osteology & arthrology of the head and neck + fascia & musculature of head and neck

Fascial planes determine the potential direction in which an

infection may spread

Platysma is a broad, thin sheet of muscle and covers what?

Covers anterolateral part of neck. External jugular vein and main cutaneous nerves of neck are deep to the platysma

Superficial fascia is a layer of fatty subcutaneous tissue surrounding the whole neck and is located between what?

Located between skin and investing layer of deep cervical fascia

Deep Fasica of the neck is several layers that compartmentalize structures in the neck which includes (4)

1. Investing fascia

2. Pretracheal fascia

3. Prevertebral fasica

4. Carotid sheath

What are the layers of the neck anterior to posterior?

Skin

Platysma

Superficial fascia

Deep fascia

What does deep fascia of the neck allow separation for?

Allow separation of tissue during surgery, and limit spread of infection. Permit sliding of structures pass over one another without difficulty

What does the investing fasica of the deep fascia encircle?

encircles the entire neck deep to superficial fascia

What is the superior attachments of the investing fasica of the deep fascia? (6)

1. Superior nuchal line of the occipital bone

2. Mastoid process of the temporal bone

3. Zygomatic arches

4. Inferior border of mandible

5. Hyoid bone

6. Spinous process of cervical vertebrae

What is the inferior attachments of the investing fascia of the deep fascia? (3)

1. Manubrium

2. Clavicles

3. Acromions and spines of scapula

What does the Pretracheal fascia of the deep fascia surround?

surrounds structures in the anterior part of neck

What are the attachments of the pretracheal fascia of the deep fascia?

extends from hyoid bone to thorax, where it blends with pericardium

The muscular part of the pretracheal fascia of the deep fascia enclosed what?

encloses infrahyoid muscles

The visceral part of the pretracheal fascia of the deep fascia enclosed what? (4)

encloses thyroid gland, trachea, esophagus, and pharynx

The Buccopharyngeal fascia is thin lamina of the prevertebral fascia that surrounds what?

fascia that surrounds the pharyngeal constrictor muscles

The prevertebral fascia of the deep fascia surrounds the vertebral column and associated muscles and attaches from

cranial base superiorly and blends inferiorly with the endothoracic fascia, communicating with the mediastinum

The carotid sheath of the deep fascia surrounds what? (3)

1. surrounds common and internal carotid artery

2. internal jugular vein

3. vagus nerve (CN X)

What does the carotid sheath of the deep fascia attach to?

extends from cranial base to root of neck, where it communicates with the mediastinum

What does the carotid sheath of the deep fascia invest?

pretracheal, and prevertebral layers contribute to the formation of the carotid sheath

The alar fascia (thin layer of fascia) of the deeps fascia extends from cranial base to root of neck and attaches at what?

at the midline to buccopharyngeal fascia and laterally to carotid sheath

The Retropharyngeal space is a interfacial space between what fasica? (3)

interfascial space between pretracheal (anteriorly), prevertebral (posteriorly), and carotid sheaths (laterally)

Where are the muscles of facial expression located?

subcutaneous tissue of scalp, face, and neck

what are the muscles of facial expression innervated by?

facial nerve (CN VII) #7

What are the muscles of facial expression on the forehead and scalp? (2)

Frontalis

Occipitalis

Where is the attachment of the frontalis muscle? what is its function?

Attachment: skin of eyebrows and root of nose

Function: elevates eyebrow and wrinkles forehead

Where is the attachment of the Occipitalis muscle what is its function?

Attachment: the lateral 2/3rds of the superior nuchal line

Function: draws scalp back and wrinkles back of head

What are the muscles of facial expression of the mouth, lips, and cheeks? (8)

1. Levator labii superioris

2. Zygomaticus major

3. Depressor anguli oris

4. Depressor labii inferioris

5. Platysma

6. Levator anguli oris

7. Buccinator

8. Orbicularis oris

Where is the attachment of the Levator labii superioris muscle what is its function?

A: from infraorbital margin to skin of upper lip

F: elevates upper lip

Where is the attachment of the Zygomaticus major muscle what is its function?

A: zygomatic bone to angle of mouth

F: elevates the corner of mouth

Where is the attachment of the Depressor anguli oris muscle what is its function?

