Head & Neck Flashcards
What veins and muscle is contained in the superficial fascia of the neck?
Contains Platysma Muscle (innervated by cervical branch of facial nerve. Attaches lower mandible and muscles of face to the pec major and deltoid)
Contains Superficial veins (External Jugular and anterior jugular vein)
Contains cutaneous nerves
What are the 3 layers of deep fascia in the neck and what do they surround?
Investing Layer - Underlying subcutaneous fat. Splits around the Sternocleidomastoid, trapezius and parotid gland. Attaches the hyoid bone and meets the ligamentum niche posteriorly. (Pierced by external and anterior jugular veins)
Pre-Tracheal Fascia - Encloses thyroid gland, trachea, oesophagus and fuses laterally with carotid sheath.
Pre-vertebral Fascia - Surrounds vertebral column, pre-vertebral muscles, scalene muscles and deep back muscles.
Describe the following as either deep or superficial to the pre-vertebral fascia
- Cervical nerve roots
- 3rd part of subclavian artery
- brachial plexus
- accessory nerve
- lymph nodes of posterior triangle
Cervical nerve roots, 3rd part of subclavian artery and brachial plexus are deep to the fascia
Accessory nerve and lymph nodes of posterior triangle are superficial to the fascia
What lies within the carotid sheath?
Lower Part:
Lateral: Internal Jugular Vein
Middle: Vagus Nerve and ansa cervicales
Medial: Common carotid
*Note the cervical sympathetic trunk lies behind the carotid sheath (between carotid sheath and pre-vertebral fascia) and the Sansa cervicalis lies anterior
Upper Part (Begins approx. C3/4):
Internal carotid artery, internal jugular and CN XI, X, XI, XII
What are the 3 Tissue Spaces of the neck and what are the anterior and posterior fascia bounding them?
- Pre-Vertebral Space (Within the pre-vertebral fascia, from base of skull to level of T3)
- Pre-Tracheal Space (Between investing layer and pre-tracheal layer)
- Retropharyngeal Space (Between the buccopharyngeal fascia (anterior) and pre-vertebral fascia (posterior). Extends anteriorly to the submandibular space and infection here causes Ludwigs angina .
Border and contents of Posterior Triangle
Border
- Anterior: Sternocleidomastoid
- Posterior: Trapezius
- Inferior: Middle 1/3rd Clavicle
- Apex: Superior nuchal line
- Roof: Investing layer
- Floor: Pre-vertebral fascia
Contents
- V: External Jugular Vein (joins subclavian vein at bottom)
- N: Brachial Plexus (at base), Cutaneous branches of Cervical Plexus (3rd and 4th cervical nerve), Accessory Nerve
- L: Occipital nodes
- M: Omo-hyoid muscle
Anterior Triangle Borders and Contents
Borders
- Superior: Mandible
- Lateral: Sternocleidomastoid
- Medial: Sagittal line down midline of neck
- Roof: Investing fascia
- Floor: Visceral fascia
Contents
- M: Supra-hyoid and infrahyoid muscles
- N: CN VII, IX, X, XI, XII, Ansa cervicales
- A+V: Common carotid, internal jugular vein
- V: Thyroid, Parathyroid, Trachea, Oesophagus
Suprahyoid Muscles
Infrahyoid muscles
Thyroid gland vascular supply
- Superior thyroid artery (branch of external carotid artery)
- Inferior thyroid artery (From thyrocervical trunk which is branch of brachiocephalic)
What is the nerve supply to the thyroid gland and what other nerve that doesn’t innervate it is at risk of injury in thyroidectomies?
Innervation:
- Parasympathetic - Vagus nerve
- Sympathetic - Middle cervical ganglion
Injury risk - external laryngeal nerve lies behind superior thyroid artery to supply cricothyroid muscle
What is the innervation and blood supply to the trachea?
Innervation - recurrent laryngeal nerve
Arterial - Inferior thyroid a.
Epithelium lining trachea?
pseudo stratified columnar epithelium, with goblet cells producing mucus
What vertebral level does the trachea and oesophagus begin?
C6
What are the layers of the oesophagus?
Adventitia
Muscular Layer (Upper 1/3 Striated, Middle 1/3 Striated and smooth, Lower 1/3 Smooth)
Submucosa
Mucosa (Non-keritinised stratified squamous)
Describe the two oesophageal sphincters
Upper:
Produced by the cricopharyngeus muscle
Lower:
Physiological sphincter (No defining anatomy - just change from oesophageal to gastric mucosa)
At level of T11 (enters abdomen at T10) the change to abdominal pressures created a physiological sphincter
Arterial and venous supply to oesophagus
Arterial
- Thoracic –> Branches of thoracic aorta and inferior thyroid artery
- Abdominal –> gastric artery
Venous
- Thoracic –> Azygous veins and inferior thyroid vein
- Abdominal –> Porto-systemic anastomosis
Innervation of oesophagus
Vagus nerve
(upper striated part from nucleus ambiguous within medulla)
(Lower smooth from dorsal motor nucleus)
When does common carotid divide into internal and external carotids?
Just below level of angle of mandible
Branches of External Carotid Artery
Some Anatomists Love 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
The external carotid artery lies superficial to the middle constrictor and stylopharyngeus. What two suprahyoid muscles does it lie immediately deep to?
Posterior belly of digastric, Stylohyoid
Structures that pass between the external and internal carotid arteries
- Glossopharyngeal nerve
- Pharyngeal branch of vagus
- Portion of the parotid gland
- Stylopharyngeus muscle
What sinuses form the internal jugular vein and what
Sigmoid sinus and inferior petrosal sinus
What anterior rami are the cervical plexus formed by and what were their motor and sensory branches
Formed by anterior rami of C1-4
Muscular Branches (Phrenic nerve, ansa cervicales, nerves to geniohyoid and thyrohyoid and a few other musclualr branches)
Sensory branches (Greater auricular nerve, lesser occipital nerve, transverse cervical nerve, supraclavicular nerves)
Where does the Cervical Sympathetic Trunk Lie within the neck and what level of the spinal cord does it originate?
Originates from T1-6
Has 3 ganglia (superior, middle, inferior)
Lies anterior to longus Colli and longus capaitis (pre-vertebral muscles) and begin the common carotid artery
In relation to the anterior scalene muscle, how does the subclavian artery run (posterior or anterior to it)?
Posterior to anterior scalene