Anatomy & Regional Flashcards
Cervical plexus derived from … and it’s branches supplies …
C1 to C4
Paravertebral muscle
Strap muscles of neck
Phrenic nerve
The prevertebral muscles receive branches from the cervical plexus. The cervical plexus is a plexus of the anterior rami of the first four cervical spinal nerves which arise from C1 to C4 cervical segments in the neck. It is located in the neck, deep to the sternocleidomastoid muscle, and supplies branches to the prevertebral muscles, strap muscled of the neck, and the phrenic nerve.
Superficial vs deep cervical block
Superficial cervical block; targets 5 cutaneous nerves
1) transverse cervical N
2) supraclavicular N
3) lesser occipital N
4) Greater occipital N
5) Greater auricular N
Done for procedures in the distribution of C2-C4 including LN dissection, carotid endarterectomy, or bilateral block for tracheostomy/thyroidectomy
Location: midpoint of posterior border of SCM
Complications: possible block the accessory (XI) nerve
Deep cervical block: are the paravertebral block of C2 to C4 as they emerge from foramina in cervical vertebrae
Location: at the C4 transverse process
Complications:
Intravascular injection
Blockade of phrenic and superior laryngeal nerve
Spread to epidural and subarachnoid spaces
3 nerves blocked for awake intubate are
1) sup laryngeal
- Location: through thyrohyoid membrane
- targets: inferior aspect of epiglottis to VC
2) Translaryngeal block (recurrent laryngeal N)
- through cricothyroid membrane
- anesthesia of trachea and below VC
3) glossopharyngeal N
- each post tonsillar pillar (extra-oral block), intra-oral block avoided due to proximity to carotid artery
- anesthesia to post 1/3 tongue, pharynx, sup surface of epiglottis
Stellate ganglion block
The mother of cervical sympathetic trunk contains 3 interconnected ganglia: sup, middle and inferior
In 80% ppl, the lowest cervical ganglia is fused with first thoracic ganglia to form cervicothoracic (stellate) ganglion
Anatomy considerations:
Anterior to prevertebral fascia
Medial to carotid sheath
* vertebral artery (branch of SC) passes anterior to stellate ganglion (at C7) and enters vertebral foramina (as it goes cephalad, 80% of ppl this artery will go posterior to the anterior tubercle of C6)
Block location -> medial to carotid pulse, anterior to the C6 transverse process (Chassaignac’s tubercle of C6)
The Chassaignac’s tubercle identified: 3 cm cephalad to sternoclavicular joint, at the medial border of SCM.
Test of good block by testing adrenergic fiber activity (thermography, plethysmography, lesser Doppler flowmetry) combined with testing sympathetic cholinergic activity (sweat test, sympathogalvanic response)
Increased skin temperature is commonly used (the presence of Horner’s dose not imply a sympathetic blockade of the arm).
Which central line placement could lead to thoracic duct injury
Left SC
Thoracic duct arches over the subclavian artery, descending to empty into the left IJ and SC
Injury could result into chylothorax EXUDATIVE plural effusion
Epidural space boundaries
Extends from foramina magnum to sacral hiatus
Anterior: posterior longitudinal ligament
Lateral: Pedicles + intervertebral foramina
Posterior: ligamentum falvum
Epidural needle go through
Midline: interspinous -> supraspinous -> L.flavum
Surface landmark and their spinous prominence
Cervical spinous prominence -> C7
Scapular spine -> T3 spinous process
Nipple lines -> T4
Inferior angle of scapula -> T7 spinous process
Lower ribs -> T12
Iliac crest -> L4-5
Posterior superior iliac spine -> S2 spinous process
Cervical plexus superficial vs deep block?
The cervical plexus is unique in that it divides early into cutaneous branches, penetrating the cervical fascia and deeper muscular branches that innervate the muscles and joints, which can be blocked separately.
The deep cervical plexus supplies the musculature of the neck segmentally and the cutaneous sensation of the skin between the trigeminally innervated face and the T2 dermatome of the trunk.
