List four dangers of the Stoppa approach
Corona Mortis (lateral 1/3 sup. pubic ramus)
Bladder (insert foley)
Obturator nerve and vessels (when exposing quad plate)
External iliac vessels (mobilize early)
What is the potential space of retzius ?
Anterior to bladder post to pubic symphisis
What muscle do you have to take down to see quadrilateral plate?
What fascia separates the middle and lateral window of the ilioinguinal approach?
List five contents of the Greater sciatic notch
superior and inferior gluteal vessels and nerves
sciatic and posterior femoral cutaneous nerves
internal pudendal vessels
nerves to the obturator internus and quadratus femoris
List the structures that separate the windows in the ilioinguinal approach
Lateral: Iliac wing to Iliopsoas and femoral nerve
Middle: psoas to External iliac vessels
Medial: External iliac vesselst to rectus abdominus
What are the Denis zones of the sacrum?
1: lateral to foramen
3: medial to foramina into spinal canal
What nerve root runs along the sacral ala?
What is the sacral ala?
Top of sacrum forming iliosacral triangle
What is the importance of iliac cortical density?
On the lateral this parallels the alar slope, you want to be below this when inserting an SI screw
On an AP pelvis is the posterior wall lateral or anterior?
Judet views describe
Obturator oblique - AC (iliopectineal line), PW
Iliac oblique - AW, PC (ilioischial line)
What is a morale lavale lesion?
Internal degloving of subcutaneous tissue off of the lumbosacral fascia
What are key SI ligaments? What are the other three important ones?
Anterior, Posterior, Interosseous Sacrotuberous, Sacrospinous, Iliolumbar ligament
Name the Contents of the Sciatic Notch Relative to Piriformis
Contents of GSN
Superior Gluteal Nerve & Artery
Pudendal nerve and internal pudendal artery
Nerve to obturator internus
Posterior femoral cutaneous nerve
Inferior gluteal artery and nerve
Nerve to quadratus femoris
What travels through LSN?
Obturator internus muscle
Nerve to obturator internus
Internal pudendal vein
What is the cruciate anastomosis made of?
First perforator of profunda
Inferior gluteal artery
The cruciate anastomosis is clinically relevant because if there is a blockage between the femoral artery and external iliac artery, blood can reach the popliteal artery by means of the anastomosis. The route of blood is:
Internal iliac –> inferior gluteal artery –> a perforating branch of the deep femoral artery –> lateral circumflex femoral artery –> its descending branch –> superior lateral genicular artery –> popliteal artery.
Nerves relative to psoas Lateral (3) Medial (2) Between iliac and psoas 1 Piercing than anterior
Lateral - iliohypogastric, lioinguinal, LFCN
Medial - obturator, lumbosacral trunk
Between - femoral
Piercing - genitofemoral
What nerve is at risk with a retractor under transverse acetabular ligament?
How can we adduct after an obturator neurectomy
What nerve is above piriformis?
Superior gluteal nerve
What structure is most at risk of posterior ICBG harvest?
Superior gluteal artery, to a lesser extent cluneal nerves
Between What muscles does the posterior obturator nerve run between?
Adductor brevis and magnus
In the anterior Smith-Peterson approach the deep interval is between?
Rectus femoris and Gluteus medius
Name the ligaments connecting the pubic sympysis
Superior pubic ligament (stronger)
Inferior (arcuate) public ligament
What type of joint is the pubic symphysis?
Synovial amphiarthroidal joint
What do the medial sacral crest and alae of the sacrum represent embryologically?
Medial sacral crest: fused spinous processes
Alae and SI articular processes: fused TP and costal processes
What strucures are near the posterior sacral foramina?
Dorsal primary rami
What structures are near the anterior sacral foramina?
Ventral primary rami
In which direction are the coccyx of men and women directed?
Men: anteriorly towards pubis (like a penis)
List the signs of sacral dysmorphism
Sacralization of L5
Lumbarization of S1
Oval or oblong foramen
Tongue in Groove sign of SI joint
What are the superficial surface markings of the SI joint?
Dimples of Venus
Name the ligaments of the SI joint
WHere does the sacrotuberous ligament, sacrosinous ligament and iliolumbar ligaments run?
Sacrotuberous: sacrum to ischial tuberosity
Sacrospinous: sacrum to ischial spine
Iliolumbar: iliac crest fo 5th lumbar TP
What are the boundaries of the greater sciatic notch?
Note: the sacrospinous ligament changes the “notch” into a “foramen”
What are the borders of the lesser sciatic foramen?
Ischial spine and tuberosity
sacrospinous ligament (superior border)
sacrotuberous ligament (inferior border)
What the obturator foramen, membrane and canal?
