Triangles of the neck Flashcards
What does the hyoid bone lie between
Manubrium of sternum and the mandible
What attachments does the hyoid have
Only muscular attachments
What function does the hyoid bone have
Serves as an attachment for anterior neck muscles and a prop to keep the airway open
Where does the subcutaneous tissue of the neck lie
Between the dermis of the skin and the investing layer of deep cervical fascia
Where is the platysma contained
Superficial fascia (subcutaneous tissue of the neck)
Where does the platysma arise from and where does it go
Arises in subcutaneous tissue covering superior parts of the deltoid and pectorals major muscles and sweeps over the clavicle to the inferior border of the mandible
What are the three fascial layers that the deep cervical fascia consists of
- INvesting
- Pretracheal
- Prevertebral
What is the purpose of the three fascial layers
Provide slipperiness that allow structures in the neck to move and pass over one another without difficulty.
Also allows separation of tissues during surgery
What is the outermost deep cervical fascia called
Investing layer
What does the investing layer split into two to surround
Sternocleidomastoid and the trapezius muscles
What are the attachments of the investing layer of the deep cervical fascia superiorly
- Superior nuchal line of the occipital bone
- MAstoid processes of the temporal bones
- zygomatic arches
- Inferior border of the mandible
- HYoid bone
- Spinous process of the cervical vertebrae
Inferiorly, what does the investing layer of deep cervical fascia attach to
- Manubrium of the sternum
- Clavicles
- Spines of the sternum
What is the investing layer of the deep cervical fascia like in relation to the manubrium
Fascia remains divided into two layers that enclose the SCM just above the manubrium and so one layer attaches to the anterior and one to the posterior surface of the manubrium. Suprasternal space lies between these layers
What does the suprasternal s[ace contain
- INferior ends of the anterior jugular veins
- Jugular venous arch
- fat
- LYmph nodes
What does the pretracheal layer of deep cervical fascia extend down to
Extends inferiorly from the hyoid bone into the thorax where it blends with fibrous pericardium
What is the pretracheal layer continuous with
Carotid sheaths on both sides of it
What does the carotid sheath contain
- Common and internal carotid arteries
- Internal jugular vein
- VAgus nerve
- Some deep cervical lymph nodes
- carotid sinus sheaths
- Sympathetic nerve fibres (carotid pre-arterial plexuses)
What space in the neck is a major pathway for the spread of infection in the neck
Retropharyngeal space
What does the retropharyngeal space do
Permits movement of the pharynx, oesophagus, larynx and trachea during swallowing
What is the platysma innervated by
Fascial nerve 7
What regions of the neck does the SCM divide
Divides each side of the neck into anterior and lateral cervical regions
What are the two heads of the SCM
Sternal head
Clavicular head
What are the two heads of the SCM separated by
Lesser supraclavicular fossa
What are the nerves of the lateral cervical region
- Spinal accessory nerve 11
- Roots of brachial plexus
- Suprascapular nerve
- CErvical plexus
Where does the spinal accessory nerve 11 pass
Deep to the SCM where it supplies it and then enters the lateral cervical region
Where does the cranial nerve 11 disappears
deep into anterior border of the trapezius at the junction of its superior two thirds with its inferior one third, then enters the muscle
Where do the roots of the brachial plexus appear
Between the anterior and middle scalene muscles
What does the supra scapular nerve arise from
Superior trunk of the brachial plexus
Where does the suprascapular nerve run
Across the lateral cervical region to supply the supraspinatus and infraspinatus muscles on the posterior aspect of the scapula
What are the ansa cervicalis part of
Cervical plexus
Where does the lesser occipital nerve arise from
C2
What does the lesser occipital nerve supply
Skin of the neck and scalp postosuperior to the auricle
Where does the great auricular nerve arise from
C3 and C2
What does the great auricular nerve supply
Skin and sheath over the gland, the posterior aspect of the auricle and the area of skin overlying the angle of mandible to the mastoid process
Where does the transverse cervical nerve arise from
C2 and C3
What does the transverse cervical nerve supply
Skin covering the anterior cervical region
Where does the transverse cervical nerve go
Curves around the middle of the posterior border of the SCM and passes anteriorly and horizontally across it, deep to the external jugular vein and platysma
Where do the supraclavicular nerves originate from
C3 and C4
Where do the supraclavicular nerves emerge from
Beneath the SCM
Where fo the supraclavicular nerves descend in
POsterior triangle of the neck beneath the platysma and the deep cervical fascia
Where does the phrenic nerve originate from
C4
What do the phrenic nerves supply in the thorax
Mediastinal pleura and the pericardium and the diaphragm
What do the phrenic nerves lie anterior to
Subclavian arteries
What do the phrenic nerves lie posterior to
Subclavian veins
What does the phrenic nerve receive contributions from
C3 and C5
What is the contribution from C5 to the phrenic nerve called
Accessory phrenic nerve
Where does the external jugular vein start
Near angle of mandible
What is the course of the external jugular vein
- Starts near angle of mandible
- Crosses the SCM obliquely deep to the platysma
- Pierces the investing layer of deep cervical fascia, which forms the roof of this region
Where does the external jugular vein terminate
Subclavian vein
What does the subclavian vein join and what does this become
IJV to form the brachiocephalic vein posterior to the medial end of the clavicle
What is the innervation of the platysma
Facial nerve 7
What is the SCM innervated by
- Spinal accessory nerve
- C2 and C3 nerves
What are the triangles in the anterior triangle
- Submandibular triangle
- Submental triangle
- Carotid triangle
- Muscular triangle
Superior attachments of SCM
- LAteral surface if mastoid process of temporal bone
- Lateral half of superior nuchal line
Inferior attachments of SCM
Sternal head- Anterior surface of the manubrium of sternum
Clavicular head- Superior surface of medial third of clavicle
What are the 4 suprahyoid muscles
- Mylohyoid
- Geniohyoid
- Stylohyoid
- Digastric muscles
Functions of suprahyoid muscles
Supports the hyoid bone in providing a base from which the tongue functions and in elevating the hyoid and larynx in relation to swallowing and tone production
What does each digastric muscle have
Anterior and posterior bellies joined by an intermediate tendon to slide anteriorly and posteriorly as it connects this tendon to the body and greater horn of the hyoid bone
What is the purpose of the infrahyoid muscles
Anchor the hyoid, sternum, clavicle and scapula and depress the hyoid and larynx during swallowing and speaking
What are the two planes of infrahyoid muscles
SUperficial plane
Deep plane
What is the superficial plane of the infrahyoid muscles made of
Sternohyoid and omohyoid
What is the deep plane of the infrahyoid muscles composed of
Sternothyroid and thyrohyoid
What is the structure of the omohyoid
HAs two bellies united by an intermediate tendon that is connected to the clavicle by a fascial sling
Where do the sternothyroid and sternohyoid lie in relation to each other
Sternothyroid lies under the sternohyoid
