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Neck Anatomy

Organs in the Neck (3)
1. Thyroid
2. Parathyroid
3. Larynx
Bony Framework of Neck (4)
1.Cervical vertebrae
2. Hyoid Bone
3. Manubrium
4. Clavicles
Features of Cervical Vertebrae
1. Foramen Transversarium
2. Anterior/Posterior Tubercles
3. Large Vertebral Foramina
4. Bifid Spinous Processes
Where is the vertebral foramen largest?
C1 (Atlas)
Features of Hyoid Bone (4)
1. Level of C3
2. Site of muscle attachment
3. Assists in keeping airway Open
4. Does not articulate with other bones
Which bone is likely to fracture due to strangulation by compression of the throat?
Hyoid Bone.
Inability to elevate the hyoid bone makes swallowing and separation of the esophagus and trachea difficult.
Contents of the Superficial Fascia of the Neck (5)
1. Fatty Connective Tissue
2. Cutaneous Nerves
3. Lymphatics
4. Blood Vessels
5. Platysma (anteriorly)
What is the grimace muscle?
Supplied by CN 7
Arises from deltoid and pectoralis major fascia
What are the 3 Layers in the deep fascia of the neck?
1. Investing
2. Pretracheal
3. Prevertebral
What is in the carotid sheath?
1. Carotid arteries
2. Internal jugular vein
3. Vagus nerve (CN X)
4. Lymph nodes
5. Nerve to carotid sinus
6. Sympathetic nerve fibers (carotid plexus)
Regions of the Neck
1. Sternocleidomastoid
2. Posterior Cervical Region
3. Lateral Cervical Region
4. Anterior Cervical Region
Borders of the Lateral Cervical Region
1. Sternocleidomastoid
2. Trapezius
3. Clavicle
4. Investing layer of deep fascia (roof)
5. Prevertebral layer of deep fascia (floor)
Triangles in the Lateral Cervical Region
Occipital Triangle
Omoclavicular/Subclavian Triangle
(divided by omohyoid muscle)
1. Vertebral Artery
2. Internal Thoracic Artery
3. Thyrocervical Trunk
Arteries of the Lateral Cervical Region
a. Inferior Thyroid Artery
b. Transverse Cervical Artery
c. Suprascapular artery
3 Divisions of the Thyrocervical Trunk
Veins of the Lateral Cervical Region (2)
1. External Jugular Vein
-pierces investing fascia
-terminates in the subclavian vein
2. Subclavian Vein
What vein is used for central line placement?
Subclavian Vein
(Lateral Cervical Region)
↑ External Jugular Venous pressure is a sign of (4)?
1. Heart failure
2. SVC obstruction
3. Enlarged lymph nodes
4. Increased intrathoracic pressure
A. Spinal Accessory Nerve (CN XI)
B. Sensory Branches of the Cervical Plexus (C1-C4)
Nerves of the Lateral Cervical Region
1. Lesser Occipital Nerve (C2)
2. Greater Auricular Nerve (C2/C3)
3. Transverse Cervical Nerve (C2/C3)
4. Supraclavicular Nerves (C3/C4)
Sensory Branches of the Cervical Plexus (C1-C4) in the Lateral Cervical Region
Contents of the Sternocleidomastoid Region
1. Sternocleidomastoid Muscle
2. Superior Portion of EJV
3. Sensory Branches of Cervical Plexus
Sensory Branches of the Cervical Plexus in the Sternocleidomastoid Region
1. Greater auricular nerve
2. Transverse cervical nerve
Clinical Correlation: Patient with twisted neck/slanted head
Contraction or shortening of cervical muscles. Torn SCM/fibrous tissue tumor.
Extrinsic Back Muscles
Latissimus dorsi
Levator Scapulae
Innervation of SCM
CN XI (motor)
C2, C3 (sensory)
Function of SCM
Maintain position of cervical vertebrae
Intrinsic Back Muscles
Maintain posture and move vertebral column and head
Muscles in Suboccipital Region of the Neck
Intrinsic Back Muscles
4 Small Muscles
A. Rectus Capitis Posterior Major
B. Rectus Capitis Posterior Minor
C. Obliquus Capitis Inferior
D. Obliquus Capitis Superior
Four Small Muscles in the Suboccipital Triangle
Suboccipital Triangle
1. Four small muscles (RCPMa, RCPMi, OCI, OCS)
2. Floor: atlanto-occipital membrane and posterior arch of C1
3. Roof: Intrinsic back muscle
Contents of the Suboccipital Triangle
1. Vertebral artery
2. Suboccipital nerve (C1)
3. Greater Occipital nerve (C2)
Parts of the Vertebral Artery
1. Cervical part - arises from first part of subclavian artery (left vertebral artery can come off aorta directly)
2. Vertebral part - goes thru transverse foramina of C1-6
3. Suboccipital part - enters cranial cavity thru foramen magnum and pierces posterior altanto-occipital membrane
4. Cranial part
What does the cranial part of the vertebral artery supply?
