Vasculature of the Back — MCQs
The vein of Galen is formed by which structure?
The thyrocervical trunk is a branch of which part of subclavian artery?
In anterior spinal artery syndrome which of the following is spared
Posterior communicating artery is a branch of?
Which of the following parts of the vertebral canal shows the first secondary curve to develop?
In a diving accident that severed the spinal cord below the sixth cervical vertebra, which of the following muscles would be affected?
Muscles attached to the greater tubercle of the humerus include which of the following?
Which of the following muscles is not in the pectoral region?
Muscle inserting on medial border of scapula -
A crush injury of the vertebral column can cause the spinal cord to swell. Which structure would be trapped between the dura and the vertebral body by the swelling of the spinal cord?
Vasculature of the Back Indian Medical PG Practice Questions and MCQs
Question 1: The vein of Galen is formed by which structure?
- A. Internal cerebral veins (Correct Answer)
- B. Basal veins of Rosenthal
- C. Inferior sagittal sinus
- D. Superior sagittal sinus
Explanation: ***Internal cerebral veins*** - The **great cerebral vein of Galen** is formed by the union of two **internal cerebral veins** and two **basal veins of Rosenthal**. - It plays a crucial role in draining the deep venous system of the brain, including the **thalamus**, **basal ganglia**, and **choroid plexus**. - While both internal cerebral veins and basal veins contribute to its formation, "internal cerebral veins" is the most commonly tested answer. *Basal veins of Rosenthal* - The **basal veins of Rosenthal** also contribute to forming the great cerebral vein of Galen along with the internal cerebral veins. - However, in most examination contexts, the internal cerebral veins are considered the primary answer. - The basal veins primarily drain structures in the midbrain, thalamus, and insula. *Inferior sagittal sinus* - The **inferior sagittal sinus** does not form the great cerebral vein. - Instead, it merges with the **great cerebral vein** to form the **straight sinus**. - The inferior sagittal sinus runs along the lower border of the falx cerebri. *Superior sagittal sinus* - The **superior sagittal sinus** does not form the great cerebral vein. - It drains into the **confluence of sinuses** (torcular Herophili), which then connects to the transverse sinuses. - It runs along the superior border of the falx cerebri and drains the superior aspects of the cerebral hemispheres.
Question 2: The thyrocervical trunk is a branch of which part of subclavian artery?
- A. 1st part (Correct Answer)
- B. 2nd part
- C. 3rd part
- D. 4th part
Explanation: ***1st part*** - The **thyrocervical trunk** is one of the three primary branches arising from the **first part** of the subclavian artery. - The first part lies medial to the **anterior scalene muscle**. *2nd part* - The **second part** of the subclavian artery gives rise to the **costocervical trunk**. - This part lies posterior to the **anterior scalene muscle**. *3rd part* - The **third part** of the subclavian artery typically has no branches or may give off the **dorsal scapular artery**. - This part lies lateral to the **anterior scalene muscle**. *4th part* - This option is incorrect as the **subclavian artery has only three parts**, divided by their relationship to the anterior scalene muscle. - There is no anatomical fourth part of the subclavian artery.
Question 3: In anterior spinal artery syndrome which of the following is spared
- A. Lateral spinothalamic tract
- B. Posterior columns (Correct Answer)
- C. Anterior spinothalamic tract
- D. Corticospinal tract
Explanation: ***Posterior columns*** - The **anterior spinal artery** supplies the anterior two-thirds of the spinal cord, leaving the **posterior columns** (dorsal columns) and often the dorsal horns with intact blood supply from the **posterior spinal arteries** [1]. - This sparing results in preserved **fine touch**, **vibration**, and **proprioception** (dorsal column function), which are the defining clinical features distinguishing it from other spinal cord syndromes [1]. *Lateral spinothalamic tract* - This tract, responsible for **pain** and **temperature** sensation, is located within the territory supplied by the **anterior spinal artery** [3]. - Damage to this tract leads to bilateral loss of pain and temperature sensation below the level of the lesion [3]. *Anterior spinothalamic tract* - The **anterior spinothalamic tract** mediates crude touch and pressure and is located anteriorly, within the vascular distribution of the **anterior spinal artery**. - Injury to this tract contributes to the overall sensory deficit observed in anterior spinal artery syndrome. *Corticospinal tract* - The **corticospinal tracts** (also known as the pyramidal tracts), responsible for **voluntary motor control**, are situated in the anterior and lateral funiculi of the spinal cord [2]. - These tracts are supplied by the **anterior spinal artery**, leading to **bilateral motor paralysis** below the lesion in anterior spinal artery syndrome.
