Neck anatomy Flashcards
1
Q
How are the fascial layers of the neck broadly divided into?
A
-Superficial cervical fascia
-Deep cervical fascia
2
Q
Where is the superficial cervical fascia found?
A
Beneath dermis. Surrounds neck, muscles of facial expression and platysma. Contains fat, neurovascular bundles and lymphatics
3
Q
Name the different layers of the deep cervical fascia
A
External investing layer
Pretracheal
–> parietal
–>visceral
–> buccopharyngeal
–> carotid sheath
Prevertebral fascia
4
Q
Where is the external investing layer of deep fascia found?
A
-Surrounds neck and surrounds trapezius, sternocleidomastoid, muscles of mastication, parotid and submandibular glands
5
Q
Describe how the middle layer of the deep fascia is subdivided
A
Middle layer of the deep fascia is subdivided into two parts: carotid sheath and pre-tracheal fascia:
-Carotid sheath contains internal jugular vein, carotid artery (common and internal), vagus nerve and deep lymph nodes
Pretracheal fascia is divided into
-Muscular: infrahyoid muscles
-Visceral: thyroid and parathyroid glands
-Buccopharyngeal: pharynx and oesophagus
6
Q
Describe internal layer of deep fascia (prevertebral fascia)
A
-Deepest layer of cervical fascia
-Limited to the posterior neck
-thicker than pretracheal fascia, encloses the vertebral muscles and prevertebral muscles
7
Q
Identify the structures on this image (fascial layers of the neck)
A
-A: Cervical vertebra
-B: prevertebral muscles
-C: Pretracheal fascia
-D: Internal jugular vein
-E: Vagus nerve
-F: Investing layer deep cervical fascia
-G: Scalenus Medius
-H: trapezius
-I: Semispinalis colli
-J: Skin and superficial fascia
-K: Levator scapulae
-L: Scalenus anterior
-M: Spinal nerve
-N: Splenius capitis
-O: Semispinalis capitis
-P: Prevertebral fascia
-Q: Spinal cord
-R: carotid sheath
-S: Common carotid artery
-T: sternocleidomastoid
8
Q
What is the role of fascia in the neck?
A
-Provides attachments to various muscles in the neck
-Allows certain structures to glide (larynx and trachea) or expand (pharynx and oesophagus
-Acts as a barrier to prevent spread of infection/malignancy
9
Q
What is the retropharyngeal space?
A
Posterior to the pharynx and oesophagus, between the pretracheal and prevertebral fascia
10
Q
What is the clinical significance of the retropharyngeal space?
A
Infection of retropharyngeal space can extend from skull to T1-T2 and can therefore result in mediastinitis or empyema
11
Q
What is meant by the ‘danger space?’
A
-Lies posterior to retropharyngeal space
-Infection in this space can be extensions of retropharyngeal, parapharyngeal or prevertebral infecitons
12
Q
What is the clinical significance of the ‘danger space’?
A
Infection in this space tends to occur rapidly due to presence of loose areolar tissue. This can result in retropharyngeal abscess, mediastinitis, cutaneous emphysema and sepsis
13
Q
Describe the presentation of a patient with a retropharyngeal abcess
A
neck swelling, difficulty swallowing, sepsis, drooling, neck stiffness. Definite diagnosis is made on CT
14
Q
What are the principles of management of a retropharyngeal abscess?
A
Investigations: Bloods for inflammatory markers, imaging with CT scan
Treatement: IV antibiotics. If required, surgical drainage can be performed via oropharynx
In patients with airway obstruction due to oedema, a surgical tracheostomy may also be indicated
15
Q
How many levels of lymph nodes are there in the neck?
A
7
16
Q
Where are level 1 nodes found?
A
1a: submental (between anterior bellies of digastric muscle
1b: submandibular (between anterior and posterior bellies of digastric muscle)
17
Q
What is the clinical significance of the enlargement of level 1 nodes?
A
-1a: infections/tumour of tongue/floor of mouth/lower lip
-1b: infections/tumour of mouth, anterior nasal cavity, submandibular gland, soft tissue structures of mid face
18
Q
What is meant by the jugular group of lymph nodes
A
-Group of nodes that run along internal jugular vein from base of skull to clavicle
-Divided into three levels by two transverse lines at level of hyoid bone and cricoid cartilage
19
Q
Where are the level two nodes found?
A
-Upper jugular (or level 2) nodes can be found in anterior triangle at following anatomical locations:
–> Anterior to posterior border of sternocleidomastoid
–> Posterior to posterior border of submandibular gland
–> Along a line from the base of the skull to the lower border of hyoid bone
20
Q
What is the clinical significance of the enlargement of the level two lymph nodes?
