triangles of the neck

Question 1

what are the origin and insertion points of platysma

Answer 1

Origin: skin & fascia of supra& infraclavicular regions
Insertion: lower border of the mandible & skin of lower lip

Question 2

what is the action of the platysma

Answer 2

Action: depress the mandible and angle of mouth & tense the skin of neck

Question 3

what is the nerve supply of the platysma

Answer 3

Nerve supply: cervical branch of facial nerve

Question 4

what are the boundries of the anterior triangle of the neck

Answer 4

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.

Question 5

inside the anterior triangle of the neck there are 3 and half more triangles, what are their names

Answer 5

Muscular.
Carotid.
Digastric.
½ submental.

Question 6

what are the boundries of the carotid triangle

Answer 6

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.

Question 7

the floor of the carotid triangle has an anterior and posterior part what are they

Answer 7

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.

Question 8

what vessels are contained in the carotid triangle

Answer 8

• upper part of carotid artery
• internal and external carotid artery
• internal jugular vein

Question 9

what nerves are in the carotid triangle

Answer 9

• Hypoglossal nerve.
• Vagus nerve.
• Spinal accessory nerve.
• Ansa cervicalis (C1, 2,3).
• Sympathetic chain

Question 10

what are the boundries of the digastric triangle?

Answer 10

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

Question 11

what is the origin and insertion points of the myelohyoid muscle

Answer 11

Origin: myelo- hyoid line
Insertion: hyoid bone

Question 12

what is the action of the myelohyoid muscle

Answer 12

Action: elevation of floor of mouth & hyoid bone especially in swallowing and speech

Question 13

what is the nerve supply to the myelohoid muscle

Answer 13

Nerve supply: mandibular nerve

Question 14

what is the origin of the digastric muscle, the anterior and posterior belly

Answer 14

anterior belly > digastric fossa

posterior belly > mastoid notch

Question 15

what is the action of the digastric muscle

Answer 15

Action: raising hyoid & opening the mouth.

Question 16

what is the nerve supply of the anterior and posterior belly of the digastric muscle

Answer 16

anterior belly > mandibular nerve

posterior belly > facial nerve.

Question 17

what glands and vessels are contained in the digastric triangle

Answer 17

Submandibular gland.
Submandibular lymph node.
Parotid gland.

Facial artery & vein.
External carotid artery.

Question 18

what are the boundries of the submental triangle

Answer 18

Base: hyoid bone.
Apex: the chin.
On either side: the anterior belly of the digastric.
Floor: mylohyoid muscle.

Question 19

which 4 infra-hyoid muscles are contained in the muscular triangle

Answer 19

superficial:
- sternohyoid
- omohyoid

deep:

• sternothyroid
• thyrohyoid

Question 20

what actions does the muscular triangle perform

Answer 20

step 1 of swallowing:
thyrohyoid closes laryngeal inlet

step 2 of swallowing:
sternohyoid/omohyoid/sternothyroid
depress larynx to open larnygeal inlet

Question 21

which nerves supply the muscular triangle

Answer 21

All are supplied by ansa cervicalis except thyrohyoid which is supplied by the nerve to thyrohyoid

Question 22

what are the boundries of the posterior triangle of the neck

Answer 22

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).

Question 23

what is the roof of the posterior triangle made up of

Answer 23

Skin.
Superficial fascia (containing the platysma).
The investing layer of the deep cervical fascia.

Question 24

what is the floor of the posterior triangle made up of

Answer 24

Floor : formed by muscles from below upwards are 
Scalenus medius.
Levator scapulae.
Splenius capitis. 
A small part of semispinalis capitis.

Question 25

what nerves are contained in the posterior triangle

Answer 25

- 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

Question 26

parslysis of the levator scapulae and trapezius muscle indicates injury to which nerve

Answer 26

the spinal accessory nerve

Question 27

what vessels are contained in the posterior triangle

Answer 27

- The 3rd part of occipital artery - The 3rd part of the subclavian artery - Transverse Cervical artery. - Supra - scapular artery. - Subclavian V

Question 28

which muscles are found in the posterior triangle

Answer 28

- Inferior belly of omohyoid. | - sternocleidomastoid

Question 29

what is the origin of the sternocleidomastoid muscle

Answer 29

Sternal head : from the front of the manubrium sterni. Clavicular head : from the the medial 1/3 of the clavicle.

Question 30

what is the insertion point of the sternocleidomastoid muscle

Answer 30

Lateral surface of the mastoid process. | The lateral 1/2 of the superior nuchal line.

Question 31

which nerve supplies the sternocleidomastoid muscle

Answer 31

Spinal accessory nerve.

Question 32

what actions does the sternocleidomastoid muscle perform

Answer 32

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).