Pelvis/Hip/Thigh Flashcards
Between which muscles does the posterior obturator nerve run?
Adductor Brevis & Magnus
Describe the vascular tree from the Aorta
- Aorta bifurcates at L4
- Common Iliacs bifurcate at S1
- Internal Illiac
- Obturator A.
- Vesicular A.
- Lateral Sacral A.
- Inf & Sup Gluteal A.
- Internal Pudendal A.
- External Iliac
- Profuda Femoris
- MFCA
- LFCA
- Superficial Femoral A
- Profuda Femoris
- Internal Illiac
What is the importance of the iliac cortical density?
- Density: on the lateral, overylying slope of the sacral ala
- Want to be behinding it when inserting SI screws to avoid L5 nerve root
Muscles Making up the Floor of the Femoral Triangle
Lateral to Medial:
- Illiacus
- Psoas
- Pectineus
- Adductor Longus
In the lateral approach to the hip, where does the superior gluteal nerve run?
3-5cm proximal to the tip of the GT. Be careful when splitting gluteus medius
Signs of Sacral Dimorphism.
- Tongue in Groove Sign
- Lumberalized S1
- Sacralized L5
- Mamillary Bodies
- Oblong/Oval Foramen
*clinical significance: SI joint screw placement
Orientation of the Acetabulum
Anteverted 15-20 degrees
Space of Retzius
Potential space posterior to the pubic symphasis, infront of the bladder.
Which artery supplies artery of the ligmentum teres?
Obturator A.
What kind of joint is the hip joint?
Synovial Spheroid (Ball & Socket)
What landmark is used to determine coxa profund & protrusio?
Ilioischial Line
Centre Edge Angle of Wiberg
Angle between
- Vertical line passing through centre of femoral head
- Line from centre of femoral head to lateral edge of sourcil
- Normal 25-40 degrees
- Sign of hip dysplasia- acetabular coverage
- Lateral Centre Edge Angle - measured on false profile view
- Anterior Centre Edge Angle - measured on AP
Which Xray views do you order to assess adult hip dysplasia?
- AP Pelvis
- Crossover sign
- Anterior center edge angle - acetabular coverage
- Ischial Spine Sign
- Protrusio/Coxa Profunda
- Crowe Classification
- False Profile
- Assess acetabular coverage with lateral center edge angle
- Dunn View
- Assess femoral-head neck offset with alpha angle
- Assess version of femoral neck
Which nerve root lays on the Sacral Ala?
L5
Muscles Innervated by the Femoral Nerve
- Illiacus
- Psoas
- Pectineus
- Rectus Femoris
- Vastus Medialis
- Vastus Intermedius
- Vastus Lateralis
- Sartorius
Describe the Blood Supply to the Proxmal Femur
- Femoral Head: retincular branches of MFCA
- GT: LFCN
- Femoral Head via Ligamentum Teres: Branches of Obturator A.
Muscles Innervated by the Obturator N.
- Adductor Magnus (also innervated by tibial branch of sciatic n.)
- Adductor Longus
- Adductor Brevis
- Gracilis
Label the Diagram Below
How many vertebrae are fused in the Sacrum? Coccyx?
- Sacrum - 5
- Coccyx - 4-5
Describe the course of the Femoral Nerve
- Emerges between psoas and illiacus
- Superficial and medial to psoas
- Passes under inguinal ligament into femoral triangle (deep to sartorius). Gives off Saphenous N. branch
- Divides to innervate the quads
Muscles of the Anterior Compartment of the Thigh (4)
- Rectus Femoris
- Vastus Lateralis
- Vastus Medialis
- Vastus Intermedius
Muscles of the Posterior Compartment of the Thigh
- Biceps Femoris
- Semimembranosus
- Semitendinosus
Layers of the Abdominal Wall Encountered in a Pfannensteil Approach
Superifical to Deep
- Skin
- Subcutaneous Tissue
- Campers Fascia
- Anterior Rectus Sheath
- Rectus Abdominus
- Transversalis Fascia
- Extraperitoneal Connective Tissue
- Peritoneum
Variations in the course of Lateral Femoral Cutaneous Nerve?
- Sartorius Type (36%): between sartorius and ITB
- Posterior Type (32%): two main branches, one between sartorius and ITB, second crosses over ITB and runs posteriorly
- Fan Type (32%): fans out between sartorius and ITB
At what age to do the SI joints fuse?
50 years old
Blocks To Reduction in Dislocated Pediatric Hip
- Psoas Tendon
- Redundant Capsule
- Inverted Labrum
- Inverted Limbus
- Pulvinar
- Hypertrophied Ligamentum Teres
- Transverse Acetabular Ligament
Morel- Lavalee Lesion
- Internal degloving of subcuatneous tissue off of underlying fascia
- Usually reserved for lesions overlying the GT but can happen anywhere
Branches of the Lumbosacral Plexus (hint, also the nerves of the posterior abdominal wall)
- Subcostal N. (T12)
- Iliohypogastric N.
- Ilioinguinal N.
- Genitofemoral N.
- Lateral Femoral Cutaneous N.
- Femoral N.
- Obturator N.
- Lumbosacral Trunk
When does the triradiate cartilage fuse?
14-16 years old
Ligamentes of the Pubic Symphasis
- Superior Pubic Ligament (stronger)
- Inferior (Arcuate) Public Ligament
What denotes an adequate AP Pelvis?
- Coccyx in line with symphasis
- Symmetric teardrops
- Symmetric obturator foramen
- Sacrococcygeal junction to superior symphasis
- 32mm in men
- 47mm in women
- Tip of coccyx to superior symphsis 1-3 cm
What two tendons make up the conjoint tendon of the thigh?
Long Head of Biceps Femoris & Semitendonosis
What fascia separates the middle and lateral window in the ilioinguinal approach?
Iliopectineal Fascia
Which nerve roots contribute to the Lumbar Plexus? Sacral Plexus?
- Lumbar: L1-L4
- Sacral L5-S4
*all except S4 divides into anterior and posterior branch
In patients undergoing S1 SI joint screw fixation. What is the most common deficit in this screw trajectory?
Great toe extension (L5 nerve root)
What is a reliable landmark for positioning of the acetabular cup in THA?
Transverse Acetabular Ligament
Nerves of the Posterior Abdominal Wall
- Emerging Lateral to Psoas
- Ilioinguinal N.
- Illiohypogastric N.
- LFCN
- Emerging Medial to Psoas
- Obturator N.
- Lumbosacral Trunk
- Emerging Between Psoas and Iliacus: Femoral N.
- Peircing then running anterior to Psoas: Genitofemoral N.
Acetabular Zones & Dangers
Made by two intersecting perpendicular lines:
- ASIS to centre of acetabulum
- Line perpendicular to first
- Posterior Superior (SAFE ZONE)
- Risks: Sciatic N., Superior Gluteal N & vessels
- Posterior Inferior
- Next saftest zone. Keep screws <20mm
- Risks: Sciatic N, inferior gluteal N and vessels, internal pudendal N and vessels
- Anterior Superior (Avoid)
- Risks: External Illiac A & V
- Anterior Inferior (Avoid)
- Risks: Obturator N & vessels
Structures at risk with posteior illiac crest bone graft harvest?
- Superior gluteal A.- runs in scaitic notch, stay superior to notch
- Cluneal N - runs 8cm lateral to SI joint stay medial and use vertical incision
Peripheral Nerves of the Lumbosacral Plexus
SIPPS
Superior Gluteal N., N to Quadratus Femoris
Inferior Gluteal N, N. to Obturator Internus
Posterior Femoral Cutaneous N.
Pudendal N.
Sciatic N.