A: anterolateral base of mandible to angle of mouth

F: depresses corner of mouth

Where is the attachment of the Depressor labii inferioris muscle what is its function?

A: from mandible to skin of lower lip

F: depresses lower lip

Where is the attachment of the Platysma muscle what is its function?

A: from fascia and skin over clavicular region to base of mandible, angle of mouth, lower part of face

F: depresses mandible, tenses skin of inferior face and neck

Where is the attachment of the Levator anguli oris muscle what is its function? What muscle is it deep to?

A: from maxilla (just below infraorbital foramen) to angle of mouth

F: elevates corner of the mouth

Deep to levator labii superioris muscle, an accessory muscle to zygomaticus major.

Where is the attachment of the Buccinator muscle what is its function? What muscle is it deep to?

A: anteriorly angle of mouth and posteriorly to mandible, maxilla, and pterygomandibular raphe tendon, a tendinous extension of buccopharyngeal fascia.

***F: mastication (keeps cheeks taut), smiling

Deep to the Masseter. Forms principal substance of cheeks

Where is the attachment of the Orbicularis Oris muscle what is its function?

A: encircles mouth and attaches into upper and lower lips. Oral sphincter

F: Articulation and mastication

What are the muscles of facial expression of the eyes, ear, and nose? (7)

1. Eyes

- Orbicularis Oculs

2. Ear

- Auricularis anterior

- Auricularis posterior

- Auricularis superior

3. Nose

- Procerus

- Nasalis

4. Depressor septi

Where is the attachment of the Orbicularis oculi muscle what is its function? (E,E,N)

A: Circular muscle around orbital margin into eyelids, sphincter of eyes

F: Closes orbital opening, encourages flow of tear by helping empty lacrimal sack

Where is the attachment of the Auricularis (Anterior, Posterior, Superioer) Muscles? (E,E,N)

A: skin of the auricle of ear

Where is the attachment of the Procerus muscle what is its function? (E,E,N)

A: from forehead to skin over bridge of nose

F: depresses medial angle of eyebrows (when very serious)

Where is the attachment of the Nasalis muscle what is its function? (E,E,N)

A: from maxilla to bridge and alar cartilage of nose

F: Widen nasal aperture

Where is the attachment of the depressor septi muscle what is its function? (E,E,N)

A: from incisive fossa of maxilla to nasal septum

F: Depresses and widen nasal aperture

What are the muscles of mastication? (4)

1. Temporalis

2. Masseter

3. Medial pterygoid

4. lateral pterygoid

Where is the attachment of the temporalis muscle what is its function? (Mastication M)

Occupies temporal fossa

A: from temporal fossa to coronoid process of mandible

F: elevation, retraction, lateral excursion of mandible

Where is the attachment of the Masseter muscle what is its function? (Mastication M)

Very strong, thick muscle

A: zygomatic arch to lateral surface of ramus and angle of mandible

F: elevation, and protraction of mandible, clenches teeth

All muscles of mastication are innervated by the

mandibular branch of the trigeminal nerve (CN V3) #5

Where is the attachment of the Medial pterygoid muscle what is its function? (Mastication M)

Located in the infratemporal fossa.

A: from lateral pterygoid plate and maxillary tuberosity to medial (or internal) surface of ramus and angle of mandible

F: elevation, protraction, and lateral excursion of mandible. Synergistic with masseter m.

Where is the attachment of the Lateral pterygoid muscle what is its function? (Mastication M)

Deep in the temporal fossa. Short, strong, and runs horizontally

A: lateral pterygoid plate and greater wing of sphenoid to neck of mandible and penetrating the TMJ capsule inserts on the articular disc

F: depression, protraction, and lateral excursion of mandible

What is the muscle of the neck? What does it attach to? What is its function?

Sternocleidomastoid (SCM)

A: from mastoid process and lateral 1/2 of superior nuchal line to manubrium of sternum and medial 1/3rd of clavicle

F: Unilaterally—rotating head to left and right. Bilaterally—flexes neck

What is the Sternocleidomastoid innervated by?

accessory nerve (CN XI)

CLINCIAL RELEVANCE!

What is used to test the integrity of the SCM and accessory nerve (CNXI)?

unilateral contraction

What are the Suprahyoid muscles? (3)

1. Mylohyoid muscle

2. Geniohyoid muscle (posterior)

3. Digastric muscle

4. Stylohyoid muscle (Dr. Toldeo said this)

What does the Digastric muscles of the suprahyoid muscles attach to? What is its fuction?

