skull, muscles of face and neck final version

8/12/2019 Skull, Muscles of Face and Neck Final Version

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THE SKULL

by PASA MD


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INTRODUCTION

ANTERIOR ASPECT OF CRANIUM

LATERAL ASPECT OF CRANIUMOCCIPITAL ASPECT OF CRANIUM

SUPERIOR ASPECT OF CRANIUM

EXTERNAL SURFACE OF CRANIAL BASE

INTERNAL SURFACE OF CRANIAL BASE

TABLE OF CONTENTS


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INTRODUCTION

CRANIUM (SKULL)

skeleton of the head

2 PartsNeurocranium

Viscerocranium


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1. Neurocranium

Cranial vault

Is the bony case of

the brain plus the

cranial meninges,

proximal parts ofcranial nerves and

vasculature of the

brain

INTRODUCTION


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The neurocranium is

formed by a series of

8 bones

SphenoidalTemporal (2sets)

Occipital

Parietal (2 sets)Frontal

Ethmoidal

INTRODUCTION


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Has a dome like roof called the calvaria or skullcap

Calvaria (superior view) Calvaria (inferior view)

FRONTAL

BONE

PARIETAL

BONE

PARIETAL

BONE

OCCIPITAL

BONE

INTRODUCTION


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Has a floor or cranial base called the basicranium

Basicranium

INTRODUCTION


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2. Viscerocranium

facial skeleton

forms the anterior part of the

cranium

consists of bones surroundingthe orbits, nose and mouth

Viscerocranium

INTRODUCTION


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consists of 15 irregular bones

A. 3 singular bones

Mandible

Ethmoid

Vomer

B. 6 bones as bilateral pairs

Lacrimal

Inferior nasal conchae

Maxillae

Palatine

Nasal

Zygomatic

INTRODUCTION


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Orbitomeatal Plane or The

Frankfort Horizontal Plane

In the anatomic position

the inferior margin of theorbit and superior margin

of the external acoustic

meatus lie in the same

horizontal plane

Orbitomeatal Plane

INTRODUCTION


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Development of Craniumbones of calvaria and

cranial base develop

by intramembranous

ossification and byendochondral ossification

at birth the bones of thecalvaria are smooth and

unilaminar

Cranium of Newborn

INTRODUCTION


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Development of Cranium

disproportionately large;

frontal and parietal

eminences are prominent

facial aspect is small

compared to calvaria

increase in size of calvaria

is greatest during the first

2 yrs. due to rapid brain

development. Cranium of Newborn

INTRODUCTION


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Development of Craniumat birth the frontal bones

consists of two halves; union

begins in the 2ndyr.

halves of frontal bone are

separated by frontal suture;

obliterated by the 8thyr.

frontal and parietal bones areseparated by the coronal

suture

INTRODUCTION

Cranium of Newborn


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Metopic Suture

remnant of frontal suture

that persists

in the middle of the glabella

8% of people

must not be interpreted as

fracture in radiograph

Metopic Suture

INTRODUCTION

CLINICAL NOTES


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Development of Craniumintermaxillary suture

separates the maxillae

INTRODUCTION

Cranium of Newborn


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mandibular symphysis

separates the mandible;

halves of the mandible

fuse early in the 2ndyr.

obliteration of sutures

begin bet. ages 30 and40 years on the internal

surface and 10 years

later on the external

surface

INTRODUCTION

Cranium of Newborn


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Development of Craniumno mastoid and styloid

process in newborn; facial

nerves are close to the

surface and can be injured

by forceps delivery

mastoid process formsduring the 1styr; SCM pulls

on the petromastoid parts

of temporal bonesCranium of Newborn

INTRODUCTION


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Development of Cranium1. Anterior Fontanelle

-diamond or star-shaped

-bounded by frontal bone

anteriorly and parietal bone

posteriorly

-18 mos. no longer palpable

-future site of bregma

INTRODUCTION


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Development of Cranium2. Posterior Fontanelle

-triangular

-bounded by parietal

bones anteriorly and

occipital bone posteriorly

-at junction of lambdoid

and sagittal sutures;future site of lambda

-no longer palpable at the

end of 1styr.

INTRODUCTION


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3. Sphenoid and Mastoid

Fontanelles

-temporal muscle overliesthese fontanelles

-fuse during infancy

INTRODUCTION


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palpation of fontanelles

enables the physician to

determine the:

progress of growth offrontal and parietal bones

degree of hydration

(depressed fontanelle

means dehydration)level of intracranial

pressure (bulging means

increased pressure)

