General Organisation Flashcards
How many bones are there in the skull
Skull – 22 individual bones
How can the skull be divided into two parts?
Neurocranium – part of the skull where the brain is kept
Viscerocranium – everything else, including the jaw and face
What visceral structure are located in the anterior portion of the neck that are visible and palpable?
Thyroid gland located at the base of the neck, above this are some cartilages; as we ascend these are the cricoid cartilage and the thyroid cartilage and then the hyoid bone above this.
What is the purpose of the cartilages in the neck?
The cartilages protect and support the underlying larynx.
What are infrahyoid muscles and suprahyoid muscles?
A series of strap like muscles attach to the hyoid bone running either superiorly or inferiorly. Muscles that run inferiorly from the hyoid are called infrahyoid muscles. These muscles are located anteriorly to the cartilages and thyroid gland.
Describe the Platysma
Platysma – . Innervated by the facial nerve VII and arises as a broad sheet that is very superficial within the superficial fascia. It overlies the sternocleidomastoid. It acts to draw the corners of the mouth inferiorly and skin of the neck superiorly if teeth clenched.
Describe the Sternocleidomastoid
innervated by the accessory nerve XI and arises from the mastoid bone inserting into the clavicle and sternum. Deep to platysma but visible. Its action is to laterally flex the neck or nod the head depending whether but are contracted or just one. This articulation takes place at the atlanto-occipital joint.
Describe the Trapezius
– is innervated by the accessory nerve XI and arises from the back of the skull, nuchal ligament and spinous process of vertebrae and inserts onto the lateral 1/3 of the clavicle, acromion and spine of the scapula. It acts to elevate and rotate the scapula e.g. shoulder shrugging.
How do you test the integrity of the facial and accessory muscles
BY testing the movement on platysma and sternocleidomastoid
What are the borders of the anterior triangle?
The anterior triangle – superior margin is the inferior margin of the mandible; anterior/medial border is the midline of the neck and the posterior/lateral border is the anterior margin of the sternocleidomastoid.
What are the borders of the posterior triangle?
The posterior triangle – posterior margin is the anterior margin of the trapezius; the inferior margin is the middle 1/3 of the clavicle and the anterior margin is the posterior margin of the sternocleidomastoid. Floor is formed by prevertebral fascia and the whole triangle is covered by the investing fascia.
What is the purpose of the fascial layers in the neck
It forms natural planes, allows for ease of movement over each other such as swallowing and contains the spread of infections to one area.
What are the 5 main layers of fascia in the neck and what type of connective tissue forms them
Superficial cervical fascia – loose connective tissue includes fat, platysma, lymph nodes, and blood vessels.
Deep cervical fascia – dense connective tissue involves 4 layers: investing layer, carotid sheath, pre-tracheal fascia and pre-visceral fascia.
What does the investing layer of fascia contain?
All structures in the neck except the platysma muscle
What is cotnained within the pre-vertebral fascia?
Vertebrae, pre-veretebral muscles and para-vertebral muscles.
What is contained within the carotid sheaths?
Carotid artery (sometimes internal carotid), Internal jugular vein, deep cervical lymph nodes and the vagus nerve.
What is contained within the pre tracheal fascia
Thyroid, oesophagus, trachea and infrahyoid muscles
How is the pre tracheal fascia divided?
Infra hyoid muscles are located within the muscular compartment of the pre-tracheal sheath in front of the trachea. The trachea, oesophagus and trachea lie within the visceral compartment of pre-tracheal fascia.
What is the buccopharyngeal fascia?
Another name for the posterior portion of the pre tracheal fascia
How does the anterior and posterior portions of the pre-tracheal fascia differ?
Anterior portion of pre-tracheal fascia only continues until the hyoid bone whilst the buccopharyngeal fascia continues the length of the neck.
Where is the retropharyngeal space?
Space between the buccopharyngeal fascia and the pre vertebral fascia
What is the clinical significance of the retropharyngeal space?
How is the retropharygneal space subdivided?
If an infection trapped in the retropharyngeal space this can lead to mediastinitis. This can also occur in the pre-tracheal space which is between the anterior portion of the pre-tracheal fascia and the investing fascia. Note the alar fascia splits the retropharyngeal space into two compartments – the true retropharyngeal space which is more anterior and the danger space which can reach deeper into the mediastinum.
What does the ligamentum Nuchae do in the necK?
The ligamentum Nuchae connects the spinous process of the vertebrae to the pre-vertebral fascia
At what level does the cartoid artery bifurcate?
At C4 carotid artery bifurcates into the internal and external artery, internal remains in the sheath.
What’s the difference between the internal and external jugular vein?
Internal jugular vein found in the carotid sheath and is the main vein draining the face, external jugular vein is superficial drains the scalp and face and shares no relationship to the internal jugular vein.
What innervates the muscles of facial expression?
Cranial nerve VII (facial)
What innervates the muscles of mastication?
Cranial nerve V (trigeminal)
How does the trigeminal nerve subdivide and what does each do?
Trigeminal nerve had 3 branches all three provide sensory information from the skin. ophthalmic branch (top of the head around the eyes and tip of the nose), maxillary branch (thin strip from temple to temple including top of cheek and between the nose and lips) and mandibular branch (bottom of the cheek and chin), mandibular also innervates muscles of mastication.
What special functions does the facial nerve have?
Facial Nerve provides innervation to facial muscles and has special function in tongue and parasympathetic innervation to salivary and lacrimal glands.
What important structure does the facial nerve pass through?
It passes through parotid gland and can be damage from parotid gland pathologies
What are the 5 key branches of the facial nerve
5 key branches: Temporal, Zygomatic, Buccal, Marginal Mandibular and Cervical branches. (To Zanzibar by motor car)
What are the main muscles involved in mastication and what do they do?
Muscles involved in mastication: Lateral pterygoid opens the mouth and medial pterygoid closes the mouth whilst the temporalis and masseter muscles close the mouth
What are the layers of the scalp?
Layers of the Scalp: Skin, Connective Tissue (Dense), Aponeurotic layer, Loose Connective tissue and Pericranium (periosteum of skull). The aponeurotic layer or epicranial aponeurosis is the aponeurosis of the Occipttofrontalis muscle.
What nerves innervate the scalp?
Innervation of the scalp anterior to the vertex and ear is by the trigeminal nerve whilst posterior to this it is from the spinal cord levels C2 and C3.
What is the blood supply of the scalp?
Blood supply comes from branches of the external carotid artery (Superficial temporal, occipital and posterior auricular) or from the ophthalmic artery (supraorbital and supratrochlear) which is a branch of the internal carotid artery. Venous drainage is by similar vessels.
What is the contents of the anterior triangle?
The anterior triangle contains: the infra and suprahyoid muscles, the common carotid artery which bifurcates in the triangle, the internal jugular vein and the facial VII, glossopharyngeal IX, vagus X, accessory XI and hypoglossal XII cranial nerves.
What is the contents of the posterior triangle?
The posterior triangle contains the omohyoid muscle, scalene muscles, Splenius capitis and levator scapulae covered.
The external jugular vein which lies superficially, it pierces the investing layer of fascia and empties into the subclavian vein. The transverse cervical and suprascapular vein join with the external jugular vein within the triangle. All these veins (bar jugular) are accompanied by their respective arteries.
Finally the cervical plexus and the accessory nerve innervating the sternocleidomastoid muscle can be found in the posterior triangle.
