WEEK 10/1 > NERVES OF THE LOWER LIMB 1 AND 2 Flashcards
List the spinal cord segments
- rootlets
- dorsal root
- dorsal root ganglion
- spinal nerve
- anterior primary ramus
- posterior primary ramus
- plexus
- peripheral nerve
- vertebral canal
- intervertebral canal
do al peripheral nerves arise from a peripheral plexus
no
but some are continuation of anterior rami
LUMBOSACRAL PLEXUS
what does the lumbosacral plexus form from
- anterior primary rami of lumber spinal cord segments 2,3,4,5
where is the lumbosacral plexus located
on the posterior wall of the abdominal cavity partly within psoas major
what do the anterior division in lumbosacral plexus give rise to
obturator nerve and the lumbosacral trunk
what does the posterior division of LSP give rise to
LCNT and femoral nerve
where does the femoral nerve travel on the side of
LATERAL
where does the femoral nerve travel on the side of
LATERAL side of psoas then enters the femoral triangle of thigh by passing under inguinal ligament
where is obturator nerve initially located
medial side of psoas then enters the pelvic caviry passing over the alar of sacrum
where is the lumbosacral trunk initially on
medial side of psoas then passes over alar of sacrum into the pelvic cavity where it joins the sacral plexus on the posterior wall
what does the sacral part of the plexus form
lumbosacral trunk and the anterior primary rami of spinal cord segments 1,2,3
where is the sacral part of the plexus located
posterior wall of the pelvic cavity anterior to piriformis muscle
what does the anterior division of the sacral plexus give rise to
tibial nerve and part of the pCNT
the posterior division in sacral plexus gives rise to
superior gluteal nerve , inferior gluteal nerve and common peroneal nerve
where do super/inferior gluteal nerve, and common peroneal nerve enter the lower limb via
gluteal region and the greater sciatic foramen
what are the tibial and common peroneal nerve initially joined together as
sciatic nerve
SMALLER NERVES OF THE LOWER LIMB
LCNT (lateral cutaneous. nerve of thr thigh) derives from?
lumbar plexus
what does the LCNT supply
the thigh
where do small muscular branches go to in lower limb
psoas major and iliacus arise from posterior division of L 23 and 24
what are the other cutaneous nerves
genitofemoral and ilionguinal
where does the posterior cutaneous nerve of the thigh arise from
sacral plexus
- cutaneous nerve supplying the posterior thigh and roof of popliteal fossa
nerves supplying to the gluteal region
- piriformis, nerve to obturator internus, superior gemellus and quadratus femoris
what does the roof of the femoral triangle include
- subcostal
- genitofemoral
- ilionguinal nerve
LARGER NERVES OF THE LOWER LIMB
- superior gluteal nerve
- inferior gluteal nerve
- femoral nerve
- obturator nerve
- tibial nerve
- common peroneal nerve
- superficial peroneal nerve
- deep peroneal nerve
SUPERIOR GLUTEAL NERVE
- FORMS from the posterior division of the sacral plexus
spinal cord segments L45 S1
where does the superior gluteal nerve leave from
- leaves the pelvic cavity via the greater sciatic foramen, above piriformis
what structures in the leg does superior gluteal nerve supply
- gluteus medius
- gluteus minimus
- tensor fascia lata
what is superior gluteal nerve tested by
hip joint abduction
INFERIOR GLUTEAL NERVE
- forms from the posterior division of sacral plexus
where does iGA leave pelvic cavity via
- greater sciatic foramen, below piriformis,
what muscle does IGA supply
gluteus maximus
FEMORAL NERVE
forms from the posterior division of the lumbar plexus
femoral nerve located
- initially lateral to psoas major in the abdominal cavity, enters the femoral triangle
where is the femoral nerve in the femoral triangle
- lateral to the femoral artery and outside to the femoral sheath
OBTURATOR NERVE
- forms from the anterior division of the lumbar plexus
where is obturator nerve located
- medial to psoas in the abdominal cavity it then enters the pelvic cavity
where does the obturator nerve exit from
- via the pelvic cavity via the obturator foramen with the obturator artery
where does the obturator nerve divide in the medial thigh
around adductor brevis
TIBIAL NERVE
FORMS from the anterior division of the sacral plexus
where is the tibial. nerve initially joined to
common peroneal nerve to form the sciatic nerve
where does the tibial nerve exit from
- exits pelvic cavity via the greater sciatic foramen below piriformis and enters the gluteal region
where does the tibial nerve travel from
- posterior compartment of the thigh beneath the posterior thigh muscle on the adductor magnus
what nerve does the tibial nerve divide from
- common peroneal nerve near the upper extent of the popliteal fossa
where does the tibial nerve pass through after dividing from common peroneal nerve
middle of the popliteal fossa where it gives rise to the sural branch
COMMON PERONEAL NERVE
Forms from the posterior division of the sacral plexus
what does the common peroneal nerve innervate
- short head of biceps in the thigh and gives rise to the lateral cutaneous nerve of the leg at the level of the knee
SUPERFICIAL PERONEAL NERVE
where does the superficial peroneal nerve travel
- in the lateral compartment of the leg where it supplies peroneus longus and brevis
what does the superficial peroneal nerve become in the mid to lower leg
- cutaneous, passes anterior to the ankle joint and onto the dorsum of the foot
what does the superficial peroneal nerve supply once it becomes cutaneous
skin to the mid dorsal foot
DEEP PERONEAL NERVE
where does the deep peroneal nerve travel
- in the anterior compartment of the leg on the interosseous membrane within the anterior tibial artery > supplies ALM
where does the deep peroneal nerve pass anterior to
ankle joint into the dorsum of the foot > which supplies the dorsal intrinsic foot muscles
DERMATOMES OF THE LOWER LIMB
distributes roughly down the anterior and posterior surface of the lower limb
where does the L1 dermatome distribute to
- upper anterior thigh including the femoral triangle
where does the L2 dermatome distribute to
- anterior and lateral mid thigh
where does the L3 dermatome distribute to
anterior and medial lower thigh
where does the L4 dermatome distribute to
- anterior and medial leg and big toe
where does the L5 dermatome distribute to
- anterior and lateral leg and toes 2,3,4
where does the S1 dermatome distribute to
- lateral ventral foot and toe 5 and lower posterior leg
where does the S2 dermatome distribute to
- S2 posterior leg and thigh including over the popliteal fossa
where does the S3 dermatome distribute to
- S3 gluteal region
MYOTOMES OF THE LOWER LIMB
distribute proximally to distally
sacral plexus formed from
anterior rami of spinal nerves s1-s4
where do most nerves leave via
pelvis inferior to the pisiformis muscle via greater sciatic foramen
where does superior gluteal nerve originate from
l4-s1
where does inferior gluteal nerve orifinate from
l5-s2
where does the inferior gluteal nerve enters the gluteal region via
inferiorly to the piriformis muscle
what muscle does inferior gluteal nerve innervate
gluteus maximus
components of the sciatic. nerve
tibial and fibula component
what does the tibial component innervate
posterior compartment of thigh except for short head of biceps femoris
fibular component innervates
short head of biceps femoris and anterior, lateral leg
