1.
Your 30-year-old patient has a lower neck injury. During the physical examination, you realize that the wound is in the omoclavicular triangle. You know that this injury might be dangerous because important structures are passing through this area. Which of the following structures might be in danger?
Correct Answer
B. Ansa cervicalis
Explanation
The ansa cervicalis is a nerve loop formed by the superior root of the cervical plexus. It innervates the infrahyoid muscles, including the sternohyoid and omohyoid muscles. Injuries to the omoclavicular triangle can potentially damage the ansa cervicalis, leading to weakness or paralysis of these muscles. This can result in difficulty swallowing and changes in voice quality. Therefore, the ansa cervicalis is at risk in this situation.
2.
The anterior scalene muscle is an important accessory muscle of respiration. Its innervation is:
Correct Answer
D. Brachial plexus
Explanation
The anterior scalene muscle is innervated by the brachial plexus. The brachial plexus is a network of nerves that originates from the ventral rami of spinal nerves C5-T1. It supplies motor and sensory innervation to the upper limb, including the anterior scalene muscle. This muscle is involved in the movement of the neck and also plays a role in respiration as an accessory muscle. Therefore, the brachial plexus is responsible for innervating the anterior scalene muscle.
3.
A resident is attempting her first placement of a central line into the right internal jugular vein. To correctly locate the point of insertion, she should place the needle at the:
Correct Answer
A. Between the two heads of the right sternocleidomastoid muscle
Explanation
The correct answer is "Between the two heads of the right sternocleidomastoid muscle". When inserting a central line into the right internal jugular vein, it is important to locate the point of insertion accurately. The right internal jugular vein lies between the two heads of the sternocleidomastoid muscle. Placing the needle between these two heads ensures proper entry into the vein and reduces the risk of complications.
4.
An 18-year-old male presented to the Emergency Room bleeding profusely from a deep cut in the left occipital triangle of his neck and undergoes emergency surgery to repair his internal jugular vein. He survives his injury but he is found on neurological examination to have left-sided weakness in shrugging his shoulder, cannot turn his head to the left against resistance, has a flat left soft palatal arch, and lacks a gag reflex on the left side. What additional clinical signs would be expected in this patient?
Correct Answer
E. Dry mouth
Explanation
The patient's presentation is consistent with Horner syndrome, which is caused by damage to the sympathetic innervation of the face. In addition to the given clinical signs, other expected signs of Horner syndrome include ptosis (drooping of the eyelid) on the affected side that disappears on upward gaze, miosis (constriction of the pupil) on the affected side, and anhidrosis (lack of sweating) on the affected side. These signs are not mentioned in the given options, but they are commonly associated with Horner syndrome. Dry mouth is not typically associated with Horner syndrome.
5.
You are called on to do a venous catheterization to measure central venous pressure in the heart. You insert the catheter using the indentation between the two inserting heads of the right sternocleidomastoid muscle as a landmark. Which vessel is the target of this procedure?
Correct Answer
E. Anterior jugular vein
6.
This patient is a 33-year-old woman with a 17-pack-year history of smoking. She presents with mild right-sided ptosis, the constricted pupil (miosis), and decreased sweating on the right side of her face. She is diagnosed with a tumor in the apex of her right lung at the root of the neck. Damage to what anatomical structure explains her symptoms?
Correct Answer
A. Ansa cervicalis
Explanation
The patient's symptoms of mild right-sided ptosis, constricted pupil (miosis), and decreased sweating on the right side of her face are consistent with Horner's syndrome. Horner's syndrome occurs due to damage to the sympathetic pathway, which includes the ansa cervicalis. The ansa cervicalis is a loop of nerves that innervates the muscles of the neck and helps regulate sympathetic function. Damage to the ansa cervicalis can lead to the symptoms described in the patient.
7.
A victim of a motor vehicle accident suffers a cranial base fracture that extends through the jugular foramen and damages the nerves that exit here. Motor deficits in the neck that this patient will evince include weakness or paralysis of:
Correct Answer
B. Muscles enclosed in the visceral layer of pretracheal fascia
Explanation
The cranial base fracture in this patient extends through the jugular foramen, which is a passageway for several nerves. The nerves that exit through the jugular foramen innervate the muscles enclosed in the visceral layer of pretracheal fascia. Therefore, damage to these nerves would result in weakness or paralysis of the muscles enclosed in the visceral layer of pretracheal fascia. The other options, muscles enclosed in the deep investing fascia of the neck and muscles enclosed in prevertebral fascia, are not directly affected by the damage to the nerves in this specific scenario.
8.
A young mountain climber falls 20 feet before grasping a tree root. He injures the lower trunk of the brachial plexus. Which of the following signs or symptoms might you expect to find?
Correct Answer
E. Inability to abduct the thumb
Explanation
The brachial plexus is a network of nerves that innervates the upper limb. Injuries to the lower trunk of the brachial plexus can result in weakness or paralysis of certain muscles in the upper limb. The thumb is primarily innervated by the median nerve, which is a branch of the brachial plexus. Therefore, an injury to the lower trunk of the brachial plexus could lead to an inability to abduct the thumb.
9.
A student was shot by a bullet in the left side of the neck. The wound left him bleeding profusely and paralyzed the sternomastoid, trapezius, and stylopharyngeus muscles on the same side. The posterior third of the tongue lost taste sensation. The bullet had pierced which of the following sites?
Correct Answer
D. Jugular foramen
Explanation
The bullet had pierced the jugular foramen. This is because the symptoms described, such as bleeding, paralysis of certain muscles, and loss of taste sensation in the posterior third of the tongue, are consistent with damage to the structures that pass through the jugular foramen. The jugular foramen is a large opening in the base of the skull through which the internal jugular vein and several cranial nerves, including the glossopharyngeal nerve and the vagus nerve, pass. Damage to these structures can result in the symptoms described.
10.
A 25-year old male patient presents with a sharp knife-stab on the right side of the neck about 3 cm superior to the clavicle after a pub fight. Observing the patient, the ER resident finds dyspnea as the major symptom. An emergency chest x-ray shows a normal lung image. The resident suspects the injury of one of following structures :
Correct Answer
D. pHrenic nerve
Explanation
The patient's presentation of dyspnea suggests that the injury is affecting the phrenic nerve. The phrenic nerve is responsible for controlling the diaphragm, which is the main muscle involved in the process of breathing. Since the patient is experiencing difficulty in breathing, it indicates that the phrenic nerve, which controls the diaphragm, has been affected by the knife-stab injury. The other options, such as the external jugular vein, parietal pleura, subclavian artery, and vagus nerve, would not typically cause dyspnea as a major symptom.