A
Tumours/infections of:
–> oral cavity, nasal cavity, nasopharynx, oropharynx, larynx, parotid gland, soft tissue of face and ear
21
Q
Where are the level 3 lymph nodes found?
A
-middle jugular nodes (level 3) can be found in anterior triangle at following levels:
–> Anterior to posterior border of sternocleidomastoid
–> Along a line from the lower border of cricoid cartilage and lower border of the hyoid bone
22
Q
What is the clinical significance of enlargement of level 3 nodes?
A
Infections or tumours in:
–> oral cavity, nasopharynx, oropharynx, larynx
23
Q
Where can level 4 (lower jugular) nodes be found?
A
Between lower border of cricoid cartilage and clavicle
24
Q
What is the clinical significance of enlargement of level 4 nodes?
A
larynx, thyroid, cervical oesophagus
25
Where can level 5 lymph nodes be found?
-Posterior triangle of the neck
-Va: above the level of the spinal accessory nerve
-Vb: below the level of the spinal accessory nerve
26
What is the clinical significance of enlargement of level 5 nodes?
-Nasopharynx, oropharynx, skin of scalp and neck
27
Where are the level 6 nodes located?
-Inferior border of hyoid to manubrium in midline. Anterior to 3 and 4
28
What is the clinical significance of the enlargement of level 6 nodes?
Thyroid gland, larynx, Cervical trachea, cervical oesophagus
29
Where are the level 7 (superior mediastinal) nodes located?
Between common carotid arteries and manubrium sternum
30
What is the clinical significance of enlargement of level 7 nodes?
Lung, chest wall and thyroid
31
What are the different types of neck dissections?
Radical neck dissection
Modified radical
Selective
Extended radical
32
Describe what structures are sacrificed in radical neck dissection
-Lymph nodes 1-5
-Internal jugular vein
-Spinal accessory nerve
-Sternocleidomastoid muscle
33
What structures are sacrificed in modified radical?
-Lymph node groups 1-5
-One of the vital structures is spared (SCM, spinal accessory nerve, internal jugular vein)
34
What structures are sacrificed in selective neck dissection?
-Removal of one or more levels of lymph nodes
-No vital structures are sacrificed
35
What structures are sacrificed in extended radical neck dissection?
Removal of additional structures not normally sacrificed during radical neck dissection. These may include:
-Parapharyngeal/paratracheal lymph nodes
-Carotid artery
-hypoglossal nerve
-Vagus nerve
36
Describe the boundaries of the anterior triangle of the neck
Anterior: midline of the neck
Posterior: sternocleidomastoid anterior border
Superior: Mandible inferior border
Roof: platysma and subcutaneous tissue
Floor: pharynx, larynx, thyroid gland
37
Describe the boundaries of the posterior triangle of the neck:
Posterior: anterior border of trapezius
Anterior: posterior border of sternocleidomastoid
Inferior: clavicle
Roof: investing layer deep cervical fascia
Floor: muscles covered by prevertebral fascia
38
Identify the structures marked A-I on the image
A: posterior belly of digastric
B: carotid triangle
C: Anterior belly of digastric
D: Superior belly of omohyoid
E: Occipital triangle
F: Sternocleidomastoid
G: Inferior belly omohyoid
H: Trapezius
I: Stylohyoid
39
Name the boundaries of the occipital triangle
Anterior: posterior border sternocleidomastoid
Posterior: anterior border trapezius
Inferior: Inferior belly of omohyoid
40
What are the contents of the occiptial triangle?
Vessels:
--> Transverse cervical artery, external jugular vein
Nerves:
--Spinal accessory nerve
--Cutaneous branches cervical plexus
--trunks brachial plexus
Occipital lymph nodes
41
Name the boundaries of the supraclavicular (subclavian) triangle?
Superior: inferior belly of omohyoid
Inferior: clavicle
Anterior: posterior border SCM
42
What are the contents of the supraclavicular (subclavian) triangle?
Vessel: suprascapular artery, subclavian artery , subclavian vein
Nerves: Lower trunk of brachial plexus
Other: supraclavicular lymph nodes, apex of lung and phrenic nerve medially, thoracic duct on left side
43
What are the differential diagnoses of a swelling in the anterior triangle of the neck?
Thyroglossal cyst
Thyroid pathology
Salivary gland swelling
Skin condition including malignancy
Lymph node
Carotid artery aneurysm/carotid body tumour
Branchial cyst
44
What are the differential diagnoses of a swelling in the posterior triangle of the neck
Cystic hygroma
Pharyngeal pouch
Subclavian artery aneurysm
Cervical rib
Skin conditions including malignancy
Lymph node
45
Describe the risks of inserting a central line
-Bleeding/haematoma
-Infection
-Pneumothorax
-malposition
-Thrombosis
-Air embolus
-Arrhythmia
46
What is the clinical deficit associated with injury to the spinal accessory nerve? What is the most common cause for accessory nerve palsy?