1. medulla
2. spinal cord
3. cerebellum
4. posterior dura
What joins to form the basillar artery and then the vertebral arterial circle?
The cranial part of the vertebral artery.
Borders of the Anterior Cervical Region (3)
1. Median line of the neck
2. Anterior border of SCM
3. Inferior border of the mandible
4. Roof - Subcutaneous tissue containing platysma
5. Floor - Pharynx, larynx, thyroid gland
Hyoid muscles
Stabilize and move the hyoid/larynx
1. Suprahyoid - floor of the mouth; elevates hyoid and larynx when swallowing
2. Infrahyoid - depresses hyoid and larynx when swallowing and speaking
Suprahyoid Muscles
1. Mylohyoid (CN V3)
2. Geniohyoid (C1, hitchhiker on CNXII)
3. Stylohyoid (CN VII)
4. Digastric
-anterior belly (CN V3)
-posterior belly (CN VII)
1. Mylohyoid
2. Geniohyoid
3. Stylohyoid
4. Digastric (anterior/posterior belly)
Suprahyoid muscles in the Anterior Cervical Region
Infrahyoid Muscles - Superficial Plane
1. Sternohyoid muscle
2. Omohyoid muscle
Infrahyoid Muscles - Deep Plane
1. Sternothyroid muscle (below oblique line on thyroid cartilage)
2. Thyrohyoid muscle (above oblique line to hyoid)
Strap Muscles (4)
Superficial and Deep Plane of Infrahyoid Muscles
1. Sternohyoid
2. Omohyoid
3. Sternothyroid
4. Thyrohyoid
Strap Muscles
1. Sternohyoid
2. Omohyoid
3. Sternothyroid
4. Thyrohyoid
Name these muscles of the anterior cervical region of the neck.
Nerves of the Anterior Cervical Region of the Neck
1. Transverse cervical nerve
2. Hypoglossal nerve
3. Glossopharyngeal nerve
4. Vagus nerve
What vertebral levels supply the transverse cervical nerve?
What vertebral level supply the hypoglossal nerve?
What vertebral level supplies the glossopharyngeal nerve?
What are the roots of the cervical plexus?
Anterior rami of C1-C4
Irregular nerve loops and branches
-superficial branches are sensory
-deep branches are motor
Deep Branches of the Cervical Plexus
Motor nerves.
1. Ansa Cervicalis Nerve
2. Phrenic Nerve
Ansa Cervicalis Nerve roots (2)
1. Superior Root (C1/C2)
-descends from hypoglossal nerve (CN XII)
2. Inferior Root (C2/C3)
-supplies infrahyoid muscles
What nerve passes between the subclavian vein and artery to enter the thorax?
Phrenic nerve - deep branch of the cervical plexus (motor)
"C3, 4 and 5 keep the diaphragm alive"
What does the phrenic nerve supply?
1. diaphragm
2. mediastinal pleura
3. pericardium
Arteries of the Anterior Cervical Region
1. Internal Carotid Artery
2. External Carotid Artery (& its branches)
1. Ascending Pharyngeal Artery
2. Occipital Artery
3. Posterior Auricular Artery
4. Superior Thyroid Artery
5. Lingual Artery
6. Facial Artery
Branches of the External Carotid Artery* in the Anterior Cervical Region of the Neck
What artery branches off the Superior Thyroid Artery?
Superior Laryngeal Artery
What is the path of the Lingual Artery?
Passes deep to the hypoglossal nerve and hypoglossus muscle
What is the path of the Facial Artery?
Passes under the digastric and stylohyoid muscles and over the angle of the mandible.
What is the carotid sinus?
Dilation of the proximal portion of the internal carotid artery.
