lecture 4 - lower limb nerves/vessels Flashcards
What does the white matter of the spinal cord contain?
Myelinated neurons
What does the grey matter of the spinal cord contain?
unmyelinated neurons
What structures does the white matter of the spinal cord form?
columns (dorsal, lateral, ventral)
What structures does the grey matter of the spinal cord form?
horns (dorsal, lateral ventral)
What matter are the horns of the brain stem made of?
grey matter
What matter are the columns of the brain stem made of?
white matter
What root of the brain stem is afferent to the brain?
dorsal root
What root of the brain stem is efferent to the brain?
ventral root
What does afferent to the brain mean?
sensory information carryied from the PNS to the CNS
What does efferent to the brain mean?
motor information carried from the CNS to the PNS
What type of information is carried by the dorsal root?
sensory
What type of information is carried by the ventral root?
motor
What type of information is carried by the spinal nerves?
mixed (sensory & motor)
What 2 components form the spinal nerve?
Dorsal & ventral roots carrying sensory and motor information respectively
Where do spinal nerves exit the spine?
Via the intervertebral foramen between vertebrae
What do the spinal nerves divide into after leaving the vertebral column?
Dorsal & ventral rami
What do the dorsal rami supply?
The deep muscles, joints & skin of the back
What do the ventral rami supply?
innervate the limbs, form plexuses
How many pairs of spinal nerves are there?
31
How many cervical spinal nerve pairs are there?
8 (C1-C8)
How many thoracic spinal nerve pairs are there?
12 (T1-T12)
How many lumbar spinal nerve pairs are there?
5 (L1-L5)
How many sacral spinal nerve pairs are there?
5 (S1-S5)
How many coccygeal spinal nerve pairs are there?
1 pair (Co1)
Which spinal nerves form the cervical plexus?
C1-C4
Which spinal nerves form the brachial plexus?
C5-T1
Which spinal nerves form the intercostal nerves?
T1-T11
Which spinal nerves form the lumbar plexus?
L1-L4
Which spinal nerves form the sacral plexus?
L1-S4
Which spinal nerves form the coccygeal plexus?
S4-Co1
How are the spinal nerves named?
Based on the vertebrae they exit below, except for the cervical vertebrae (which are named after the the vertebrae they exit above until C8)
Which spinal nerves form the lumbosacral plexus?
L1-S4 (combined lumbar plexus (L1-L4) and sacral plexus (L4-S4))
Which plexus supplies the lower limb?
Lumbosacral plexus
Which spinal nerves connect to form the lumbarsacral trunk that joins the lumbar and sacral plexuses to form the lumbarsacral plexus?
L4 & L5
What structure of. the L4 and L5 spinal nerves forms the connection between the lumbar and sacral plexuses?
Lumbarsacral plexus
What muscle is the lumbar plexus formed in?
Psoas major
What muscle is the sacral plexus formed in?
Piriformis muscle
What are the components of the sacral plexus?
Lumbosacral trunk (L4 &L5 spinal nerves), ventral rami of S1-s3
Which spinal nerves does the femoral nerve arise from?
L2-L4
Which spinal nerves does the obturator nerve arise from?
L2-L4
Which spinal nerves does the Superior gluteal nerve arise from?
L4, L5, S1
Which spinal nerves does the inferior gluteal nerve arise from?
L5, S1, S2
Which spinal nerves does the sciatic nerve arise from?
L4, L5, S1, S2, S3
What are the 2 nerves that form the sciatic nerve?
Common fibular nerve, tibial nerve
What does the femoral nerve supply?
Anterior thigh
What does the obturator nerve supply?
Medial thigh
What does the superior gluteal nerve supply?
Gluteus medius & gluteus minimus, tensor fasciae latae
What does the inferior gluteal nerve supply?
Gluteus maximus
What nerve supplies the medial thigh?
Obturator nerve
What nerve supplies the tensor fascaie latae, gluteus medius & gluteus maximus?
Superior gluteal nerve
What nerve supplies the gluteus maximus?
Inferior gluteal nerve
What nerve supplies the posterior thigh and leg muscles?
Sciatic nerve
What does the sciatic nerve supply?
muscles of Posterior thigh, entire leg (though splits into tibial & common peroneal/fibular)
What does the tibial nerve supply?
Posterior thigh, posterior leg muscles
What nerve supplies the posterior thigh & posterior leg muscles?
tibial nerve
What does the common peroneal/fibular nerve supply?
muscles of anterior & lateral compartments of leg (via deep and superficial fibular nerves)
What are the 2 divisions of the common peroneal/fibular nerve?
Deep fibular/peroneal, superficial fibula/peroneal
What is the alternative term for peroneal?
Fibula
What nerve supplies the anterior compartment of the leg muscles?
Deep peroneal nerve
What does the deep peroneal/fibula nerve supply?
muscles of anterior compartment of the leg
What nerve supplies the lateral compartment muscles of the leg?
Superficial peroneal/fibula nerve
What does the superficial peroneal/fibula nerve supply?
lateral compartment of the leg muscles
What muscles does the femoral nerve supply?
Anterior thigh muscles (except psoas major)
Which muscle of iliopsoas is not supplied by the femoral nerve, but instead directly from L1-L3?
Psoas major - as it originates at the vertebral columns
What is the sensory supply of the femoral nerve?
Skin of anterior & medial thigh
What is the motor supply by the obturator nerve?
All medial thigh muscles
What is the sensory supply by the obturator nerve?
medial thigh
Which 2 nerves supply the adductor magnus, despite it being in the medial compartment?
Obturator (anterior part) AND tibial (posterior part)
Which foramen does the obturator nerve pass through before supplying muscle?