-Atrophy of sternocleidomastoid/trapezius
-Inability to shrug shoulders/turn head to affected side
Most common cause of accessory nerve palsy is:
--> lymph node biopsy to posterior triangle
--> Radical neck dissection
47
How would carotid body tumour present?
-Asymptomatic palpable neck masses
-10% can have cranial nerve palsy (hypoglossal/glossopharyngeal/recurrent laryngea/spinal accessory)
48
What are the indications for carotid endarterectomy?
-Stable neurological symptoms from acute non-disabling stroke or TIA who have carotid stenosis of 50-99%
-Can be considered in asymptomatic patients with moderate to severe stenosis (50-99%)
https://www.nice.org.uk/guidance/ng128/chapter/Recommendations?fbclid=IwAR0D4BH7Rv4pGkn7PPC0-d2w83RB2i9eaK15xFtBuinIIRQ98jKqfU8B2ag#surgery-for-people-with-acute-stroke
https://www.bradfordhospitals.nhs.uk/wp-content/uploads/2022/07/179679-WYVAS-CAROTID-Booklet.pdf
49
What are the boundaries of the submental triangle?
-Superior: mandible
-Lateral: anterior belly digastric
-Anterior: midline
50
What are contents of the submental triangle?
-Anterior jugular vein
-Lymph nodes
51
What are the boundaries of the digastric (submandibular) triangle?
-Anterior: anterior belly digastric
-Posterior: posterior belly digastric
-Superior: inferior border of the mandible
52
What are the contents of the digastric (submandibular) triangle?
Vessels:
--> Submental artery
--> Facial artery
--> Facial vein
Nerves
--> hypoglossal nerve
--> marginal mandibular branch of facial nerve
--> nerve to mylohyoid
--> lingual nerve
Other
--> submandibular gland
--> lymph nodes
53
What are the boundaries of the carotid triangle?
-Anterior: superior belly omohyoid
-Posterior: sternocleidomastoid
-Superior: posterior belly digastric
54
What are the contents of the carotid triangle?
-Vessels
—> internal carotid
--> common carotid bifurcaiton, branches external carotid
--> Internal jugular vein
Nerves:
--> vagus nerve
--> ansa cervicalis
55
What are the boundaries of the muscular triangle?
Medially: midline
Lateral superior : superior belly omohyoid
Lateral inferior: scm
Superior: hyoid bone
56
What are the contents of the muscular triangle?
Strap muscles: sternohyoid, sternothyroid and thyrohyoid
Larynx, thyroid, parathyroid, lymph nodes
Recurrent laryngeal lies in tracheo-oesophageal groove
57
Describe the anatomy of the cervical plexus
-Plexus of the first 4 cervical spinal nerves located from C1-C4 in the neck
-Located laterally to the transverse processes and emerge from posterior triangle midway on the posterior border of SCM
-They anastomose with the accessory nerve, hypoglossal nerve and sympathetic trunk
-The cervical plexus has two types of branches: cutaneous and muscular
58
Name the four cutaneous branches of the cervical plexus and their innervations
Lesser occipital: C2 only--> lateral occipital region
Greater auricular: C2, C3--> inferior auricle, parotid
Transverse cervical: C2, C3--> anterior region of the neck
Supraclavicular: C3, C4--> supraspinatus, shoulder, upper thoracic region
59
Name the four muscular branches of the cervical plexus and their innervations
-Communicating branches (C1): geniohyoid and thyrohyoid
-Ansa cervicalis (C1-C3): sternohyoid, sternothyroid, omohyoid
-Segmental branches (C1-C4): Supplies anterior and middle scalene muscles
-Phrenic (C3-C5): diaphragm and pericardium
60
Name the suprahyoid and infrahyoid strap muscles in the neck
Suprahyoid
-Digastric (anterior and posterior belly)
-Geniohyoid
-Stylohyoid
-Mylohyoid
Infrahyoid
-Sternohyoid
-Sternothyroid
-Thyrohyoid
-Omohyoid (superior and inferior belly)
61
What is the nerve supply of the digastric muscle?
-Anterior belly: Nerve to mylohyoid, branch of V3
-Posterior belly: digastric branch of facial nerve
62
What is Erb's point?
-Halfway along posterior border sternocleidomastoid
-Where cutaneous branches of cervical plexus emerge to become superficial and supply the skin
-These nerves include: lesser occipital, greater auricular, transverse cervical, supraclavicular
-Additionally branches of supraclavicular nerve and nerve to subclavius (from upper trunk of brachial plexus)
63
What is the clinical significance of Erb's point?
