Clinical Aspects of Back Disorders — MCQs

10 questions

In ankylosing spondylitis, which of the following is commonly seen on MRI?

A patient presented with Saddle anaesthesia with bladder and bowel involvement and muscle power is normal. The diagnosis is:

All of the following are true regarding ankylosing spondylitis except:

Tuberculosis of the spine; what is the most common site affected?

CEAP score indicates-

Occlusion of blood supply of the area marked in red will lead to all of the following except:

In adults, the spinal cord normally ends at what level?

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?

Q9Easy

In adults, the spinal cord ends at the lower border of which vertebra?

Q10Medium

If injury occurs at the C7 nerve root, in which part of the arm will sensation be lost?

Clinical Aspects of Back Disorders Indian Medical PG Practice Questions and MCQs

Question 1: In ankylosing spondylitis, which of the following is commonly seen on MRI?

A. Schmorl's nodes
B. Intervertebral disc prolapse
C. Sacroiliitis (Correct Answer)
D. Bamboo spine

Explanation: ***Sacroiliitis*** - **Sacroiliitis**, inflammation of the **sacroiliac joints**, is the hallmark and earliest radiological finding in **ankylosing spondylitis** and is readily visualized on MRI. - MRI is highly sensitive for detecting both **bone marrow edema** (indicating active inflammation) and **erosions** in the sacroiliac joints, even before changes are visible on conventional X-rays. *Schmorl's nodes* - **Schmorl's nodes** are **vertebral endplate infarctions** where the intervertebral disc herniates into the vertebral body, typically due to degeneration or trauma. - While they can be seen in various spinal conditions, they are **not specifically diagnostic** or characteristic of **ankylosing spondylitis**. *Intervertebral disc prolapse* - An **intervertebral disc prolapse**, commonly known as a **slipped disc**, involves the bulging or rupture of a disc, often causing nerve root compression. - This is a common cause of back pain in the general population but is **not a primary feature** or direct consequence of the inflammatory process in **ankylosing spondylitis**. *Bamboo spine* - **Bamboo spine** refers to the **fusion of vertebral bodies** due to syndesmophyte formation, leading to a rigid spine. - This is a **late-stage radiological change** seen on plain X-rays, representing chronic, irreversible damage, whereas MRI is used for early detection of active inflammation like sacroiliitis.

Question 2: A patient presented with Saddle anaesthesia with bladder and bowel involvement and muscle power is normal. The diagnosis is:

A. L4-L5 disc prolapsed
B. L3-L4 root involvement
C. Conus medullaris lesion (Correct Answer)
D. Cauda equina syndrome

Explanation: ***Conus medullaris lesion*** - A **conus medullaris lesion** typically presents with **saddle anesthesia**, early and severe **bladder and bowel dysfunction**, and often **symmetrical neurological deficits** [1], [3]. - **Motor weakness in the legs** is usually minimal or absent, which aligns with the patient's normal muscle power in this case. *L4-L5 disc prolapsed* - A **L4-L5 disc prolapse** primarily causes **radicular pain** and weakness in the distribution of the L5 nerve root (e.g., foot drop, weakness of ankle dorsiflexion) [2]. - While it can cause some sensory changes, **saddle anesthesia** and severe bladder/bowel dysfunction are not typical features. *L3-L4 root involvement* - **L3-L4 root involvement**, often from a disc herniation, would typically present with **quadriceps weakness**, absent patellar reflex, and sensory loss over the medial thigh [2]. - It would not cause **saddle anesthesia** or significant bladder/bowel dysfunction as a primary symptom. *Cauda equina syndrome* - **Cauda equina syndrome** presents with **saddle anesthesia** and **bladder/bowel dysfunction**, but it is generally characterized by **significant motor weakness** in the lower extremities (e.g., severe leg weakness, foot drop), which is absent here. - The onset of bladder and bowel symptoms in cauda equina syndrome is often more gradual and less severe initially compared to conus medullaris lesions.