The superficial cervical plexus is blocked at the midpoint of the posterior border of the sternocleidomastoid muscle. The deep cervical plexus block is a paravertebral block of the C2 to C4 spinal nerves as they emerge from the foramina in the cervical vertebrae.
A 56-year-old patient presents to the preop clinic for evaluation. He has a history of hepatic cysts that require surgical removal. Which one of the following percentages of blood flow is supplied to the liver from the hepatic artery and portal vein?
A. 90% hepatic artery and 10% portal vein
B. 50% hepatic artery and 50% portal vein
C. 25% hepatic artery and 75% portal vein
D. 10% hepatic artery and 10% portal vein
E. 75% hepatic artery and 25% portal vein
The hepatic artery supplies about 25% of total hepatic blood flow, while the portal vein supplies 75% of total hepatic blood flow. Because the blood flowing through the hepatic artery has a higher oxygen content, the hepatic artery and portal vein each end up delivering approximately 50% of the total oxygen supply to the liver.
A healthy patient presents for ankle fusion surgery and regional anesthesia is planned. Which nerve has a characteristic anatomic bifurcation which is often used in identifying the structure with ultrasound?
A. Obturator block B. Lateral femoral cutaneous block C. Sciatic block, popliteal approach D. Femoral nerve block E. Saphenous nerve block below the knee F. Axillary block
The sciatic nerve is a single structure from the subgluteal/upper portion of the leg but bifurcates into the tibial and common peroneal nerves in the popliteal fossa. This “splitting” of the nerve is a pathognomonic sign for the identification of the sciatic nerve. The femoral nerve also bifurcates into anterior and posterior branches, but this bifurcation is not consistent and is not used sonographically for the purposes of performing a regional block.
A 23-year-old, woman with idiopathic intracranial hypertension is scheduled to have a ventriculoperitoneal shunt placed under general anesthesia. The shunt will be placed into the anterior aspect of the patient’s right lateral ventricle. How does cerebral spinal fluid from the lateral ventricle pass into the third ventricle?
A. Through the foramen of Magendie B. Through the foramen of Luschka C. Through the aqueduct of Sylvius D. Through the foramen of Monro E. Through the cisterna magna
This patient has a type of communicating hydrocephalus requiring shunting in order to limit damage to the optic nerve.
Cerebral spinal fluid (CSF) is formed in the choroid plexuses located in the cerebral ventricles. CSF from the two lateral ventricles proceeds through the foramen of Monro into the third ventricle. From the third ventricle, CSF passes through the aqueduct of Sylvius into the fourth ventricle. From the fourth ventricle, CSF moves through the lateral foramen of Luschka and middle foramen of Magendie into the cisterna magna. CSF then flows through the subarachnoid spaces in a superior direction towards the arachnoid villi where it is absorbed into venous circulation.
Which one of the following choices listed below includes structures associated with the basal ganglia?
A. Putamen, caudate nucleus, globus pallidus, subthalamus and corpus callosum
B. Putamen, caudate nucleus, substantia gelatinosa, substantia nigra and corpus callosum
C. Hippocampus, caudate nucleus, substantia nigra, putamen and lateral geniculate body
D. Putamen, caudate nucleus, corpus callosum, lateral geniculate body and subthalamus
E. Putamen, caudate nucleus, globus pallidus, substantia nigra and subthalamus
The limbic system consists of the hippocampus and basal ganglia. A large portion of the basal ganglia’s signals are inhibitory in nature and this structure plays an important role in movement disorders such as Parkinson’s disease. The basal ganglia consist of 5 structures, namely the putamen, caudate nucleus, globus pallidus, substantia nigra and subthalamus. Damage to the caudate and putamen cause choreiform movements, while destruction of the substantia nigra results in the rigidity characteristic of Parkinson’s disease.
The corpus callosum consists of fibers that connect the two hemispheres of the cerebral cortex, making information stored in one hemisphere available to the other hemisphere. The substantia gelatinosa is a portion of the dorsal horn containing intermediate neurons that transmit temperature, pain, and tactile information to the spinothalamic tract. Finally, the lateral geniculate bodies are areas where the optic tracts synapse before passing to the occipital area of the cerebral cortex.