Fontanelles

INTRODUCTION

CLINICAL NOTES


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Rapid Growth of Facecoincides with the eruption

of deciduous teeth

dento-alveolar development

of the alveolar bone

associated with the increase

in size of paranasal sinuses

Cranium of Newborn

INTRODUCTION


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Primary Craniosynostosis

premature closure of

cranial sutures1 per 2000 births

unknown cause/genetic

more common in males

usually does not affect

brain development

Craniocytosis

CLINICAL NOTES

INTRODUCTION


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A. Scaphocephaly

premature closure of

sagittal suture

anterior fontanelle is

small or absent

long, narrow wedge-

shaped cranium

Scaphocephaly

CLINICAL NOTES

INTRODUCTION


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B. Plagiocephaly

premature closure of the

coronal or lambdoid

suture on one side only

cranium is twisted and

asymetrical

Plagiocephaly

CLINICAL NOTES

INTRODUCTION


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C.Oxycephaly/Turricephaly

premature closure of the

coronal suture

high tower-like cranium

more common in females

oxycephaly

CLINICAL NOTES

INTRODUCTION


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squamous (flat)part

forms the skeleton of the

forehead

articulates with nasal and

zygomatic bones inferiorly

articulates with lacrimal,

ethmoid and sphenoidsFrontal Bone

FRONTAL BONE


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the intersection of the

frontal and nasal bones

is the nasion

the glabellais the smooth

prominence superior to the

root of the nose

FRONTAL BONE

GlabellaNasion


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supraorbital margin is the

angular boundary between

the squamous and orbitalparts

supraorbital foramen at the

supraorbital margin; forpassage of supra-orbital

nerve and vessels

FRONTAL BONE

Supra-orbital foramen

Supra-orbital margin


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the superciliary arch is a

prominent ridge superior

to the supraorbital marginand deep to the eyebrows;

extends laterally on each

side from the glabella

FRONTAL BONE


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bilateral bony cavities

resemble quadrangular

pyramids

contain and protect the

eyeball and accessoryvisual structures

Orbits

ORBITS


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superior wall (roof)

-orbital part of horizontal bone

-lesser wing of sphenoid

medial wall

-orbital plate of ethmoid-plus frontal process of maxilla,

lacrimal and sphenoid bones

Orbits

ORBITS


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inferior wall (orbital floor)

-maxilla and partly by

zygomatic and palatinebones

-demarcated from the

lateral wall by the inferior

orbital fissure

Orbits

ORBITS


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fossa for the lacrimal gland is

the shallow depression in the

orbital part of the frontal bone

Orbits

ORBITS



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cheek bones or malar

bones

form prominences of

cheeks

lie on inferolateral sides

of orbits and rests on

maxillae

Zygomatic Bone

ZYGOMATIC BONE


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articulates with the frontal,

sphenoid, maxillae and

temporal bones

zygomaticofacial foramen

pierces the lateral aspect

of the zygomatic bones

passage of zygomaticofacial

nerve and vesselsZygomaticofacial Foramen

ZYGOMATIC BONE



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Piriform Aperture

-pear-shaped anterior nasal

opening in the cranium-inferior to the nasal bones

Nasal Septum

-divides the nasal cavityinto right and left parts

Piriform Aperture

NASAL REGION



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Nasal Conchae

-curved bony plates on the

lateral wall of each nasal

cavity

Nasal Septum and Nasal Conchae

NASAL REGION



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form upper jaw; form the

infraorbital margins medially

alveolar processes include

the tooth sockets called

alveoli

supporting bone for maxillary

teeth

Maxillae

MAXILLAE



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surround piriform aperture

the two maxillae are united

at the intermaxillary suturearticulates with zygomatic

bone

infraorbital foramen for

passage of infraorbital nerve

and vessels

Infraorbital Foramen

MAXILLAE



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Fractures of the Maxillae

Dr. Le Fort classified 3

variants of fractures of themaxillae

Le Fort I Fracture

Le Fort II Fracture

Le Fort III Fracture

Le Fort Fracture

CLINICAL NOTES




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Le Fort I Fracture

-horizontal fracture of themaxillae

-passing superior to the

maxillary alveolar process

crossing the bony nasalseptum

Le Fort I Fracture

CLINICAL NOTES




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Le Fort II Fracture

-passes from theposterolateral parts of the

maxillary sinuses through

the infra-orbital foramina

lacrimals or ethmoids tobridge of nose

Le Fort II Fracture

CLINICAL NOTES




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-horizontal fracture

-passes through the superior

orbital fissures, ethmoid and

nasal bones, extending to the

greater wings of sphenoidand frontozygomatic sutures


CLINICAL NOTES




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U-shapedbone

alveolar process thatsupport mandibular teeth

consists of the body,

angle and ramus

Mandible

MANDIBLE


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CLINICAL NOTES


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CLINICAL NOTES

Fractures of the Mandible

fractures of the neck of the

mandible are transverse

fractures of the angle of

the mandible are usually

oblique

fractures of the body of

mandible pass through

socket of canine toothMandibular Fracture

CLINICAL NOTES

LATERAL ASPECT OF CRANIUM


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The lateral aspect consists of:

Temporal Fossa

Zygomatic Arch

Ext. Acoustic Opening

Mastoid Process

Infratemporal Fossa

Lateral aspects of maxillaand mandible

Lateral Aspect of Cranium



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bounded by:

-superiorly and posteriorly:

by the superior temporal line

and inferior temporal line

-anteriorly: by frontal and

zygomatic bones

-inferiorly by zygomatic arch

Temporal Fossa

TEMPORAL FOSSA



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formed by the union of

temporal process of

zygomatic bone and

zygomatic process oftemporal bone

Zygomatic Arch

ZYGOMATIC ARCH



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entrance to external

acoustic meatus or canal

External Acoustic Opening

EXTERNAL ACOUSTIC OPENING



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posteroinferior to the

external acoustic opening

anteromedial is a pointed

projection, the styloid

process

Mastoid Process and Styloid Process

MASTOID PROCESS



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inferior and deep to the

zygomatic arch and

mandible

posterior to maxilla

Infratemporal Fossa

INFRATEMPORAL FOSSA



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note: the pterion is an H-shaped

formation of sutures that unite the

frontal, parietal, greater wing of

sphenoid and temporal bones.

Pterion



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Fracture of the Pterion

hard blow to side of head

life threatening because it

ovelies anterior branches of

middle meningeal vessels

if untreated may lead to

middle meningeal artery

hemorrhage Pterion

CLINICAL NOTES


OCCIPITAL ASPECT OF CRANIUM


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the external occipital

protuberance is palpable

in the median plane

most prominent point of

the external occipital

protuberance is the Inion

External Occipital Protuberance

OCCIPITAL BONE



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the external occipital crestdescends from theprotuberance toward the foramen magnum

External Occipital Crest and Foramen Magnum

OCCIPITAL BONE



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the superior nuchal line

marks the superior limit

of neck and extends

laterally from each side

of the protuberance

the inferior nuchal line isless distinct

Superior Nuchal Line

OCCIPITAL BONE


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The superior aspect is

somewhat oval in form

and broadens posterolaterally

at the parietal eminences

Superior Aspect of Cranium



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Coronal suture-separates the frontal

and parietal bones

Sagittal suture-separates the parietal

bones

Lamdoid suture

-separates parietal andtemporal bones from

occipital bone

Sutures

CRANIAL SUTURES



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Bregma

-at junction of sagittal

and coronal sutures

Vertex-most superior pointof

the calvarianear the

midpoint of the sagittal

suture

Bregma and Vertex

CRANIOMETRIC POINTS



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Lambda

-at junction of lambdoid

and sagittal sutures

Lambda

CRANIOMETRIC POINTS



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Parietal foramen

-located posteriorly in the

parietal bone near the

sagittal suture

Emissary foramina

-transmit emissary veins

Parietal Foramen

PARIETAL LANDMARKS


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External Surface of Cranial Basealso known as the Basicranium

inferior portion of neurocranium

and viscerocranium minus the

mandible

External Surface of Cranial Base


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A. Incisive Foramen

posterior to central

incisor teeth

depression in the

midline of bony palate

into which the incisivecanals open

Incisive Fossa and Greater Palatine Foramina

HARD PALATE



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B.Greater Palatine Foramen

medial to 3rdmolar tooth

transmit -greater palatine

nerves and vessels

C. Lesser Palatine Foramen

Posterior to greaterpalatine foramen

Transmit-lesser palatine

nerves and vessels Incisive Fossa and Greater Palatine Foramina

HARD PALATE



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SU C O C S

two large openings superior

to the posterior edge of the

palate

posterior nasal aperture

separated from each other

by the vomer

Choanae

CHOANAE



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trapezoidal in shape

flat, unpaired bone

forms a major part of the

bony nasal septum

Vomer

VOMER


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the foramen magnum is

the large opening in the

basal part of the occipital

bone

Foramen Magnum

FORAMEN MAGNUM



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large protuberances on the

lateral parts of occipital bone

where the cranium articulates

with the vertebral column

Occipital Condyles

OCCIPITAL CONDYLE


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lies posterior to the base

of the styloid process

transmits the facial nerve

and stylomastoid artery

Stylomastoid Foramen

STYLOMASTOID FORAMEN


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formed by:

-frontal bone (anteriorly)

-ethmoid (middle)

-body and lesser wings of

sphenoid (posteriorly)

anterior and inferior partsof frontal lobe of brain occupy

this area

Anterior Cranial Fossa

ANTERIOR CRANIAL FOSSA



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A. Orbital Parts of the

Frontal Bone

the horizontal part of the

frontal bone forms the roofof the orbit and the floor of

the anterior cranial fossa

forms the greatest part ofthe anterior cranial fossa

surface show brain

markings of orbital gyri Frontal Bone as seen in theAnterior Cranial Fossa



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D. Crista Galli

thick, median ridge

posterior to foramen

cecum

projects superiorly from

the ethmoid bone

Latincocks combCrista Galli




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E. Cribriform plate of

the ethmoid

lie on each side of

the crista galli

the tiny foramina of

the cribriform plate

transmit the olfactorynerves (CN I) to the

olfactory bulbs of the

brainCribriform Plate of the Ethmoid

Cribriform

Plate of the

Ethmoid



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G. Lesser Wing of Sphenoid

sphenoidal crest separates the

anterior cranial fossa from the

middle cranial fossa laterally

sphenoidal limbus separates

the anterior cranial fossa fromthe middle cranial fossa

centrally




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butterfly-shaped

postero-inferior to theanterior cranial fossa

separated from the anterior

cranial fossa by the ff:

-spenoidal crests (laterally)

-sphenoidal limbus(centrally)Middle Cranial Fossa

MIDDLE CRANIAL FOSSA


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the lateral parts of the

fossa are formed by

Greater wings of the

sphenoidSquamous part of

the temporal bone

Petrous part of the

temporal bone




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A. Sella turcica

saddle-like bony

formation

surrounded by theanterior and posterior

clinoid processes

composed of 3 parts:Tuberculum sellae

Hypophysial fossa

Dorsum sellae Sella Turcica




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Tuberculum Sellae

-median elevation

-forms the posterior

boundary of the

prechiasmatic sulcus

and anterior boundary

of hypophysial fossa

Tuberculum Sella




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Hypophysial Fossa

-median depression in the

body of the sphenoid

-accomodates the pituitary

gland

Hypophysial Fossa




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Dorsum Sellae

-square plate of bone

-forms the posterior

boundary of the sellaturcica

-superolateral angles

make up the posterior

clinoid process

Dorsum Sellae




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A. Optic Canal

transmits the:

Optic nerve

Ophthalmic artery

Optic Canal




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B. Superior Orbital Fissure

-located between the

greater and lesser wing

of sphenoid-opens anteriorly in the

orbit

Supraorbital Fissure



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D. Foramen Ovale

-large foramen postero-lateral

to the foramen rotundum

-opens into the infratemporal

fossa

Foramen Ovale


-transmits:

Mandibular nerveAccessory meningeal artery



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E. Foramen Spinosum

-posterolateral to the

foramen ovale

-opens into the infratemporal fossa

Foramen Spinosum


-transmits:

Middle meningeal

artery and vein

Meningeal branch of

mandibular nerve


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G. Groove for the Greater andLesser Petrosal Nerve

-lie on the anterosuperior

surface of the petrous part oftemporal bone

-extends laterally from the

foramen lacerum

-contents:

Greater petrosal nerve

Petrosal br. of middle meningeal

artery




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largest and deepest

formed mostly by the

occipital bone

lodges the ff:

cerebellum

pons

medulla oblongata

Posterior Cranial Fossa

POSTERIOR CRANIAL FOSSA



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the dorsum sellae of the

sphenoid marks its anterior

boundary centrally

petrous and mastoid parts

of the temporal bones

contributes its anterolateralwalls.

Posterior Cranial Fossa




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A. Clivus

located in the center of

the anterior part of the

fossa leading to theforamen magnum

clivus




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B. Cerebellar Fossae

bilateral concave impressions

Cerebellar Fossae



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E. Jugular Foramen-located at the petrous

ridge of the temporal bone

Jugular Foramen


-transmits:

Meningeal br. of ascendingpharyngeal and occipital a.

Accessory nerve

Sigmoid sinus

Sup. bulb of int. jugular veinInferior petrosal sinus

Vagus nerve

Glossopharyngeal nerve



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E. Internal Acoustic Meatus

-located anterosuperior to

the jugular foramen

-transmits:Facial nerve

Vestibulocochlear nerve

Labyrinthine artery

Internal Acoustic Meatus




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F. Hypoglossal Canal

-located superior to the

anterolateral margin of

the foramen magnum-transmits:

Hypoglossal nerve

Hypoglossal Canal




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G. Foramen Magnum

major structures passing

through this large foramen

are:Dural veins

Ant./post. Spinal arteries

Medulla and MeningesSpinal accessory n.

Vertebral arteriesForamen Magnum


END OF CHAPTER 1


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TABLE OF CONTENTS


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MUSCLES OF FACIAL EXPRESSIONOCCIPITOFRONTALISORBICULARIS OCULI

CORRUGATOR SUPERCILLI

PROCERUSNASALIS

LEVATOR LABII SUPERIORIS ALAE QUE NASI

ORBICULARIS ORISLEVATOR LABII SUPERIORIS

TABLE OF CONTENTS


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MUSCLES OF FACIAL EXPRESSIONZYGOMATICUS MAJOR AND MINOR

LEVATOR ANGULI ORIS

RISORIUS

BUCCINATORDEPRESSOR ANGULI ORIS

DEPRESSOR LABII INFERIORIS

MENTALISPLATYSMA

OCCIPITOFRONTALIS


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flat digastric muscle

(+) frontal and occipitalbellies that share a

common tendon the

epicranial aponeurosis

OCCIPITOFRONTALIS (Frontal Belly)


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ORIGINepicranial aponeurosis

INSERTIONskin and subcutaneous

tissue of eyebrows and

forehead

OCCIPITOFRONTALIS (Frontal Belly)


