General Organisation Of Head And Neck Flashcards
What are the components of the Head
Scalp
Skull
Brain and its coverings (meninges)
Define the region of the neck
What are the divisions of the Cranium?
Extends from lower margin of mandible to suprasternal notch of the manubrium and the upper border of clavicle
Neurocranium (around brain) and viscerocranium (facial skeleton)
What are the 2 main vessels in the face
Facial artery and vein
Describe the branches of the Aortic Arch
AA-> Brachiocephalic trunk, Left common carotid artery, left subclavian artery
BC Trunk-> Right Subclavian and Right common carotid artery
(The common carotids split at C4 bone into internal- neurocranium and external- viscerocranium )
Outline the boundaries of the Anterior and Posterior triangles in the neck
Anterior triangle:
Superior boundary- Mandible (Inferior border)
Medial boundary- Imaginary mid-saggital line
Lateral boundary- SCM Muscle (Anterior border)
Posterior triangle:
Anterior boundary- SCM Muscle (Posterior border)
Posterior boundary- Trapezius muscle (Anterior border)
Inferior boundary- Clavicle (Superior border)
Compare the routes of the structures passing through the Anterior and Posterior neck triangles
Anterior: Structures passing between head and thorax
Posterior: Structures passing between thorax/ neck and upper limb
Name the 3 boundaries of the Carotid Triangle (within the anterior triangle)
- Superior: Digastric Post. Belly
- Anterior: Omohyoid Sup. Belly
- Lateral: SCM
Neck structures are compartmentalised by layers of cervical fascia. Name the layers.
- Superficial cervical fascia
Deep cervical fascia:
- Investing Layer (most superficial, surrounds entire neck)
- Pretrachial Layer (Anterior and lateral neck only)
- Carotid Sheath (formed from parts of other 3 layers)
- Prevertebral Layer (deepest)
State the contents of the Superficial Cervical Fascia
Remember: SCALP
Superfical blood vessels Cutaneous nerves Adipose Lymph nodes Platysma
Name the Superior, Posterior and Inferior attachments of the Investing Layer
Superior: Lower mandible, Mastoid Process, Superior Nuchal Line, External Occipital Protuberance
Posterior: Ligamentum Nuchae and Spinous Processes
Inferior: Upper Manubrium, Clavicle, Acromion and Spine of Scapula
Name the Superior and Inferior attachments of Pretrcheal layer
Superior: Hyoid bone
Inferior: Extends into thorax and blends with fibrous pericardium
What are the 2 layers of the Pretracheal layer
What does each layer enclose?
Muscular layer encloses Infrahyoid muscles
Visceral layer enclosed Trachea, Oesophagus, Thyroid Gland
What is the pretracheal layer called as it runs posteriorly to enclose muscles of the pharynx and oesophagus?
What are this structure’s superior and inferior attachments
Buccopharyngeal fascia
Superior: Base of skull
Inferior: Diaphragm
The Carotid Sheath is a tubular, fibrous structure.
Name its superior and inferior attachments
List its 3 main contents
Superior: Base of skull
Inferior: Arch of aorta
Common Carotid Artery
Internal Jugular Vein
Vagus Nerve (Cranial Nerve X)
State the Superior and Inferior attachments of the Prevertebral layer.
Describe its extension laterally
Superior: Base of skull
Inferior: T3 vertebrae
Extends laterally as the axillary sheath that surrounds the axillary vessels and Brachial Plexus of nerves running into upper limb
Fascial compartmentalisation of neck structures lead to spaces between fascial planes.
Infections/ abscesses between planes can cause these spaces to distend.
What is this kind of infection called?
List 4 sources (can spread)
Deep neck space infections. (Rare but dangerous)
Teeth
Pharynx tissues
Sinuses
Middle ear
Name the deep neck space between the Buccopharyngeal fascia and Prevertebral layer.
Up until the age of 3-4, what does the superior part of this space contain?
Retropharyngeal Space (allows pharynx to expand when swallowing)
Lymph nodes which drain areas of nose, oral cavity and upper pharynx.
Considering that the the Retropharyngeal Space extends into Mediastinum, where can infections spread into?
What can develop?
Can spread into thorax, risking Mediastininits (Rare but life threatening)
List 6 signs of a Retropharyngeal Abscess
- Bulge on Oropharynx
- Sore throat
- Hard to swallow
- Stridor (high pitched wheezing sound caused by disrupted airflow)
- Reluctance to move neck
- High temperature
List 4 signs of Retrosternal extension of a Goitre (T Gland enlargement)
- Breathlessness and stridor (due to tracheal compression)
- Facial oedema (due to compression impeding venous drainage from head and neck)
List the 2 groups of muscles of Head and Face and list their nerve supply
Muscles of facial expression (Including Buccinators and Occipitofrontalis)- Facial Nerve (CNVII) ( 5 key branches)
Muscles of Mastication (Chewing)- (Mandibular division of Trigeminal Nerve)
The Facial Expression Muscles often lie in Subcutaneous tissue, and attach to Bone/ Fascia and to each other.
How do they act and what is the exception?
Act as Sphincters (Concentric) or Dilators around the orifices of the face (Eye orbits, Nose, Mouth)
Exception: Buccinators (Cheek muscles) keep the cheek taut, to keep food in the Oral Cavity Proper (prevent food gathering between teeth and cheek)
Branches of the Facial Nerve innervate all the muscles of facial expression, as well as the Platysma muscle.
Outline the path of the facial nerve briefly
- Originates at Brainstem
- Exits at base of skull
- Runs superficially through parotid gland (Inferior and Anterior to ear) (So vulnerable to damage)
- In gland, the nerve divides into 5 key branches
List the 5 key branches of the Facial Nerve (Cranial Nerve VII) from Superior to Inferior
Remember: To Zanzibar By Motor Car
Temporal (Forehead level) Zygomatic (Eye level) Buccal (Cheek Level) Marginal Mandibular (Chin Level) Cervical (Neck Level) (This branch supplies Platysma)
