Anatomy Flashcards
Describe the boundaries of the anterior triangle of the neck
Anterior: Midline of the neck
Posterior: anterior border SCM
Superior: inferior border of mandible
Roof: Subcut tissue and platysma
Floor: Pharynx, larynx and thyroid
What are the subdivisions of anterior triangle of the neck?
-Muscular
-Submental
-Submandibular
-Carotid triangle
What are the boundaries of the muscular triangle?
Superior: hyoid bone
Medial: midline
Superolateral: Omohyoid
Inferolateral: SCM
Boundaries of submental triangle?
Medial: midline of neck
Lateral: anterior belly digastric
Inferior: hyoid
What are the boundaries of the submandibular triangle?
Superior: mandibule
Anteiror: anterior belly digastric
Posterior: posterior belly of diagastric
What are the boundaries of the carotid triangle?
Anterior: superior belly omohyoid
Posterior: Sternocleidomastoid
Superior: posterior belly of digastric
How are the anterior and posterior triangles divided?
-The inferior belly of omohyoid divides the posterior triangle into an superior occipital triangle and inferior subclavian triangle
-The superior belly of omohyoid divides the anterior triangle into a superior carotid triangle and an inferior muscular triangle
What are the borders of the posterior triangle?
Anteiror: sternocleidomastoid
Posteiror: trapezius
Inferior: clavicle middle 1/3rd
Roof: investing layer of deep cervical fascia
Floor: prevertebral fascia
What is the innervation of omohyoid?
Ansa cervicalis C1-C3
What are the extrinsic muscles of the tongue and what are their innervation
-Styloglossus
-Genioglossus
-Hyoglossus
-Palatoglossus
All supplied by hypoglossal except palatoglossus: pharyngeal plexus
What three nerves pass through the submandibular gland?
-Lingual nerve
-Hypoglossal nerve
-marginal mandibular branch of facial nerve
What kind of secretions does the submandibular gland produce?
-Submandibular gland produces thick mucoid saliva which has a high concentration of calcium
-In contrast parotid gland produces serous saliva
If you ligate the facial artery, will you cause necrosis of the muscles it supplies?
No, as it forms an anastamosis with the lingual artery
At what level does the carina bifurcate?
T4/5 vertebral level
Identify the glossopharyngeal nerve. What does it supply?
Sensory: Innervates the oropharynx, carotid body and sinus, posterior 1/3 of the tongue, middle ear cavity and Eustachian tube.
Special sensory: Provides taste sensation to the posterior 1/3 of the tongue.
Parasympathetic: Provides parasympathetic innervation to the parotid gland.
Motor: Innervates the stylopharyngeus muscle of the pharynx.
Identify external carotid artery. What nerve passes anteiror to external carotid artery?
Hypoglossal nerve. p. 169 in atlas
Shown cerebral angio. Identify vessels
Overton anatomy book (page 112)
How would you treat a berry aneurysm?
-Endovascular coiling
-Surgical clipping
What type of haemorrhage occurs when cerebral aneurysm ruptures?
Subarrachnoid haemorrhage
Signs of middle cerebral artery infarct
- Paralysis (-plegia) or weakness (-paresis) of the contralateral face and arm (faciobrachial)
- Sensory loss of the contralateral face and arm.
- Damage to the dominant hemisphere (usually the left hemisphere) results in aphasia (i.e. Broca’s area or Wernicke’s)
- Damage to the non-dominant hemisphere (usually the right hemisphere) results in contralateral neglect syndrome, inaccurate localization in the half field, impaired ability to judge distance (nondominant parietal lobe).
- Large MCA infarcts often have déviation conjuguée, a gaze preference towards the side of the lesion, especially during the acute period. Contralateral homonymous hemianopsia is often present.
Where do the vertebral arteries enter the skull?
Through the foramen magnum
How do the vertebral arteries cross the atlas?
