction) and overhead activities.
*Phrenic nerve*
- The **phrenic nerve** primarily innervates the **diaphragm** and is crucial for respiration.
- Damage to the phrenic nerve would cause respiratory compromise, not a winged scapula or difficulty pushing doors.
*Spinal accessory nerve*
- The **spinal accessory nerve (cranial nerve XI)** innervates the **sternocleidomastoid** and **trapezius muscles**.
- Injury to this nerve can cause scapular winging due to **trapezius paralysis**, but the winging is typically **medial** with the inferior angle moving medially, unlike the lateral winging from serratus anterior paralysis.
- The mechanism of injury (lateral chest trauma during tackling) and inability to push are classic for **long thoracic nerve** injury, not spinal accessory nerve.
*Greater auricular nerve*
- The **greater auricular nerve** is a cutaneous nerve that provides sensation to the skin over the parotid gland, mastoid process, and auricle.
- Damage to this nerve would result in sensory loss in these areas and is unrelated to muscle weakness or a winged scapula.
*Musculocutaneous nerve*
- The **musculocutaneous nerve** innervates the **biceps brachii**, **brachialis**, and **coracobrachialis muscles**, responsible for elbow flexion and forearm supination.
- Damage to this nerve would primarily affect these movements and sensation in the lateral forearm, not leading to a winged scapula.
Anatomical terminology and positions US Medical PG Question 5: An MRI of a patient with low back pain reveals compression of the L5 nerve root. Which of the following muscles would most likely show weakness during physical examination?
- A. Tibialis posterior
- B. Tibialis anterior (Correct Answer)
- C. Gastrocnemius
- D. Quadriceps femoris
Anatomical terminology and positions Explanation: ***Tibialis anterior***
- The **L5 nerve root** primarily innervates muscles responsible for **dorsiflexion** of the foot, with the **tibialis anterior** being the primary dorsiflexor.
- Weakness of the tibialis anterior would manifest as difficulty lifting the front of the foot, potentially leading to a **foot drop** gait.
*Tibialis posterior*
- The **tibialis posterior** is primarily innervated by the **tibial nerve** (S1-S2) and is responsible for **plantarflexion** and **inversion** of the foot.
- Weakness in this muscle would not be the most likely presentation of L5 nerve root compression.
*Gastrocnemius*
- The **gastrocnemius** muscle is primarily innervated by the **tibial nerve** (S1-S2) and is a powerful **plantarflexor** of the foot.
- Weakness in this muscle would indicate an S1 or S2 nerve root issue, not typically L5.
*Quadriceps femoris*
- The **quadriceps femoris** is innervated by the **femoral nerve**, predominantly originating from the **L2, L3, and L4 nerve roots**.
- Weakness would manifest as difficulty extending the knee, which is not characteristic of L5 compression.
Anatomical terminology and positions US Medical PG Question 6: A 24-year-old woman comes to the emergency department because of abdominal pain, fever, nausea, and vomiting for 12 hours. Her abdominal pain was initially dull and diffuse but has progressed to a sharp pain on the lower right side. Two years ago she had to undergo right salpingo-oophorectomy after an ectopic pregnancy. Her temperature is 38.7°C (101.7°F). Physical examination shows severe right lower quadrant tenderness with rebound tenderness; bowel sounds are decreased. Laboratory studies show leukocytosis with left shift. An abdominal CT scan shows a distended, edematous appendix. The patient is taken to the operating room for an appendectomy. During the surgery, the adhesions from the patient's previous surgery make it difficult for the resident physician to identify the appendix. Her attending mentions that she should use a certain structure for guidance to locate the appendix. The attending is most likely referring to which of the following structures?
- A. Epiploic appendages
- B. Right ureter
- C. Deep inguinal ring
- D. Ileocolic artery
- E. Teniae coli (Correct Answer)
Anatomical terminology and positions Explanation: ***Teniae coli***
- The **teniae coli** are three distinct longitudinal bands of smooth muscle that run along the length of the cecum and colon, converging at the base of the **appendix**.
- Following these bands inferiorly from the ascending colon or cecum during surgery is a reliable method to locate the **vermiform appendix**, especially in the presence of adhesions.
*Epiploic appendages*
- These are small, fat-filled sacs that protrude from the surface of the **large intestine** but are not directly used as a reliable landmark for locating the appendix.
- While present in the vicinity, they do not consistently lead to the base of the appendix like the teniae coli.
*Right ureter*
- The **right ureter** is located retroperitoneally, deep to the cecum and appendix, and is not a direct anatomical landmark used for identifying the appendix during an appendectomy.