-Cervical plexus block can be achieved by infiltrating LA here (can provide block for procedures involving neck, occipital region, shoulder, upper pectoral region
-Spinal accessory nerve can be found 1cm above erb's point
64
What is the most likely diagnosis in a child presenting with a small pit on the anterior neck present since birth and having a recurrent mucinous discharge?
-Right second branchial cleft sinus/fistula
-Second branchial cleft anomalies account for the majority of branchial anomalies (up to 90%)
-They are most frequently identified along anterior border of SCM (junction of middle and lower 1/3rd)
65
What is the likely anatomical course of a second branchial cleft sinus/fistula?
-Runs from skin of lateral neck, pierces platysma
-Ascends between internal and external carotid arteries
-Close relation of the hypoglossal and glossopharyngeal nerve
-Opens into the oropharynx (usually palatine tonsil)
66
Describe the nerves, muscles and bony structures of the six pharyngeal arches: 1st
Nerve:
-CN V3
Muscles:
-Muscles of mastication, tensor palatini, tensor tympani, mylohyoid, anterior belly of digastric
Bones/cartilages:
-From maxillary process: Maxilla, zygoma, squamous part of temporal bone
-From mandibular process: mandible, malleus, incus, sphenomandibular ligament
Arteries:
-maxillary artery
67
Describe the nerves, muscles and bony structures of the six pharyngeal arches: 2nd
Nerve:
-CN VII
Muscles
-Muscles of fascial expression, stapedius, stylohyoid, posterior belly of digastric
Bones/cartilages:
-Stapes, styloid process, part of body and lesser horn of hyoid bone, stylohyoid ligament
Artery:
-Stapedial artery
68
Describe the nerves, muscles and bony structures of the six pharyngeal arches: 3rd
-Nerve: 9
-Muscles: stylopharyngeus
-Bones/cartilagres: body and greater horn of hyoid bone
-Artery: CCA and part of ICA
69
Describe the nerves, muscles and bony structures of the six pharyngeal arches: 4th
-Nerve: X
-Muscles: cricothyroid, pharyngeal constrictor, levator veli palatini
-Bones/cartilages: Thyroid cartilage
-Arteries: left: arch of aorta, right: sub-clavian
70
Describe the nerves, muscles and bony structures of the six pharyngeal arches: 6th
Nerve: RLN (X)
Muscles: all laryngeal muscles except cricothyroid
Bones and cartilages: Cricoid, arytenoid, corniculate and cuneiform cartilages
Arteries; pulmonary arteries
71
Describe the anatomy of the thyroid gland
-Two lobes with central isthmus
-Lobes at level of C5-T1 vertebrae
-Isthmus lies anterior to second and third tracheal rings
-Thyroid gland is surrounded by a capsule
-The capsule is surrounded by pretracheal fascia
72
What is the function of the thyroid gland?Which cells produce what hormone?
-Produces T3 and T4 via the colloid cells which is involved in regulating metabolism and growth
-Parafollicular C cells also produce calcitonin which is involved in calcium metabolism
73
Describe the blood supply of the thyroid gland
-Superior thyroid (external carotid)
-Inferior thyroid (thyrocervical trunk from subclavian)
-Thyroid IMA (<10%) usually originates from brachiocephalic trunk but can originate from common carotid, subclavian or aorta directly
74
What is the lymphatic drainage of the thyroid gland?
-Paratracheal/deep cervical lymph nodes
75
What are complications of surgery to the thyroid gland?
General
-Pain, infection, bleeding, scarring, haematoma, seroma
Specific:
-Hypocalcaemia (removal of parathyroid gland)
-damage to recurrent laryngeal nerve (hoarse voice, stridor if bilateral)
-Damage to superior laryngeal nerve (difficulty with high pitched voice)
-Need for long term thyroxine replacement therapy
76
Describe the nerve supply of the larynx?
Nerve supply to larynx divided into superior and recurrent laryngeal nerve
Superior laryngeal divided into internal and external:
-Internal: Sensory mucosa above vocal cords
-External: cricothyroid muscle which is adductor and tensor of the cords
Recurrent laryngeal:
-sensory to mucosa below the cords
-all intrinsic muscles except cricothyroid
77
How would you investigate a thyroid lump?
-Triple assessment: Clinical examination, USS, FNA
Thyroid function tests + thyroid autoantibodies
Flexible nasoendoscopy to assess for movement of the cords (recurrent laryngeal nerve function)
78
What is the most common type of thyroid cancer? what are its features?
