Anatomy Flashcards
What are the structures 1-5?
- Thyroid gland
- Thyroid cartilage
- Carotid sheath
- Vagus nerve
- Oesophagus
What are the proximal and distal borders of the trachea?
Proximal at lower border of cricoid cartilage (C6)
Distal termination at sternal angle (T4) where it bifurcates into 2 main bronchi
What forms the walls of the trachea?
Fibrous tissue reinforced by 15-20 incomplete semicircular cartilaginous rings.
What type of mucosa lines the trachea?
Respiratory epithelium - ciliated pseudostratified columnar epithelium
What lies immediately posterior to the trachea?
Oesophagus with the recurrent laryngeal nerve
What major vascular structures traverse the trachea anteriorly?
The brachiocephalic artery and left brachiocephalic vein
What is the blood supply to the trachea?
Inferior thyroid artery (arterial supply) - arises from thyrocervical trunk
Inferior thyroid veins (venous drainage) and these drain into right and left brachiocephalic veins
What nerve supplies the trachea?
Recurrent laryngeal branch nerves (brances of the vagus) with an additional sympathetic supply from the middle cervical ganglion
Name structures 1-6
- Nerve to subclavius
- Long thoracic nerve
- Musculocutaneous nerve
- Axillary nerve
- Median nerve
- Radial nerve
What are the origins of the brachial plexus?
Anterior primary rami of C5,6,7,8 and T1
What is the course of the brachial plexus?
- emerges as five roots
- lies anterior to scalenus medius and posterior to scalenus anterior
- trunks lie at the base of the posterior triangle of the neck and pass over the first rib, posterior to the third part of the subclavian artery, to descend behind the clavicle
- divisions form behind the middle third of the clavicle
What are the branches of the lateral cord of the brachial plexus?
- Lateral pectoral nerve to pectoralis major
- Musculocutaneous nerve to corachobrachialis, biceps, brachialis and the elbow joint. It continues as the lateral cutaneous nerve of the forearm, supplying the radial surface of the forearm
- Lateral part of the medial nerve
What are the branches of the medial cord?
- Medial pectoral nerve
- Medial cutaneous nerves of the arm and forearm
- Ulnar nerve
- Medial part of median nerve
Which nerves may be missed using the axillary approach?
- intercostobrachial nerve supplying the superomedial surface of the arm (intercostobrachial nerve can be blocked by subcutaneous infiltration)
- musculocutaneous nerve
What are complications are associated with supraclavicular nerve blocks?
- Intravascular injection of local anaesthetic
- Temporary and permanent nerve damage
- Bleeding
- Failure
- Phrenic nerve palsy
- Recurrent laryngeal nerve palsy
- Pneumothorax
Label the great veins of the neck
- Facial vein
- Anterior jugular vein
- RIJ vein
- Right brachiocephalic vein
- Right subclavian vein
- Right vertebral vein
- External jugular vein
- Posterior auricular vein
What sinuses combine to form the internal jugular vein?
- sigmoid sinuses
- inferior petrosal sinuses
These form the internal jugular vein which then pases through the jugular foramen at the base of the skull.
Where does the internal jugular vein terminate?
Behind the sternoclavicular joint as it unites with the subclavian vein to form the brachiocephalic vein
What is the relationship between the internal jugular vein and the carotid artery?
The internal jugular vein lies posterior to the carotid artery at the level of C2, posterolateral at C3 and then lateral to the artery at C4.
The vein and artery are contained within the carotid sheath along with the vagus nerve.
Which veins combine to form the external jugular vein?
- posterior auricular vein
- posterior division of the retromandibular vein
Where do the anterior and external jugular veins join?
They pierce the deep fascia of the neck, usually posterior to the clavicular head of sternocleidomastoid, and unite before draining into the subclavian behind the midpoint of the clavicle
Label the structure of the ACF
- Biceps
- Radial nerve
- Brachial artery
- Median nerve
- Radial artery
- Ulnar artery
- Pronator teres
- Brachialis
What are the borders of the ACF?
Proximally - a line between the humeral epicondyles
Laterally - brachioradialis
Medially - pronator teres
The floor - supinator and brachialis
The roof - deep fascia with median cubital vein and median cutaneous nerve on top
What are the contents of the ACF?
Median, radial and posterior interosseous nerves, the brachial artery (dividing into radial and ulnar arteries) and the biceps tendon.
What is the path of the radial nerve through the antecubital fossa?
- descends in the upper arm, lying between the medial and long heads of the triceps
- enters the ACF between the lateral epicondyle of the humerus and the musculospiral groove
- runs lateral to biceps and under brachioradialis
- then divides into superficial and deep branches
Where does the ulnar nerve traverse the elbow joint?
Ulnar nerve arises medial to axillary artery.
Continues medial to brachial artery, lying on corachobrachialis, to the midpoint of humerus
Here it leaves the anterior compartment by passing posteriorly through medial intermuscular septum.
