Lower Limb Flashcards
What Roots Make up the Lumbar Plexus?
How many major peripheral nerves does it give off?
And where is it located?
T12-L4
Gives off 6 major peripheral nerves -
iliohypogastric,
ilioinguinal,
genitofemoral,
lateral cutaneous nerve of the thigh,
obturator nerve,
femoral nerve
Located within the psoas major muscle and anterior to the transvers processes of the lumbar vertebrae
What roots does the iliohypogastric nerve contain?
What is its course?
and what is its motor and sensory function?
Roots: T12, L1
Path: Runs to the iliac crest, across the quadratus lumborum muscle of the posterior abdominal wall then perforates transferse abdominis and divides into terminal branches
Motor:
Innervates internal oblique and transverse abdominis
Sensory: innervates posterolateral gluteal skin in the pubic region
What root does the ilioinguinal nerve contain?
What is its course?
and what is its motor and sensory function?
L1
Path is same as iliohypogastric nerve. In anterior abdominal wall, lies between internal oblique and transversus abdominis. Peirves internal oblique and passes under external oblique through the superficial inguinal ring
Motor Function:
Innervates internal oblique and transversus abdominis (Same as iliohypogastric n.)
Sensation:
Innervates upper middle thigh,
Males: the root of penis and anterior 1/3 scrotum
Females - mons pubis and labia majora
What roots does the genitofemoral nerve contain?
What is its course?
and what is its motor and sensory function?
Roots: L1,L2
Path: After leaving the psoas major muscle, it divides into:
i) genital branch - enters spermatic cord, doesnt go to skin
ii) femoral branch (L1 only) - runs down external iliac artery. Passes beneath the inguinal ligament into the femoral sheath and passes anteriorly through it to supply the femoral triangle skin
Motor:
Genital Branch enters spermatic cords and inervats cremasteric reflex and doesnt reach skin
Sensory:
Femoral branch innervates the skin on the upper anterior thigh
What roots does the Lateral Cutaneous Nerve of the Thigh contain?
What is its course?
and what is its motor and sensory function?
Roots: L2,3
Path: Lateral border of the psoas, incorporated within iliac fascia, lites in a firbous tunned a cm medial to the ASIS. Enters thigh at lateral aspect of the inguinal ligament, where it provides cutaneous innervation to the skin. Enters thigh deep to fascia lata and divides into anterior (L3) and posterior (L2) branches.
No motor function
Sensation: innervates the anterior and lateral thigh down to the level of the knee
What roots does the Obturator Nerve contain?
What is its course?
and what is its motor and sensory function?
Roots: Anterior divisions of anterior rami L2,3,4
Path: Emerges at medial border of psoas, runs posterior to iliac arteries and laterally to the obturator foramen. It then enters the thigh through the obturator canal and splits into anterior and posterior divisions
Anterior division descends between adductor longus and brevis then pierces the fascia latal to become the cutaneous branch of the obturator nerve
The postrior division descends through the obturator externis muscle before passing anteriorly to adductor magnus and the capsule of the knee joint
Motor:
Innervates the obturator externus, pectineus, adductor longus, adductor brevis, adductor magnus, gracilis
Sensory:
Innervates the skin over the medial thigh
What roots does the femoral nerve contain?
What is its course?
and what is its motor and sensory function?
Roots: L2,3,4
Path:
Descends through psoas major muscle. Lies in the fossa between the psoas and illiacus. The nerve then travels underneath the inguinal ligament into the thigh to the femoral triangle where it is lateral to the femoral vessels.
4cm below the inguinal ligament it divides into anterior and posterior divisions:
- Anterior
Medial femoral cutaneous nerve L2,3 (supply medial thigh)
Intermediate femoral cutaneous nerve L2,3 (Supply anterior thigh)
branch to sartorius, branch to pectineus
- Posterior
(Saphenous nerve, branches to quadriceps femoris).
The terminal branch is the saphenous nerve which continues, with the femoral atery and vein
Motor:
Anterior thigh muscles - iliacus, pectineus, sartorius, rectus femoris, vastus lateralis, vastus medialis, vastus intermedius
Sensory:
Skin of the anterior thigh (anterior cutaneous branch) and medial leg (saphenous nerve)
What forms the patellar plexus
Network of nerves near the patellar
Formed by the terminal branches of the medial and intermediate femoral cutaneous nerves of the femoral nerve, the lateral femoral cutaneous nerve and the infrapatellar branch of the saphenous nerve
What nerve roots form the sacral plexus?
