Pre-Practical 1 Flashcards
What structures organise the neck?
The deep fascia.
Split into 4 fascias it seperates the neck into compartments
What are the neck compartments and their surrounding fascia?
- Deep Cervical fascia surround the whole neck
- Prevertebral fascia surrounds spine and bulk of muscle (Muscular Compartment)
- Pretracheal Fascia surrounds the visceral compartment (Oesophagus and trachea etc)
- Carotid Sheath surrounds the carotid/jugular etc on left and right forming two neurovascular compartments
How many bones make up the skull?
22
- 8 make up cranium
- 14 make up the facial skeleton
What are the layers of the scalp?
Skin Connective Tissue Aponeurosis Loose Connective Tissue Periosteum of cranium (Pericranium)
What type of skin is the the skin of the scalp?
Thin skin
Meaning it contains hair follicles and sebaescous glands (unlike the thick skin of the palms etc)
Why do you bleed so profusely from the scalp?
Because the connective tissue layer is bound tightly to the aponeurosis which cant contract so vasoconstriction is limited in the event of injury
Explain the venous supply of the scalp?
- Valveless Emissary veins traverse the scalp & Cranium connecting intercranial venous sinuses to superficial veins in the skin.
- They also pass through the diploe of spongy bones in the cranium making contact with the red marrow.
- They’re the main route of intracranial infection.
What nerves supply the dermatomes of the head and neck?
The trigeminal nerve (Cr N V) supplies the skin of the face/anterior scalp (basically everything in front of the ear)
C2-4 supply the skin of the posterior scalp/head and the neck
Are cranial nerves sensory/motor or sympathetic?
Some are sensory
Some motor
Some parasympathetic (e.g. Oculomotor nerve [Cr N 3] contains some parasympathetic fibres)
Some are a mix of the above
What types of sensory nerve fibres are there?
General sensory - Touch temp pain etc
Special Sensory - Vision/hearing/olfaction/taste
How do sympathetic fibres reach regions supplied by cranial nerves?
The postgangionic fibres from the sympathetic chain form a plexus then hitch a ride on blood vessels
What are the 3 main branches of the trigeminal nerve?
Forms a ganglion then divides: Sup -> Inferior V1 - Ophthalmic division V2 - Maxillary Division V3 - Mandibular Division
What fibres are contained in hte main branches of the trigeminal nerve? (Cr N V)
Mainly general sensory
V3 (Mandibular division) also contains motor fibres
What are the key muscles of facial expression?
Orbicularis Oculi - round eye
Obicularis Oris - round mouth
Occipitofrontalis - connects to eyebrows and aponeurosis of scalp, which stretches to the occipital bone
Buccinator - Provides cheek shape and prevents you chewing your own cheek by accident
What nerve innervates the muscles of facial expression?
Cr N 7, the facial nerve innervates the muscles of facial expression such as the buccinator/occiptofrontalis/obicularis oculi/oris
What fibres are in the facial nerve (Cr N 7) and what are their functions?
Motor - Muscles of facial expression
Special Sensory - Taste from front 2/3rds of tongue
Parasympathetic - Innervates all glands in head/neck except parotid salivary gland
Why doesn’t the facial nerve innervate the parotid salivary gland?
It passes through it but after it exits the head through the stylomastoid foramen at which point it is purely motot fibres.
What structures pass through the parotid gland?
- Motor fibres of facial nerve (Cr N 7)
- External carotid splits into its terminal branches here
- Retromandibular vein
- Also gives off parotid duct
Terminal branches of the external carotid artery?
- Maxillary
- Superficial temporal artery (the one on people temples, can take a pulse off it)
How do we divide the neck from the side?
Into 2 triangles:
Anterior triangle -> SCM -> Posterior triangle -> Trapezius
Each triangle contains arteries/veins/nerves/muscles
How does Sternocleidomastoic contraction move the neck?
The headtilts to the same side but turns at the same time to face away from the contacting SCM
What structures are found in the neurovascular compartments?
The carotid arteries
Internal jugular vein
Vagus nerve
All surrounded by the deep fascia known as the carotid sheaf
What do the internal vs external carotid supply?
The external supplies the neck, face and scalp
The internal passes inside the cranial cavity to supply the brain
How do we deliniate the internal vs external jugulars and what do they supply?
Internal:
- Thick
- Internal to SCM
- Drains brain
External:
- Thin
- External to SCM
- Drains much of the scalp/upper face
What do we call veins in the cranial cavity?
Intracranial venous sinuses
What nerves form the cervical plexus and what does it do?
C1-C4 and part of C5
From here arises sensory and motor branches to the skin and muscles of the neck
What are the “strap Muscles”
The suprahyoid and infrahyoid muscles
They link the hyoid bone to the voice box skeleton and move it.
What are the nerves and blood supply of the thyroid gland?
Nervous:
- External Laryngeal Nerve branch of superior laryngeal nerve
- Recurrent laryngeal nerve
Both are sources from the vagus
Arterial:
- Sup Thyroid Art - Branch of the ECA
- Inf Thyroid Art - Branch of the Subclavian
Venous:
- Sup & middle thyroid vein drain to IJV
- Inf Thyroid vein drains to brachiocephalic
