triangles of the neck Flashcards
what are the origin and insertion points of platysma
Origin: skin & fascia of supra& infraclavicular regions
Insertion: lower border of the mandible & skin of lower lip
what is the action of the platysma
Action: depress the mandible and angle of mouth & tense the skin of neck
what is the nerve supply of the platysma
Nerve supply: cervical branch of facial nerve
what are the boundries of the anterior triangle of the neck
anterior- middle line of neck
posterior-anterior border of sterno - mastoid.
Base :
Superiorly.
Lower border of the mandible & a line extends to the mastoid process.
Apex :
Inferiorly.
Suprasternal notch.
inside the anterior triangle of the neck there are 3 and half more triangles, what are their names
Muscular.
Carotid.
Digastric.
½ submental.
what are the boundries of the carotid triangle
Posteriorly : upper part of sterno - mastoid.
Antero - inferiorly: superior belly of the omohyoid muscle muscle.
Antero - superiorly: posterior belly of the digastric muscle & stylohyoid muscles.
the floor of the carotid triangle has an anterior and posterior part what are they
Anterior part is formed by: Hyoglossus (above) & Thyro - hyoid (below) the hyoid bone. Posterior part is formed by : The middle constrictor (above) & The inferior constrictor (below) the hyoid bone.
what vessels are contained in the carotid triangle
- upper part of carotid artery
- internal and external carotid artery
- internal jugular vein
what nerves are in the carotid triangle
- Hypoglossal nerve.
- Vagus nerve.
- Spinal accessory nerve.
- Ansa cervicalis (C1, 2,3).
- Sympathetic chain
what are the boundries of the digastric triangle?
Anteroinferiorly: anterior belly of digastric.
Poster inferiorly: posterior belly of the digastric + stylohyoid.
Above: the base of the mandible and a line drawn from mandibular angle to the mastoid process.
Floor: formed by hyoglossus muscle covered partially by the mylohyoid muscle
what is the origin and insertion points of the myelohyoid muscle
Origin: myelo- hyoid line
Insertion: hyoid bone
what is the action of the myelohyoid muscle
Action: elevation of floor of mouth & hyoid bone especially in swallowing and speech
what is the nerve supply to the myelohoid muscle
Nerve supply: mandibular nerve
what is the origin of the digastric muscle, the anterior and posterior belly
anterior belly > digastric fossa
posterior belly > mastoid notch
what is the action of the digastric muscle
Action: raising hyoid & opening the mouth.
what is the nerve supply of the anterior and posterior belly of the digastric muscle
anterior belly > mandibular nerve
posterior belly > facial nerve.
what glands and vessels are contained in the digastric triangle
Submandibular gland.
Submandibular lymph node.
Parotid gland.
Facial artery & vein.
External carotid artery.
what are the boundries of the submental triangle
Base: hyoid bone.
Apex: the chin.
On either side: the anterior belly of the digastric.
Floor: mylohyoid muscle.
which 4 infra-hyoid muscles are contained in the muscular triangle
superficial:
- sternohyoid
- omohyoid
deep:
- sternothyroid
- thyrohyoid
what actions does the muscular triangle perform
step 1 of swallowing:
thyrohyoid closes laryngeal inlet
step 2 of swallowing:
sternohyoid/omohyoid/sternothyroid
depress larynx to open larnygeal inlet
which nerves supply the muscular triangle
All are supplied by ansa cervicalis except thyrohyoid which is supplied by the nerve to thyrohyoid
what are the boundries of the posterior triangle of the neck
Anteriorly : the posterior border of the sterno - mastoid muscle.
Posteriorly : the anterior border of the trapezius muscle.
Base : the intermediate 1/3 of the clavicle.
Apex : formed by the meeting of sternomastoid and trapezius muscles (at the superior nuchal line).
what is the roof of the posterior triangle made up of
Skin.
Superficial fascia (containing the platysma).
The investing layer of the deep cervical fascia.
what is the floor of the posterior triangle made up of
Floor : formed by muscles from below upwards are Scalenus medius. Levator scapulae. Splenius capitis. A small part of semispinalis capitis.
what nerves are contained in the posterior triangle
- spinal accesory nerve(c1-c5 spinal)
- 4 cutaneous branches of cervical plexus
1. lesser occipital nerve
2. great auricular nerve
3. transverse cervical nerve
4. supraclavicular nerves
-1st and 2nd stages of brachial plexus
parslysis of the levator scapulae and trapezius muscle indicates injury to which nerve
the spinal accessory nerve
what vessels are contained in the posterior triangle
- The 3rd part of occipital artery
- The 3rd part of the subclavian artery
- Transverse Cervical artery.
- Supra - scapular artery.
- Subclavian V
which muscles are found in the posterior triangle
- Inferior belly of omohyoid.
- sternocleidomastoid
what is the origin of the sternocleidomastoid muscle
Sternal head : from the front of the manubrium sterni.
Clavicular head : from the the medial 1/3 of the clavicle.
what is the insertion point of the sternocleidomastoid muscle
Lateral surface of the mastoid process.
The lateral 1/2 of the superior nuchal line.
which nerve supplies the sternocleidomastoid muscle
Spinal accessory nerve.
what actions does the sternocleidomastoid muscle perform
Acting alone :
It flexes the head to its own side & so the face is turned to the opposite side.
Acting together :
Flex the neck forwards.
Assist in deep inspiration (through elevation of clavicle & sternum).