Papillary carcinoma
Features: 65-70% of thyroid malignancy, 3rd-4th decade, more common in women, lymphatic metastasis
79
What are the other types of thyroid cancers?
Follicular carcinoma: 5th decade, haematogenous metastasis, more common in women, 30% of thyroid malignancy
Anaplastic: 7th decade, very aggressive, local invasion
Medullary: MEN 2, equally common in both genders, 5th decade, lymphatic metastasis, tumour of parafollicular c cells, neuroendocrine rather than thyroid tumour
80
What investigations can be used to follow-up patients following thyroid cancers?
-Thyroglobulin (papillary and follicular carcinomas)
-T4
-TSH
-Calcitonin (medullary)
-CEA (medullary: secreted by C cells)
81
Describe how the parathyroid glands are subdivided
-4 parathyroid glands: 2 on posterior surface of each thyroid gland lobe
-2 inferior and 2 superior
82
Where are the superior and inferior parathyroid glands normally found?
-superior glands are in more consistent position compared to inferior
-Superior are at inferior border of cricoid cartilage 1cm superior to entry point of inferior thyroid artery into thyroid gland
-Inferior: near inferior pole of thyroid gland or >1cm inferior to entry of Inferior thyroid artery into thyroid gland
-~5% lie in atypical positions e.g. mediastinum or within thyroid gland
83
What is the embryological origin of the parathyroid gland?
-Superior parathyroid: from 4th pharyngeal pouch
-Inferior parathyorid: from 3rd pharyngeal pouch
84
What is the blood supply to the parathyroid gland?
-Supplied by inferior thyroid artery
-Branch of thyrocervical trunk from subclavian artery
85
What are the functions of the parathyroid glands?
-The major function of the parathyroid gland is the homeostasis of calcium metabolism
-Increase in parathyroid hormone causes increased calcium absorption from the gut, increased activity of osteoclasts and increased calcium absorption from the kidneys
-Also plays a role in phosphate metabolism
86
What is the role of calcitonin on the parathyroid gland?
-Rise in calcium causes increase in calcitonin secretion
-Results in reduced effect of parathyroid hormone
-Reduction in amount of calcium absorbed in gut and kidney, and reduced activity of osteoclasts to release calcium from bone
-However like parathyroid hormone, calcitonin reduces phosphate absorbed by kidney
87
What are the clinical signs of hypocalcaemia?
CATs go numb
-Convulsions,Chvostek's
-Arrhythmias
-Tetany, Troisseau's
-Perioral numbness and tingling
Troisseau's sign: Muscular contraction following inflation of sphygmomanometer cuff for several minutes (neuromuscular excitability caused by hypocalcaemia)
Chvostek's (tapping on facial nerve causes twitching of facial muscles)
88
Name some causes of parathyroid gland enlargement
-Adenoma
-Carcinoma
-Hyperplasia
89
How would you investigate a patient with an enlarged parathyroid gland?
Bloods: PTH, calcium, U + E, vitamin D
Urine: calcium
USS
MRI
Bone density
Sestamibi scan
90
What are the indications for parathyroidectomy?
-Hypercalcaemia in patients <50
-Symptomatic hypercalcaemia in any age group
-Hypercalcaemia >3 in any age group
-Excessive urinary excretion of calcium in any age group
-Deterioration in renal function
-Progressive reduction in bone density
-Any suspicion of malignant disease
91
Describe the anatomy of the pharynx
-Fibromuscular tube extending from the base of the skull to the inferior border of the cricoid cartilage
92
Describe how the pharynx is further subdivided:
From superior to inferior:
1. Nasopharynx (base of skull to soft palate)
2. Oropharynx (Soft palate to epiglottis)
3. Laryngopharynx (Epiglottis to cricoid cartilage)
93
How are the muscles of the pharynx arranged?
The pharynx contains an external circular and internal longitudinal group of muscles
Note: this is the opposite to elsewhere in the alimentary tract
94
Name the internal longitudinal muscles
-Palatopharyngeus
-Stylopharyngeus
-Salpingopharyngeus
95
What is the function of the internal longitudinal muscles?
Elevate the pharynx and larynx during speech and swallowing
96
What is the origin and insertion of the external circular muscles?
Superior constrictor:
-O: pterygoid posterior border, pterygomandibular raphe
-I: Median raphe
Middle constrictor:
-O: Stylohyoid ligament
-I: median raphe
Inferior constrictor
-O: thyroid cartilage, cricoid cartilage
-I: median raphe
97
What is the function of the external circular group of muscles?
