neck 1

what divides the neck into 2 large triangles

sternocleidomastoid muscle

Anterior triangle

the area anterior to the SCM and below the inferior border of the mandible

Posterior triangle

area posterior to the SCM and is limited posteriorly by the trapezius muscle

Subdivisions of anterior triangle

– Digastric

– Submental

– Carotid

– Muscular

Subdivisions of posterior triangle

* occipital
* supraclavicular

Origin of sternocleidomastoid muscle

sternal head: manubrium sterni

clavicular head: medial 2/3 of clavicle

insertion of sternocleidomastoid muscle

mastoid process of temporal bone and lateral half of superior nuchal line

action of sternocleidomastoid muscle

bilaterally flexes the neck, single rotates the head to the opposite side and flexes laterally to the same side

nerve supply of sternocleidomastoid

spinal accessory nerve of the same side

parts of trapezius muscle

* descending


* transverse
* ascending

origin of trapezius

* external occipital protuberance
* medial half of superior nuchal line
* ligamentum nuchae
* lower cervical spine
* all the thoracic spines

insertion of trapezius

fibers originating from head insert into lateral third of clavicle, remaining fibers insert into acromion process and spine

action of trapezius

contract to rotate and elevate the scapula, while the cervical portion can act. ilaterally to extend the head and can act singly to rotate the head and face to the opposite side

nerve supply of trapezius

spinal accessory nerve

muscles of the anterior triangle of the neck

infrahyoid and suprahyoid muscles

infrahyoid muscles

• omohyoid

• sternohyoid

• thyrohyoid

• sternothyroid

omohyoid muscle origin

inferior belly: superior border of scapula

superior belly: intermediate tendon

omohyoid insertion

inferior belly: intermediate tendon

superior belly: lower border of body of hyoid bone

action of omohyoid

depresses hyoid bone and larynx

nerve supply of omohyoid

ansa cervicalis

origin of sternohyoid muscle

manubrium of sternum posteriorly and the sternal end of the clavicle

insertion of sternohyoid muscle

lower border of body of hyoid bone

action of sternohyoid

depresses hyoid bone and larynx

sternohyoid nerve supply

ansa cervicalis

sternothyroid origin

manubrium of sternum posteriorly

insertion of sternothyroid

oblique line of thyroid cartilage

action of sternothyroid

depresses the larynx

nerve supply of sternothyroid

ansa cervicalis

origin of thyrohyoid muscle

oblique line of thyroid cartilage

insertion of thyrohyoid muscle

body and greater horn of hyoid

action of thyrohyoid

depresses hyoid bone

nerve supply of thyrohyoid bone

thyrohyoid branch of hypoglossal nerve

suprahyoid muscles

* stylohyoid
* posterior belly of digastric muscle
* anterior belly of digastric belly
* mylohyoid
* geniohyoid

stylohyoid origin

styloid process

stylohyoid insertion

body of hyoid bone

action of stylohyoid

elevates hyoid bone

nerve supply of stylohyoid

facial nerve

posterior belly of digastric muscle origin

digastric notch of temporal bone at base of skull

insertion of posterior belly of digastric muscle

intermediate tendon

action of posterior belly of digastric muscle

elevates hyoid bone

nerve supply of posterior belly of digastric muscle

facial nerve

anterior belly of digastric muscle origin

intermediate tendon

anterior belly of digastric muscle insertion

digastric fossa of mandible

anterior belly of digastric muscle action

elevates the hyoid bone

nerve supply of anterior belly of digastric muscle

nerve to mylohyoid

mylohyoid origin

mylohyoid line on medial aspect of mandibular body

mylohyoid insertion

median raphe and body of hyoid

action of mylohyoid

elevates hyoid bone, base of tongue and floor of the mouth

nerve supply of mylohyoid line

nerve to the mylohyoid muscle

geniohyoid origin

genial tubercle of mandible

insertion of geniohyoid

body of hyoid

action of geniohyoid

elevates hyoid bone, base of the tongue and floor of the mouth

nerve supply of geniohyoid muscle

c1 via hypoglossal nerve

anterior boundary of anterior triangle

median line of neck

posterior boundary of anterior triangle

anterior border of the sternocleidomastoid muscle

superior boundary of anterior triangle

inferior border of mandible

inferior boundary of anterior triangle

suprasternal notch at meeting point of anterior border of scm and anterior midline

