Anterior Cervical Region (anterior triangle of the neck):

Anterior boundary: formed by the median line of the neckPosterior boundary: formed by the anterior boundary edge of the sternocleidomastoid muscle (SCM)Roof: formed by the subcutaneous tissue containing the platysmaFloor: formed by the pharynx, larynx, thyroid gland

The two muscles digastrics and the omohyoid muscles divide the region into 4 smaller triangles

Hypoglossus muscle is under the mylohyoid muscleSternothryoid is under the thyrohyoid muscle and sternohyoid muscle

How did the tumor cause breathlessness? Since the thyroid is anterior to the trachea, an abnormal mass can push on the trachea and partially occlude the lumen, causing breathlessness.

Which lymph nodes should the physician examine for metastases if a malignant tumor is suspected? The thyroid gland is drained primarily by the deep cervical lymph nodes.

The two main arteries supplying the gland are accompanied by nerves that can be damaged druing thyroidectomy. The superior thyroid artery is related to the external laryngeal nerve. This nerve supplies the cricothyroid and cricopharyngeus muscles. The inferior thyroid arteries are related to the recurrent laryngeal nerve.

Why would patients with goiter be likely to have shortness of breath and dysphagia?The enlarged thyroid will press initially on the trachea. Pressure will increase when it reaches a large size since the sternothyroid muscle will be forced down to the superior mediastinum, and the trachea and esophagus will be compressed.

Which vessels should be ligated before doing lower subtotal thyroidectomy?The inferior thyroid artery, a branch of the thyrocervical trunk, runs posterior to the carotid sheath to reach the posterior aspect of the gland. It divides into several branches, which pierce the pretracheal fascia to supply the inferior pole of the gland. Other vessels to be dealt with are the middle and inferior thyroid veins.

What are the most likely complications that may arise from such an operation?Bleeding is possible due to the rich blood supply to the thyroid. Injury to the recurrent laryngeal nerve may result in temporary hoarseness of the voice, permanent loss of voice, or even death due to laryngeal spasm. Another possible complication of thyroidectomy is the inadvertent removal of the parathyroid glands, which may cause a severe convulsive disorder known as tetany.

Carotid triangle is where the common carotid artery branches into 2

Goiter: enlargement of the thyroid gland. A goiter is not cancerous. A goiter can be associated with normal, elevated (hyperthyroidism) or decreased (hypothyroidism) thyroid hormone levels in the blood. Tracheostomy: The surgical creation of an artificial airway in the trachea (windpipe) on the anterior surface of the neck.

Cricothyrotomy: an emergency procedure where a cut or passageway is made in the cricothyroid membrane.

Thyroidectomy: surgery to remove part or all of the thyroid gland. This might be done to remove a tumor or treat hyperthyroidism or goiter (enlarged thyroid gland). The goal of surgery in hyperthyroidism is to remove just enough thyroid gland so that a normal amount of thyroid hormone is produced. If too much thyroid is removed, the patient will produce too little thyroid hormone (hypothyroidism) and need treatment to return the thyroid status to normal

(euthyroid). The complications of surgery can include vocal cord paralysis (if the recurrent laryngeal n. is cut) and accidental removal of the parathyroid glands (located behind the thyroid gland), resulting in low calcium levels (the parathyroid glands regulate calcium).

Thyroglossal duct cyst: a thyroglossal cyst is a fluid-filled sac that is present at birth and located in the midline of the neck. A thyroglossal cyst is a result of incomplete closure of a segment of a tube-like structure (the thyroglossal duct) that is present, and normally closes, as the embryo develops. A thyroglossal cyst is also called a thyrolingual cyst.

Torticollis: a wry neck, a contracted state of the cervical muscles, producing twisting of the neck and an unnatural position of the head.

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.

The layer of encircling cervical fascia that splits to enclose sternocleidomastoid and trapezius muscles is the: The superficial layer of deep cervical fasciaThe 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.

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 supraclavicular nervesThe 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.

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 (transverse cervical, greater auricular, lesser occipital, supraclavicular nerves)

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.

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 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.

Exploration of the tracheoesophageal groove at the level of the thyroid gland would reveal what important structure bilaterally? Recurrent laryngeal nerves

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.

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).

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.

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.

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? Just below the thyroid cartilageTo 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.

The submandibular triangle is bounded anteriorly by the anterior belly of the digastric, posteriorly by the posterior belly of the digastric, and superiorly by the lower border of the mandible. It contains the superficial portion of the submandibular gland and the facial artery and vein. The submental triangle is laterally bordered by the anterior bellies of the digastric muscles. It is inferiorly bordered by the hyoid bone. Submental lymph nodes are found in this triangle.

The omoclavicular triangle: It is found in the posterior triangle of the neck. This triangle is bounded superiorly by the inferior belly of the omohyoid muscle, anteriorly by the sternocleidomasoid muscle, and inferiorly by the clavicle. The third part of the subclavian artery and the subclavian vein are located in this triangle.

The muscular triangle is found in the anterior triangle of the neck. It is bounded by the midline as its medial border, the superior belly of the omohyoid as its superolateral border, and sternocleidomastoid as its inferolateral border. The strap muscles, thyroid, and parathyroids are found in this triangle. Since the thyroid is found at the midline, deep to the strap muscles, you would need to cut into this triangle to perform surgery on the thyroid gland.