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ACTION

elevates eyebrows

contraction of the frontal

belly protracts the scalp

transverse wrinkles across

the forehead

gives the face a surprised

look

OCCIPITOFRONTALIS (Occipital Belly)


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ORIGINlateral 2/3 of superior

nuchal line

INSERTION

epicranial aponeurosis

OCCIPITOFRONTALIS (Occipital Belly)


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ACTION

contraction of the occipital

belly retracts the scalp

the occipital belly with bonyattachments works as a

synergist with the frontal belly

retracts the scalp;increasing

effectiveness of frontal belly

ORBICULARIS OCULI (ORBITAL PART)


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concentric circles aroundorbital margin

closes eyelids and wrinklesforehead vertically

assists in the flow of lacrimal

fluid (tears)

ORBICULARIS OCULI (ORBITAL PART)


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ORIGINmedial orbital margin

medial palpebral ligament

lacrimal bone

INSERTION

skin around margin of orbit

superior and inferior tarsal

plates


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ORBICULARIS OCULI (PALPEBRAL PART)


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ORIGIN

medial palpebral ligament

INSERTIONlateral palpebral raphe

ORBICULARIS OCULI (PALPEBRAL PART)


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ACTIONcloses eyelids gently



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ORIGINMedial end of superciliary

arch

INSERTION

Skin superior to middle of

supraorbital margin and

superciliary arch



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ACTIONDraws eyebrow medially

and inferiorly creating

vertical wrinkles above

the nose

Demonstrate concern or

worry

PROCERUS PLUS TRANSVERSE PART OFNASALIS


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ORIGINFascia aponeurosis

covering nasal bone and

lateral nasal cartilage

INSERTION

Skin of inferior forehead

between eyebrows

PROCERUS PLUS TRANSVERSE PART OFNASALIS


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ACTIONDepresses medial end of

eyebrow

Wrinkles skin over dorsum

of nose

Convey disdain or dislike

ALAR PART OF NASALIS


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ORIGINMaxilla

INSERTIONAla of nose

ALAR PART OF NASALIS PLUS LEVATORLABII SUPERIORIS ALAEQUE NASII


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ORIGINFrontal process of maxilla

(inferomedial margin of

the orbit)

INSERTION

Major alar cartilage

ALAR PART OF NASALIS PLUS LEVATORLABII SUPERIORIS ALAEQUE NASII


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ACTIONDepresses ala laterally

dilating anterior nasal

aperture

Flaring nostrils during

anger or exertion

ORBICULARIS ORIS (ORAL SPHINCTER)


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Encircles the mouth

within the lips

Control entry and exitthrought oral fissure

Important during speech



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ORIGINMedial maxilla and

mandible

Deep surface of perioralskin

Angle of mouth

INSERTION

Mucous membrane of

lips



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ACTIONCloses oral fissure

Compresses andprotrudes lips (kissing)

Resists distention

(when blowing)

LEVATOR LABII SUPERIORIS


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ORIGINInfraorbital margin (maxilla)

INSERTIONSkin of upper lip

LEVATOR LABII SUPERIORIS


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ACTIONPart of dilators of mouth

Retract (elevate) / evertupper lip

Deepen nasolabial sulcus(sadness)

ZYGOMATICUS MINOR


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ORIGINAnterior aspect of zygomatic

bone

INSERTION

Skin of upper lip

ZYGOMATICUS MINOR


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ZYGOMATICUS MINOR


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Retract (elevate) or evertupper lip

Deepen the nasolabial sulcus

(showing sadness)

ZYGOMATICUS MAJOR


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ORIGINLateral aspect of zygomatic

bone

INSERTION

Angle of mouth

ZYGOMATICUS MAJOR


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ZYGOMATICUS MAJOR


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Elevates labial commissurebilaterally to smile(happiness)

Unilaterally to sneer(disdain)

BUCCINATOR (CHEEK MUSCLE)


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thin, flat rectangular

more closely related to

the buccal mucosa

fibers mingle medially

with orbicularis oris



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ORIGINMandible

Alveolar processes of

maxilla and mandible

Pterygomandibular raphe

INSERTION

Angle of mouth

Orbicularis oris



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ACTIONPresses cheeks against

molar teeth

Works with tongue to

keep food between

occlusal surfaces and

out of oral vestibule

Resists distention (whenblowing)

LEVATOR ANGULI ORIS


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ORIGINInfra-orbital maxilla

(canine fossa)

INSERTION

Angle of mouth

LEVATOR ANGULI ORIS


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Widens oral fissure(grinning or grimacing)

RISORIUS


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ORIGINParotid fascia

Buccal skin

INSERTION

Angle of mouth


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DEPRESSOR ANGULI ORIS


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ORIGINAnterolateral base of the

mandible

INSERTION

Angle of mouth

DEPRESSOR ANGULI ORIS


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ORIGINPlatysma

Anterolateral body

of mandible

INSERTION

Skin of lower lip



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ORIGINPlatysma

Anterolateral body

of mandible

INSERTION

Skin of lower lip



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Retracts (depresses)and/or everts lower lip

