Lecture 1 - general organisation Flashcards
Name the muscles of mastication
Temporalis
Masseter
Medial pterygoid
Lateral pterygoid
Which nerve supplies the muscles of mastication
Mandibular branch of the trigeminal nerve (Vc)
Differences between the muscles of mastication and muscles of facial expression
Muscles of facial expression:
- Dilators/sphincters
- Supplied by facial nerve CN VII
- Attach to bone, skin, fascia of face and other muscles
Muscles of mastication:
- Supplied by Vc
- Open and close jaw
- Act on the TMJ
5 extra-cranial branches of the facial nerve
Temporal Zygomatic Buccal Marginal mandibular Cervical
What can damage the facial nerve in the parotid gland?
Tumour causes the parotid gland to enlarge which compresses the facial nerve
Therefore Bell’s palsy
Mumps does not compress the facial nerve
3 branches of the trigeminal nerve and role
Opthalmic - sensory
Maxillary - sensory
Mandibular - sensory and motor to muscles of mastication
Difference between the ICA and ECA
ECA:
branches in the neck supplies the scalp and face
Superficial
ICA:
does not branch in the neck
supplies the head and neck structures
Deeper
Which nerve receives facial drainage
ICA via the facial vein
What is the level of birfucation of the common carotid artery?
C4
Is the left or right common carotid artery longer?
Left as comes directly off the aorta
Platysma muscle origin, insertion, action and innervation
Origin: Clavicle, pec major and acromion
Insertion: Lower margin of the mandible
Action: Tenses skin and depress the corners of the mouth and mandible
Innervation - facial nerve
Features of the platysma muscle
Very thin and superficial
Lies in the superficial cervical fascia
Sternocleidomastoid origin, insertion, action and innervation
Origin: Mastoid process
Insertion:
1 head - medial clavicle
other head- sternum
Action:
Lateral flexion of head
Tilt chin to controlateral side
Rotation of neck
Innervation: Accessory nerve
Trapezius origin, insertion, action and innervation
Origin: Occipital protuberance and superior nuchal line
Insertion: Spinous processes of vertebrae
Lateral 1/3rd of clavicle
Action: Elevate shoulders
Innervation: Accessory nerve
Presentation of accessory nerve damage
Wasting away of trapezius muscle
Anterior triangle borders
Superiorly: Lower margin of the mandible
Medially: Imaginary midline of neck
Laterally: anterior surface of the SCM
Posterior triangle
Medially: Posterior surface of the SCM
Laterally: trapezius
Floor- scalene muscles
Inferiorly - clavicle
What runs in the posterior triangle
Subclavian artery and vein
Brachial plexus trunks
Carotid triangle
Within the anterior triangle
Superiorly: Posterior belly of diagastric
Laterally: Anterior surface of SCM
Inferiorly: Superior belly of omohyoid
What runs through the carotid triangle
IJV - catheter and intravenous BP
External Carotid artery - carotid pulse is easier to feel
Carotid sinus- carotid sinus massage - increases parasympathetic drive and decreases sympathetic drive therefore treats supraventricular tachycardia
Vagus and hypoglossal nerve
What do the suprahyoids do?
Attach to the hyoid bone superiorly
Elevate the hyoid bone
Depress the mandible
What do the infrahyoids do?
Attach to the hyoid bone inferiorly
Anterior to the thyroid and larynx
Depress the hyoid and stabilise it
Name the fascial layers of the neck
Superficial cervical fascia
Deep: Investing fascia Pretracheal fascia and buccopharyngeal Prevertebral fascia Carotid sheath
Location of the neck
From the lower margin of the mandible to the suprasternal notch of the manubrium and upper border of the clavicle
What does the superficial cervical fascia contain?
Superficial blood vessels - EJV Cutaneous nerves Adipose Lymph nodes Platysma
(SCALP)
Borders of the investing fascia
Superiorly:
- Lower margin of the mandible
- Mastoid process
- Superior nuchal line
- External occipital protuberance
- Spinous processes of vertebrae
- Ligamentum nuchae
Inferiorly:
- Upper border of the manubrium
- Upper surface of the clavicle
- Acromion
- Spine of the scapula
What does the investing fascia enclose
Trapezius
SCM
Submandibular and parotid salivary glands
What are the two layers of the pretracheal fascia and what do they enclose
Muscular layer - infrahyopids
Visceral layer - thyroid gland, trachea, oesophagus, pharynx and larynx
Margins of the pretracheal fascia
Superior and anterior surface of the hyoid bone
Blends with the pericardium
Buccopharyngeal fascia
Posterior layer of pretracheal fascia behind the oesophagus
From base of skull to the diaphragm
Prevertebral fascia margins
Base of the cranium to T3
Extends laterally as the axillary sheath surrounding the axillary vessels and brachial plexus
What doe the prevertebral fascia enclose
The muscles of the back and the vertebral column
Risks of the retropharyngeal space
Extends to the mediastinum
Potential space for infections to spread to the mediastinum and cause mediastinitis secondary to URTI
Most common in children under 5 as space contains lymphnodes that drain the oral and nasal pharynx
Presentation of a retropharyngeal abscess
Visible bulge on the oropharynx Sore throat Dysphagia Stridor High temperature Reluctance to move neck
Carotid sheath margins
From base of the skull to the arch of the aorta (adventitia)
Contents in the carotid sheath
IJV
Vagus nerve
Common carotid artery