A: mandible and mastoid process of Temporal bone. Both bellies attach to intermediate tendon, which is tied down to the hyoid bone by a sling of fascia

F: Depress mandible, open mouth, and elevate hyoid bone

What is the Digastric muscles (2 bellys) of the suprahyoid muscles Innervated by?

Posterior belly—facial nerve (CN VII) Anterior belly—trigeminal nerve (CN V)

Where does the Mylohyoid muscle of the suprahyoid muscles attach to? What is its function?

A: medial surface of mandible to hyoid bone

F: elevates hyoid, floor of mouth, and tongue during swallowing and speaking. Forms the floor of the oral cavity

What is the Mylohoyid muscle of the suprahyoid muscles innervated by?

trigeminal nerve (CN V)

Where is the attachment of the Geniohyoid muscle of the suprahyoid muscles? What is its function?

A: from genio (or bend) of mandible to hyoid bone

F: elevate hyoid, shortens floor of mouth

What is the Gleniogyoid muscle of the suprahyloid muscles innervated by?

C1 via hypoglossal nerve (CN XII)

What are the Infrahyoid muscles? (4)

1 Sternohyoid muscles

2. Omohyoid muscle

3. Sternothyorid muscle

4. Thyrohyoid muscle

What is the Omohyoid muscle of the infrahyoid muscles attach to and function?

A: superior border of scapula and hyoid bone Both bellies attached to intermediate tendon, which is tied down to clavicle by sling of fascia

F: Depress, retracts, and steadies hyoid

What is the Omohyoid muscle innervated by?

Ansa cervicalis

What is the attachment of the sternohyoid muscle of the infrahyoid muscles? What is its function?

A: from manubrium of sternum and medial end of clavicle to hyoid

F: Depress hyoid bone after elevation during swallowing

What is the sternohyoid muscle Innervated by?

Ansa cervicalis

What is the attachment of the sternothyroid muscle of the infrahyoid muscle? What is its function?

A: from manubrium of sternum to thyroid cartilage of larynx

F: Depress hyoid and larynx

What is the sternothyroid muscle innervated by?

Ansa cervicalis

What is the attachment of the Thyrohyoid muscle of the infrahyoid muscles? What is its fuction?

A: from thyroid cartilage of larynx to hyoid bone

F: Depress hyoid bone and elevate larynx

What is the Thyrohyoid muscle Innervated by?

C1 via hypoglossal nerve (CN XII)

What are the prevertebral muscles? (5) what is their location?

1. Anterior Scalene

2 .Middle Scalene

3. Posterior Scalene

4. Longus capitis

5. Longus colli

Location: Deep to prevertebral fascia and posterior to retropharyngeal space

What is the attachment of the anterior scalene muscle of the prevertebral muscles? What is its function?

A: from transverse process of C3 – C6 to 1st rib

F: flex neck, and elevates 1st rib

What is the anterior scalene muscle Innervated by?

Cervical spinal nerves C4 - C6

What is the attachment of the middle scalene muscle of the prevertebral muscles? What is its function?

A: from posterior tubercle of transverse process of C2 – C7 to 1st rib

F: flex neck laterally, and elevates 1st rib

What is the middle scalene muscle innervated by?

Anterior rami of cervical spinal nerves

What does the posterior scalene muscle of the prevertebral muscles attach to and what is its function?

A: from posterior tubercle of transverse process of C5 – C7 to 2nd rib

F: flex neck laterally, and elevates 2nd rib

What is the posterior scalene muscle innervated by?

Anterior rami of spinal nerves C7 - C8

What is the attachment and function of the longus capitis muscle of the prevertebral muscles?

A: from basilar part of Occipital bone to anterior tubercles of C3 - C6 transverse processes

F: Flexion of head

What is the Longus capitis muscle innervated by?

anterior rami of spinal nerves C1 - C3

What is the attachment and function of the Longus colli muscle of the prevertebral muscles?

A: from anterior tubercle of C1, bodies of C1 – C3, and transverse processes of C3 – C6 to bodies of C5 – T3, and transverse processes of C3 – C5

F: flexion of the neck (bilateral) and slight rotation of neck to contralateral side (unilateral)

What is the longus colli muscle innervated by?

