Head and neck practice questions
A 20 year old man was brought into the emergency room with a stab wound in the upper part of the neck. Although there was no major damage done, he lost sensation from the skin over the angle of the jaw. Which nerve has been cut? Supraclavicular n. Transverse cervical n. Great auricular n. Greater occipital n. Lesser occipital n.
Great auricular n. The great auricular nerve comes from C2 and C3 branches of the cervical plexus; it provides sensory innervation to the ear and the skin below the ear, including the angle of the jaw. The supraclavicular nerves come from C3 and C4 in the cervical plexus. These cutaneous nerves provide sensory innervation to the skin of the root of the neck, upper chest, and upper shoulder. The transverse cervical nerves also come from the cervical plexus--they are from C2 and C3 and provide sensory innervation to the skin of the neck anteriorly. Finally, the lesser occipital nerve comes from C2--it innervates the skin behind the ear. The greater occipital nerve is not from the cervical plexus, which is the ventral rami of C1-4--it is the cutaneous branch of the DORSAL primary ramus of spinal nerve C2. It provides cutaneous innervation to the posterior scalp.
The triangle in which the superior branch of the ansa cervicalis separates from the hypoglossal nerve is the: Carotid Muscular Subclavian Submental Occipital
Carotid The superior branch of ansa cervicalis runs with the hypoglossal nerve until the carotid triangle. In this triangle, the superior branch of ansa cervicalis separates from the hypoglossal nerve and runs in the carotid sheath, anterior to the carotid artery. Remember--the carotid sheath is found in the carotid triangle, a space bounded laterally by the sternocleidomastoid muscle, superiorly by the posterior belly of the digastric, and anteriorly by the superior belly of omohyoid. The other triangles listed are not the spaces where ansa cervicalis separates from the hypoglossal nerve.
Following surgery on the upper pole of the right lobe of the thyroid gland, a patient complains of hoarseness and weakness of voice. What nerve may have been injured? Ansa cervicalis External branch of the superior laryngeal Inferior laryngeal Internal branch of the superior laryngeal Recurrent laryngeal
The correct answer is: Exernal branch of the superior laryngeal The external branch of the superior laryngeal nerve travels with the superior thyroid artery toward the superior pole of the thyroid. So, it's in the right place to be injured by surgery on the upper pole of the gland. The external branch of the superior laryngeal nerve innervates cricothyroid, the muscle responsible for elongating the vocal cords. The patient's symptoms of horseness and a weak voice would fit with an injury to this nerve and the denervation of this muscle. The inferior laryngeal and recurrent laryngeal nerves are one in the same--the recurrent laryngeal changes its name to the inferior laryngeal at the inferior border of cricopharyngeus. This nerve innervates all of the other muscles of the larynx, besides cricothyroid. It runs with the inferior thyroid artery to the inferior poles of the thyroid--it could be injured in any surgery involving the inferior thyroid artery or inferior aspects of the gland. The internal branch of the superior laryngeal nerve pierces the thyrohyoid membrane along with the superior laryngeal artery--it is a sensory nerve only. It supplies sensory innervation to the mucosa of the larynx, superior to the vocal folds. Ansa cervicalis is a branch of the cervical plexus which innervates the strap muscles. It does not innervate any muscles in the larynx.
A patient is brought into the Emergency Room in respiratory distress. It is quickly decided to create an emergency airway to restore respiration. At what level could you rapidly create an airway below the vocal cords with a minimum danger of hemorrhage?
The correct answer is: Just below the thyroid cartilage To create an emergency airway, a midline cut can be made through the cricothyroid ligament and membrane. So, an opening is created between the thyroid cartilage and the cricoid cartilage. Since this is below the glottis and the tracheal inlet (which is the usual place where things get lodged), this is a good spot to make the cut. It is also easy to find the thyroid cartilage on a patient and make the incision right below that spot.
Which of the following is a dorsal ramus of a spinal nerve? Supraclavicular n. Transverse cervical n. Great auricular n. Greater occipital n. Lesser occipital n.
