ANATOMY Flashcards
DESCRIBE THORACIC PARAVERTEBRAL SPACE - CONTENTS, RELATIONSHIPS. COMPLICATIONS
TPVS = spinal nerves , grey and white rami communicates, fat, sympathetic chain, intercostal vessels, Anterior laterally = Pleura (Visceral/Parietal) + Lung Laterally = posterior intercostal membrane and intercostal space Posterior = superior costotransverse ligament Medial = posterior lateral vertebral body/disc and foramen Landmark Transverse Process = 2.5cm lateral to Spinous Process Needle walked off into SCTL LORTS 1cm = epidural space Disadvantages Pneumothorax, spinal, LAST
DESCRIBE ANATOMY RELEVANT TO POPLITEAL SCIATIC NERVE BLOCK WHAT ARE SOME OF THE ADVANTAGES/DISADVANTAGES OF BLOCK
Sciatic nerve origin lumbosacral plexus L4-S3 Travels down the posterior thigh Divides in common peroneal and tibial nerves ~6cm above popliteal crease (but variable 5-18cm) CPN and TN contained within common fascial sheath Nerves are superficial and lateral to PA and PV TN usually lies more medially and closer to vessels Aim to find the point where sciatic divides - so as not to miss one nerve Usually shallow ~2cm deep Using Ultrasound and in plane technique can follow needle from skin so unlikely to cause vascular injury Advantages Excellent analgesia Up to 16hrs with adjuncts Can do case just with block eg debridement suitable for catheter technique Disadvantage May not cover both nerves Saphenous coverage still needed for complete analgesia (consider max doses) Avoid adrenaline containing solutions - poor blood supply
Describe the anatomy of the popliteal fossa
CONTENTS Tibial and common peroneal nerves Short saphenous vein Popliteal Vein Popliteal Artery Popliteal lymph nodes and fat ANATOMY SuperiorMedial = semimembranosus and semitendinosus SuperiorLateral = medial border of biceps femoris Inferior = gastrocnemius Roof = fascia lata Floor = capsule of knee joint, popliteal surface of knee
Describe anatomy for ankle block using landmark techniques
DESCRIBE SENSORY INNERVATION OF ANKLE
WHICH NERVE IN BRACHIAL PLEXUS
Describe anatomy of relevant to performing an erector spinae block
Erector spinae muscles are group of muscles that run bilaterally from the skull to the pelvis.
They include iliocostalis, longisimus, spinalis muscle
Extend from spinous process to transverse process and ribs
Anatomy Erector Spinal Space
Posterior to Transverse Process
Anterior to the Rhomboids and Trapezius muscles
Lateral is superior costotransverse ligament
Medical - spinous process/vertebrae
Aim to inject between TP and ESM
Unknown mechanism - ?TPBV or blocks dorsal rami nerves
Ultrasound = paramedian saggital view
VOLUME BLOCK
Describe anatomy relevant to transversus plane block
Located between costal angle and illiac crest
abdominal wall layers - skin,fat, external oblique internal oblique
aim to place local between internal and external oblique
Risk = bowel perforation.
Analgesia below umbilicus
Describe anatomy relevant for performing an infraclavicular block
Landmarks are clavicle and coracoid process - ultrasound if placed in infraclavicular fossa
Anterior: pectoralis major and minor muscles
Posteriorly,subscapularis muscle
Superiourly the clavicle and coracoid process
Medially the ribs and intercostal muscles
Laterally humerus
The location of the cords of the brachial plexus is deeper from the skin (4 cm) compared with the brachial plexus at other locations.
The cords Lateral , Posterior and Medical surround the axillary artery and are named this way
Analgesia: mid humerus, elbow, forearm, hand
The IC-BPB can provide a more reliable block of the ulnar nerve than more proximal approaches, with fewer episodes of phrenic nerve palsy, pneumothorax, and Horner’s syndrome
musculocutaneous, axillary, and medial nerve of the forearm leave the brachial plexus proximally, which may require several needle redirections to block these nerves when performing an axillary brachial plexus block. This is avoided when an
COmplications:
Block failure
Pneumothorax (0.7%)7
Nerve injury
Phrenic nerve palsy (3%; rare, however may occur if a large volume of local anaesthesia is used)9
Intravascular injection
Infection
Haematoma formation
LA systemic toxicity
Catheter-related complications
Displacement Intravascular placement Kinking
Describe the anatomy relevant to subclavian vein cannulation
Subclavian is a large central vein it originates at outer border of first rib as a continuation of axillary vein.
It courses behind the clavicle and combines with the internal jugular at the medial border of the anterior scalene muscle to form the brachiocephalic vein at the venous angle. The venous angle received the thoracic duct on the left and the lymphatic duct on the right
Landmarks: Clavicle and Sternal Notch. Point of need insertion is at the lateral 1/3 of clavicle with shallow needle angulation 15 degrees with need directed towards sternal notch
The vein remains anteior to the subclavian artery from which it is seperated by the anterior scalene muscle
Relationships
Anterior clavicle
Inferior: pleura,
Posterior : subclavian artery , anterior scalene muscle, first rib
Complications
Pneumothorax - needle parallel to flor
Subclavian Artery Puncture aim needle towards notch
Thoracic Duct injury (left side)
Superiorly overlying the first rib, in sequence from anterior to posterior, are the clavicle, subclavian vein, anterior scalene muscle, and subclavian artery.
