To what level of vertebrae does the marked structure correspond?
Identify the pelvis type given below.
In the sagittal section of the brain given below the colored area represents the paracentral lobule. Which of the following structures are affected in a lesion to this area?
FMGE 2023 - Anatomy FMGE Practice Questions and MCQs
Question 21: To what level of vertebrae does the marked structure correspond?
- A. At the junction of L1 & L2
- B. At the junction of L2 & L3
- C. At the junction of T12 & L1
- D. At the junction of L3 & L4 (Correct Answer)
Explanation: ***At the junction of L3 & L4*** - The umbilicus, indicated by the arrow, is a key surface landmark that typically corresponds to the level of the **intervertebral disc** between the **L3 and L4 vertebrae**. - This anatomical relationship is important for clinical procedures, as the **supracristal plane** (a line between the iliac crests) crosses near the L4 vertebra, helping to landmark sites for **lumbar puncture**. *At the junction of L1 & L2* - This vertebral level corresponds to the **transpyloric plane**, which is a different landmark located superior to the umbilicus. - Important structures at the L1/L2 level include the **pylorus of the stomach**, the hila of the kidneys, and the termination of the spinal cord (**conus medullaris**) in adults. *At the junction of L2 & L3* - This level is superior to the anatomical position of the umbilicus. - It corresponds to the location of the inferior border of the third part of the **duodenum** and the origin of the **inferior mesenteric artery** is often around L3. *At the junction of T12 & L1* - This is a much higher vertebral level, associated with the origin of the **celiac trunk** and the **superior mesenteric artery** from the abdominal aorta. - It is located significantly superior to the umbilicus and is near the **diaphragmatic hiatus** for the aorta.
Question 22: Identify the pelvis type given below.
- A. Platypoid
- B. Anthropoid
- C. Android (Correct Answer)
- D. Gynecoid
Explanation: ***Android*** - This pelvis is characterized by a **heart-shaped** or triangular inlet, with a narrow forepelvis, as seen in the image. - It features **prominent ischial spines** and a narrow subpubic arch, making it unfavorable for vaginal delivery and associated with a higher risk of **dystocia**. *Platypoid* - The platypoid pelvis has a **kidney-shaped** or **transversely oval** inlet, where the transverse diameter is significantly wider than the anteroposterior diameter. - This type is the rarest and is unfavorable for childbirth as the fetal head may have difficulty engaging in the short anteroposterior diameter. *Anthropoid* - The anthropoid pelvis has a **long, narrow, oval-shaped** inlet, where the anteroposterior diameter is greater than the transverse diameter. - This shape often leads to the engagement of the fetal head in the **occiput-posterior** position but is generally favorable for vaginal delivery. *Gynecoid* - This is the classic female pelvis, featuring a **rounded** or slightly oval inlet with a wide transverse diameter, which is most favorable for childbirth. - It has a wide **subpubic arch** (greater than 90 degrees), non-prominent ischial spines, and a spacious pelvic cavity, facilitating an uncomplicated vaginal delivery.
Question 23: In the sagittal section of the brain given below the colored area represents the paracentral lobule. Which of the following structures are affected in a lesion to this area?
- A. Perineum and leg (Correct Answer)
- B. Face and neck
- C. Trunk and shoulder
- D. Scapular region and neck
Explanation: ***Perineum and leg*** - The **paracentral lobule**, located on the medial surface of the cerebral hemisphere, contains the primary motor and somatosensory cortical areas for the contralateral **leg**, **foot**, and **perineum**. - A lesion in this area, often due to an **anterior cerebral artery (ACA) stroke**, typically results in motor and sensory deficits in the contralateral leg and foot, and may also cause **urinary incontinence** due to involvement of the cortical micturition center. *Scapular region and neck* - The cortical representations for the scapular region and neck are located on the **superolateral surface** of the precentral and postcentral gyri, not on the medial surface where the paracentral lobule lies. - These areas are supplied by the **middle cerebral artery (MCA)**, not the ACA. *Trunk and shoulder* - According to the **motor and sensory homunculus**, the trunk and shoulder areas are located more superiorly and laterally on the cerebral cortex, lateral to the paracentral lobule. - A lesion affecting these areas would involve the superolateral convexity of the hemisphere, which has a different vascular supply (MCA). *Face and neck* - The cortical areas for the face and neck are situated on the **inferolateral aspect** of the precentral and postcentral gyri. - Lesions here are characteristic of an **MCA stroke** and would result in contralateral facial weakness and sensory loss, sparing the lower limbs.