Head & Neck Flashcards
What are the 3 layers of Deep Cervical Fascia?
Investing, Pretracheal + Prevertebral
What is contained within the Investing layer of deep cervical fascia?
This is the most superficial layer surrounding the entire deep neck, it splits in two where it meets the trapezius and the sternocleidomastoid completely surrounding them
Whats contained in the Pretracheal layer of deep cervical fascia?
Situated anteriorly in the neck it spans the hyoid bone to where it blends into the pericardium. It contains the trachea, oesophagus, thyroid gland and infrahyoid muscles
Describe the prevertebral layer of deep cervical fascia
The prevertebral layer surrounds the vertebral column from the base of the skull to the endothoracic fascia of the ribcage at T3, it also extends laterally as the axillary sheath
What is contained within the Carotid Sheaths?
Common carotid artery, Internal Jugular Vein, Vagus nerve, Cervical Lymph nodes
What is the Retropharyngeal space (danger space) and why is it dangerous?
Potential space between the pretracheal and prevertebral fascial layers, it allows movement of structures in the neck while swallowing. There is a risk of mediastinitis which is due to the face that infections can track all the way down into the chest cavity, this is normal caused by upper respiratory tract infections
What is the Parapharyngeal space and why can it be dangerous?
Found parallel to the pharynx infections of this space can lead to damage to the carotids, infections don’t tend to track down as far as in the retropharyngeal space. Can be caused by very bad tonsillitis or poor dental hygiene.
Name the 4 Suprahyoid muscles and their innervation
Geniohyoid (hypoglossal) Mylohyoid (Mandibular) Digastric (Mandibular) Stylohyoid (Mandibular)
Name the 4 Infrahyoid muscles and their innervation
Sternohyoid (Ansa Cervicalis C1-C3) Omohyoid (Ansa Cervicalis C1-C3) Thyrohyoid (C1 on Hypoglossal nerve) Sternothyroid (Ansa Cervicalis C1-C3)
Name the 4 muscles of Mastication and their innervation
Masseter Temporalis Medial Pterygoid Lateral Pterygoid All innervated by the mandibular nerve
What are two muscles of the orbital group of muscles of facial expression and what are their actions?
Obicularis Oculi - closes eye Corrugator Supercilii - draws eyebrows together
What are the two parts of Obicularis Oculi and what is the risk of damage to the facial nerve?
Outer orbital and inner palpebral parts Patients with damage to facial nerve can’t close their eyes which can lead to exposure keratitis
Name two muscles of the nasal group of muscles of facial expression and name their actions
Nasalis - Transverse part compresses the nares and Alar part opens them Procerus - Pulls eyebrows downwards to wrinkle nose
Name two muscle son the oral group of muscles of facial expression and name their actions
Obicularis Oris - Purses the lips Buccinator - Pulls cheek inwards against the teeth preventing the build up of food in this area
Name the superior, lateral and medial boarder of the anterior triangle of the neck
Superior - Inferior boarder of mandible Lateral - Medial boarder of sternocleidomastoid Medial - Imaginary line down middle of neck
What are the contents of the anterior triangle of the neck?
Supra and infrahyoid muscles Common carotid bifurcates within the triangle Internal jugular vein Cranial nerves; Facial (VII), Glossopharyngeal (IX), Vagus (X), + Hypoglossal (XII)
What are the superior, lateral and inferior borders of the carotid triangle?
Superior - Posterior belly of digastric Lateral - Medial boarder of sternocleidomastoid Inferior - Superior belly of omohyoid
What are the contents of the carotid triangle?
Bifurcation of the common carotid Carotid sinus Internal jugular vein (JVP) Hypoglossal and vagus nerves
Name the anterior, posterior and inferior borders of the posterior triangle
Anterior - Posterior boarder of SCM Posterior - Anterior boarder of trapezius Inferior - Middle 1/3 of clavicle
What are the contents of the posterior triangle?
Inferior belly of omohyoid divides it into the occipital and subclavian triangles. External jugular vein Subclavian artery and vein Accessory nerve (CN XI) Cervical plexus Phrenic nerve (innervates diaphragm)
Which two structures can be found at the bifurcation of the external carotid artery?
Carotid Sinus Carotid Bodies
Name the 8 main arteries which arise from the external carotid
- Superior Thyroid - Lingual - Facial - Ascending Pharyngeal - Occipital - Posterior Auricular - Maxillary - Superficial Temporal
Which arteries supply the scalp?
Occipital Posterior Auricular Superficial Temporal Supraorbital + Supratrochlear of the Internal Carotid
What 3 reasons can help to cause heavy bleeding from scalp injuries?
- Walls of the arteries are tightly bound to underlying connective tissue preventing it from constricting to limit blood loss after laceration. 2. Numerous anastomoses form a densely vascularised area. 3. Deep lacerations can involve the epicranial aponeurosis which is worsened by the opposing pulls of the occipital and frontal muscles.
Where is the Middle Meningeal artery at risk of laceration?
Pterion
What is the laceration of the middle meningeal artery called? How would it present?
- Extradural haematoma - Increased intracranial pressure causing vomiting, seizures, bradycardia ect.
Why are you at higher risk of atheroma formation in the internal carotid artery? What can it lead to?
- Carotid sinus causes turbulent flow - Can lead to TIA’s and Strokes
Where does the internal carotid artery enter the skull?
Through the carotid canal in the petrous part of the temporal bone
Describe the path of the Vertebral arteries. What do they give rise to?
Arise from subclavian arteries and ascend up the posterior side of the neck through the foramen transversarium of cervical vertebrae. Give rise to the basilar arteries which supply the brain.
Which 4 arteries arise from the thyrocervical trunk?
- Suprascapular 2. Transverse Cervical 3. Inferior Thyroid 4. Ascending Cervical
Where do you find the dural venous sinuses? Where do they collect venous blood from?
- Between the periosteal and meningeal layers of dura matter. - Collect blood from the brain, skull and scalp.
How does blood pass from the scalp to the dural venous sinuses? Why can this be dangerous?
Through emissary veins which can provide a path of infection from the scalp to the meninges.
From where does the internal jugular vein arise and leave the skull?
Continues from the sigmoid sinus leaving the skull through the jugular foramina.
Which veins of the face can provide a route for infection into the skull? And why?
Superior and inferior ophthalmic veins and the facial vein are all valveless allowing easy flow between them and the cavernous sinus.
Where do the deep facial veins drain?
Pterygoid venous plexus