- Identifying the ureter is important to avoid injury, but not for localizing the appendix.
*Deep inguinal ring*
- The **deep inguinal ring** is an opening in the transversalis fascia, involved in the formation of the inguinal canal, and is located far anterior and inferior to the region of the appendix.
- It has no anatomical relationship that would guide a surgeon to locate the appendix.
*Ileocolic artery*
- The **ileocolic artery** branches from the superior mesenteric artery and supplies the terminal ileum, cecum, and appendix. While it provides blood supply to the appendix, it is not a direct or consistent surface landmark for locating the appendix itself, especially in complex cases with adhesions.
- Locating the artery would be more complex and less reliable for initial identification compared to the teniae coli.
Anatomical terminology and positions US Medical PG Question 7: Linear growth of bone is disturbed when a fracture occurs in which part?
- A. Epiphysis
- B. Diaphysis
- C. Metaphysis
- D. Epiphyseal plate (Correct Answer)
- E. Periosteum
Anatomical terminology and positions Explanation: ***Epiphyseal plate***
- The **epiphyseal plate**, also known as the **growth plate**, is a cartilaginous disc responsible for the **longitudinal growth** of long bones.
- A fracture in this region can damage the **chondrocytes** and disrupt the normal process of endochondral ossification, leading to **growth arrest** or limb length discrepancy.
*Epiphysis*
- The **epiphysis** is the end part of a long bone, often covered by **articular cartilage**, forming a joint.
- While an epiphyseal fracture can affect joint function, it typically does not directly disturb the **linear growth** of the bone unless it extends into the growth plate.
*Diaphysis*
- The **diaphysis** is the main or midsection of a long bone, composed primarily of **compact bone**.
- Fractures in the diaphysis generally heal through **callus formation** and remodeling, usually without significantly impacting the overall **linear growth** of the bone.
*Metaphysis*
- The **metaphysis** is the wider portion of a long bone, adjacent to the growth plate and diaphysis.
- Though highly vascular, fractures to the metaphysis usually heal well and do not directly control **linear bone growth** like the epiphyseal plate.
*Periosteum*
- The **periosteum** is the fibrous membrane covering the outer surface of bones, important for **appositional growth** (bone widening) and fracture healing.
- While it contains osteogenic cells that contribute to bone repair and thickness, it does not control **longitudinal bone growth**, which is the function of the epiphyseal plate.
Anatomical terminology and positions US Medical PG Question 8: A 14-year-old boy is brought to the physician for the evaluation of back pain for the past six months. The pain is worse with exercise and when reclining. He attends high school and is on the swim team. He also states that he lifts weights on a regular basis. He has not had any trauma to the back or any previous problems with his joints. He has no history of serious illness. His father has a disc herniation. Palpation of the spinous processes at the lumbosacral area shows that two adjacent vertebrae are displaced and are at different levels. Muscle strength is normal. Sensation to pinprick and light touch is intact throughout. When the patient is asked to walk, a waddling gait is noted. Passive raising of either the right or left leg causes pain radiating down the ipsilateral leg. Which of the following is the most likely diagnosis?
- A. Spondylolisthesis (Correct Answer)
- B. Overuse injury
- C. Ankylosing spondylitis
- D. Disc herniation
- E. Facet joint syndrome
Anatomical terminology and positions Explanation: ***Spondylolisthesis***
- The patient presents with **back pain worse with exercise and reclining**, along with **palpable displacement of adjacent vertebrae** at different levels, which are classic signs of spondylolisthesis. The **waddling gait** and pain radiating down the leg upon passive leg raising (suggesting nerve root irritation) further support this diagnosis.
- Spondylolisthesis, particularly **isthmic type**, is common in adolescent athletes involved in sports like swimming and weightlifting due to repetitive hyperextension leading to stress fractures in the pars interarticularis.
*Overuse injury*
- While overuse injuries are common in athletes, they typically present with generalized pain or tenderness in the affected area without distinct **vertebral displacement** or neurological signs like radiating pain and a waddling gait.
- The specific signs of palpable vertebral displacement and nerve root irritation point to a more severe structural issue than a simple overuse soft tissue injury.
*Ankylosing spondylitis*
- **Ankylosing spondylitis** usually presents with **inflammatory back pain** that improves with exercise, not worsens, and often affects young adults, not typically a 14-year-old with these specific physical findings.
- It would not explain the **palpable vertebral displacement** or the sudden onset of neurological symptoms like radiating leg pain and waddling gait.