-They are involved in constricting the pharynx during swallowing
98
Name all the constrictor muscles of the pharynx
-Palatopharyngeus
-Stylopharyngeus
-Salpingopharyngeus
-Superior constrictor
-Middle constrictor
-Inferior constrictor
99
Name the structures which passes between the middle and inferior constrictors
Membrane between the middle and inferior constrictor is pierced by the internal laryngeal nerve and superior laryngeal vessels
100
Name the structure which passes below the inferior constrictor
Recurrent laryngeal nerve and inferior laryngeal vessels
101
Describe the nerve supply to the pharynx
-Motor and sensory innervation of most of pharynx (except nasopharynx) is supplied by pharyngeal plexus
Pharyngeal plexus is formed by:
-Pharyngeal branches vagus nerve
-Pharyngeal branches glossopharyngeal nerve
-External laryngeal nerve
-Sympathetic fibres from superior cervical ganglion
Sensory:
-Predominantly glossopharyngeal nerve
-nasopharynx innervated by maxillary nerve
Motor
-All vagus except stylopharyngeus (glossopharyngeal)
102
What is the blood supply to the pharynx?
-Ascending pharyngeal (external carotid)
-Facial (external carotid)
-Inferior thyroid (thyrocervcial trunk)
103
What is a pharyngeal pouch?
-Pharyngeal diverticulum which occurs through killian's dehiscence: area of weakness in inferior constrictor muscle of pharynx between thyropharyngeus and cricopharyngeus muscles
(inferior pharyngeal external constrictor consists of two parts)
104
What are the clinical symptoms of a pharyngeal pouch?
-Regurgitation, halitosis, cough, dysphagia
105
What investigations can aid the diagnosis of a pharyngeal pouch?
-Barium swallow
-Endoscopy
106
How would you manage a pharyngeal pouch?
-Conservative: if pt unfit for surgery
-Endoscopic stapling (most common)
-open/external approach (if endoscopic stapling has failed)
107
What is the pharyngeal lymphoid ring or waldeyer's ring?
-Collective anatomical term for the annular arrangement of lymphoid tissue in the pharynx.
-Surrounds the nasopharynx and oropharynx
108
What forms the pharyngeal lymphoid ring?
Formed by:
-2 palatine tonsils
-1 adenoid (nasopharyngeal tonsil)
-1 lingual tonsil
-2 tubal tonsils
-2 lateral pharyngeal lymphoid bands
pharyngeal lymphoid ring is collectively referred to as nasal associated lymphoid tissue
109
What is the function of the pharyngeal lymphoid ring?
-Lymphoid tissue of pharyngeal lymphoid ring is situated at entrance to respiratory and alimentary tract
-Belongs to mucosa associated lymphoid tissue (MALT)
-Main function is production of antibodies against common environmental antigens
-help in production of B cells and plasma responses
110
Which vertebral level corresponds to the position of the larynx?
-C3-C6 vertebral level
111
What are the cartilages of the larynx?
3 paired and 3 unpaired
Unpaired:
Superior to inferior:
--> Epiglottis
--> Thyroid
--> Cricoid
Paired:
-Arytenoid x2
-Corniculate x2
-Cuneiform x2
112
What is the blood supply to the larynx?
laryngeal branches of superior and inferior thyroid arteries
113
Name the intrinsic and extrinsic membranes of the larynx
The extrinsic membranes connect the laryngeal cartilage to surrounding structures for support (hyoid bone and trachea)
--> Thyrohyoid membrane
--> Hyoepiglottic ligament
--> Cricotracheal membrane
Intrinsic: hold cartilages of larynx together as one functional unit
-Cricothyroid ligament
-Quadrangular membrane
-Thryoepiglottic ligament
114
Name the extrinsic muscles of the larynx and their function?
Suprahyoid (elevates larynx)
-Digastric
-Stylohyoid
-Mylohyoid
-Geniohyoid
Infrahyoid (depresses larynx)
-Omohyoid
-Sternohyoid
-Sternothyroid
-Thyrohyoid
115
Extrinsic muscles of larynx
116
Extrnisic muscles of larynx
117
membranes of the larynx
118
membranes of the larynx
119
Name the intrinsic muscles of the larynx
1. Abductors/adductors:
--> Adductor: lateral cricoarytenoid muscle (main), transverse arytenoids muscles
--> abductor: posterior cricoarytenoid muscles-only muscle able to open the vocal cords
2. Sphincters (Muscles to close laryngeal inlet during swallowing)
-Lateral cricoarytenoid
-Transverse arytenoids
-Oblique arytenoids
3. Tensors (muscles to raise pitch of voice)
-Cricothyroid
4. Relaxers (muscles altering pitch of voice)
-Thyroarytenoid
-Vocalis
120
What is the funciton of the intrinsic muscles of the larynx?