Question 4: Posterior communicating artery is a branch of?
- A. Internal carotid (Correct Answer)
- B. External carotid
- C. Middle cerebral
- D. Superior cerebellar
Explanation: ***Internal carotid*** - The **posterior communicating artery** connects the **internal carotid artery** circulation (anterior circulation) with the posterior cerebral artery (vertebrobasilar circulation). - It is a key component of the **circle of Willis**, ensuring collateral blood flow to the brain. *External carotid* - The **external carotid artery** primarily supplies the face, scalp, and neck, not the intracranial structures directly involved in the circle of Willis. - Its branches include the **superficial temporal artery** and **facial artery**, which are distinct from cerebral circulation. *Middle cerebral* - The **middle cerebral artery** is a **direct continuation** of the internal carotid artery, supplying large parts of the cerebral hemispheres. - While it arises from the internal carotid, the posterior communicating artery branches off the internal carotid **before** the middle cerebral artery. *Superior cerebellar* - The **superior cerebellar artery** is a branch of the **basilar artery**, supplying the superior cerebellum and parts of the brainstem. - This artery is part of the **vertebrobasilar system**, which is distinct from the primary origin of the posterior communicating artery.
Question 5: Which of the following parts of the vertebral canal shows the first secondary curve to develop?
- A. Lumbar Vertebral Canal
- B. Thoracic Vertebral Canal
- C. Cervical Vertebral Canal (Correct Answer)
- D. Sacral Vertebral Canal
Explanation: ***Cervical Vertebral Canal*** - The **cervical curve** is the **first secondary curve** to develop as an infant learns to hold their head up (around 3-4 months). - This **lordotic curve** is concave posteriorly and helps to balance the head on the vertebral column. - It develops before the lumbar curve, making it the earliest secondary curvature. *Lumbar Vertebral Canal* - The **lumbar curve** is also a **secondary curve** but develops later when an infant begins to stand and walk (around 12-18 months). - It is a **lordotic curve**, concave posteriorly, and helps maintain an upright posture. - This is the second secondary curve to develop. *Thoracic Vertebral Canal* - The **thoracic curve** is a **primary curve**, meaning it is present at birth. - This **kyphotic curve** is convex posteriorly and accommodates the thoracic organs. *Sacral Vertebral Canal* - The **sacral curve** is another **primary curve**, also present at birth. - It is a **kyphotic curve**, convex posteriorly, and contributes to the pelvic basin's shape.
Question 6: In a diving accident that severed the spinal cord below the sixth cervical vertebra, which of the following muscles would be affected?
- A. Deltoid
- B. Infraspinatus
- C. Levator Scapulae
- D. Latissimus Dorsi (Correct Answer)
Explanation: ***Latissimus Dorsi*** - The **latissimus dorsi muscle** is primarily innervated by the **thoracodorsal nerve**, which arises from the **C6, C7, and C8** nerve roots (with C7 and C8 being the predominant contributors) [1]. - A spinal cord injury below the sixth cervical vertebra would affect the C7 and C8 segments, thereby disrupting the nerve supply to the latissimus dorsi, leading to weakness or paralysis. - This muscle is responsible for adduction, extension, and internal rotation of the shoulder. *Deltoid* - The **deltoid muscle** is innervated by the **axillary nerve**, which arises predominantly from the **C5 and C6** nerve roots. - Since the injury is below the C6 vertebra, the upper cervical segments (C5 and C6) would remain intact above the level of injury. - Therefore, deltoid function would be preserved. *Infraspinatus* - The **infraspinatus muscle** is innervated by the **suprascapular nerve**, which arises from the **C5 and C6** nerve roots. - Similar to the deltoid, its innervation originates above the level of the spinal cord injury and would be spared. *Levator Scapulae* - The **levator scapulae muscle** receives innervation from the **C3, C4, and C5** spinal nerves, as well as contributions from the dorsal scapular nerve (predominantly C5). - All of these nerve roots originate well above the level of injury, so this muscle would not be affected.
Question 7: Muscles attached to the greater tubercle of the humerus include which of the following?
- A. Latissimus dorsi
- B. Teres major
- C. Pectoralis major
- D. Supraspinatus (Correct Answer)
Explanation: ***Supraspinatus*** - The **supraspinatus muscle** is one of the four rotator cuff muscles and inserts onto the **superior facet of the greater tubercle** of the humerus. - Its primary function is to **abduct the arm** in the initial 15 degrees. *Latissimus dorsi* - The **latissimus dorsi** inserts onto the **floor of the bicipital groove** of the humerus, not the greater tubercle. - It is primarily responsible for **extension, adduction, and internal rotation** of the arm. *Teres major* - The **teres major muscle** inserts onto the **medial lip of the bicipital groove** (intertubercular sulcus) of the humerus. - Its actions are similar to the latissimus dorsi, including **adduction, extension, and internal rotation** of the arm. *Pectoralis major* - The **pectoralis major muscle** inserts onto the **lateral lip of the bicipital groove** (intertubercular sulcus) of the humerus. - Its main actions are **adduction, internal rotation**, and **flexion of the humerus**.