What nerves arise from it?
Roots: L4,L5, S1-S4
Located on the surface of the posterior pelvic wall, anterior to the piriformis muscle. The nerve roots have one of two destinations:
i) Remain in the pelvis
ii) Leave pelvis via the greater sciatic foramen
Gives rise to:
- Superior Gluteal Nerve
- Inferior gluteal nerve
- Sciatic Nerve
- Posterior femoral nerve
- Pudendal nerve
Sacral plexus:
What roots does the Superior gluteal nerve contain?
What is its course?
and what is its motor and sensory function?
L4,L5,S1
Path:
Leaves pelvis via greater sciatic foramen, entering gluteal region superiorly to the piriformis muscle (accompanied by the superior gluteal artery and vein)
Motor function:
innervates gluteus minimus, gluteus medias and tensor fascia lata
No sensory function
Sacral plexus:
What roots does the Inferior gluteal nerve contain?
What is its course?
and what is its motor and sensory function?
L5,S1,S2
Path: Leaves pelvis via greater sciatic foramen, intering gluteal region inferiorly to piriformis (accompanies inferior gluteal artery and vein)
Motor: Gluteus maximus
No sensory function
Sacral plexus:
What roots does the Sciatic nerve contain?
What is its course?
and what is its motor and sensory function?
L4,L5, S1, S2,S3
Path: Leaves pelvis via greater sciatic foramen into gluteal region. Emerges inferiorly to the piriformis muscle. Crosses posterior to obturator internus. Enters posterior thigh by passing deep to long head of bicep femoris.
Motor:
Innervates muscles of posterior compartment of thigh + hamstring component of adductor magnus (apart from short head of biceps femoris)
*Nerve gives off tibial and common fibular nerve
The tibial nerve.
What is its course?
and what is its motor and sensory function?
Path:
Tibial nerve is a branch of the sciatic nerve, and arises at the apex of the popliteal fossa
Travels posterior leg, between heads of gastrocnemius, deep to soleus, supplying posterior leg muscles and sural nerve (sensory lateral post. leg)
At foot it passes posteriorly and inferiorly to the medial malleoulus through the tarsal tunnel
Terminates by dividing into 3 sensory branches (Medial calcaneal, medial plantal and lateral plantar nerve)
Motor:
- Posterior compartment of leg and muscles in the sole of the foot
- Deep (Popliteus, flexor hallucis longus, flexor digitorum longus, tibialis posterior)
- Superficial (Plantaris, Soleus, gastrocnemius)
Sensory:
- Posterolateral leg (sural nerve) and posterolateral + medial surfaces of the foot and sole of foot (medial calcaneal branch, lateral and medial plantar nerve)
The common peroneal nerve
What is its course?
and what is its motor and sensory function?
Path:
From sciatic nerve. Begins at apex of popliteal fossa, where sciatic nerve bifurcates
Follows medial border of biceps femoris, running in a lateral, inferior direction over lateral head of gastrocnemius and fibular origin of soleus
Here it gives of two cutaneous branches
i) Peroneal communicating nerve (combines with sural nerve from tibial n.)
ii) lateral cutaneous nerve
iii) Superior and inferior genicular nerves
iv) recurrent genicular nerve
The nerve wraps around the neck of the fibula, passing between the attachments of the fibularis longus muscle.
Here the nerve terminates into a superfiical peroneal and deep peroneal nerve
i) superficial peroneal nerve - innervates muscles of the lateral compartment of leg (acting to evert the foot) and dorsal foot, anterolateral leg
ii) Deep fibular nerve - innervates the muscles of the anterior compartment of the leg (acting to dorsiflex the foot, extend digits) and dorsal foot
Summary:
Motor - All muscles in anterior and lateral compartments
Sensory - skin on anterolateral surface of the leg and dorsal aspect of the foot
Sacral plexus:
What roots does the Posterior Femoral Cutaneous Nerve contain?
What is its course?
and what is its motor and sensory function?