(pouting, sadness)

MENTALIS


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ORIGINBody of mandible

(anterior to roots of

inferior incisors)

INSERTION

Skin of chin (mentolabial

sulcus)

MENTALIS


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ACTIONElevates and protrudes lower

lip

Elevates skin of chin

(showing doubt)

PLATYSMA


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ORIGINSubcutaneous tissue of

infraclavicular and

supraclavicular regions

INSERTION

Base of mandible

Skin of cheek and lower

lipAngle of mouth

Orbicularis oris

PLATYSMA


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ACTIONDepresses mandible

against resistance

Tenses skin of inferior

face and neck

(tension and stress)

CLINICAL NOTES


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BELL PALSY

injury to facial nerve

(CN VII)

paralysis of facial

muscles on affectedside result to:

sad look when face is

relaxed

markedly contorted smile

weakened lips affect

speech

food accumulation

CLINICAL NOTES


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Thrombophlebitis of Facial Veindanger triangle of the face

-triangular area from upper lip to

bridge of nose

inflammation of facial vein with

secondary thrombus formation

and pieces of an infected clot

result from laceration of the noseby squeezing pimples

END OF CHAPTER 2


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CHAPTER 3


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MUSCLES OF THE NECK

TABLE OF CONTENTS


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CUTANEOUS AND SUPERFICIAL MUSCLES OF NECK

MUSCLES OF THE ANTERIOR CERVICAL REGION

PREVERTEBRAL MUSCLES

LATERAL VERTEBRAL MUSCLES


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CUTANEOUS AND SUPERFICIALMUSCLES OF THE NECK

PLATYSMASTERNOCLEIDOMASTOID

TRAPEZIUS

PLATYSMA


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(G. flat plate)

Broad thin sheet of

muscle

Covers the anterolateral

aspect of the neck

PLATYSMA


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Decussate over the chin

and blend with facial

muscles

Inferiorly the fibersdiverge

Deep to the platysmaare the extenal jugular

vein and cutaneous

nerves of the neck


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PLATYSMA


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INNERVATIONCervical branch of facial

nerve (CN VII)

note: refer to netter-facialnerve schema

PLATYSMA

ACTION


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ACTION

Draws corners of mouth

inferiorly and widens it

(grimace/sadness/fright)

PLATYSMA

ACTION


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ACTION

Draws the skin of neck

superiorly when teeth

are clenched producing

vertical skin ridges

PLATYSMA


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TESTING THE PLATYSMAThe platysma can be seen

as a sheet of muscle by

asking the patient to

clench the jaws firmly.

STERNOCLEIDOMASTOID


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Divides each side of theneck into anterior and

lateral cervical region

Broad strap-like muscle

Has two heads

a. Sternal Headb. Clavicular Head

STERNOCLEIDOMASTOID


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Has two headsa. Sternal Head

b. Clavicular Head

The two heads are

separate inferiorly by a

space called the lesser

supraclavicular fossa

STERNOCLEIDOMASTOID

SUPERIOR ATTACHMENT


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SUPERIOR ATTACHMENT

Lateral surface of mastoid

process of temporal bone

Lateral half of superior

nuchal line

STERNOCLEIDOMASTOID

INFERIOR ATTACHMENT


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INFERIOR ATTACHMENT

Sternal head:anterior surface of

manubrium of sternum

Clavicular head:

superior surface of medial

third of clavicle

STERNOCLEIDOMASTOID


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INNERVATIONSpinal accessory nerve

(CN XI, motor)

C2 and C3 nerves

(pain and proprioception)

note: refer to netter

-accessory nerve schema

STERNOCLEIDOMASTOID


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ACTIONUnilateral contraction:

tilts head to same side

and rotates it so face is

turned superiorly towardthe opposite side

STERNOCLEIDOMASTOID

ACTION


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ACTION

Bilateral contraction: Flexion

Flexes cervical vertebrae so

that the chin approaches the

manubrium

Flexion of the Neck

STERNOCLEIDOMASTOID

ACTION


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ACTION

Bilateral contraction: Flexion

Flexion also occur when

lifting the head off the

ground while lying supineprotruding the chin while

keeping the head level

Lifting head off the ground

STERNOCLEIDOMASTOID

ACTION


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ACTION

Bilateral contraction:Extension

(especially for posterior

fibers of the SCM)

Extends neck at atlanto-

occipital joints; elevating

the chin

STERNOCLEIDOMASTOID


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TESTING THE SCMThe head is turned to the

opposite side against

resistance (hand against

the chin)

Normal when muscle is

seen and palpated

L fl t t i l l

TRAPEZIUS


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Large flat triangular muscle