Just medial to the junction of the medial and middle thirds of the clavicle, the subclavian vein is attached by fibrous tissue to both the first rib and the clavicle, stabilizing its position and diameter. At this site, the size of the subclavian vein is only slightly affected by respiration, the Trendelenburg position, or the Valsalva maneuver. This region of the vein is the intended target of subclavian venipuncture using the infraclavicular approach.
The infraclavicular approach is most common, and one of two skin insertion sites is used: either 1 to 2 cm inferior to the clavicle at the junction of its medial and middle thirds, or just inferior to the clavicle at its midpoint. Needles are advanced medially along a coronal (frontal) plane—skirting beneath the clavicle—toward the sternal notch. At the first site, the underlying first rib offers protection against pneumothorax. At the second site (clavicular midpoint), less effort is needed to maintain the shallow angle of insertion that keeps the needle in the coronal plane.
Right subclavian cannulation, versus left, is sometimes preferred because it avoids the thoracic duct and because the right pleural apex is lower than the left. Left cannulation is sometimes preferred (especially for pulmonary arterial catheterization) because it affords a direct, less angular path to the superior vena cava, with less chance of misdirected catheterization of the internal jugular vein.
What are the components of the femoral triangle
DISCUSS THE RELEVANT ANATOMY FOR FEMORAL VEIN CANNULATION
Hollow area in anterior thigh providing relatively easy access to the femoral neurovascular bundle
Contents = Femoral sheath - femoral artery , femoral vein, femoral canal, femoral nerve , femoral branch of genitofemoral nerve
Medial - adductor longus
Lateral - sartorius
Roof - areolar tissue, fascia lata, subcutaneous tissue, skin
Floor - illiacus , pectineus, psoas muscles
Superior - inguinal ligament
Landmarks Femoral artery is the mid point between ASIS and Pubic symphysis. NERVE is lateral, Vein is medial
The femoral vein and artery are accessible within the femoral triangle, which is defined by the inguinal ligament superiorly, the adductor longus muscle medially, and the sartorius muscle laterally.
The inguinal ligament spans between the symphysis pubis and the anterior superior iliac spine.
The femoral artery is palpated inferior to the inguinal ligament, typically at or just medial to its midpoint.
The femoral vein lies medially adjacent to the femoral artery. With increasing distance from the inguinal ligament, the vein runs under the artery.
The desired point of femoral vein puncture is 1 to 2 cm inferior to the inguinal ligament. Bleeding due to a vascular impalement here can be controlled by externally compressing the vessels against the femoral head.
The retroperitoneal space lies superior to the inguinal ligament. Bleeding due to a vascular impalement here causes retroperitoneal bleeding, and external compression of the vessels may be impossible.
Describe the antomy of the epidural space
What are the clinical implications fo the differences between thoracic and lumbar epidural spaces and managment of epidural analgesia?
Epidural space is a potenial space that runs from foramen magnum to sacral hiatus.
Contains - dural sac and spinalcord until L1 then cauda equina, paired spinal nerves, epidural fat, blood vessels and connective tissues
Boundaries:
Posterior : Ligamentum flavum and laminae
Anteriorly : vertebral bodies:
Laterally : vertebral foraminae and pedicles
Distance from skin to epidural space is approx 4cm in a normal sized adult
Clinical Implications
Level chosen affects distribution of analgesia - 2 dermatomes above and 4 below
ie T6 - thoracic/upper abdominal surgery
T12 lower abdominal surgery, L2 lower limb surgery
Thoracic spinous process have steeoer angle and with osteophytes in older patients make this route difficult - may use paramedian approach.
Sympathetic chain extends T1-T12
Cardiac accelatory symapthetic fibres T1-T4 - high block may given bradycardia
PLUS
Vasodilation from sympathetic blockage
So thoracic epidurals usually require HDU environment due to hypotension.
LUMBAR PLEXUS MCQ
Describe the anatomy relevant to an adductor canal block
Saphenous nerve is the terminal sensory brach of the femoral nerve supplies medial aspect of leg down to ankle and superfiscal structures of knee (skin and patella branches)
Adductor canal = femoral artery and saphenous nerve
superfiscally = sartorius
antero Lateral = vastus medialis
posteriormedial = adductor magnus and adductor longus
Landmarks
Divide Leg into 1/3 - adductor canal is located around border and distal 1/3 of leg
Place transducer on medial aspect of leg
Identify FA, FV and sartorius
Identify limits of femoral triangle point where sartorius meets adductor longus - scan distally until this muscle shortens
Insert needle lateral to medial
Draw image of adductor canal block
DRAW Fascial Iliaca Infrainguinal
Draw SUPRAInguinal Fascial Iliaca
