UPSC-CMS 2012 — Anatomy

Q: The pancreas is supplied by all of the following arteries except

Left gastric. ***Left gastric*** - The **left gastric artery** primarily supplies the lesser curvature of the stomach and the abdominal esophagus. - It does not directly supply the pancreas; pancreatic blood supply originates from branches of the splenic, common hepatic, and superior mesenteric arteries. *Splenic* - The **splenic artery** gives rise to multiple branches that supply the pancreas, including the great pancreatic artery, dorsal pancreatic artery, and caudal pancreatic arteries. - These branches are crucial for the blood supply to the body and tail of the pancreas. *Common hepatic* - The **common hepatic artery** gives rise to the gastroduodenal artery, which further branches into the anterior and posterior superior pancreaticoduodenal arteries. - These arteries supply the head of the pancreas and the duodenum. *Superior mesenteric* - The **superior mesenteric artery** gives rise to the inferior pancreaticoduodenal arteries (anterior and posterior branches). - These arteries anastomose with the superior pancreaticoduodenal arteries to supply the head of the pancreas and the uncinate process. [Practice more Anatomy PYQs on OnCourse]

Q: A fracture of the middle cranial fossa may result in an injury of the

Sixth cranial nerve. ***Sixth cranial nerve*** - The **abducens nerve (CN VI)** passes through the **Dorello's canal (or petroclival ligament)**, located in the vicinity of the middle cranial fossa. - Fractures in this region can lead to **stretching or compression** of the abducens nerve, resulting in **lateral rectus palsy** and *diplopia*. *Tenth cranial nerve* - The **vagus nerve (CN X)** exits the skull via the **jugular foramen**, located in the **posterior cranial fossa**. - Injury to this nerve is less likely with a fracture specifically confined to the middle cranial fossa. *Eighth cranial nerve* - The **vestibulocochlear nerve (CN VIII)** courses through the **internal auditory meatus** in the **petrous part of the temporal bone**, which is part of the posterior cranial fossa. - While acoustic trauma or petrous bone fractures can affect it, it's not a primary concern with general middle cranial fossa fractures. *Eleventh cranial nerve* - The **spinal accessory nerve (CN XI)** exits the skull through the **jugular foramen**, similar to the vagus nerve, placing it in the **posterior cranial fossa**. - Damage to this nerve would primarily cause weakness in the **sternocleidomastoid** and **trapezius muscles**, and is not typically associated with isolated middle cranial fossa fractures. [Practice more Anatomy PYQs on OnCourse]

Q: A meningomyelocele is most commonly situated in the

Lumbosacral spine. ***Lumbosacral spine*** - The **lumbosacral region** (L5-S1) is the most frequent anatomical site for meningomyelocele due to the timing of neural tube closure. - This area is the last portion of the **neural tube** to close, making it more susceptible to defects if closure is incomplete [1]. *Thoracic spine* - While meningomyeloceles can occur in the thoracic region, it is far less common than in the lumbosacral area [1]. - Defects in the thoracic spine are usually associated with a higher level of neurological impairment [1]. *Dorsolumbar spine* - This term encompasses the lower thoracic and upper lumbar regions; while possible, it is not the most common singular site. - The lumbosacral region has a higher prevalence of meningomyelocele formation. *Cervical spine* - Meningoceles and meningomyeloceles in the cervical spine are much rarer. - These defects often present with different neurological findings compared to lumbosacral lesions, such as upper limb weakness. [Practice more Anatomy PYQs on OnCourse]

3 Previous Year Questions with Answers & Explanations

Questions

All Subjects Anatomy (3)Anesthesiology (1)Biochemistry (7)Community Medicine (16)ENT (2)Internal Medicine (7)Microbiology (2)Obstetrics and Gynecology (37)Ophthalmology (2)Orthopaedics (1)Pathology (2)Pediatrics (4)Pharmacology (6)Physiology (2)Surgery (17)