Roots: S1,2,3
Path:
Leaves pelvis via greater sciatic foramen, entering gluteal region inferiorly to piriformis muscle
Descends deep to gluteus maximus and runs down back of thigh to knee
No Motor Function
Sensory: Innervates skin of the posterior surface of the thigh and perineum
What roots does the Pudendal nerve contain?
What is its course?
and what is its motor and sensory function?
Roots S2,3,4
Leaves pelvis via greater sciatic foramen then re-enters via the lesser sciatic foramen
Moves anteriosuperiorly along the lateral wall of the ischiorectal fossa, and terminates dividing into several branches
(Nerve to piriformis, obturator internus, quadratus femoris)
Motor:
Innervates skeletal muscles in peroneum, external urethral sphincter, external anal sphincter, levator ani
Sensory:
Penis/ clitoris
Describe the femoral artery, its course and branches
FEMORAL ARTERY
External iliac artery becomes the femoral artery when it crosses under the inguinal ligament at the mid-point between the ASIS and pubic symphysis
On top of the psoas muscle
Emerges from femoral sheath and continues down anterior surface of thigh under sartorius, via adductor canal (which ends at the opening of adductor magnus - called the adductor hiatus). Femoral a. moves through this opening and enters the posterior thigh. Proximal to entering the posterior knee it becomes the POPLITEAL ARTERY,
Branches:
Gives off profunda femoris in femoral triangle
It gives off 3 main superficial arteries just below the inguinal ligament
1 Superficial iliac circumflex aryery
2 Extenral pudendal artery
3 profunda femoris
PROFUNDA FEMORIS
Given off in In the femoral triangle 4cm below inguinal ligament. Then spirals deep to adductor longus. The profunda femoris artery arises from the posterolateral aspect of the femoral artery. This gives off 3 branches:
i) Medial femoral circumflex artery (post. femur, suppyling neck and head. It can be easily damaged ina NOF)
ii) Lateral femoral circumflex artery
a) Ascending branch (runs up vastus lateralis - gives branch to trochanteric anastaomosis then goes to ASIS and anastomoses with circumflex iliac arteries) Must be careful in anterior approach to THR going between sartorius and tensor fascia lata not to hit this.
b) Transverse branch - winds around femur
c) Descending branch
iii) Perforating branches –> muscles in posterior/ medial thigh
Describe the internal iliac arteries supply of the leg and its branches
Internal iliac arterty gives off:
1) Gluteal region supplied by superior and inferior gluteal arteries (passes under and over piriformis with corresponding nerve)
2) Obturator artery - which breaks into a posterior and anterior branch
i) anterior - pectineus, obturator externus, adductor muscles, gracilis
ii) posterior - deep gluteal muscles
Describe the Popliteal artery course and its branches
Popliteal artery descends posterior thigh, through popliteal fossa, exits between gastrocnemius and popliteus muscles.
Gives off the sural arteries that supply heads of gastrocnemius and the genicular arteries which supply the knee.
At the border of the popliteus it divides into anterior and posterior tibial arteries
i) Anterior tibial artery which travels through the interosseous membrane of tibia and fibula then becomes dorsalis pedis artery
ii) Posterior tibial artery is accompanied by tibial nerve, deep to the soleus, and enters sole of foot via the tarsal tunnel. Gives off a fibular artey branch in the leg that supplies the lateral compartment of the leg.
Describe the arterial system in the foot
Posterior tibial artery enters through tarsal tunnel and splits into lateral and medial plantar arteries which suply plantar foot
Anterior tibial artery becomes the dorsalis pedis (felt between extensor hallus longus and brevis) which anastamoses with the lateral plantar artery to form the deep plantar arch
Dorsalis pedis also gives off branches of dorsum off foot - namely lateral tarsal a. and arcuate a.
Describe the deep veins of the leg
Deep veins accompany major arteries
Dorsal venous arch –> anterior tibial vein
Medial and lateral plantar veins –> posterior tibial and fibular veins
anterior tibial, posterior tibial and fibular veins units to form popliteal vein
popliteal vein –> enters thigh via adductor cannal –> femoral vein
The Profunda femoris vein joins the femoral vein, which then leaves the thigh under the inguinal ligament, at which point it is the external iliac vein
What are the superficial veins of the leg
Superficial veins found in the subcutaneous tissue
i) Great saphenous vein
- Formed by dorsal venous arch of foot and dorsal vein of great toe.