-muscle of neck

-muscle of pectoral girdle

-superficial muscle of back

Covers the posterolateral

aspect of the neck and thorax

Attaches the pectoral girdle to

the cranium and vertebral

column

TRAPEZIUS

ORIGIN


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ORIGIN

Medial third of

superior nuchal line

External occipital

protuberance

Nuchal ligament

Spinous process (C7-

T12)Lumbar and sacral

spinous processes


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TRAPEZIUS

INNERVATION


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INNERVATION

Spinal Accessory Nerve

(CN XI; motor)

C2 and C3 Nerves

(pain and proprioception)

note: refer to netter

-accessory nerve schema


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TRAPEZIUS


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ACTIONUnilateral contraction:

-produces lateral flexion

on the same side

Bilateral contraction:

-extends the neck

Lateral Flexion on same side

TRAPEZIUS


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TESTING THE TRAPEZIUSThe shoulder is shrugged

against resistance

Normal when the superior

border of the muscle is

seen and palpated

If the muscle is paralyzed

the shoulder droops


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SUPRAHYOID MUSCLES


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Superior to the hyoid and connect it to the cranium

These muscles constitute the substance of the

floor of the mouth

Support the hyoid in providing a base from which

the tongue functions

Elevate the hyoid and larynx in relation to

swallowing and tone production

MYLOHYOID


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ORIGINMylohyoid line of mandible

INSERTIONMylohyoid raphe and body

of hyoid

Note:refer to netter

-Mandible and Floor of Mouth

MYLOHYOID

INNERVATION


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Nerve to mylohyoid, a

branch of inferior alveolar

nerve (from mandibular

nerve, CN V3)

Note: refer to netter

-nerves of oral and pharyngeal

regions

MYLOHYOID


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ACTIONElevates the following during

swallowing and speaking:

Hyoid

Floor of mouth

Tongue

GENIOHYOID


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ORIGINInferior mental spine of

mandible

INSERTION

Body of hyoid


-tongue and mandible

GENIOHYOID

INNERVATION


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C1 via hypoglossal nerve


-Hypoglossal nerve schema

GENIOHYOID


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ACTIONPulls hyoid anterosuperiorly

Shortens floor of mouth

Widens pharynx

STYLOHYOID


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ORIGINStyloid process of the

temporal bone

INSERTION

Body of hyoid

STYLOHYOID


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INNERVATION

Stylohyoid branch of the

preparotid facial nerve


-Facial nerve schema

STYLOHYOID


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ACTIONElevates and retracts hyoid;

elongating the floor of the

mouth

Has two bellies joined by

DIGASTRIC


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Has two bellies joined by

an intermediate tendon

A. Anterior Digastric

B. Posterior Digastric

A fibrous sling connects

the intermediate tendon to

the body and greater hornof the hyoid

DIGASTRIC

ORIGIN


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Anterior Belly: digastricfossa of mandible

Posterior Belly: mastoid

notch of temporal bone

INSERTION

Intermediate tendon tobody and greater horn of

hyoid

DIGASTRIC


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INNERVATIONAnterior Belly: nerve to

mylohyoid, a branch of

inferior alveolar nerve

Posterior Belly: digastric

(preparotid) branch of

facial nerve

DIGASTRIC


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ACTIONWorking with infrahyoid muscles,

depresses mandible against

resistance

Elevates and steadies hyoid

during swallowing and speaking

MUSCLES OF THE ANTERIOR


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CERVICAL REGION

INFRAHYOID MUSCLESSTERNOHYOID

OMOHYOID

STERNOTHYROIDTHYROHYOID

INFRAHYOID MUSCLES


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Often called strap muscles because of their

ribbon like appearance

Anchor the hyoid, sternum, clavicle and scapula

Depress the hyoid during swallowing and speaking

Work with the suprahyoid muscles to steady thehyoid providing a firm base for the tongue

INFRAHYOID MUSCLES


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Arranged in two planes

A. Superficial Plane

-Sternohyoid

-OmohyoidB. Deep Plane

-sternothyroid

-thyrohyoid

STERNOHYOID


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ORIGINManubrium of sternum and

medial end of clavicle

INSERTION

Body of hyoid

STERNOHYOID

INNERVATION


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C1-C3 by a branch of

ansa cervicalis

Note: refer to netter-Hypoglossal nerve schema

to see the ansa cervicalis

STERNOHYOID


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ACTIONDepresses hyoid after

elevation during swallowing

OMOHYOID


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Has two bellies united byan intermediate tendon

A. Superior Belly

B. Inferior Belly

The fascial sling for the

intermediate tendon

connects to the clavicle

OMOHYOID


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ORIGINSuperior border of scapula

near suprascapular notch

INSERTION

Inferior border of hyoid

OMOHYOID

INNERVATION


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C1-C3 by a branch ofansa cervicalis