Greater occipital n. The greater occipital nerve is the cutaneous branch of the dorsal primary ramus of spinal nerve C2 - it provides cutaneous innervation to the posterior scalp. The other nerves listed are all nerves from the cervical plexus, which is formed by ventral primary rami C1-C4. The supraclavicular nerves come from C3 and C4 in the cervical plexus. These cutaneous nerves provide sensory innervation to the skin of the root of the neck, upper chest, and upper shoulder. The great auricular nerve comes from C2 and C3 branches; it provides sensory innervation to the ear and the skin below the ear. The lesser occipital nerve comes from C2 only - it innervates the skin behind the ear. The transverse cervical nerve is also a cutaneous branch from the cervical plexus--from C2 and C3, providing sensory innervation to the skin of the neck anteriorly.
The cervical plexus innervates all of the following structures EXCEPT: Diaphragm Omohyoid muscle Platysma Skin over thyroid cartilage Skin over clavicle
Platysma Platysma is a muscle of facial expression. It inserts into the skin and helps lower the angle of the mouth and depress the mandible. It is innervated by the cervical branch of the facial nerve (CN VII). All of the other muscles or areas of skin are innervated by branches of the cervical plexus, a plexus made of the ventral primary rami of the C1-C4 spinal nerves. The diaphragm is innervated by the phrenic nerve, which is made from the C3, C4 and C5 ventral primary rami. The omohyoid muscle is innervated by ansa cervicalis, a motor branch of the cervical plexus. The skin over the thyroid cartilage is innervated by the transverse cervical nerve, a cutaneous sensory nerve from C2 and C3 roots of the cervical plexus. The skin over the clavicle is innervated by other cutaneous sensory nerves from the C3 and C4 roots of the cervical plexus--the supraclavicular nerves.
A 35 year old woman was diagnosed with an adenoma of the thyroid gland. This required excision of the lower pole (left lobe) of the gland and ligation of the artery supplying that region. Which of the following nerves accompanying the artery is most likely to be damaged if the surgeon is not careful? External branch of the superior laryngeal Internal branch of the superior laryngeal Recurrent laryngeal Vagus proper Sympathetic trunk
Recurrent laryngeal The inferior thyroid artery supplies the lower lobes of the thyroid. It is a branch of the thyrocervical trunk. Branches of this artery cross the recurrent laryngeal nerve, so this is the nerve that might be damaged during the surgery. The external branch of the superior laryngeal nerve runs with the superior thyroid artery--this artery and nerve might be damaged when removing the superior lobes of the thyroid. The internal branch of the superior laryngeal nerve runs with the superior laryngeal artery, piercing the thyrohyoid membrane. The vagus nerve proper runs with the common carotid artery, in the carotid sheath. It gives off the recurrent laryngeal nerve, but it does not come as close to the inferior thyroid artery. Finally, the sympathetic trunk is in the deep neck, near the vertebral bodies. It should not be damaged in thyroid surgery.
A man has metastatic carcinoma and enlarged deep cervical lymph nodes. One of his symptoms is a hoarse voice, barely heard above a whisper. Subsequently he succumbs to the disease and at autopsy it is found that one of the enlarged nodes has put pressure on a nerve in the tracheoesophageal groove. Presumably this was the reason for the hoarse voice. What nerve was involved? External branch of the superior laryngeal nerve Internal branch of the superior laryngeal nerve Nerve to the cricothyroid muscle Pharyngeal branch of the glossopharyngeal nerve Recurrent laryngeal branch of vagus
Recurrent laryngeal nerve Damage to the recurrent laryngeal nerve is one possible cause of hoarseness. The recurrent laryngeal nerve changes its name to the inferior laryngeal nerve at the level of the inferior border of the cricoid cartilage. The inferior laryngeal nerve goes on to innervate all the intrinsic muscles of the larynx except cricothyroideus. So, if this nerve innervating all the muscles of the larynx was damaged, a patient would have a hoarse voice. A very significant piece of information that tells you that the recurrent laryngeal nerve was injured is the location of the injury-- remember, recurrent laryngeal travels in the tracheoesophageal groove. The external and internal branches of the superior laryngeal nerve innervate cricothyroid, the inferior pharyngeal constrictor, and provide secretomotor fibers to mucosal glands of the larynx above the vocal folds. The pharyngeal branch of the glossopharyngeal nerve provides sensory innervation to the pharynx. None of these nerves are running in the tracheoesophageal groove!