Move and alter length and tension of vocal cords, and size and shape of rima glottidis
121
Name the subdivisions of the laryngeal cavity
1. Vestible
2. Middle (ventricle/laryngeal sinus)
3. infraglottic space
122
Name some causes of vocal cord palsy
1. Malignancy (30%): bronchus, oesohpagus, thyroid, nasopharynx
2. Iatrogenic (25%): thyroid, parathyroid, oesophageal, pharyngeal pouch, left lung surgery
3. External trauma (15%)
4. Idiopathic (15%)
5. Others (15%): neurological disorders, myopathies
123
What are the different types of vocal cord palsies?
-Unilateral or bilateral
-Temporary or permanent
124
What is the clinical significance of a bilateral vocal cord palsy?
Bilateral vocal cord palsies present with stridor
125
What forms the superior laryngeal aperture?
-Anterior: epiglottis
-Posterior: arytenoid cartilages
-Lateral: aryepiglottic fold
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Label this external anterior view of the larynx
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Label this saggital view of the larynx
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Label this endoscopic view of the larynx
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Label the laryngeal cartilages
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Arytenoid cartilages can move laterally and medially, and about a vertical axis. When muscular process moves backwards and forwards, the vocal process is abducted and adducted
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Arytenoid cartilages can move laterally and medially, and about a vertical axis. When muscular process moves backwards and forwards, the vocal process is abducted and adducted
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Vocal ligaments run from thyroid cartilage to the tips of the vocal processes of the arytenoid cartilages. Between them is the vocal opening, or rima glottidis. Tension is affected by the tilt of the cricoid cartilage. Gap between them (rima glottidis) is affected by the rotation of the arytenoid cartilage
Vocal opening shape:
Diamond shaped in quite breathing
Widens to triangle in deep breathing
Narrows to slit during speech
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What is the action of the cricothyroid muscle?
-The cricothyroid muscle pulls the arch of the cricoid cartilage upwards.
- In doing so, it pulls the arytenoid cartilages backwards, making the vocal folds longer and tighter.
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What is the action of the posterior and lateral cricoarytenoid? label this picture.
Right side of thyroid cartilage and cricothyroid have been removed
Both muscles converge on muscular process of arytenoid cartilage
The posterior crico-arytenoid pulls the muscular process backwards. This rotates the arytenoid cartilage, thus widening the vocal opening.
The lateral crico-arytenoid pulls the arytenoid cartilage forwards and laterally, drawing the vocal ligament towards the midline
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What are the actions of the thyro-arytenoid and transverse arytenoid muscles?
The next two muscles that we’ll see, the thryro-arytenoid and transverse arytenoid muscles, act to shorten
and narrow the vocal opening.
The thyro-arytenoid muscle arises
from here on the inner aspect of the thyroid cartilage. It inserts here in front of the lateral border of the
arytenoid cartilage.
The transverse arytenoid muscle, also called
the arytenoideus, is a sheet of muscle that bridges the gap between the posterior surfaces of the two
arytenoid cartilages.
Contraction of the thyro-arytenoid muscle rotates the arytenoid cartilage inward and pulls it forward, along with the cricoid cartilage. This action slackens the vocal
ligament, and shortens the vocal opening from front to back.
Contraction of the transverse arytenoid muscle brings the two arytenoid cartilages closer together, thus
closing the posterior part of the vocal opening.
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Describe vocalis
The most medial part of the thyro-arytenoid muscle, which is attached to the vocal ligament, has a special
function. It’s known as the vocalis muscle. It makes fine adjustments to the tension of the vocal ligament.
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Describe the anatomy of the parotid gland
Parotid gland is in the parotid area
-Superior: Zygomatic arch
-Inferior: ramus of manidle
-Anterior: masseter muscle
-Posterior: sternocleidomastoid and external ear
Parotid gland is divided into a deep and a superficial lobe and is encased in parotid sheath from investing layer of deep cervical fascia
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Describe the surface markings of the parotid duct
-Lies in middle 1/3rd of a line drawn from the tragus of the ear to midway between the alar of the nose and the lateral commisure of mouth.
-Traverses masseter, pierces buccinator and opens into buccal vestibule at level of second upper molar
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Describe the blood supply to the parotid gland
Arterial supply:
-From external carotid via superficial temporal and posterior auricular arteries
Venous drainage
-Via retromandibular vein
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What is the nerve supply to the parotid gland?
