Triangles of the Neck — MCQs
A 60-year-old woman presents with progressive loss of voice, numbness, loss of taste on the back part of her tongue, and difficulty in shrugging her shoulders. Her MRI scan reveals a dural meningioma that compresses the nerves leaving the skull. These nerves leave the skull through which of the following openings?
Following a penetrating injury in the submandibular triangle, the tongue of a 45-year-old patient deviates to the left on protrusion. Which of the following nerves is likely injured?
A patient presents with winging of the scapula. Which nerve is most likely involved?
Delphian's nodes are not related to which of the following? (ENT)
Submandibular nodes are classified as
The fascia around the nerve bundle of the brachial plexus is derived from?
During a knife fight, a person is injured in the neck region and presents with weakness in raising the right arm above the head. On further examination, winging of the right scapula is noted. The injury has damaged:
Which of the following muscles is not attached to the medial border of the scapula?
All of the following cranial nerves pass through the jugular foramen except :
Which nerve passes through the structure shown? (Recent NEET Pattern 2019)
Triangles of the Neck Indian Medical PG Practice Questions and MCQs
Question 1: A 60-year-old woman presents with progressive loss of voice, numbness, loss of taste on the back part of her tongue, and difficulty in shrugging her shoulders. Her MRI scan reveals a dural meningioma that compresses the nerves leaving the skull. These nerves leave the skull through which of the following openings?
- A. Foramen spinosum
- B. Foramen rotundum
- C. Internal auditory meatus
- D. Jugular foramen (Correct Answer)
Explanation: ***Jugular foramen*** - The **jugular foramen** transmits **cranial nerves IX (glossopharyngeal), X (vagus), and XI (accessory)**, which correspond to the patient's symptoms of loss of taste on the back of the tongue, progressive loss of voice, and difficulty shrugging shoulders. - Compression of these nerves by a **dural meningioma** at this location would explain the clinical presentation. *Foramen spinosum* - The **foramen spinosum** primarily transmits the **middle meningeal artery** and the **nervus spinosus** (a recurrent branch of the mandibular nerve). - Compression here would not explain the patient's symptoms related to voice, taste, or shoulder shrugging, as these nerves do not pass through it. *Foramen rotundum* - The **foramen rotundum** exclusively transmits the **maxillary nerve (V2)**, a branch of the trigeminal nerve. - Compression of this nerve would primarily lead to sensory deficits in the midface and upper teeth, not the symptoms observed in the patient. *Internal auditory meatus* - The **internal auditory meatus** transmits the **facial nerve (VII)** and the **vestibulocochlear nerve (VIII)**. - Compression in this area would typically cause **facial paralysis**, hearing loss, or vertigo, which are not the primary symptoms reported by the patient.
Question 2: Following a penetrating injury in the submandibular triangle, the tongue of a 45-year-old patient deviates to the left on protrusion. Which of the following nerves is likely injured?
- A. Left hypoglossal nerve (Correct Answer)
- B. Right glossopharyngeal nerve
- C. Left glossopharyngeal nerve
- D. Right accessory nerve
Explanation: ***Left hypoglossal nerve*** - Injury to the **hypoglossal nerve (CN XII)** on one side causes weakness and **atrophy** of the ipsilateral intrinsic and extrinsic muscles of the tongue. - **Key clinical rule**: The tongue deviates **toward the side of the lesion** on protrusion. - This occurs because the **genioglossus muscle** (innervated by CN XII) normally protrudes the tongue to the **opposite side**. When the left CN XII is injured, the **unopposed right genioglossus** pushes the tongue to the left (toward the weak side). - Location: The hypoglossal nerve courses through the **submandibular triangle**, making it vulnerable to penetrating injuries in this region. *Right glossopharyngeal nerve* - The glossopharyngeal nerve (CN IX) primarily mediates **taste from the posterior one-third of the tongue**, **general sensation from the pharynx**, and motor innervation to the **stylopharyngeus muscle**. - Its injury would result in difficulty swallowing, loss of gag reflex, and altered taste, **not tongue deviation on protrusion**. *Left glossopharyngeal nerve* - Similar to a right glossopharyngeal nerve injury, a left-sided injury would manifest as dysphagia, absent gag reflex, and sensory deficits in the pharynx and posterior tongue. - It does **not control the motor function** of the tongue muscles responsible for protrusion. *Right accessory nerve* - The accessory nerve (CN XI) innervates the **sternocleidomastoid** and **trapezius muscles**, controlling head and shoulder movements. - Injury would lead to weakness in shrugging the shoulder and turning the head, with **no impact on tongue movement** or deviation.