Exploration of the tracheoesophageal groove at the level of the thyroid gland would reveal what important structure bilaterally? Cervical sympathetic trunk Phrenic nerve Pyramidal lobe Recurrent laryngeal nerve Superior thyroid artery
Recurrent laryngeal nerve The left and right recurrent laryngeal nerves can be found in the left and right tracheoesophageal grooves. This is a very characteristic relationship that you need to know! The cervical sympathetic trunk is much deeper in the neck--it lies in the prevertebral fascia, in front of the prevertebral muscles. The phrenic nerve lies on the surface of the anterior scalene muscles before it descends into the thorax to innervate the diaphragm. The pyramidal lobe of the thyroid gland is a small tract of tissue that may extend upward from the isthmus of the thyroid. This is a developmental remnant that marks the thyroid's route of migration from the foramen cecum of the tongue. The superior thyroid artery is a branch of the external carotid artery--it travels to the superior lobes of the thyroid and runs with the external branch of the superior laryngeal nerve.
You are called on to do a venous catheterization to measure central venous pressure in the heart. Which muscle of the neck would provide the best area of approach to the internal jugular vein? Anterior scalene Digastric Omohyoid Sternocleidomastoid Sternohyoid
Sternocleidomastoid The internal jugular vein is found in the carotid triangle, which is bounded medially by omohyoid, laterally by sternocleidomastoid, and superiorly by the posterior belly of digastric. Of these three muscles, sternocleidomastoid is the easiest landmark to find on the neck and the most practical muscle to find when looking for the carotid triangle and the internal jugular vein. The anterior scalene is posterior to the internal jugular vein, and is not related to the vessel. Sternohyoid is a strap muscle in the muscular triangle; it is not associated with the internal jugular vein.
Which muscle is innervated by a branch of the ansa cervicalis? Sternocleidomastoid Platysma Sternohyoid Trapezius
Sternohyoid The sternohyoid muscle is one of the strap muscles which runs from the manubrium and the sternal end of the clavicle to the hyoid bone. It is innervated by the ansa cervicalis, and it depresses and stabilizes the hyoid bone. Platysma is a muscle of facial expression; it is innervated by the cervical branch of CN VII, the facial nerve. Sternocleidomastoid and trapezius are both innervated by the accessory nerve (CN XI). Sternocleidomastoid receives fibers from C2 and C3 for proprioception, while trapezius receives proprioceptive fibers from C3 and C4.
The layer of encircling cervical fascia that splits to enclose sternocleidomastoid and trapezius muscles is the: Superficial fascia Superficial layer of deep fascia Infrahyoid fascia Prevertebral fascia Visceral fascia
Superficial layer of deep fascia The superficial layer of deep cervical fascia extends between trapezius and sternocleidomastoid in the posterior triangle and between the paired sternocleidomastoid muscles in the anterior triangle. Superficial fascia is the same as subcutaneous tissue--the tissue that you see as you remove the skin. Infrahyoid fascia is the layer of deep fascia that covers the strap muscles in a sheet. Prevertebral fascia is the deep fascia surrounding the vertebral column and the associated muscles (like the scalenes). Finally, the visceral fascia is the fascia that encloses the deep structures of the neck, including the thyroid, the larynx and trachea, and the esophagus. The anterior part of that fascia is the pretracheal fascia, and the posterior part of the visceral fascia is the buccopharyngeal fascia.
Which structure or area receives NO nerve fibers from the cervical plexus? Diaphragm Skin over the angle of the mandible Skin over the external occipital protuberance Thyrohyoid muscle
The correct answer is: Skin over the external occipital protuberance The skin over the external occipital protuberance is innervated by the greater occipital nerve, which is from the dorsal primary ramus of C2. Since the cervical plexus is made of the ventral primary rami of C1 through C4, the greater occipital nerve has no connection with the cervical plexus. The diaphragm is innervated by the phrenic nerve, which receives contributions from the ventral primary rami of C3, C4, and C5. The skin over the angle of the jaw is innervated by the great auricular nerve, which comes from C2 and C3 branches of the cervical plexus. Finally, the thyrohyoid muscle is innervated by the ansa cervicalis (specifically, C1 and C2 fibers carried by hypoglossal nerve), a motor component of the cervical plexus that innervates the strap muscles.