Once they have passed through the transverse foramen of C1 (also known as the atlas), the vertebral arteries travel across the posterior arch of C1 before entering the foramen magnum.[
Name the dural venous sinuses
Superior sagittal sinus
Inferior saginttal sinus
Straight sinus
Transverse sinuses
Sigmoid sinuses
Occipital sinus
Cavernous sinuses
Superior petrosal sinuses
Inferior petrosal sinuses
Basilar sinuses
Superior sagittal sinus
lies in superior falx cerebri and runs from crista gali anteriorly to the internal occipital protuberance posteriorly (confluence of sinuses)
Inferior sagittal sinus
lies in inferior border of falx cerebri and joins great cerebral vein to become the straight sinus
Straight sinus
formed by confluence of inferior sagittal sinus and great cerebral vein, runs inferoposteriorly to the internal occipital protuberance (confluence of sinuses)
Transverse sinus
(right and left) pass laterally from the internal occipital protuberance (confluence of sinuses) to become the sigmoid sinuses
Sigmoid sinuses
curve medially and then exit through jugular foramina to become the internal jugular veins
Cavernous sinuses
Cavernous sinuses- lie on either side of the sella turcica: these sinuses drain the ophthalmic, sphenoparietal and middle cerebral veins into the superiror and inferior petrosal sinuses
Superior petrosal sinuses
Superior petrosal sinuses - run from the cavernous sinuses to the junction of the transverse and sigmoid sinuses
Inferior petrosal sinuses
Inferior petrosal sinuses - run from the cavernous sinuses to empty directly into the internal jugular veins
Identify ventricles and flow of CSF
Page 112 atlas
What is this MRI? What are differentials
Astrocytoma
oligodendroglioma
meningioma
hemangioblastoma
Motor innervation of mandibular division of trigeminal nerve:
-Mylohyoid
-Muscles of mastication
-Anterior belly of digastric
Identify pituitary gland on cervical XR
Identify paranasal sinuses on XR
(144 atlas)
Name the paranasal sinuses
Maxillary
Ethmoid
Sphenoid
Frontal
Identify oesophagus, trachea and vagus nerve
Page 162 in atlas
What level does trachea branch
T4-T5
What type of glands do parotid and submandibular glands have?
Parotid–> serous acini
Submandibular –> mixed mucous and serous acini, high in calcium content
Where does wharton’s duct open?
Opens lateral to the lingual frenulum
Where does stensen’s duct open?
Overlies masseter, pierces buccinator and opens within buccal vestibule at level of upper 2nd molar tooth
Which parasympathetic ganglion supplies the parotid gland?
Otic ganglion
Which region of the body do the pre-auricular nodes drain?
superficial areas of the face and temporal region
On the base of the skull, where does the facial nerve exit?
Stylomastoid foramen
On atlas, identify facial artery, vagus nerve, parotid gland, submandibular gland, ducts of salivary gland
?
What passes directly in front of common carotid artery bifurcation?
Hypoglossal nerve
How does injury to hypoglossal nerve present?
Patients will present with deviation of the tongue towards the damaged side on protrusion, as well as possible muscle wasting and fasciculations (twitching of isolated groups of muscle fibres) on the affected side.
What is the surface marking of the facial artery:
at the anteroinferior angle of the masseter muscle against the bony surface of the mandible.
What are the diploic veins?
The diploic veins drain the skull and drain into the dural venous sinuses. They are connected to the superficial veins of the scalp by the valveless emissary veins. Infections of the scalp can therefore lead to osteomyelitis of the skull, as well as cavernous sinus thrombosis.
What passes through the foramen spinosum?
Middle meningeal artery and vein
Stryctures attached to the styloid process
Stylohyoid
Styloglossus
Stylopharyngeus
stylomandibular ligament
stylohyoid ligament
Identify vertebra on C-spine XR:
MRCS radiology book
What is the odontoid process?
superior projecting bony element from the second cervical vertebrae (C2, or the axis). The first cervical vertebrae (atlas) rotates around the odontoid process
What kind of joint is the joint between odontoid process and atlas?
Pivot synovial joint
What age does the mastoid process develop?