Question 3: A patient presents with winging of the scapula. Which nerve is most likely involved?
- A. Thoracodorsal nerve
- B. Lateral pectoral nerve
- C. Long thoracic nerve (Correct Answer)
- D. Musculocutaneous nerve
Explanation: ### Long thoracic nerve - The long thoracic nerve innervates the **serratus anterior muscle**, which is responsible for scapular protraction and upward rotation. - Damage to this nerve paralyzes the serratus anterior, leading to **winging of the scapula** as the medial border and inferior angle of the scapula become prominent. ### Thoracodorsal nerve - This nerve supplies the **latissimus dorsi muscle**, which is involved in adduction, extension, and internal rotation of the humerus [1]. - Injury to the thoracodorsal nerve would weaken movements of the shoulder, but not directly cause **scapular winging**. ### Lateral pectoral nerve - The lateral pectoral nerve innervates the **pectoralis major muscle** (upper and middle parts) [1]. - Damage to this nerve primarily affects shoulder adduction and internal rotation, but does not result in **scapular winging**. ### Musculocutaneous nerve - This nerve innervates the **coracobrachialis**, **biceps brachii**, and **brachialis muscles** in the anterior compartment of the arm. - Injury to the musculocutaneous nerve would impair elbow flexion and forearm supination, and is unrelated to **scapular movement**.
Question 4: Delphian's nodes are not related to which of the following? (ENT)
- A. Retropharyngeal
- B. Upper deep cervical
- C. Pre-laryngeal
- D. Posterior triangle (Correct Answer)
Explanation: ***Posterior triangle*** - **Delphian nodes** are part of the deep cervical lymph node chain and are named for their clinical significance in detecting subclinical disease, typically related to recurrent laryngeal cancer. - The posterior triangle of the neck contains lymph nodes, but they are not specifically known as Delphian nodes; these nodes drain different regions and are generally not indicative of laryngeal involvement. *Retropharyngeal* - The **retropharyngeal lymph nodes** are located behind the pharynx and drain the posterior nasal cavity, paranasal sinuses, nasopharynx, and oropharynx. - While they are part of the head and neck lymphatics, they are distinct from Delphian nodes, which are more anterior and midline. *Upper deep cervical* - The **upper deep cervical lymph nodes** are a primary drainage pathway for many head and neck structures, including the larynx. - While Delphian nodes are distinct, their close proximity and shared drainage patterns mean they are functionally related to the larger deep cervical chain in assessing laryngeal cancer spread. *Pre-laryngeal* - **Delphian nodes**, also known as cricothyroid or pre-laryngeal nodes, are located in the prelaryngeal space, anterior to the cricothyroid membrane [1]. - Their involvement is highly suspicious for thyroid or laryngeal carcinoma, making them crucial for early detection of advanced disease [1].