The obturator foramen via the obturator canal
Where does the sciatic nerve run before it divides?”
Down the posterior compartment of the thigh, medial to the femur
Where does the sciatic nerve divide into the tibial & common fibula?
Just superior to the popliteal fossa
Which quadrant of the gluteal region should be injected into to avoid injury to the sciatic nerve?
Upper lateral quadrant
What is the motor supply by the tibial nerve?
Posterior thigh, posterior leg, sole of foot
What are the 2 terminal divisions of the tibial nerve?
Medial plantar nerve, lateral plantar nerve
Which nerves supply the sole of the foot (2)?
Medial plantar nerve, lateral plantar nerve
Where does the common fibula peroneal nerve divide into the deep and superficial fibula nerves?
At the neck of the fibula (superficial at this site)
Which nerve is likely to be damaged during a fracture to the neck of the fibula?
Common fibula
What is a dermatome?
An area of skin supplied by a single nerve or spinal level
What is a myotome?
region of skeletal muscle innervated by a single nerve or spinal level
What is the difference between a dermatome & myotome?
Dermatomes are areas of skin while myotomes are areas of muscle innervated by nerves
How are myotomes and demratomes named?
Based on the spinal nerve that ultimately supplies them
Which region of spinal nerves supply the dermatomes of the anterior lower limb?
lumbar
Which region of spinal nerves supply the dermatomes of the posterior lower limb?
Mostly sacral
Which myotomes control hip flexion?
L1, L2
Which myotomes control knee extension?
L3, L4
Which myotomes control knee flexion?
L5-S2
Which myotomes control plantarflexion?
S1, S2
Which myotomes control adduction of the digits in the foor?
S2,S3
What is the aortic bifurcation?
The point where the abdominal aorta forks into the left and right common iliac arteries
At which vertebral level is the bifurcation of the aorta?
L4
Which landmark marks the name change of the external iliac artery to the femoral artery?
Passing under the inguinal ligament
When the external iliac artery passes under the inguinal ligament what does it become?
Femoral artery
What is the first major branch of the femoral artery?
deep femoral artery
What artery supplies the anterior compartment of the thigh?
Deep femoral artery
What artery supplies the posterior compartment of the thigh?
Deep femoral artery
Which arteries supply the medial compartment of the leg?
Deep femoral artery, obturator artery
What does the deep femoral artery supply?
All compartments of the thigh
What does the femoral artery become at the knee?
Popliteal artery
Which aspect of the knee does the femoral artery pass to before changing to the popliteal artery?
Posterior
What are the 2 divisions of the popliteal artery?
Anterior tibial artery, posterior tibial artery
What artery supplies the anterior compartment of the leg?
Anterior tibial artery
What artery supplies the posterior compartment of the leg?
Posterior tibial artery
What artery supplies the lateral compartment of the leg?
Fibular artery
What major artery comes off the posterior tibial artery to supply the lateral compartment of the leg?
Fibular/peroneal artery
Which artery supplies the foot?
Anterior tibial artery which changes name to the dorsalis pedis
When does the tibial artery change name to the dorsalis pedis?
When crossing under the extensor retinaculum on the superior aspect of the foot
What artery supplies the dorsum of the foot?
Dorsalis pedis artery
What are the boundaries of the femoral triangle?
Inguinal ligament (base), adductor longus (medial), sartorius (lateral), pectineous/iliospoas (floor), fascia lata (roof)
What muscles form the ‘floor’ of the femoral triangle?
Pectineus, iliopsoas
What is the acronym to remember the contents of the femoral trangle?
NAVY - nerve, artery, vein, lymph (lateral to medial)
What are the vessels of the femoral triangle (lateral to medial)?
femoral nerve, femoral artery, femoral vein, lymphatics
What structure of the femoral triangle contains the femoral artery, femoral vein & femoral canal?
Femoral sheath
What is the femoral sheath?
A funnel-shaped fascial sleeve that contains the femoral artery, femoral vein and femoral canal in the femoral triangle
What is contained within the femoral canal?
Inguinal lymphatics
What is the name for the upper opening of the femoral canal?
Femoral ring
What structure is the continuation of the femoral triangle and contains the descending vessels?
Fascial canal
What is the shape of the popliteal fossa?
Diamond
What aspect of the knee is the popliteal fossa found on?
Posterior
Which artery is found in the popliteal fossa?
Popliteal artery
Which vein is found in the popliteal fossa?
Popliteal vein
Which nerve is found in the popliteal fossa?
Tibial nerve
Which muscles are found on the superomedial boundary of the popliteal fossa?
Semimembranosus, semitendonosus
Which muscle is found on the superlateral boundary of the popliteal fossa?
Biceps femoris
Which muscle is found on the inferolateral boundary of the popliteal fossa?
lateral head of gastrocnemius
Which muscle is found on the inferomedial boundary of the popliteal fossa?
medial head of gastrocnemius
How are the deep veins of the lower limb named in regards to arteries?
In similar way to the arteries
What are the 2 key superficial veins of the lower limb?
Great saphenous, small saphenous
What does the small saphenous vein drain into?
The popliteal vein -> femoral vein
What does the great saphenous vein drain into?
Femoral vein (proximal aspect)
What are the relative lengths of the great and small saphenous veins?
Great extends from ankle to proximal thigh, while small extends from ankle to knee
Which veins of the limbs are prone to varcicose veins?
The superficial veins
What is the cause of varicose veins?
Defective valves cause back-flow in lower limb veins, increasing pressure and weakening vessels.
What is deep vein thrombosis?
The formation of clots in the veins, typically of the lower limbs
What are the lymphnodes found at the superior part of the thigh?
Inguinal lymphnodes