What nerves innervates the carotid sinus?
Glossopharyngeal nerve (CN 9) and vagus nerve (CN 10)
What is the carotid body?
Mass of tissue on medial side of bifurcation of the common carotid.
What nerves innervate the carotid body?
The glossopharyngeal nerve (CN 9) and the vagus nerve (CN 10)
*same innervation as the carotid sinus
What is the largest vein in the neck?
Internal Jugular Vein.
-in carotid sheath
-passes deep to SCM
What two veins converge to form the brachiocephalic vein?
the internal jugular vein and the subclavian vein
1. Submental Triangle
2. Submandibular Triangle
3. Carotid Triangle
4. Muscular Triangle
4 Triangles in the ACR of the Neck
1. Hyoid bone
2. Anterior bellies of Digastric Muscle
3. Mylohyoid muscles
4. Mandibular symphysis
Boundaries of the Submental Triangle (in AC Region)
What does the submental triangle contain?
1. Small submental lymph nodes
2. Veins
A. Inferior border of mandible
B. Anterior and posterior bellies of the digastric muscle
C. Mylohyoid muscle
Boundaries of the Submandibular Triangle (in AC Region of Neck)
What are the contents of the Submandibular Triangle?
1. Submandibular gland
2. Hypoglossal nerve (CN 12)
3. Facial artery and vein
1. Superior belly of Omohyoid Muscle
2. Posterior belly of the Digastric Muscle
3. Anterior border of SCM
What are the boundaries of the Carotid Triangle? (AC Region)
4. Common Carotid Artery
5. Internal Carotid Artery
6. External Carotid Artery
7. Internal Jugular Vein
8. Ansa Cervicalis lies on top of sheath
-deep cervical lymph nodes
-vagus nerve
What does the Carotid Triangle contain?
1. Superior belly of Omohyoid Muscle
2. Anterior border of SCM
3. Median plane of the neck
What are the borders of the Muscular Triangle (AC Region)?
What are the contents of the Muscular Triangle (AC Region of the Neck)?
Infrahyoid muscles
Thyroid gland
Parathyroid gland
1. Visceral compartment
2. Vascular compartment
3. Vertebral compartment
Divided by the fascia of the neck: investing, pretracheal, prevertebral
What are the compartments of the neck? What are they divided by?
Prevertebral muscles of the neck: Anterior Group
Anterior Scalene
Middle Scalene
Posterior Scalene
Prevertebral muscles of the neck: Lateral Group
Splenius Capitis
Levator Scapulae
What is the function of the prevertebral muscles of the neck?
Flexion of the head and neck.
What are the three main pairs of major nerves in the neck?
1. Vagus (CN 10)
2. Phrenic (C3-5)
3. Sympathetic trunks
Horner's syndrome is caused by what?
Lesion of sympathetic trunk (in the neck).
Patient presents with miosis, ptosis, enopthalmos, and anhydrosis.
Horners Syndrome
Endocrine Viscera of the Neck (2)
1. Thyroid
2. Parathyroid
Respiratory viscera of the neck (2)?
1. Larynx
2. Trachea
Alimentary viscera of the neck?
1. Pharynx
2. Esophagus
Where is the thyroid gland?
Enclosed within pretracheal layer of deep cervical fascia. Lies deep to Sternothyroid and Sternohyoid muscles (C5-T1)
What does the thyroid gland produce?
thyroid hormone and calcitonin
What serves as the voice box?
Vertebral level C3-C6
Maintains patent airway
What 3 cartilages are visible in the anterior neck?
1. Thyroid cartilage
2. Cricoid cartilage
3. Trachea
1. Thyroid Cartilage
2. Cricoid cartilage
3. Trachea
A. Thyrohyoid membrane
B. Laryngeal prominence
C. Cricothyroid membrane
Name these cartilages on the anterior neck (respiratory layer).
What are the functions of the extrinsic and intrinsic laryngeal muscles?
Extrinsic: move the larynx as a whole (suprahyoid-elevate/ infrahyoid-depress)
Intrinsic: move the laryngeal cartilages
What important anatomical concerns are involved in a tracheostomy?
Inferior thyroid veins
Thyroid artery
Left brachiocephalic vein
Thymus (infants and kids)
Small, mobile trachea in infants
What are the three parts of the pharynx?
1. nasopharynx
2. oropharynx
3. laryngopharynx