Question 5: Submandibular nodes are classified as
- A. Level III neck nodes
- B. Level II neck nodes
- C. Level 1B neck nodes (Correct Answer)
- D. Level 1A neck nodes
Explanation: ***Level 1B neck nodes*** - The **submandibular nodes** are located anterior to the posterior belly of the digastric muscle and lateral to the anterior belly of the digastric muscle, placing them within **Level 1B** of the neck lymph node classification [1]. - This level primarily drains the oral cavity, face, and submandibular gland [1]. *Level III neck nodes* - **Level III** nodes are the middle jugular nodes, located between the level of the hyoid bone and the cricoid cartilage. - These nodes are typically found along the **internal jugular vein** and drain structures such as the larynx, hypopharynx, and thyroid. *Level II neck nodes* - **Level II** nodes, or upper jugular nodes, are located from the skull base to the inferior border of the hyoid bone, along the internal jugular vein. - This level is further divided into Level IIA (anterior to the spinal accessory nerve) and Level IIB (posterior to the spinal accessory nerve) and drains structures like the nasopharynx, oropharynx, and parotid gland. *Level 1 A neck nodes* - **Level 1A** nodes refer to the **submental nodes**, which are located between the anterior bellies of the digastric muscles [1]. - These nodes primarily drain the central lower lip, floor of the mouth, anterior tongue, and chin [1].
Question 6: The fascia around the nerve bundle of the brachial plexus is derived from?
- A. Superficial cervical fascia
- B. Pretracheal fascia
- C. Investing layer
- D. Prevertebral fascia (Correct Answer)
Explanation: ***Prevertebral fascia*** - The **brachial plexus** and the subclavian artery emerge between the **anterior and middle scalene muscles**. - As they exit the neck, they become surrounded by a tubular sheath derived from the **prevertebral fascia**, forming the **axillary sheath**. *Pretracheal fascia* - This fascia surrounds the **trachea**, esophagus, thyroid gland, and infrahyoid muscles. - It lies anterior to the vertebral column and has no direct involvement in forming the sheath around the brachial plexus. *Investing layer* - The investing layer of deep cervical fascia encircles the entire neck, enclosing the **sternocleidomastoid** and **trapezius muscles**. - While it's a superficial layer of deep cervical fascia, it does not specifically form the immediate sheath around the brachial plexus. *Superficial cervical fascia* - This layer is synonymous with the **subcutaneous tissue** of the neck and contains the platysma muscle. - It is superficial to the deep cervical fascia layers and does not contribute to the fibrous sheath of the brachial plexus.
Question 7: During a knife fight, a person is injured in the neck region and presents with weakness in raising the right arm above the head. On further examination, winging of the right scapula is noted. The injury has damaged:
- A. Long thoracic nerve of Bell
- B. Dorsal scapular nerve
- C. Suprascapular nerve
- D. Spinal accessory nerve (Correct Answer)
Explanation: ***Spinal accessory nerve*** - **Weakness in raising the arm above the head** and **winging of the scapula** are characteristic signs of **trapezius muscle dysfunction**, which is supplied by the **spinal accessory nerve (CN XI)**. - The trapezius is essential for **upward rotation of the scapula** during overhead arm abduction (>90°). - Injury to the spinal accessory nerve in the posterior triangle of the neck causes **lateral winging** of the scapula (inferior angle moves laterally), which is most prominent when attempting to raise the arm overhead. - The combination of **scapular winging** + **inability to abduct the arm above horizontal** is pathognomonic for trapezius paralysis. *Long thoracic nerve of Bell* - Damage to the long thoracic nerve causes paralysis of the **serratus anterior muscle**, leading to **medial winging** of the scapula (medial border lifts away from chest wall). - While scapular winging occurs, it is most prominent during **forward flexion** or **pushing movements** (e.g., push-ups, pushing against a wall), not specifically when raising the arm overhead. - Patients can usually still abduct the arm overhead, though with altered scapular mechanics. *Dorsal scapular nerve* - The dorsal scapular nerve innervates the **rhomboid major and minor muscles** and the **levator scapulae**. - Injury primarily causes difficulty **retracting the scapula** (pulling shoulders back) and weakness in shoulder elevation. - Does **not** cause scapular winging or significant weakness in overhead arm movement. *Suprascapular nerve* - The suprascapular nerve innervates the **supraspinatus** and **infraspinatus muscles**. - Damage causes weakness of shoulder **initiation of abduction** (first 15° by supraspinatus) and **external rotation** (infraspinatus). - Does **not** cause scapular winging, as these are rotator cuff muscles, not scapular stabilizers.