An elderly patient with lung cancer requires the positioning of a double lumen tube via fiberoptic bronchoscopy for thoracic surgery. In what percentage of patients is the right upper lobe orifice seen in the trachea proper, as opposed to the right mainstem bronchus?
The right upper lobe (RUL) opens from the trachea in 2-3% of patients. This is important because, in these instances, a right-sided double-lumen ETT will require meticulous positioning to line up its side orifice (“Murphy eye”) with the RUL orifice. In certain anatomic variants, this may not be possible based on the geometry of the ETT, and alternate methods of lung isolation will have to be considered.
Where the CSF located in spinal cord?
Subarachnoid/interthecal space (between the pia mater and the arachnoid mater). Surrounding the spinal cord in the bony vertebral column are three membranes.
From innermost to outermost, these membranes are: the pia mater, the arachnoid mater and the dura mater. The pia mater is a highly vascular membrane that closely invests in the spinal cord and the brain. The arachnoid mater is a delicate, nonvascular membrane that functions as the principal barrier to drugs crossing into and out of the CSF.
The dura mater is the outermost of the 3 layers. The space between the pia mater and the arachnoid mater is termed as the subarachnoid or intrathecal space. Approximately 500 mL of CSF is produced daily by the choroid plexuses of the cerebral ventricles, with 30 to 80 mL occupying the subarachnoid space from T11-T12 downward. The spinal cord is continuous with the brainstem proximally and terminates distally in the conus medullaris as the filum terminale, which is the fibrous extension, and the cauda equine, which is the neural extension.
A 37-year-old woman with pancreatic cancer comes in for a celiac plexus block. A feared complication from this block is paraplegia due to injury to the arteria medullaris magna anterior. While this artery has a variable origin, where is it most commonly found?
A. T5-T8
B. T9-T12
C. L1-L5
D. S1-S3
A celiac plexus block can be useful for patients with pain caused by pancreatic or other cancers arising from between the lower esophagus to the spleen. The celiac plexus lies anterior to the aorta near the celiac artery and the location can vary from T12 to L2. Under fluoroscopy a radiocontrast dye is used to confirm location, the local anesthetic can be placed after aspiration to exclude possible intrathecal or intravascular placement. After 20 minutes, pain relief should be evaluated along with motor function and a neurolytic agent can be used. Common side effects are soreness and bruising. Orthostatic hypotension can occur along with increased gastrointestinal motility secondary to the sympathectomy. The most feared complication would be an injury to the arteria medullaris magna anterior, otherwise known as the artery of Adamkiewicz, most commonly arises between T9-T12 in 60% of patients.
Anesthesia is induced and the LMA is easily inserted. To ensure proper placement of the LMA, the anesthesiologist pushes the LMA until it comes to a stop at what structure?
A. Thyroid Cartilage
B. Cricopharyngeus Muscle
C. Cricoid Cartilage
D. Vocal Cords
A is incorrect because the thyroid cartilage sits superior and anterior to the anatomic site where the laryngeal mask airway rests.
B is correct because the cricopharyngeus represents the deepest a laryngeal mask airway can reach. You go to this point and are forced to stop. This places the laryngeal mask airway in the ideal spot: facing forward so the openings face the vocal cords for optimum ventilation.
C is incorrect because the cricoid cartilage is in the trachea, the laryngeal mask airway sits in the posterior pharynx and does not, physically cannot, enter the trachea.
D is incorrect because if you stopped at the vocal cords, the laryngeal mask airway would have unstable seating and there would be a large air leak.
Which of the following statements best describes the anatomic features associated with a lower extremity block?
A. Lumbar plexus is formed by the anterior rami of the first three lumbar nerves
B. Lumbar plexus lies between the psoas major and quadratus lumborum muscles
C. The sciatic nerve is a combination of the tibial and deep peroneal nerve trunks
D. The posterior cutaneous nerve of the thigh is derived from the first three lumbar nerves
The lumbar plexus lies between the psoas major and quadratus lumborum muscles in the so-called psoas compartment.