-Sensory fibres from auriculotemporal and greater auricular nerve
-Parasympathetic from glossopharyngeal nerve
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Name the structures within the parotid gland
For REAL (superfiical to deep)
-Facial nerve
-Retromandibular vein
-External carotid artery
-Greater auricular nerve
-Lymphatics
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What are the complications of parotid gland surgery
-Pain
-Infection
-Bleeding
-Haematoma
-Scarring
-Salivoma/parotid fistula
-Frey's syndrome (gustatory sweating)
-Facial nerve/greater auricular nerve injury
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How would you investigate parotid lump?
Triple assessment:
-History and examination
-US
-FNA
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What is Frey's syndrome?
-Parasympathetic disruption: fibres which normally supply parotid gland join with sympathetic fibres which supply scalp and face
-Results in gustatory sweating (erythema and sweating instead of salivation)
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What is the blood supply to the parotid gland?
-Submental artery (from facial artery)
-Lingual artery (from external carotid)
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What is the sensory supply to submandibular gland?
-Secretomotor from facial nerve
-Carried by chorda tympani (facial) and lingual nerve (from V3)
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Describe where the submandibular duct opening lies
-Duct is 5cm long
-Opens lateral to the lingual frenulum
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Name the nerves at risk during submandibular gland surgery
-Marginal mandibular branch of facial neve
-Hypoglossal nerve
-Lingual nerve
-Nerve to mylohyoid
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Where are the sublingual glands found?
-Deep in the floor of the mouth between the mandible and genioglossus muscle
-Small sublingual ducts open into floor of mouth between the sublingual folds
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Describe the arterial supply to the sublingual glands
Sublingual artery (from lingual artery)
Submental artery (from facial artery)
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Describe the nerve supply to the sublingual glands
-Secretomotor from facial nerve via chorda tympani and lingual nerve
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Why are stones in the submandibular gland more common than in the parotid gland?
-Parotid saliva is serous, submandibular gland saliva is thicker and mucoid
-Submandibular duct is longer, travels against gravity and has a smaller orifice
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What is the rule of 80s of parotid gland tumours?
80% of parotid gland tumours are benign
80% of parotid tumours are pleomorphic adenomas
80% of salivary pleomorphic adenomas occur in the parotid
80% of parotid pleomorphic adenomas occur in superficial lobe
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Cauises of salivary gland enlargment
Infection
-Viral (HIV, mumps)
-Bacterial (staph)
Inflammation
-Autoimmune (e.g. sjogren's)
Drugs
-Alcohol
-Thiouracil
Metabolic
-Diabetes
-Cirrhosis
Sialectasis
Benign tumour
-Pleomorphic adenoma
-Warthin's tumour
-Lymphangioma
-Haemangioma
Malignant conditions
-Adenoid cystic carcinoma
-Adenocarcinoma
-Lymphoma
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Identify the following features of the cervical vertebra on the image
A: transverse foramen
B: Vertebral foramen
C: Transverse process
D: vertebral body
E: Pedicle
F: superior articular process
G: lamina
H: bifid spinous process
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What are the characteristic features of a typical cervical vertebra (C3-c6)?
-Broad body
-Transverse foramen (for vertebral artery, vertebral vein and sympathetic fibres)
-Small bifid spinous process
-Plane of facet joints is oblique
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How does C1 differ from a typical cervical vertebra?
-Occipital condyles to articulate with the skull
-Kidney shaped
-No verbtebral body
-No spinous process
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How does C2 differ from typical cervical vertebra?
-Has odontoid process (dens)
-Does not have bifid spine
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How does C7 differ from typical spinous process?
-Vertebra prominens
-Long and non bifid spinous process
-Large transverse process but small transverse foramen, does not transmit vertebral artery
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What type of joint is the atlanto-occipital joint?
Synovial joint. Surrounded by loose capsule
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Which joint permits flexion/extension of the neck?
Atlanto-occipital joint, articulation between C1 and the occipital condyles
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What prevents excess rotation at the atlanto-occipital joint?
Alar ligaments: connect the dens to the occipital condyles
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What is the function of the dens of C2?
Allows the atlas and base of skull to rotate around it as a unit
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Describe the clinical significance of a fracture of the dens
-Can impact spinal cord, injurying or even severing it resultoing in quadriplegia
-Dens extends superiorly inro ring of C1, is therefore susceptible to shearing forces and fracture from C1 in neck injuries
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What is a hangman's fracture?
Bilateral fracture of pars interarticularis of C2. Results from hyperextension/distraction injury
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Identify the following features of the spinal cord on the image below:
A: Posterior median sulcus
B: Dorsal horn
C: grey commissire
D: Lateral column
E: Lateral horn
F: ventral horn
G: Anterior median fissure
H: ventral coloumn
I: Ventral root spinal nerve
J: Spinal nerve
K: dorsal root ganglion
L: Centarl canal
M: dorsal root of spinal nerve
N: dorsal column
