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]

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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