Any irritation of the diaphragm (e.g. infection, tumor) may create referred pain that seems (to the patient) to originate in the area atop the shoulder. This is due to the fact that the phrenic nerve shares spinal segments with what cutaneous nerve in the shoulder region? Dorsal scapular Lesser occipital nerve Long thoracic nerve Supraclavicular nerve Suprascapular nerve
The correct answer is: Supraclavicular nerve The phrenic nerve consists of contributions from the ventral primary rami of C3, C4, and C5. The supraclavicular nerves come from the C3 and C4 roots of the cervical plexus. So, these nerves share spinal segments. This explains why pain from the diaphragm is referred to the area where the supraclavicular nerves provide cutaneous innervation. The lesser occipital nerve is another cutaneous nerve from the cervical plexus, but it is mostly made of fibers from the C2 ventral rami. The other nerves listed are all motor nerves from the brachial plexus. The dorsal scapular nerve comes from the C5 ventral primary ramus-- it innervates rhomboideus major and minor and the lower portion of levator scapulae. The long thoracic nerve comes from C5, C6, and C7 ventral primary rami--it innervates serratus anterior. The suprascapular nerve comes from the superior trunk of the brachial plexus--it innervates supraspinatus and infraspinatus.
Which of the following is true of the inferior thyroid arteries? They arise from the external carotid arteries They cross over the superior cervical sympathetic ganglion They supply most of the anterior surface of the thyroid gland They often supply all four parathyroid glands
They often supply all four parathyroid glands The inferior thyroid arteries are branches of the thyrocervical trunk. (The superior thyroid arteries are branches of the external carotid artery.) The inferior thyroid arteries are closely associated with the middle cervical sympathetic ganglia and supply the inferior poles of the thyroid. They are found on the posterior surface of the thyroid gland, which is where the parathyroid glands are located. So, they are the primary source of blood for the four parathyroid glands.
A 50-year-old woman is brought to the operating room for a biopsy of a suspicious looking nevus (mole) which is found along the anterior border of her sternocleidomastoid muscle at about its midlength. What nerve must be locally anesthetized for the operation to proceed without pain? Ansa cervicalis External branch of the superior laryngeal Great auricular Supraclavicular Transverse cervical
Transverse cervical To answer this question, you want to figure out which nerves supply sensory innervation to the skin of the anterior neck. The transverse cervical nerves, which come off the C2 and C3 roots of the cervical plexus, are the nerves that supply the skin of the neck anteriorly. So, these nerves would need to be anesthetized. The great auricular and supraclavicular nerves are also cutaneous sensory nerves from the cervical plexus. The great auricular nerve innervates the skin of the ear and the area below the ear. The supraclavicular nerves innervate the skin at the root of the neck and the upper chest and upper shoulder. Ansa cervicalis is a branch of the cervical plexus which innervates the strap muscles--it's a motor nerve, not a sensory nerve. The external branch of the superior laryngeal nerve is a motor nerve, too--it innervates the cricothyroid muscle.
One of the motor components of the cervical plexus, the ansa cervicalis, innervates all of the following muscles except the: Omohyoid Sternohyoid Sternothyroid Stylohyoid Thyrohyoid
stylohyoid muscle The stylohyoid muscle runs from the posterior portion of the digastric muscle to the body of the hyoid bone. It elevates and retracts the hyoid, and it is innervated by the facial nerve (CN VII). Omohyoid, sternohyoid, sternothyroid, and thyrohyoid are all strap muscles which are innervated by ansa cervicalis (although thyrohyoid receives its branch via the hypoglossal nerve).stylohyoid muscle
A person receives a shallow knife wound just behind the sternocleidomastoid muscle and about 1 1/2 inches above the clavicle. There is an immediate numbness of the skin below the wound and over the acromion and clavicle. The nerve most likely severed was the greater auricular lesser occipital supraclavicular suprascapular transverse cervical
supraclavicular The supraclavicular nerves come from C3 and C4 in the cervical plexus. These cutaneous nerves provide sensory innervation to the skin of the root of the neck, upper chest, and upper shoulder. These nerves innervate the skin right above the clavicle, so they are the correct answer. The great auricular nerve comes from C2 and C3 branches in the cervical plexus; it provides sensory innervation to the ear and the skin below the ear. The lesser occipital nerve comes from C2 in the cervical plexus - it innervates the skin behind the ear. The transverse cervical nerve is also a cutaneous branch from the cervical plexus - it is from C2 and C3 and provides sensory innervation to the skin of the neck anteriorly. The suprascapular nerve is not a cutaneous nerve - it comes from the superior trunk of the brachial plexus and provides motor innervation to supraspinatus and infraspinatus.