- Ascends medial side of leg, passing anterior to medial malleoulus of ankle and posterior of medial condyle of knee
- drains into femoral vein immediately inferior to inguinal ligament
- contains 20 valves, mainly below knee
ii) Small saphenous vein
- Formes by dorsal venous arch
- Moves up posterior side of leg, passing poasteriorly to lateral malleolus, along lateral border of calcaneal tendon
- Moves through two heads of gastrocnemius and empties into popliteal vein in the popliteal fossa
Superficial arteries of the thigh (4 cutaneous branches of the femoral)
4 branches just below the inguinal ligament
i) superficial circumflex iliac artery (anastamoses near ASIS)
ii) superficial epigastric artery (lower abdo wall)
iii) superficial external pudendal artery (scrotum)
iv) deep external pudendal artery (scotum)
Lymph Nodes of lower limb
Lymph atcs accompany the great saphenous vein
Superficial inguinal nodes (In the subcutanous fat of femoral triangle - has 3 groups
i) vertical - deep fascia and everything superficial of lower limb
ii) Lateral- buttock, flank, back below waist
ii) medial - below umbilicus and medial to ASIS
The efferent lymphatics from these groups pass through the cribriform fascia to enter the deep inguinal nodes
What is the fascia lata
What two muscles does it enclose fully?
Fascia lata is the deep fascia that encloses the thigh
Imaging a stocking - form the top it attaches from ASIS, around external lip of iliac crest (as far back as the posterior gluteal line, where it splits to enclose the gluteus maximus and attaches on the origin on the ilium and sacrum that the gluteus maximus has. It then traces around the ischial tuberosity, ischiopubic ramus and body of the pubic bone
The fascia lata is attached below to the patella and inferior margins of the tibial condyles and head of fibula
The fascia lata encloses two muscles - the gluteus maximus and the tensor fasciae lata
What is the saphenous opening and what structures go through the saphenous opening
Saphenous opening is an opening in the fascia lata
it occurs approx 3.5cm inferior/lateral to the pubic tubercle
The lymphatic vessels and greater saphenous vein go through the opening
it is overlied by cribriform fascia
Iliotibial tract
Origin:
Thickening of the fascia lata that commences at the level of the greater trochanter where 3/4 of the gluteus maximus and tensor fasciae lata are inserted into it
Insertion:
Anterior surface of lateral condyle of tibia
Function:
When the knee is straight the tract passes in fron of the axis of flexion thus maintains the knee in hyperextended position (Not an extensor of the flexed knee)
Important in walking with a minimally flexed knee and extending knee when standing up
Also similar to gluteus medius and minimus - abducting and medially rotating hip
Note the lateral intermuscular septum attaches to the tract which in turn connects it to the linea aspera of the femur
Surface Anatomy:
The bulge of vastus lateralis is seen anterior to the iliotibial tract
Tensor Fascia Lata
- Origin
- Attachment
- Innervation
- Function
Origin:
- External lip of iliac creast between the ASIS and tubercle of the crest
Insertion: iliotibial tract
Innervation: Superior gluteal nerve (L4,5,S1)
Action: Pull upon iliotibial tract which by extending knee joint, stablisation
Femoral Triangle
- Borders
- Contents
Borders:
Superior - Inguinal Ligament
- Lateral - Sartorius
- Medial - Adductor Longus
- Roof - Fascia Lata
- Floor - Pectineus, iliopsoas
Contents (Lateral to medial)
- Femoral nerve
- Femoral artery
- Femoral Vein
- Femoral canal (Contains deep lymph nodes and vessels)
*The femoral artery, vein and canal are in a femoral sheath
What is the femoral sheath and its contents?
And what is crifriform fascia?