-Cervical plexus schema tosee the ansa cervicalis

OMOHYOID


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ACTIONDepresses, retracts and

steadies hyoid

STERNOTHYROID


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Wider than the sternohyoid

Covers the lateral lobes of

the thyroid gland


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STERNOTHYROID


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INNERVATIONC2 and C3 by a branch of

ansa cervicalis

STERNOTHYROID

ACTION


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ACTION

Depresses hyoid and larynx

THYROHYOID


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Appears to be thecontinuation of the

sternothyroid muscle

Runs superiorly from

the oblique line of the

thyroid cartilage to thehyoid

THYROHYOID

ORIGIN


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Oblique line of thyroid

cartilage

INSERTION

Inferior border of body

and greater horn of hyoid

THYROHYOID


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INNERVATION

C1(via hypoglossal nerve-CN XII)

Note: refer to netter-Hypoglossal nerve schema

THYROHYOID

ACTION


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Depresses hyoid

Elevates larynx



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LONGUS COLLILONGUS CAPITIS

RECTUS CAPITIS ANTERIOR

RECTUS CAPITIS LATERALISSPLENIUS CAPITIS

LEVATOR SCAPULAE

ANTERIOR SCALENE

MIDDLE SCALENE

POSTERIOR SCALENE



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Deep to prevertebral layer of deep cervical fascia

Can be grouped to either:

A. Anterior Vertebral Muscles

-Longus colli

-Longus capitis

-Rectus capitis anterior

-Anterior scalene

B. Lateral Vertebral Muscles

-Rectus capitis lateralis-Splenius capitis

-Levator scapulae

-Middle Scalene and Posterior Scalene

LONGUS COLLI

SUPERIOR ATTACHMENT


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anterior tubercle of C1

bodies of C1-C3

transverse processes of

C3-C6 vertebrae

INFERIOR ATTACHMENT

bodies of C5-T3


C3-C5 vertebrae

LONGUS COLLI


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INNERVATION

Anterior rami of C2-C6

spinal nerves


-cervical plexus in situ

LONGUS COLLI

ACTION


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Acting unilaterally:

Flexes the neck with

rotation (torsion) to

opposite side

LONGUS CAPITIS

SUPERIOR ATTACHMENT


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Basilar part of occipital

bone

INFERIOR ATTACHMENT

Anterior tubercles of C3-

C6 transverse processes

LONGUS CAPITIS

INNERVATION


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Anterior rami of C1-C3

spinal nerves


-Cervical plexus in situ

ACTION

Flex head

RECTUS CAPITIS ANTERIOR

SUPERIOR ATTACHMENT


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Base of cranium, anterior

to occipital condyle

INFERIOR ATTACHMENT

Anterior surface of lateral

mass of atlas C1 vertebra


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ANTERIOR SCALENE

SUPERIOR ATTACHMENT


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Transverse processes of

C3-C6 vertebrae

INFERIOR ATTACHMENT

1strib


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RECTUS CAPITIS LATERALIS

SUPERIOR ATTACHMENT


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jugular process of occipital

bone

INFERIOR ATTACHMENT

transverse process of atlas

(C1 vertebra)

RECTUS CAPITIS LATERALIS

INNERVATION


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Branches from loop

between C1 and C2

spinal nerves

ACTION

Flexes head and helps

stabilize it

SPLENIUS CAPITIS

SUPERIOR ATTACHMENT


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Inferior half of nuchal

ligament

spinous processes of

superior 6 thoracic vert.INFERIOR ATTACHMENT

lateral aspect of mastoid

processlateral third of superior

nuchal line

SPLENIUS CAPITIS


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ACTION

laterally flexes and rotates

head and neck to same side

acting bilaterally, extends

head and neck

LEVATOR SCAPULAE

SUPERIOR ATTACHMENT


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Posterior tubercle of

transverse processes

C2-C6 vertebrae

INFERIOR ATTACHMENT

Superior part of medial

border of scapula

LEVATOR SCAPULAE

INNERVATION


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Dorsal scapular nerve C5

and cervical spinal nerves

C3 and C4

ACTION

Downward rotation of

scapula and tilts its

glenoid cavity inferiorlyby rotating scapula

MIDDLE SCALENE

SUPERIOR ATTACHMENT


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posterior tubercles of

transverse processes

C5-C7 vertebrae

INFERIOR ATTACHMENT

Superior surface of 1strib;

posterior to groove forsubclavian artery

MIDDLE SCALENE

INNERVATION


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Anterior rami of cervical

spinal nerves

ACTIONFlexes neck laterally

Elevates 1st

rib duringforced inspiration

POSTERIOR SCALENE

SUPERIOR ATTACHMENT


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posterior tubercles of


C5-C7

INFERIOR ATTACHMENT

external border of 2ndrib

POSTERIOR SCALENE

INNERVATION


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Anterior rami of cervical

spinal nerves C7 and C8

ACTIONFlexes neck laterally

Elevates 2ndrib during

forced inspiration

REFERENCES

1. Clinically Oriented

Anatomy


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Anatomy

By Keith Moore

2. Clinical Anatomy by

RegionsBy Richard Snell, MD

3 Atlas of Human Anatomy

skull, muscles of face and neck final version

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