A 47-year-old woman is diagnosed as having a thyroid tumor. Surgery to remove the cancerous growth is undertaken. In which triangle of the neck will the surgeon make an incision to gain access to the gland? Muscular

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.

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? Transverse Cervical NerveTo 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.

These structures are all located in the superficial fascia of the neck EXCEPT :The omohyoid muscle is a muscle found in the anterior and posterior triangle of the neck. It depresses and stabilizes the hyoid bone. Like all muscles (except the muscles of facial expression), the omohyoid is not found in the superficial fascia. The external jugular vein is a small vein found in the superficial tissue on the lateral side of the neck. The platysma is a muscle of facial expression that draws down the corners of the mouth and depresses the mandible. It inserts into the skin, so it is found in the superficial fascia. The cervical branch of the facial nerve, which innervates the platysma, is also in the superficial fascia. Finally, the transverse cervical nerve is a branch of the cervical plexus that innervates the skin of the anterior neck. Because it is providing cutaneous innervation, it is found in the superficial fascia.

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?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.

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.The cervical plexus innervates all of the following structures EXCEPT:

Diaphragm

Omohyoid muscle

Platysma

Skin over thyroid cartilage

Skin over clavicle

The carotid triangle is bounded anteriorly by the superior belly of the omohyoid muscle, laterally by the sternocleidomastoid, and superiorly by the posterior belly of the digastric. The carotid vessels and carotid sheath can be found in this triangle. The muscular triangle is bounded by the midline as its medial border, the superior belly of the omohyoid as its superolateral border, and sternocleidomastoid as its inferolateral border.

Which structure or area receives NO nerve fibers from the cervical plexus? SKIN OVER THE THE EXTERNAL OCCIPITAL PORTUBERANCEThe 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.

If the sternocleidomastoid is damaged at birth and becomes shortened, a patient may have muscular torticollis. The neck will appear twisted and the chin elevated because the sternocleidomastoid muscle will be too short on one side. This patient has an injured right sternocleidomastoid, since his head is turned down on the right side where the sternocleidomastoid is too short. Patients may also have spasmotic torticollis, where the neck is twisted and elevated due to a temporary spasm of the sternocleidomastoid muscle.

An emergency room patient presented with considerable bleeding from a shallow stab wound in the omoclavicular triangle. Which vessel was most likely cut? The external jugular veinThe external jugular vein is a superficial vein on the lateral side of the neck. It is in the superficial fascia, so it could be easily injured by a superficial wound. Since this vein travels in the omoclavicular triangle, this is the structure that was injured. The axillary vein is the continuation of the subclavian vein lateral to the first rib--it is important in draining the upper limb, but it's not associated with the triangles of the neck. The common carotid artery is found in the carotid sheath and carotid triangle. The inferior thyroid vein and superior thyroid artery are both found near the thyroid gland; therefore, they are both in the muscular triangle.

The cervical plexus consists solely of the ventral primary rami of spinal nerves C1-C4. It supplies cutaneous innervation through nerves like the lesser occipital, great auricular, supraclavicular and transverse cervical. It also supplies motor innervation to the strap muscles through the ansa cervicalis. So, it has a motor and sensory component.

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? Supraclavicular nervesThe 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

Anterior cervical triangle o boundaries:

medial: midline lateral: anterior border of the sternocleidomastoid muscle superior: lower border of the mandible

o subdivisions: muscular triangle

medial: midline superolateral: superior belly of the omohyoid muscle inferolateral: sternocleidomastoid muscle

submandibular triangle anterior: anterior belly of the digastric muscle (this muscle is not in this lab, so for

now it is sufficient to know its location as a reference for triangle borders). posterior: posterior belly of the digastric muscle superior: lower border of the mandible

submental triangle lateral: anterior belly of digastric muscle medial: midline inferior: hyoid bone

carotid triangle lateral: sternocleidomastoid muscle superior: posterior belly of the digastric muscle anterior: superior belly of the omohyoid muscle

Posterior cervical triangleo boundaries:

anterior: sternocleidomastoid muscle posterior: trapezius muscle inferior: clavicle

o subdivisions: subclavian/omoclavicular triangle

superior: inferior belly of omohyoid muscle anterior: sternocleidomastoid muscle inferior: clavicle

occipital triangle anterior: sternocleidomastoid muscle posterior: trapezius muscle inferior: omohyoid muscle

If the parathyroid glands atrophy or are all removed during surgery, the patient suffers from tetany, severe convulsive muscle spasms resulting from a fall in serum calcium levels.

The carotid sheath contains the internal and common carotid arteries, the internal jugular vein, and the vagus nerve. Through the middle neck levels, the superior root of the ansa cervicalis lies in the sheath anteriorly. The carotid sheath is posterolateral to the thyroid gland and anterior to the prevertebral fascia. The sympathetic trunk lies behind the medial portion of the sheath

The vagus nerve runs between and posterior to the common carotid artery and the internal jugular vein in the carotid sheath (the artery is medial, the vein lateral). The rest of the question is answered above.

How does the innervation to the thyrohyoid muscle differ from the other strap muscles?Thyrohyoid innervation comes from C1 & C2 via the hypoglossal nerve, arising after the superior root of the ansa cervicalis leaves the hypoglossal nerve.