Prolongation of the extraperitoneak fascia derived from the transversalis fascia and psoas fascia
Contains the femoral artery and vein
There is a small space medial to the vein in the sheath - called the femoral canal which transmits lymphatic vessels and allows the femoral vein to expand
The canal contains the lymph node of Cloquet which drains the clitoris/ penis
The anterior wall is peirced by the femoral branch of the genitofemoral nerve
In regards to pectineus muscle. How to the following structures relate to it:
Adductor brevis
Obturator nerve
Femoral Vein
Femoral Canal
Deep to pectineus: Adductor brevis, Obturator nerve inbetween adductor brevis and behind pectineus
Superficial: Femoral canal and vein
What is the femoral ring and whats a femoral hernia
The femoral ring is the opening of the femoral canal at its abdominal end
4 boundaries:
Anterior - Medial inguinal ligament
Medial - Crescenteric edge of lacunar ligament
Posterior - pectineal ligament and pectineus
Lateral - femoral vein
it is usually closed by the femoral septum (fusion of iliopectineal fascia and transversalis fascia), however…
Significance: a femoral hernia enters the canal through this ring
(the lacunar ligament may have to be incised to release a stangulated hernia)
It then inters the groing and passes through the saphenous opening… thus the hernia is covered in fascia of the femoral seeptum and cribiform fascia and fat (which can make cough impulse test less obvious)
Potential Complications of femoral artery cannulation
Retroperitoneal haemorrhage
Perforation of gut
Arteriovenous fistula (with the femoral and external iliac vein)
Anterior Thigh Muscles
- Origin
- Attachment
- Innervation
- Function
Adductor cannal
- Border
- Contents
Borders
- Anterior - Sartorius
- Lateral - Vastus medialis
- Medial - Adductor longus (above) and magnus (below)
Contents:
- Saphenous Nerve
- Nerve to vastus medialis
- Femoral Artery and vein (as they leave the canal they become the popliteal vein and artery)
*Skin overlying is supplied by the subsartorial plexus (Fibres from intermediate cutaneous nerve of thigh, saphenous nerve, anterior division of obturator nerve)
What is the medial and lateral intermuscular septum of the thigh
The medial intermuscular septum divides the Medial and anterior compartment of the thigh
The medial intermuscular septum of thigh is a fold of deep fascia in the thigh. It is between the vastus medialis, and the adductors and pectineus.
It is thinner than the lateral septum
Medial (Adductor) compartment of thigh
- origins
- attachment
- innervation
- function
Cutaneous nervve supply to gluteal regions
cluneal nerve - derived from posterior rami of L1-3 and S1-5
Then the anterior rami of
Also iliohypogastric nerve on lateral side
and lateral femoral cutaneous nerve
Superficial gluteal muscles
- origin
- attachment
- innervation
- function
What is the greater sciatic foramen?
An opening in the posterior pelvis.
It is formed by the sacrotuberous (Sacrum –> ischial tuberosity) and Sacrospinous (Sacrum –> Ischial spine) Ligaments
The piriformin muscle passes through and occupies most its volume
What passes through it?
i) Passing over the piriformis is the superior gluteal nerve and vessels
ii) Passing below the piriformis is:
a) he inferior gluteal nerve and vessels
b) the pudendal nerve and vessels
c) the nerve to obturator internus
d) and the sciatic nerve with the posterior femoral cutaneous nerve on its surface and the nerve to quadratus femoris deep to it
Whats the lesser sciaitic foramen
between the sacrospinous and sacrotuberous ligaments, and below the greater sciatic foraemen
the obturator internus passes through this as it wraps aorund to insert on the greater trochanter
Deep muscles in gluteal region
- origin
- attachment
- innervation
- function
Hip Joint
- Ligaments
- Neurovasc
Synoial joint between femur and acetabulum (deepened by acetabular labrum made of fibrocartilage then continues as transverse ligament)
Capsule is attached circumfrentially around labrum and transverse ligament, attaching to neck of femur
Ligaments:
Intracapsular - ligament of head of femur (Acetabular fossa to fovea of femur, enclosing a branch of the obturator artery)
Extracapsular
i) Iliofemoral (AIIS - tranchanteric line of femur)
ii) Pubofemoral (Superior pubic fami - intertrochanteric line of femur)
iii) Ischiofemoral (Ischium - greater trochanter)
Vasc:
- Mainly Medial and some lateral circumflex femoral arteries (Fromprofunda femoris)
- Inferior/superior gluteal arteries + obturator artery through ligament of head of femur (usually closes age 7) provide some additional supply
Neves (hiltons law)
- femoral, sciatic, obturator