roof of anterior triangle

* skin
* superficial fascia
* platysma
* investing layer of deep cervical fascia

superior boundary of digastric triangle

lower border of mandible

anterior boundary of digastric triangle

anterior belly of digastric

posterior boundary of digastric triangle

posterior belly of digastric muscle

floor of digastric triangle

* mylohyoid muscle


* hyoglossus muscle
* middle constrictor muscle of pharynx

roof of digastric triangle

* skin
* superficial fascia
* platysma
* investing layer of deep cervical fascia

glands found in digastric triangle

submandibular and inferior portion of parotid

lymph nodes found in digastric triangle

submandibular

arteries found in digastric triangle

facial and submental

veins found in digastric triangle

facial and submental

nerves found in digastric triangle

glossopharyngeal, marginal mandibular of facial anf hypoglossal

right and left boundary of submental triangle

anterior belly of digastric of each side

base of submental triangle

body of hyoid bone

apex of submental triangle

chin or symphysis menti

floor of submental triangle

mylohyoid muscles

roof of submental triangle

* skin
* superficial fascia
* platysma
* investing layer of deep cervical fascia

contents of submental triangle

* submental lymph nodes
* submental veins
* anterior jugular veins

superior boundary of carotid triangle

posterior belly of digastric

inferior boundary of carotid triangle

superior belly of omohyoid muscle

posterior boundary of carotid triangle

anterior border of scm

floor of carotid triangle

* thyrohyoid muscle
* hyoglossus muscle
* middle constrictor muscle of pharynx
* inferior constrictor of pharynx

organs in carotid triangle

larynx and lower part of pharynx

arteries in carotid triangle

• common carotid artery

• ascending pharyngeal

• superior thyroid

• lingual

• facial

• occipital

veins found in carotid triangle

• internal jugular

• superior thyroid

• lingual

• common facial

• occipital

• ascending pharyngeal

nerves found in carotid triangle

* vagus


* accessory
* hypoglossal
* superior root of ansa cervicalis
* external and internal laryngeal \n

lymph nodes found in carotid triangle

deep cervical

carotid triangle provides a good view of all vessels and nerves present in it only when

sternocleidomastoid is retracted slightly backwards

anterior boundary of muscular triangle

by the median line of the neck from the hyoid bone to the sternum. (jugular Notch)

inferoposterior boundary of muscular triangle

by the anterior margin of sternocleidomastoid muscle

posterosuperior boundary of muscular triangle

by the superior belly of omohyoid

floor of muscular triangle

sternohyoid and sternothyroid

organs in muscular triangle

* Thyroid
* parathyroid glands
* trachea
* larynx
* pharynx
* esophagus
* lymph nodes

Arteries in muscular triangle

superior thyroid

veins in muscular triangle

* inferior thyroid
* anterior jugular

nerves in muscular triangle

ansa cervicalis

thyroid gland is found in

the muscular triangle, on either side of larynx and trachea

thyroid gland secretes

T3, T4 and calcitonin

thyroid gland consists of

2 lateral lobes connected by isthmus

lateral lobes of thyroid lie at

lower 1/3 of thyroid cartilage

base of thyroid lies at

5th or 6th tracheal rings

isthmus connects lateral lobes at

2nd or 3rd tracheal rings

what is a pyramidal lobe

remnant of thyroglossal duct extending superiorly from isthmus slightly left of midline

arteries of thyroid

* superior thyroid artery 1st branch of external carotid artery
* inferior thyroid artery from thyrocervical trunk