The plexus is formed by the anterior rami of the first four lumbar nerves (L1-L4), frequently including a branch from T12 and occasionally from L5. The psoas compartment block uses a technique in which a needle is placed into this space between the psoas major and quadratus lumborum muscles.
The sciatic nerve is a combination of two major nerve trunks, the tibial (i.e., ventral branches of the anterior rami of L4-S3) and the common peroneal (i.e., dorsal branches of the anterior rami of L4-S3), which form the sciatic nerve. The trunks separate at or above the popliteal fossa, with the tibial nerve passing medially and the common peroneal laterally.
The posterior cutaneous nerve of the thigh is derived from the first, second, and third sacral nerves (S1-S3).
Which of the following statements best describes the anatomy of brachial plexus?
A. Brachial plexus is derived from the anterior primary rami of C1-C4 cervical nerves
B. Brachial plexus consists of five trunks, three cords, and five major terminal nerves
C. The C1 and C2 nerve roots unite to form the superior trunk of the brachial plexus
D. The prevertebral fascia envelops the brachial plexus between the scalene muscles
The prevertebral fascia envelops the brachial plexus between the scalene muscles.
The brachial plexus is a network of nerves formed by the anterior primary rami of the fifth, sixth, seventh, and eighth cervical nerves and the first thoracic nerve (C5, C6, C7, C8, and T1), with variable contributions from the fourth cervical (C4) and the second thoracic (T2) nerves.
After leaving their intervertebral foramina, these nerves course anterolaterally and inferiorly to lie between the anterior and middle scalene muscles, which arise from the anterior and posterior tubercles of the cervical vertebra, respectively.
The prevertebral fascia invests the anterior and middle scalene muscles, fusing laterally to enclose the brachial plexus in a fascial sheath.
The brachial plexus consists of five roots, three trunks, six divisions (two per trunk), three cords, and five major terminal nerves.
The C5 and C6 nerve roots unite to form the superior (upper) trunk, C7 continues as the middle trunk, and C8 and T1 converge into the inferior (lower) trunk.
How could local anesthetics block larger sensory nerves more easily than smaller motor nerves with spinal anesthesia? explanation by the anatomy surface area
The dorsal nerve roots are organized into component bundles. The dorsal or posterior root of the spinal nerve is one of the two roots that emerge from the spinal cord. It emerges directly from the spinal cord and travels to the dorsal root ganglion. The dorsal root transmits sensory information, forming the afferent sensory root of a spinal nerve. The dorsal nerve roots are generally larger than the ventral or motor nerve roots and are organized into component bundles. This creates a much larger surface area on which the local anesthetics act, possibly explaining why larger sensory nerves are blocked more easily than smaller motor nerves. The spinal nerve roots are not uniform in size and structure, and there is considerable interindividual variability.
Lumbosacral CSF has a constant pressure of approximately 15 cm H2O, but its volume varies by patient, in part because of differences in body habitus and weight.
The adipose tissue in the epidural space diminishes with age, and this decrease may dominate the age-related changes in epidural dose requirements.
Brachial plexus boundiers?
the brachial plexus is a network of nerves formed by the anterior rami of the lower four cervical nerves (C5, C6, C7, and C8) and the first thoracic nerve (T1). This plexus extends from the spinal cord through the cervico-axillary canal in the neck, under the clavicle, over the first rib, into the axilla. It supplies sensory and motor function to the upper chest, shoulder, and upper extremity to the fingers.
What is the order of the tissues encountered to achieve placement of medication in the epidural space?
A. Skin, subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, epidural space, subarachnoid space
B. Skin, subcutaneous fat, posterior longitudinal ligament, interspinous ligament, ligamentum flavum, epidural space
C. Skin, subcutaneous fat, ligamentum flavum, interspinous ligament, posterior longitudinal ligament, epidural space
D. Skin, subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, epidural space.
There are 3 interlaminar ligaments that connect the vertebral processes together and they are the supraspinous ligament, interspinous ligament and the ligamentum flavum. The supraspinous ligament is the most superficial, vertical ligament and connects the tips of the spinous processes. The interspinous ligaments are horizontal ligaments that connect the bottom of a cephalad spinous process to the top of the caudal spinous process. The ligamentum flavum is the last ligament to pass through before reaching the epidural space.