The mastoid process is absent or rudimentary in the neonatal skull. It forms postnatally (starts to develop after 1 year old), as the sternocleidomastoid muscle develops and pulls on the bone. It usually finishes structural development by 2 years old.
Identify condylar processes of mandible
Condylar process of mandible
Where does condylar process of mandible articulate with the skull?
The temporomandibular joint consists of articulations between three surfaces; the mandibular fossa and articular tubercle (from the squamous part of the temporal bone), and the head of mandible
What type of joint is the temporo-mandibular joint?
Bi-articular fibrocartilagenous joint
This joint has a unique mechanism; the articular surfaces of the bones never come into contact with each other – they are separated by an articular disk. The presence of such a disk splits the joint into two synovial joint cavities, each lined by a synovial membrane. The articular surface of the bones are covered by fibrocartilage, not hyaline cartilage
What are the movements of the temporo-mandibular joint?
Protrusion –> pterygoids
Retraction –> temporalis
Lateral movement: achieved by alternately protruding and retracting
Elevation –> temporalis, masseter, medial pterygoid
Depression –> mostly gravity. If resistance: assistance from digastric, geniohyoid, and mylohyoid
Identify styloid process.
Identify suture lines from lateral skull XR
Course of hypoglossal nerve in neck
Intracranial course
1. Arises from hypoglossal nucleus in medulla
2. Passes laterally across posterior cranial fossa in subarachnoid space
3. Exits skull via hypoglossal canal
Extracranial course
1. Receives fibres from c1/2 nerve roots in cervical plexus which travel in its sheath
2. Passes inferior to angle of the mandible, crossing internal and external carotid arteries
3. Moves in anterior direction to enter tongue
The hypoglossal nerve arises from the hypoglossal nucleus in the medulla oblongata of the brainstem. It then passes laterally across the posterior cranial fossa, within the subarachnoid space. The nerve exits the cranium via the hypoglossal canal of the occipital bone.
Now extracranial, the nerve receives a branch of the cervical plexus that conducts fibres from C1/C2 spinal nerve roots. These fibres do not combine with the hypoglossal nerve – they merely travel within its sheath.
It then passes inferiorly to the angle of the mandible, crossing the internal and external carotid arteries, and moving in an anterior direction to enter the tongue.
What is the mechanism of papilloedema?
transmission of elevated ICP to the subarachnoid space surrounding the optic nerve that hinders axoplasmic transport within ganglion cell axons. Causes swelling of optic discs
Which brain lobe occupies middle cranial fossa?
Temporal lobe
Where is the anterior clenoid process? What lies lateral to it?
Internal carotid artery
Where is the trigeminal ganglion located?
lateral to the cavernous sinus, in a depression of the temporal bone. This depression is known as the trigeminal cave. The peripheral aspect of the trigeminal ganglion gives rise to 3 divisions: ophthalmic (V1), maxillary (V2) and mandibular (V3).
Where is cavernous sinus located?
The cavernous sinuses are located within the middle cranial fossa, on either side of the sella turcica of the sphenoid bone (which contains the pituitary gland
What are the contents of the cavernous sinus?
A useful mnemonic to remember the contents and their relation to one another is: O TOM CAT, where OTOM (oculomotor nerve, trochlear nerve, ophthalmic branch, maxillary branch) refers to the lateral wall contents from superior to inferior, and CAT (internal carotid artery, abducens nerve, trochlear nerve) refers to the horizontal contents, from medial to lateral.
Why does cavernous sinus thrombosis present with diplopia?
Due to 6th nerve palsy: abducens nerve lies in centre of cavernous sinus and is therefore the first to be affected
Causes of cavernous sinus thrombosis
Most commonly infection
–> nasal furuncle
–> infections in ethmoid/sphenoid sinuses
–> dental infections
Aseptic: less common
–> trauma
–> tumours (nasopharynx/skull)
–> circulatory problems (dehydration/anaemia)
Risk factors for cavernous sinus thrombosis
-Pregnancy
-Clotting disorders e.g. antiphospholipid syndrome
-Cancer
-Intracranial hypotension
Describe the middle ear cavity/where is it
The middle ear can be divided into two parts:
Tympanic cavity – located medially to the tympanic membrane. It contains three small bones known as the auditory ossicles: the malleus, incus and stapes. They transmit sound vibrations through the middle ear.