Anterior rami of spinal nerves C2 - C6

What are the posterior cervical muscles (superficial to deep)? (4)

1. Trapezius

2. Splenius capitis

3. Splenius cervicis

4. semispinalis capitis

What is the attachment of the Trapezius muscle of the posterior cervical muscles and what is its function?

A: medial third of superior nuchal line, nuchal ligament, spinous processes of cervical and thoracic vertebrae to lateral third of clavicle, and acromion and spine of scapula

F: elevate, retract, and rotate scapula superiorly

What is the trapezius muscle innervated by?

accessory nerve (CN XI)

What is the attachment and function of the Spenius capitis muscle of the posterior cervical muscles?

A: from nuchal ligament and spinous processes of C7 - T6 to mastoid process of Temporal bone and lateral third of superior nuchal line

F: extend H&N (bilaterally), rotate and flex the head to same side

What is the Splenius capitis muscle innervated by?

posterior rami of cervical spinal nerves

What is the attachment and function of the splenius cervicis muscle of the posterior cervical muscles?

A: from nuchal ligament and spinous processes of C7 - T6 to transverse processes of C1 - C4

F: extend H&N (bilaterally), rotate and flex the head to same side

What is the splenius cervicis muscle innervated by?

posterior rami of cervical spinal nerves

What is the attachment and function of the semispinalis capitis muscle of the posterior cervical muscles?

A: from transverse processes of C4 - T12 to Occipital bone and spinous processes of cervical and thoracic vertebrae

F: extend head and neck, and rotate them contralaterally

What is the semispinalis capitis muscle innervated by?

posterior rami of spinal nerves

What are the posterior cervical muscles (suboccipital muscles and triangles)? (4M 1T)

1. Rectus capitis posterior major

2. Rectus capitis posterior minor

3. Obliquus capitis inferior

4. Obliquus capitis superior

**Suboccipital triangle**

What is the attachment of the Rectus capitis posterior major muscle of the suboccipital muscles?

from spinous process of C2 to inferior nuchal line

ALL ARE Innervated by: the suboccipital nerve (posterior ramus of C1)

What is the attachment of the Rectus capitis posterior minor muscle of the suboccipital muscles?

from tubercle on posterior arch of Atlas to inferior nuchal line

ALL ARE Innervated by: the suboccipital nerve (posterior ramus of C1)

What is the attachment of the Obliquus capitis inferior muscle of the suboccipital muscles?

from spinous process of Axis to lateral mass of Atlas

ALL ARE Innervated by: the suboccipital nerve (posterior ramus of C1)

What is the attachment of the Obliquus capitis Superior muscle of the suboccipital muscles?

from lateral mass of Atlas to inferior nuchal line

ALL ARE Innervated by: the suboccipital nerve (posterior ramus of C1)

What are the boundaries of the suboccipital triangle? What artery and nerves does it contain?

Boundaries: Obliquus capitis inferior, obliquus capitis superior, and rectus capitis posterior major

Contains: vertebral artery and suboccipital nerve

CLINICAL RELIVANCE!

Where is the vertebral artery accessed in order to conduct angiography of the circle of Willis?

Suboccipital triangle

What are all muscles in the suboccipital triangle innervated by?

suboccipital nerve (posterior ramus of C1)

What are the muscles of associated to the styloid process? (3)

1. Stylohyoid muscle

2. Styloglossus muscle

3. Stylopharyngeus muscle

What is the attachment and function of the Stylohyoid muscle of the muscles assocated to the styloid process?

A: from styloid process to hyoid bone

F: elevates and retracts hyoid bone

What is the stylohyoid muscle innervated by?

facial nerve (CN VII)

What is the attachment and function of the Styloglossus muscle of the muscles assocated to the styloid process?

- Extrinsic tongue muscle

A: from styloid process to tongue

F: retract and curls (elevates sides) tongue

What is the Styloglossus muscle inntervated by?

hypoglossal nerve (CN XII)

What is the attachment and function of the Stylopharyngeus muscle of the muscles assocated to the styloid process?

A: from styloid process to thyroid cartilage of larynx and pharyngeal wall

F: elevates pharynx

What is the stylopharyngeus muscle innervated by?

glossopharyngeal nerve (CN IX)