Foramen: big hole between pubic rami
Membrane: Membrane that covers the foramen (obturator int/ext attach)
Canal: superior opening in membrane, allowing passage of obturator n/a/v
What attaches to the obturator membrane?
What is the anteversion of the femoral neck?
What is the average neck shaft angle of the femur?
What is the version of the acetabulum?
15 degrees anteverted (to match the femur)
What are the ligaments that make up the hip capusle?
Iliofemoral ligament (Y ligament of Bigelow): Strongest ligament that runs from AIIS to intertrochanteric line
Ischiofemoral ligament: attaches to femoral neck
What is the zona orbicularis?
Circular fibers that form a collar around the femoral neck
Form the annular ligament of the femoral neck
The labrum is continuous with what structure?
Transverse acetabular ligament
Describe the criteria for an adequate AP pelvis x-ray
Coccyx in line with symphysis
symmetric Obturator foramina
Symhysis:sacrococcygeal distance of:
32mm in men
47mm in women
What angle is classically measured off a Dunn view?
The alpha angle is formed by a line drawn from the center of the femoral head through the center of the femoral neck, and a line from the center of the femoral head to the femoral head/neck junction, found by the point by which the femoral neck diverges from a circle drawn around the femoral head. At present, the upper end of normal is an alpha angle of 50 - 55 degrees.
What angle is measured from a false profile view?
List the 6 fundamental lines of Letournel
roof (or dome/tectum)
iliopectineal line (anterior column)
ilioischial line (posterior column)
List the levels of:
Common iliac bifurcation
Aortic bifurcation: L4
Common iliac bifurcation: S1
Name the branches of the internal iliac artery (6)
Superior and inferior gluteal
What is the corona mortis? Where is it located?
Common Anatomic variant (+ in 83%)
Obturator + external iliac OR inferior epigastric arteries or
Located 40-96mm from the pubic symphysis (median 6cm)
What are the branhces of the profunda femoral artery?
Medial and lateral femoral circumflex arteries
Descibe the course of the femoral artery in the thigh
Enters thigh from under inguinal ligament as the common femoral artery, a continuation of the external iliac artery
Here, it lies midway between the ASIS and the symphysis pubis
The common femoral artery gives off the profunda femoris artery and becomes the superficial femoral artery
Superficial descends along the anteromedial part of the thigh in the femoral triangle
Then it enters and passes through the adductor (subsartorial) canal
Becomes the popliteal artery as it passes through an opening in adductor magnus near the junction of the middle and distal thirds of the thigh
What is the primary blood supply to femoral head?
Medial femoral circumflex artery
Describe the proximal femur blood supply
MFCA: femoral head via retinacular vessels
Obturator: vessels within ligamentum teres
What are the borders of the femoral triangle?
What makes up the floor, in what order?
Adductor longus: medially
inguinal ligament: superiorly
Floor (lat to med): iliacus, psoas, pectineus, adductor longus
What are the contents of the femoral triangle?
NAVEL (spell NAVEL towards the navel, aka lateral to medial)
Describe the safe zone for acetabular screws:
Which zone is safe? Dnagerous? What is at risk in each zone?
Divided into quadrants with one line running from ASIS to center of acetabulum and another line perpendicular to that
Posterior superior (Safest): sciatic nerve, superior gluteal n/a/v
Posterior inferior: safe if screws
Anterior superior: UNSAFE: external iliac artery/veins
Anterior inferior: UNSAFE: obturator n/a/v (b/c aiming for obturator foramen)
Name the short external rotators, from most proximal to most distal:
Name the OINA of all the muscles of the hip - see list in answers
Name the hip flexors and extensors:
Hamstrings: (ST, SM, BF)
Name the hip aB and aDDuctors
TFL (in a flexed hip)
Adductor brevis, longus, magnus
What is the innervation of adductor magnus?
Obturator (adductor) posterior division
Tibial of sciatic (hamstrings)
Name the internal rotators of the hip
Gluteus medius (anterior fibers)
Gluteus minimus (anterior fibers)
adductor magnus (posterior fibers)
Describe the lubosacral plexus +/- draw it…..
Made up of lumbar and sacral plexi from T12 - S3
Lumbar plexus: ventral rami of L1-L4 on anterior surface of quadratus lumborum within/deep to psoas major
Sacral plexus: ventral rami from L4-S4
Name the origin and course of femoral nerve
Emerges between psoas and ilicus
Runs superficial and medial to psoas tendon
Into femoral triangle
divides and innervates quads
What is the origin of LFCN and where does it exit pelvis?
Exits pelvis under inguinal ligament, 2cm distal to ASIS
Where is the sciatic nerve most likely to be found in relation to piriformis and SERs?
Deep to piriformis, superficial to SER
- Usually sits on top of SER, that’s why during a posterior approach you can use them to protect it
What is the internervous plane of the anterior approach to the hip?