Epitympanic recess – a space superior to the tympanic cavity, which lies next to the mastoid air cells. The malleus and incus partially extend upwards into the epitympanic recess.
How does infection commonly spread to cavernous sinus?
This most common cause of CST is infection, which typically spreads from an extracranial location such as the orbit, paranasal sinuses, or the ‘danger zone’ of the face. Infection is able to spread in this manner due to the anastomosis between the facial vein and superior ophthalmic veins.
Base of skull fracture presentation
-Racoon eyes
-Battle’s sign
-Haemotympanum
-CSF leak
-Cranial nerve palsy
What is the clinical significance of a fracture of the pterion?
The pterion overlies the middle meningeal artery, and fractures in this area may injury the vessel. Blood can accumulate between the skull and the dura mater, forming an extradural haematoma
Identify this bone
Atlas
Identify parts of the atlas
Identify the foramen lacerum
What are the borders of the posterior cranial fossa?
Anteromedial: dorsum sellae of sphenoir
Anterolateral: petrous part of temporal bone
Posterior: internal surface of squamous part of occipital bone
Floor: mastoid part of temporal bone, squamous/basilar/condylar parts of occipital bone
What is E
Temporalis (page 19 atlas)
What is the blood supply of temporalis?
Deep temporal artery
Where is deep temporal artery from?
Maxillary artery
What supplies the scalp over the temporalis muscle?
Superficial temporal artery
Where is superficial temporal artery from?
External carotid artery
What is the autonomic supply to the pupil?
Parasympathetic –> sphincter pupillae
Sympathetic –> iris dilator muscle
What is the deficit if marginal mandibular nerve is damaged?
Weakness of lower lip: uneven smile
What is deficit if lingual nerve is damaged?
Loss of general sensation anterior 2/3rd of tongue
Differential of lymphadenopathy
Infective
Autoimmune
Neoplastic
Describe the anatomy of the parotid gland
Superior
-Corresponds to posterior 2/3rd of lower border of zygomatic arch
Anterior
-May extend to anterior border of masseter
Inferior:
-Along the ramus of the mandible
Posterior:
-In fron of the external acoustic meatus, mastoid process and anterior border of SCM
The parotid gland is divided into larger superficial and smaller deep lobe. It is enclosed within parotid sheath derived from investing layer of the deep cervical fascia
Describe the surface markings of the parotid duct
-Lies in middle 1/3rd of a line between antitragic notch and phylum, 1cm below zygomatic arch. It overlies masseter, pierces buccinator and opens within buccal vestibule at level of upper 2nd molar
What nerve supplies parasympathetic innervation to the parotid?
Cranial nerve 9
Inflammatory causes parotid swelling
Mumps
Sjogren’s
Bacterial e.g. staphylococcus
causes parotid swelling
Infection:
-Viral e.g. hiv, mumps
-Bacterial e.g. staph
Infalmation
-Autoimmune e.g. sjogren’s
drugs
-Alcohol
Metabolic
-Diabetes, cirrhosis
Sialectasis
Benign condiciotns
-Pleomorphic adeonma
-Warthin’s
-Lymphangioma
-Haemangioma
Malignant
-Mucoepidermoid carcinoma
-Adenoid cystic carcionma
-Adenocarcionoma
-Lymphoma
What are the cranial nerves carrying parasympathetic fibres?
3, 7, 9, 10
What is the intracranial course of the facial nerve?
-Originates nervus intermedius (sensory) and facial nerve nucleus in pons (motor)
-Enters petrous part of temporal bone via internal acoustic meatus
-Runs in facial canal and gives off branches
–> greater petrosal nerve
–> nerve to stapedius
–> chorda tympani
Exits skull via stylomastoid foramen