The pancreas is supplied by all of the following arteries except

A fracture of the middle cranial fossa may result in an injury of the

A meningomyelocele is most commonly situated in the

UPSC-CMS 2012 - Anatomy UPSC-CMS Practice Questions and MCQs

Question 1: The pancreas is supplied by all of the following arteries except

A. Splenic
B. Common hepatic
C. Left gastric (Correct Answer)
D. Superior mesenteric

Explanation: ***Left gastric*** - The **left gastric artery** primarily supplies the lesser curvature of the stomach and the abdominal esophagus. - It does not directly supply the pancreas; pancreatic blood supply originates from branches of the splenic, common hepatic, and superior mesenteric arteries. *Splenic* - The **splenic artery** gives rise to multiple branches that supply the pancreas, including the great pancreatic artery, dorsal pancreatic artery, and caudal pancreatic arteries. - These branches are crucial for the blood supply to the body and tail of the pancreas. *Common hepatic* - The **common hepatic artery** gives rise to the gastroduodenal artery, which further branches into the anterior and posterior superior pancreaticoduodenal arteries. - These arteries supply the head of the pancreas and the duodenum. *Superior mesenteric* - The **superior mesenteric artery** gives rise to the inferior pancreaticoduodenal arteries (anterior and posterior branches). - These arteries anastomose with the superior pancreaticoduodenal arteries to supply the head of the pancreas and the uncinate process.

Question 2: A fracture of the middle cranial fossa may result in an injury of the

A. Sixth cranial nerve (Correct Answer)
B. Tenth cranial nerve
C. Eighth cranial nerve
D. Eleventh cranial nerve

Explanation: ***Sixth cranial nerve*** - The **abducens nerve (CN VI)** passes through the **Dorello's canal (or petroclival ligament)**, located in the vicinity of the middle cranial fossa. - Fractures in this region can lead to **stretching or compression** of the abducens nerve, resulting in **lateral rectus palsy** and *diplopia*. *Tenth cranial nerve* - The **vagus nerve (CN X)** exits the skull via the **jugular foramen**, located in the **posterior cranial fossa**. - Injury to this nerve is less likely with a fracture specifically confined to the middle cranial fossa. *Eighth cranial nerve* - The **vestibulocochlear nerve (CN VIII)** courses through the **internal auditory meatus** in the **petrous part of the temporal bone**, which is part of the posterior cranial fossa. - While acoustic trauma or petrous bone fractures can affect it, it's not a primary concern with general middle cranial fossa fractures. *Eleventh cranial nerve* - The **spinal accessory nerve (CN XI)** exits the skull through the **jugular foramen**, similar to the vagus nerve, placing it in the **posterior cranial fossa**. - Damage to this nerve would primarily cause weakness in the **sternocleidomastoid** and **trapezius muscles**, and is not typically associated with isolated middle cranial fossa fractures.

Question 3: A meningomyelocele is most commonly situated in the

A. Thoracic spine
B. Dorsolumbar spine
C. Cervical spine
D. Lumbosacral spine (Correct Answer)

Explanation: ***Lumbosacral spine*** - The **lumbosacral region** (L5-S1) is the most frequent anatomical site for meningomyelocele due to the timing of neural tube closure. - This area is the last portion of the **neural tube** to close, making it more susceptible to defects if closure is incomplete [1]. *Thoracic spine* - While meningomyeloceles can occur in the thoracic region, it is far less common than in the lumbosacral area [1]. - Defects in the thoracic spine are usually associated with a higher level of neurological impairment [1]. *Dorsolumbar spine* - This term encompasses the lower thoracic and upper lumbar regions; while possible, it is not the most common singular site. - The lumbosacral region has a higher prevalence of meningomyelocele formation. *Cervical spine* - Meningoceles and meningomyeloceles in the cervical spine are much rarer. - These defects often present with different neurological findings compared to lumbosacral lesions, such as upper limb weakness.