Option A is incorrect because while this is the correct order of tissues, it includes the subarachnoid space and the question asked about placing an epidural catheter, not providing spinal analgesia.
Option B is incorrect because the supraspinous ligament is the first ligament contacted, not the posterior longitudinal ligament. The posterior longitudinal ligament is posterior to the vertebral bodies and provides stability to the vertebral column with the help of the anterior longitudinal ligament.
Option C is incorrect because the supraspinous ligament is the first ligament contacted, not the ligamentum flavum. Additionally, the posterior longitudinal ligament is not involved in the proper placement of an epidural.
Option D is the correct order of the tissues for proper placement of an epidural catheter for labor analgesia.
A 1-year-old girl is undergoing her 2nd cranial vault remodeling for congenital craniosynostosis. While the surgeons are extending the skin flap to expose the superior aspect of the orbits, the patient experiences a drop in HR from 92 bpm to 37 bpm. Which one of the following cranial nerves is responsible for the afferent arm of this reflex?
A. CN III B. CN V1 C. CN V2 D. CN V3 E. CN VI
The oculocardiac (or trigeminovagal) reflex can occur not only during ophthalmologic surgery, where pressure or stretch on the globe or rectus muscles can elicit a response but also with traction on the periostium of the orbit during craniofacial surgery. The nerve responsible for the afferent input is the ophthalmic branch of the trigeminal nerve (V1), and the efferent output is via parasympathetic innervation of the heart by the vagus nerve. The subsequent increase in vagal tone can result in bradycardia, heart block, ventricular ectopy, or asystole. Typically, cessation of the offending action will restore normal rate and rhythm, however prophylactic or therapeutic administration of an anti-muscarinic, such as glycopyrrolate, may be warranted. It is important to note that the retrobulbar block performed for eye surgery does not always protect against the oculocardiac reflex and can precipitate the response itself. Exacerbating factors include inadequate anesthesia, hypoxia, and hypercarbia. With regard to neuroanatomy, the branches of the trigeminal nerve emerge from the gasserian ganglion. The ophthalmic branch (V1) provides sensory innervation to the forehead and eye, the maxillary branch (V2) provides sensory innervation to the mid-face and upper jaw, and the mandibular branch (V3) provides sensory innervation to the lower jaw and motor innervation to the muscles of mastication.
Which of the following statements best describes the sensory innervation of the face?
A. Sensory innervation of the face is provided by the facial nerve
B. The ophthalmic nerve innervates the lower eyelid, upper lip, and anterior area of nose
C. Sensory component of the trigeminal nerve is combined in the gasserian ganglion
D. The mandibular nerve innervates the cheek, and soft and hard palates
The sensory component of the trigeminal nerve is combined in the gasserian ganglion. The sensory innervation of the face is under the dependence of the trigeminal nerve associated with the C2-C4 cervical nerve roots that constitute the superficial cervical plexus. The trigeminal nerve provides sensory and motor components. The sensory component is combined in the trigeminal ganglion, also known as the semilunar or gasserian ganglion. This ganglion lies in the Meckel cave, an invagination of the dura mater near the apex of the petrous part of the temporal bone in the posterior cranial fossa. Postganglionic fibers exit this ganglion to form three nerves: the ophthalmic nerve, the maxillary nerve, and the mandibular nerve. The ophthalmic nerve innervates the forehead, eyebrows, upper eyelids, and anterior area of the nose. The maxillary nerve innervates the lower eyelid, upper lip, lateral portion of the nose and nasal septum, cheek, roof of the mouth, bone, teeth, sinus of the maxilla, and soft and hard palates. The mandibular nerve provides nerve supply to the anterior two-thirds of the tongue and the skin, mucosa, teeth, and the bone of the mandible.