Question 8: Which of the following muscles is not attached to the medial border of the scapula?
- A. Serratus anterior
- B. Levator scapulae
- C. Teres major (Correct Answer)
- D. Rhomboid major
Explanation: ***Teres major*** - The **teres major** muscle originates from the **inferior angle and lower part of the lateral border** of the scapula, NOT the medial border. - It inserts into the medial lip of the intertubercular groove of the humerus. - This is the correct answer as it does not attach to the medial border of the scapula. *Serratus anterior* - The **serratus anterior** muscle originates from the outer surfaces of the upper 8-9 ribs and inserts along the **entire medial border** of the scapula on its anterior (costal) surface. - It plays a crucial role in protraction and upward rotation of the scapula, keeping it applied to the thoracic wall. *Levator scapulae* - The **levator scapulae** muscle originates from the transverse processes of the C1-C4 vertebrae and inserts into the **superior angle and upper part of the medial border** of the scapula. - Its primary actions are to elevate the scapula and assist in downward rotation. *Rhomboid major* - The **rhomboid major** muscle originates from the spinous processes of T2-T5 vertebrae and attaches to the **medial border** of the scapula between the spine and inferior angle. - It acts to retract, elevate, and rotate the scapula downward.
Question 9: All of the following cranial nerves pass through the jugular foramen except :
- A. Vagus
- B. Hypoglossal (Correct Answer)
- C. Glossopharyngeal
- D. Spinal accessory
Explanation: ***Hypoglossal*** - The **hypoglossal nerve (CN XII)** exits the skull through the **hypoglossal canal**, not the jugular foramen. - Its primary function is to innervate the intrinsic and extrinsic muscles of the **tongue**. *Vagus* - The **vagus nerve (CN X)** is one of the three cranial nerves that traverse the **jugular foramen**. - It has extensive innervation, including parasympathetic supply to the **heart, lungs, and most of the gastrointestinal tract**. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** exits the skull via the **jugular foramen**. - It is responsible for **taste sensation** from the posterior one-third of the tongue and motor innervation to the **stylopharyngeus muscle**. *Spinal accessory* - The **spinal accessory nerve (CN XI)** passes through the **jugular foramen** after entering the cranial cavity through the foramen magnum. - It innervate the **sternocleidomastoid** and **trapezius muscles**, responsible for head and shoulder movements.
Question 10: Which nerve passes through the structure shown? (Recent NEET Pattern 2019)
- A. Inferior alveolar nerve (Correct Answer)
- B. Lingual nerve
- C. Buccal nerve
- D. Hypoglossal nerve
Explanation: ***Inferior alveolar nerve*** - The image points to the **mandibular foramen**, an opening on the medial surface of the mandibular ramus. - The **inferior alveolar nerve** enters the mandible through this foramen to supply sensation to the mandibular teeth. *Lingual nerve* - The **lingual nerve** typically runs anterior to the inferior alveolar nerve in the infratemporal fossa but does not pass through the mandibular foramen. - It supplies general sensation and taste to the anterior two-thirds of the tongue. *Buccal nerve* - The **buccal nerve** passes between the two heads of the lateral pterygoid muscle and supplies sensation to the buccal mucosa and gingiva, not traveling within the mandible. - It arises from the anterior division of the mandibular nerve. *Hypoglossal nerve* - The **hypoglossal nerve (CN XII)** is a motor nerve for the tongue muscles and is located entirely outside the mandible. - It exits the skull through the hypoglossal canal and runs in the neck and floor of the mouth.
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