Question 8: Which of the following muscles is not in the pectoral region?
- A. Pectoralis major
- B. Infraspinatus (Correct Answer)
- C. Pectoralis minor
- D. Subclavius
Explanation: ***Infraspinatus*** - The **infraspinatus** muscle is located in the **posterior scapular region**, specifically on the posterior aspect of the scapula, filling the infraspinous fossa. - Its primary function is **external rotation** of the humerus, and it is a key component of the **rotator cuff**. *Pectoralis major* - The **pectoralis major** is a large, superficial muscle located in the **anterior chest wall**, forming the bulk of the chest. [1] - It plays a significant role in **adduction**, **flexion**, and **medial rotation** of the humerus. *Pectoralis minor* - The **pectoralis minor** is a smaller, triangular muscle situated beneath the pectoralis major in the **anterior thoracic wall**. [1] - Its functions include **stabilizing the scapula** by pulling it inferiorly and anteriorly, and assisting in forced inspiration. [1] *Subclavius* - The **subclavius** is a small, triangular muscle located inferior to the clavicle in the **pectoral region**. - Its primary role is to **depress and stabilize the clavicle**, protecting the underlying neurovascular structures.
Question 9: Muscle inserting on medial border of scapula -
- A. Subscapularis
- B. Teres minor
- C. Latissimus dorsi
- D. Serratus anterior (Correct Answer)
Explanation: ***Serratus anterior*** - The **serratus anterior** muscle originates from the outer surface of the upper eight or nine ribs and inserts along the entire medial border of the scapula. - Its primary action is to **protract the scapula** (pull it forward around the chest wall) and stabilize it against the thoracic wall. *Subscapularis* - The **subscapularis** muscle originates from the **subscapular fossa** (anterior surface) of the scapula and inserts onto the **lesser tubercle of the humerus**. - It is a rotator cuff muscle involved in **medial rotation of the humerus**. *Teres minor* - The **teres minor** muscle originates from the lateral border of the scapula and inserts onto the **greater tubercle of the humerus**. - It is another rotator cuff muscle, primarily responsible for **lateral rotation and adduction of the humerus**. *Latissimus dorsi* - The **latissimus dorsi** is a large, broad muscle of the back that originates from the thoracolumbar fascia, iliac crest, and lower ribs, inserting into the **intertubercular groove of the humerus** [1]. - It has no direct insertion on the medial border of the scapula; it primarily extends, adducts, and internally rotates the humerus.
Question 10: A crush injury of the vertebral column can cause the spinal cord to swell. Which structure would be trapped between the dura and the vertebral body by the swelling of the spinal cord?
- A. Alar Ligament
- B. Cruciform Ligament
- C. Anterior Longitudinal Ligament
- D. Posterior Longitudinal Ligament (Correct Answer)
Explanation: ***Anterior Longitudinal Ligament*** - The **anterior longitudinal ligament** is located on the anterior aspect of the vertebral bodies and disks, *not* within the vertebral canal where the spinal cord and dura are situated [1]. - While robust, its position makes it unlikely to be directly trapped *between the dura and the vertebral body* due to spinal cord swelling in the posterior compartment. *Alar Ligament* - The **alar ligaments** connect the dens to the occipital condyles and are crucial for the stability of the craniocervical junction. - These ligaments are located superiorly in the cervical spine and are not found along the general length of the vertebral column to be trapped by swelling lower down. *Cruciform Ligament* - The **cruciform ligament** is located in the upper cervical spine, consisting of the transverse ligament of the atlas and longitudinal bands connecting to the occiput and axis. - Its position is high in the cervical region, and it would not be trapped between the dura and a vertebral body in a general crush injury of the vertebral column. *Posterior Longitudinal Ligament* - The **posterior longitudinal ligament** is situated *within the vertebral canal*, running along the posterior surfaces of the vertebral bodies and intervertebral discs, anterior to the spinal cord and dura [1]. - If the spinal cord swells, it would expand posteriorly towards the dura and anteriorly towards this ligament, causing the ligament to be directly compressed *between the swollen spinal cord (and dura)* and the vertebral body.
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