*Disc herniation*
- While disc herniation can cause **radiating leg pain** and back pain, it typically doesn't present with **palpable vertebral displacement** or a waddling gait in an adolescent without a history of significant trauma.
- The physical exam finding of displaced vertebrae is more indicative of a structural instability like spondylolisthesis rather than an isolated disc problem, even though a father has a history.
*Facet joint syndrome*
- Facet joint syndrome usually results in localized back pain that **worsens with extension and rotation** but typically does not cause **palpable vertebral displacement** or neurological deficits like radiating pain and a waddling gait.
- It is also more common in older adults due to degenerative changes, rather than a 14-year-old athlete.
Anatomical terminology and positions US Medical PG Question 9: A 53-year-old man with a history of alcoholic liver cirrhosis was admitted to the hospital with ascites and general wasting. He has a history of 3-5 ounces of alcohol consumption per day for 20 years and 20-pack-year smoking history. Past medical history is significant for alcoholic cirrhosis of the liver, diagnosed 5 years ago. On physical examination, the abdomen is firm and distended. There is mild tenderness to palpation in the right upper quadrant with no rebound or guarding. Shifting dullness and a positive fluid wave is present. Prominent radiating umbilical varices are noted. Laboratory values are significant for the following:
Total bilirubin 4.0 mg/dL
Aspartate aminotransferase (AST) 40 U/L
Alanine aminotransferase (ALT) 18 U/L
Gamma-glutamyltransferase 735 U/L
Platelet count 11,000/mm3
WBC 4,300/mm3
Serology for viral hepatitis B and C are negative. A Doppler ultrasound of the abdomen shows significant enlargement of the epigastric superficial veins and hepatofugal flow within the portal vein. There is a large volume of ascites present. Paracentesis is performed in which 10 liters of straw-colored fluid is removed. Which of the following sites of the portocaval anastomosis is most likely to rupture and bleed first in this patient?
- A. Superior and middle rectal vein – inferior rectal veins
- B. Umbilical vein – superficial epigastric veins
- C. Esophageal branch of left gastric vein – esophageal branches of azygos vein (Correct Answer)
- D. Paraumbilical veins – inferior epigastric veins
- E. Short gastric veins – intercostal veins
Anatomical terminology and positions Explanation: ***Esophageal branch of left gastric vein – esophageal branches of azygos vein***
- The gastroesophageal junction is the most frequent site of **life-threatening variceal bleeding** in patients with portal hypertension due to liver cirrhosis. The elevated portal pressure forces blood from the **left gastric (coronary) vein** into the thinner-walled esophageal veins which drain into the azygos system.
- The patient's history of **alcoholic liver cirrhosis** makes portal hypertension and subsequent esophageal varices highly likely. While other portocaval anastomoses exist, esophageal varices are clinically the most significant due to their propensity for rupture and severe hemorrhage.
*Superior and middle rectal vein – inferior rectal veins*
- This anastomosis concerns the rectums, involving the **superior rectal vein (portal system)** and the **middle/inferior rectal veins (systemic system)**.
- While portal hypertension can lead to **anorectal varices**, also known as hemorrhoids, these are less prone to life-threatening hemorrhage compared to esophageal varices and typically present with bleeding on defecation or discomfort.
*Umbilical vein – superficial epigastric veins*
- This anastomosis is responsible for the formation of a **caput medusae**, which is a sign of portal hypertension where prominent periumbilical veins radiate from the navel. The patient presents with prominent "radiating umbilical varices," which is consistent with this finding.
- While visually striking and indicative of portal hypertension, these superficial varices are generally **not associated with significant or life-threatening hemorrhage** compared to esophageal varices.
*Paraumbilical veins – inferior epigastric veins*
- The paraumbilical veins run within the falciform ligament and connect the portal system to the systemic circulation via the **epigastric veins**.
- This anastomosis contributes to the formation of caput medusae but is **not a common site for clinically significant bleeding** requiring intervention compared to esophageal varices.
*Short gastric veins – intercostal veins*
- The short gastric veins drain into the splenic vein (part of the portal system) and connect to systemic veins such as the intercostal veins via retroperitoneal anastomoses.
- While this is a potential site of portosystemic shunting, the short gastric veins are more commonly implicated in **gastric varices**, particularly in the fundus. However, gastric varices are less frequent and **rupture less commonly than esophageal varices**, although hemorrhage from them can be more severe when it does occur.
Anatomical terminology and positions 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)
Anatomical terminology and positions 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.
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