It lies between the intermuscular septum and the medial head of triceps, passing posterior to the medial humeral epicondyle, and enters the forearm between the 2 heads of flexor carpi ulnaris.
What nerves are you targeting in an ankle block?
4 cutaneous branches of the sciatic nerve:
- posterior tibial
- sural
- deep peroneal
- superficial peroneal
- also one cutaneous branch of the femoral nerve - saphenous nerve
From which spinal nerve do the nerves blocked by an ankle block originate?
Posterior tibial = L5-S3
Sural = L5 - S2
Deep peroneal = L4 - S2
Superficial peroneal = L4 - S2
Saphenous = L3 - L4
Where on a foot do you put local anaesthetic for an ankle block?
What are the indications for an ankle block?
Any foot or toe surgery
What local anaesthetic mixtures can you use for an ankle block?
2% lignocaine
- 5% bupivicaine
- 5% ropivicaine
(speed of onset + duration dictate choice)
Why is adrenaline in an ankle block contraindicated?
Due to the risk of peripheral ischaemia (same as hand blocks)
Label this diagram of the Circle of Willis
- Anterior cerebral artery
- Opthalmic artery
- Superior cerebellar artery
- Basilar artery
- Vertebral artery
- Anterior spinal artery
- Pontine arteries
- Posterior communicating artery
- Internal carotid artery
- Middle cerebral artery
- Anterior communicating artery
Which arteries supply the Circle of Willis?
The internal carotids and both vertebral arteries (which form the basilar artery)
Where do the arteries supplying the Circle of Willis enter the skull?
Internal carotids enter via the carotid canal while the vertebral arteries enter through the foramen magnum
What is normal cerebral blood flow?
15% of cardiac output = 750 ml/min
(50ml/100g/min)
How does blood flow to the grey and white matter differ?
Grey has a higher proportion of blood flow to white (70ml/100g/min vs 20ml/100g/min)
What factors affect cerebral blood flow?
- MAP
- arterial PO2
- arterial PCO2
- cerebral metabolic rate
- body temp
- anaesthetic agents - volatiles, ketamine, propofol
Describe the production and circulation of CSF
- 150ml of CSF which is constantly circulating from brain to spinal cord
- produced in choroid plexuses of lateral, 3rd + 4th ventricles at a rate of 500ml/24hrs
- passes from lateral ventricle to third ventricle via foramen of Munro
- from 3rd-4th ventricle via Sylvian aqueduct
- leaves 4th ventricle through foramina of Luschka laterally
- foramen Magendie medially
- absorbed by arachnoid villi in brain and in spinal arachnoid villi
Label the canals/foramina of the Base of Skull and state which nerves pass through them.
- Optic canal
- optic nerve (II), opthalmic artery, sympathetic nerves
- Cribiform plate
- olfactory nerve (I)
- Foramen rotundum
- maxillary division of trigeminal nerve (V)
- Foramen ovale
- mandibular branch of trigeminal nerve (V), accessory meningeal artery
- Foramen spinosum
- middle meningeal vessels, meningeal branch of mandibular nerve
- Internal auditory meatus
- facial nerve (VII), vestibulocochlear nerve (VIII)
- Hypoglossal canal
- hypoglossal nerve (XII)
- Foramen magnum
- medulla oblongata, vertebral arteries, spinal arteries
What are the branches of the trigeminal nerve and what do they do?
- provides sensory to the face and scalp through three branches
- opthalmic
- maxillary
- mandibular
- opthalmic branch leaves trigeminal ganglion and travels through superior orbital fissure
- provides sensory branches (lacrimal frontal and nasociliary) to supply sensation to anterior aspect of the scalp and superior parts of face incl. cornea
- maxillary branch passes through foramen rotundum and supplies sensation to mid-face
- mandibular branch - mixed sensory/motor, exits skull via foramen ovale
- sensory innervation to mandibular area, up to temporomandibular joint and temple, anterior 2/3rds of tongue
- motor supply to masseter, temporalis, pterygoid muscles
How do you test the trigeminal nerve?
- test for light touch, pinprick and temperature in the 3 separate distributions
- test the corneal reflex
- ask the patient to clench their jaw and palpate masseter and temporalis muscles for volume and tone
- open mouth and observe for mandibular deviation
- test lateral jaw movement against resistance
What are the functions of cranial nerve VII?
Facial Nerve.
Exits the skull via the internal auditory meatus along with vestibulocochlear nerve (VIII).
Motor
- most facial muscles
- frontalis, orbicularis oculi, orbicularis oris, platysma, stapedius
- allows blinking, frowning, smiling
Sensory
- taste to anterior 2/3 tongue
- secretory function to lacrimal gland, nose and mouth, submandibular and sublingual salivary glands
What are the structures 1-4?
- Central tendon of diaphragm
- Inferior vena cava hiatus
- Aorta/aortic hiatus
- Oesophagus/oesophageal hiatus
At what levels are the 3 diaphragmatic foramina?
T8 - inferior vena cava
T10 - oesophagus
T12 - aorta