Question 3: All of the following are true regarding ankylosing spondylitis except:

A. 50% of patients may have urinary infection (Correct Answer)
B. Involvement of sacroiliac joint
C. Bamboo spine may be a radiological feature
D. Most of people are HLAB27 positive

Explanation: ***50% of patients may have urinary infection*** - Urinary tract infections are **not a characteristic feature** or a common complication of **ankylosing spondylitis**. - This statement is incorrect as there is no significant epidemiological or pathophysiological link between AS and a high incidence of UTIs. *Involvement of sacroiliac joint* - **Sacroiliitis**, inflammation of the sacroiliac joints, is one of the **hallmark features** and often the earliest sign of ankylosing spondylitis [1]. - It is typically **bilateral and symmetrical**, and its presence is crucial for diagnosis [1]. *Bamboo spine may be a radiological feature* - **Bamboo spine** is a characteristic late radiological finding in ankylosing spondylitis, resulting from **syndesmophyte formation** (ossification of spinal ligaments) and fusion of vertebral bodies [1]. - This appearance signifies severe spinal rigidity and advanced disease. *Most of people are HLAB27 positive* - The **HLA-B27 allele** is strongly associated with ankylosing spondylitis, being present in around **90% of Caucasian patients** [1]. - While not diagnostic on its own, its presence significantly increases susceptibility and supports the diagnosis in the right clinical context.

Question 4: Tuberculosis of the spine; what is the most common site affected?

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

Explanation: ***94ed055d-c7da-4d18-a2fd-52720dfe8b6e*** - The **dorsolumbar (thoracolumbar)** region is the most common site of **spinal tuberculosis (Pott's disease)** [1] due to its high vascularity, facilitating hematogenous spread. - **Spinal tuberculosis** typically affects the vertebral bodies, leading to their destruction, kyphosis (angular deformity), and potentially neurological deficits [1]. *aebdfe6c-98dc-4073-892f-bb24d047bab4* - The **sacral** region can be affected by **tuberculosis**, but it is considerably less common than the thoracolumbar region. - Involvement of the sacrum is often associated with **direct extension** from adjacent structures, such as the sacroiliac joint, rather than primary vertebral involvement. *15c1feef-e3ca-496f-a180-127d52b77bfa* - **Cervical spine tuberculosis** is relatively rare, accounting for a small percentage of all spinal tuberculosis cases. - While possible, it presents with specific challenges due to the proximity of vital neurological and vascular structures. *d05d4d13-bb83-4f26-aa2d-c9c0203d299c* - The **lumbosacral region** (L5-S1) can be involved in **tuberculosis**, but it is less frequently affected than the thoracolumbar region. - While the lumbar spine is a common site, the entire lumbosacral region as a single entity is not the most common spot for spinal TB.

Question 5: CEAP score indicates-

A. Atrial disorders
B. Venous disorder (Correct Answer)
C. Trauma disorder
D. Neurological disorder

Explanation: ***Venous disorder*** - The **CEAP classification** is a widely recognized system used to categorize and describe chronic venous disorders. The acronym stands for **Clinical, Etiological, Anatomical, and Pathophysiological** factors. - It provides a standardized framework for clinicians to classify the severity and characteristics of **venous disease**, ranging from spider veins to active ulcers. *Atrial disorders* - **Atrial disorders** refer to conditions affecting the atria of the heart, such as **atrial fibrillation** or **atrial flutter**. - These are cardiovascular conditions distinct from venous disorders, which involve the veins (blood vessels returning blood to the heart). *Neurological disorder* - A **neurological disorder** is a condition affecting the **nervous system**, including the brain, spinal cord, and nerves. - The CEAP classification is specifically designed for vascular conditions and has no direct relevance to neurological diseases. *Trauma disorder* - A **trauma disorder** is a condition resulting from a **physically or psychologically traumatic event**. - While trauma can sometimes lead to venous issues (e.g., deep vein thrombosis from immobilization), the CEAP score itself is a classification system for chronic venous disease, not for traumatic conditions in general.

Question 6: Occlusion of blood supply of the area marked in red will lead to all of the following except:

A. Urinary incontinence
B. Rectal incontinence
C. Apraxia (Constructional) (Correct Answer)
D. Peri-anal anaesthesia

Explanation: ***Apraxia (Constructional)*** - The area marked in red represents the **medial portion of the precentral gyrus (motor cortex)** and **postcentral gyrus (sensory cortex)**, as well as the **paracentral lobule**, which are supplied by the **anterior cerebral artery (ACA)**. - Constructional apraxia is typically associated with **posterior parietal lobe lesions**, particularly in the non-dominant hemisphere, which is supplied by the posterior cerebral artery and middle cerebral artery branches, not the ACA. *Urinary incontinence* - The **paracentral lobule**, located in the area supplied by the ACA (marked in red), contains centers for **bladder control** and voluntary micturition. - Damage to this region can lead to **urinary incontinence** due to disrupted cortical control over bladder function. *Rectal incontinence* - Similar to bladder control, the **paracentral lobule** also plays a role in **voluntary bowel control**. - Ischemia in this region due to ACA occlusion can therefore result in **rectal incontinence**. *Peri-anal anaesthesia* - The **somatosensory cortex** representing the lower limbs and perineum is located in the **paracentral lobule** (postcentral gyrus part). - Occlusion of the ACA, supplying this region, can lead to **sensory deficits**, including **anaesthesia** in the peri-anal area.