Femoral and superior gluteal nerve
Superficial: sartorius & TFL
Deep: Rectus femoris and gluteus medius
In the lateral approach to the hip, where does the superior gluteal nerve run?
3-5cm above GT
What is the interval for the medial (Ludloff) approach to the hip?
Incision: 3cm below pubic tubercle
No real internervous plane
Superficial: adductor longus/gracilis: both anterior division of obturator nerve
Deep: adductor brevis and adductor magnus: posteriorly by sciatic nerve, anterior adductor division by the posterior division of the obturator nerve
Anterior division of obturator nerve between longus/brevis
Posterior division of obturator nerve on magnus & under brevis
Medial femoral circumflex artery on distal psoas
Name the dangers of the ilioinguinal approach
Femoral nerve: running beneath inguinal canal on iliopsoas
LFCN: medial to ASIS beneath external oblique
Femoral vessels: in femoral sheath
Inferior epigastric artery: medial to inginal ring. Ligate
Spermatic cord/round ligament
Where do the cluneal nerves run in a posterior bone graft approach?
8cm lateral to midline, so stay medial
Where do the superior gluteal vessels run in a posterior approach to bone graft?
Near the sciatic notch
Stay proximal to sciatic notch
What is the most common nerve injured during THA?
Sciatic, peroneal division b/c it is more lateral
What is the only muscle innervated by peroneal nerve proximal to the fibular neck?
Short head of biceps femoris
What is the most common complication in posterior iliac crest bone graft harvesting?
Injury to the superior gluteal artery
Which vessel provides the dominant supply to the femoral head?
Lateral epiphyseal vessels of the MCFA
A patient is undergoing percutaneous S1 SI screw fixation for a sacroiliac joint diastasis. What is the most common strength deficit sequela of this proposed screw trajectory?
- Loss of hip flexion
- Loss of knee extension
- Loss of ankle dorsiflexion
- Loss of great toe extension
- Loss of ankle plantar flexion
4: Loss of great toe extension due to damage to L5
What is the only hip approah with a true internervous plane? What is the plane?
Anterior (Smith Peterson) approach
Femoral & superior gluteal nerves
Superficial: Sartorius & TFL
Deep: G. med & rectus femoris
What are the dangers of the anterior approach to the hip?
LFCN: 2.5cm below ASIS, passing over sartorius
- Go through fascia of TFL (Hueter approach) to avoid damaging it
Femoral artery and nerve
Ascending branch of LFCA
What are the planes and dangers of the lateral approach to the hip?
Plane: No true internervous plane:
Muscle splitting: Gluteus medius (SGN) proximally and v.laterais (femoral) distally
SGN: 3-5cm proximal to GT
Femoral bundle: gentle anterior retractor placement
Transverse branch of the lateral femoral circumflex artery
What is the plane and dangers of the anterolateral approach to the hip?
Plane: No true internervous plane: SGN
femoral n/a/v overlying psoas: protect with careful anterior retraction
What is the plane/dangers of the posterior approch to the hip?
Plane: No true plane: ITB/glut maximus split
Sciatic nerve: reflect SER to protect it. Beware early division variant
Inferior gluteal artery: when splitting g.max, ligate/coagulate if seen. May retract into pelvis causing uncontrollable bleeding
Ascending branches of medial femoral circumflex artery. Protect by preserving quadratus femoris. Safe to release the proximal 1cm of quadratus femoris
What is the most common position of the sciatic nerve in relation to the piriformis? What are the other variants?
Describe the position, incision, plane and dangers of the surgical dislocation of the hip:
Incision: Lateral skin incision or one that is just anterior to the usual posterior approach incision
Plane: None: SGN only
Incise TFL & ID g. medius
Elevate g. minimus and capsule
Describe the medial approach to the hip:
Position: Supine with hip flexed, abducted and ER (figure 4)
Incision: 3cm below pubic tubercle. Can be either mini transverse (for adductor release) or longitudinal down adductor longus
Superficial: adductor longus/gracilis. Both anterior division of the obturator nerve
Deep: Adductor brevis/Adductor magnus. Posteriorly by sciatic nerve. Anteriorly by posterior division of the obturator nerve
Anterior division of obturator nerve: between longus and brevis
Posterior division of obturator nerve: runs on adductor magnus and under brevis
Medial femoral circumflex artery: runs medally on distal part of psoas tendon
What are the dangers in a posterior approach to PSIS for bone grafting? what is more commonly injured?
Superior gluteal a/v (more commonly injured)
Cluneal nerves: 8cm lateral to midline at PSIS
What does the external iliac artery become?
Common femoral artery, after the inguinal ligament
At what age are the SI joints fused by?