Surface Anatomy of the Neck Flashcards
Learning outcomes
After this lecture, time spent in the dissecting room, and further private study you should be able to:
- Describe the general structure of the neck as composed of vertical columns surrounded by fascial sheets with potential spaces between
- Describe the concept of the anterior and the posterior triangles of the neck, and their boundaries
- Describe the form and position of the common and internal carotid arteries and the internal jugular vein
- Describe the form and position of the external carotid artery, external jugular vein and anterior jugular vein
- Discuss the nerves, lymph nodes and muscles adjacent to the above vessels
- State the bony and cartilaginous landmarks used to locate and demonstrate the above structures on a living model or patient
Describe the general structure of the neck
Posteriorly there is the euro-musculo-skeletal column with prevertebral fascia
Anteriorly there is a visceral column with pretracheal and buccopharangeal fascia
In between there are potential spaces to allow for movement
On each side there is a carotid neuromuscular bundle with carotid sheath
Everything is surrounded by a layer (collar) of surrounding fascia
What are the fascial layers of the neck?
Superficially there is the investing (superficial) fascia
Pretrachial fascia
2x carotid sheath
prevertebral fascia
Where are some important potential spaces in the neck?
Retropharangeal space
Bounded by the buccopharyngeal fascia anteriorly and the alar fascia posteriorly (sometimes considered a part of prevertebral fascia, sometimes not).
And DANGER space
It is bounded at the top by the skull base, at the front by the alar fascia and behind by the prevertebral fascia. It comes to an end at the level of the diaphragm.
Why is the danger space called such a cool name?
The risk of an infection travelling from here to the thorax/mediastinum and its bilateral structure allows infection to spread to either side. It is dangerous
Also dental abscesses can spread into mediastinum
What does the “True” Retropharyngeal Space allow?
Movement, as do all potential spaces:
– Permits movement during swallowing of pharynx, oesophagus,
trachea and larynx
What are the potential retropharangeal abcesses?
– Nasopharynx, paranasal sinuses or middle ear infections
What are the two triangles of the neck?
Posterior triangle
Anterior triangle
What are the borders of the posterior triangle?
Anterior – posterior border of the SCM Posterior – anterior border of the trapezius muscle Inferior – middle 1/3 of the clavicle
What are the borders of the anterior triangle?
Superiorly – inferior border of the mandible Laterally – anterior border of SCM Medially – sagittal line down the midline of the neck
What is the clinical relevance of the triangles of the neck?
When looking for Neck Lumps
Location – Anterior triangle – Posterior triangle – Midline Size/Depth Pulsatile Solitary or multiple lumps Tenderness Heat/Inflammation Movement -Swallowing -Sticking out tongue
Name the big bony landmarks of the skull
Mastioid
Zygoma and external acoustic meatus
Angle of the mandible
Position of transverse process of the atlas between mastoid and angle of the mandible
How many horns does the hyoid bone have?
Two pairs, Lesser and Greater horns
Describe the thyroid cartilage
Largest cartilage of the laryngeal skeleton Two lamina, lesser and greater horns Laryngeal Prominence – Fusion of inferior 2/3 of two lamina – Adam’s Apple – prominent in males Articulates with cricoid cartilage – Rotation and gliding of thyroid cartilage – Change length/sound of vocal cords
What are the branches of the aorta? (sans coronary arteries)
Brachiocephalic trunk leading to right subclavian and right common carotid
Left common carotid
Left subclavian
Describe the brachiocephalic trunk
Largest branch of arch of aorta
Anteriorly covered by;
– Right sternohyoid and sternothyroid muscles
Passes superolaterally to the right and divides
– Right common carotid and right subclavian arteries -> posterior to the sternoclavicular joint
Describe the subclavian arteries
Passes Rib 1 on way to upper limb 3 parts, according to the anterior scalene muscle 1st part – Vertebral artery – Thyrocervical trunk – Internal thoracic artery 2nd part – Costocervical trunk 3rd part – Dorsal scapular artery Becomes the axillary artery
Describe the common carotid arteries
Bifurcates at the level of superior border of thyroid cartilage
– Internal carotid artery
– External carotid artery
Proximally covered by muscles
Distally exposed allowing palpation of pulse
– Normally internal carotid artery
Describe carotid bifurcation
Level of the superior border of the thyroid cartilage
External carotid artery
Internal carotid artery
– Dilatation of proximal internal carotid artery
Describe the carotid body and carotid sinus
Nerve innervation
– Afferent glossopharyngeal
• Carotid sinus nerve
– Efferent Vagus nerve
Carotid Sinus - Baroreceptor
– Reacts to change in arterial blood pressure
Carotid Body – Chemoreceptor
– Monitors the partial pressure of CO2
Describe the internal carotid artery
Covered by the carotid sheath
Carotid sheath
– Internal jugular – Internal carotid – Vagus nerve
Supplies intracranial structures
Describe the external carotid artery
Shitton of branches, look at a tube map for their path
Acronym: Some Anatomists Like Freaking Out Poor Medical Students
Superior thyroid artery Ascending pharyngeal artery Lingual artery Facial artery Occipital artery Posterior auricular artery Maxillary artery Superficial temporal artery
Describe venous drainage of the neck
Facial veins
– Superficial
– Deep
Cervical veins
– External jugular vein
– Anterior jugular vein
– Vertebral vein
Cranial veins – Cerebral veins – Dural venous sinuses – Diplopic veins – Emissary veins
Describe the cranial veins
Drained by – Dural venous sinuses • Superior sagittal sinus • Inferior sagittal sinus • Sinus rectus – Sigmoid sinus • Becomes internal jugular vein
The posterior compartment of the jugular foramen transmits the sigmoid sinus (becoming the internal jugular vein)
Describe the internal jugular vein
Drains intracranial structures, superficial parts of face and neck
Within the carotid sheath
– Vagus and internal carotid artery
Initially lies posterior to the internal carotid artery, moves laterally then anterior of the common carotid
Jugular Venous Pulse Wave is visible along the trajectory of the IJV
What is the internal jugular veins relationship with other structures?
Close to many very important structures!
Vagus
Phrenic nerve
Brachial plexus
What is the clinical relevance of the internal jugular vein?
Central Venous Access or Central Venous Catheterisation
Most commonly inserted in the internal jugular vein (sometimes subclavian)
Measure central venous pressure (CVP)
– Normal CVP is <8 cm H2O
Administration of fluids, medications
Complications
– Pneumothorax
– Puncture of subclavian artery
– Nerve injury
Note: Risk of air embolism if external jugular vein used
Describe the external jugular vein
Descends from the angle of the mandible to the middle of the clavicle Formed by; – Posterior division of the retromandibular vein – Posterior auricular vein
- Crosses the SCM obliquely, deep to the platysma, and enters the antero- inferior part of the posterior triange.
- Pierces the investing fascia at the posterior border of the SCM.
- Descends and terminates in the subclavian vein.
- Drains most of the scalp and side of the face.
Describe the anterior jugular vein
Inferior to the hyoid bone • Drains into external jugular or subclavian veins • Anterior jugular veins of both sides join • Jugular venous arch
Describe the nerves of the neck
Cutaneous branches of the cervical plexus
Erb's point – four cutaneous branches become superficial – Lesser occipital – Great auricular nerve – Transverse cervical – Supraclavicular
• Accessory nerve
– Motor control of
trapezius and SCM
– Passes across the posterior triangle
Describe the lymph nodes in the neck
- No lymph nodes in the scalp or face
* Except parotid/buccal region