Question 7: In adults, the spinal cord normally ends at what level?

A. Lower border of L3
B. Lower border of S1
C. Lower border of L5
D. Lower border of L1 (Correct Answer)

Explanation: ***Lower border of L1*** - In adults, the **spinal cord** typically terminates at the level of the **L1 vertebral body**, or specifically, its lower border [1]. - This marks the anatomical transition from the solid spinal cord to the **conus medullaris**, which then continues as the **cauda equina** [1]. *Lower border of L3* - While the spinal cord in **newborns** can extend as low as L3, it retracts with growth, and this level is incorrect for adults. - An adult spinal cord ending at L3 would be considered an **abnormal finding**, potentially indicating a **tethered cord syndrome**. *Lower border of S1* - The spinal cord never extends to the S1 level in healthy individuals, even in newborns. - The **sacrum (S1-S5)** is well below the normal termination point of the spinal cord. *Lower border of L5* - The spinal cord typically terminates well above L5 in adults. - The **cauda equina**, not the spinal cord itself, extends through the lumbar and sacral regions to L5 and beyond.

Question 8: 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

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.

Question 9: In adults, the spinal cord ends at the lower border of which vertebra?

A. L1
B. L1 (Correct Answer)
C. L3
D. L5

Explanation: The spinal cord is a continuation of the medulla oblongata and terminates as the **conus medullaris**. In adults, the spinal cord typically ends at the **lower border of the L1 vertebra** [1] (or the L1-L2 intervertebral disc). This anatomical position is a result of differential growth rates during development; the vertebral column grows faster and longer than the spinal cord (ascensus medullae). **Analysis of Options:** * **Option A & B (L1):** This is the correct anatomical level in adults [1]. It is the standard landmark for the termination of the spinal cord. * **Option C (L3):** This is the level where the spinal cord ends in **neonates/infants**. As the child grows, the vertebral column outpaces the cord, shifting the relative position of the conus medullaris upward to the L1 level. * **Option D (L5):** The spinal cord never terminates this low. By the end of the first trimester of fetal life, the cord extends the entire length of the vertebral canal (S1 level), but it moves cranially thereafter. **High-Yield Clinical Pearls for NEET-PG:** * **Lumbar Puncture (LP):** To avoid injuring the spinal cord, an LP is typically performed at the **L3-L4 or L4-L5** interspace, well below the termination of the cord. * **Tethered Cord Syndrome:** A clinical condition where the conus medullaris is located abnormally low (below L2), often associated with neurological deficits. * **Subarachnoid Space:** While the cord ends at L1, the subarachnoid space (containing CSF) continues down to the **S2 level**. * **Filum Terminale:** A delicate strand of fibrous tissue (pia mater) that extends from the conus medullaris to the coccyx [1].

Question 10: If injury occurs at the C7 nerve root, in which part of the arm will sensation be lost?

A. Upper medial
B. Lower medial
C. Posterior
D. None of the above (Correct Answer)

Explanation: **Explanation:** The correct answer is **None of the above** because the C7 nerve root provides sensory innervation to the **middle finger** and the **central aspect of the hand** (both palmar and dorsal surfaces), rather than the arm itself. [1] **1. Why the correct answer is right:** Dermatomes of the upper limb follow a specific longitudinal pattern. The C7 dermatome specifically covers the middle finger and the center of the hand. While C7 provides motor supply to the triceps (extension of the elbow), its sensory distribution does not encompass the medial or posterior aspects of the arm. **2. Analysis of incorrect options:** * **Upper medial arm (A):** This area is primarily supplied by the **T2** nerve root (Intercostobrachial nerve). * **Lower medial arm (B):** This area is supplied by the **T1** nerve root (Medial cutaneous nerve of the arm). * **Posterior arm (C):** Sensation to the posterior aspect of the arm is provided by the **C5 and C6** nerve roots (via the Posterior cutaneous nerve of the arm, a branch of the radial nerve). **Clinical Pearls for NEET-PG:** * **C7 Radiculopathy:** Often presents with weakness in elbow extension (Triceps), loss of the triceps reflex, and numbness specifically in the **middle finger**. * **Dermatome "Rule of Thumb":** * C6 = Thumb and lateral forearm. * C7 = Middle finger. * C8 = Little finger and medial hand. * T1 = Medial forearm. * **High-Yield Association:** C7 is the most common site for cervical disc herniation. Always look for "Triceps weakness" and "Middle finger numbness" as the classic clinical triad.

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