Internal Iliac Artery and Sacral Plexus Flashcards
Internal iliac artery supplies
- Pelvic region
- Perineum
- Gluteal regions
Internal iliac artery
- Begins L5/S1 disc level
- Variation in branching patterns
- Divides into anterior/posterior divisions
Obturator artery pathway
- Exits pelvis through obturator canal
- Gives of pubic branches
If obturator artery is absent
- Replaced by a large pubic branch from inferior epigastric
- At risk during femoral hernia surgery
Internal pudendal artery pathway
- Leaves pelvis between piriformis and coccygeus
- Through GSF
- Re-enters through LSC
Internal pudendal artery supplies
- Perineum
Inferior gluteal artery pathway
- Can arise from posterior division
- Passes between S1/2 or S2/3 sacral nerves
- Exits pelvis through GSF
- Inferior to piriformis
Inferior gluteal artery supplies
- Gluteal region muscles
- Sciatic nerve
Corona Mortis
- Anastomosis between external iliac or inferior epigastric and obturator artery and/or vein
- Common variant
- Different patterns
Branches of internal iliac artery posterior division
- Iliolumbar artery
- Lateral sacral artery
- Superior gluteal artery
Iliolumbar artery
- 1st branch of posterior trunk
- Ascends anterior to SI joint and lumbosacral trunk
- Lumbar and iliac branches
Lumbar branch of iliolumbar artery supplies
- Psoas major
- Iliacus
Iliac branch of iliolumbar artery supplies
- Iliacus
Lateral sacral artery
- Can be multiple branches
- Enters anterior sacral foramina
Lateral sacral artery supplies
- Sacral ala and dorsum
- Sacral nerve roots
Lateral sacral artery anastomoses with
- Median sacral artery
Superior gluteal artery pathway
- Largest branch
- Passes between lumbosacral trunk and S1 sacral nerves
- Exits pelvis through GSF, above piriformis
Superficial branch of superior gluteal artery supplies
- Gluteus maximus
Deep branch of superior gluteal artery supplies
- Gluteus medius
- Gluteus minimus
- TFL
- Hip
Median sacral artery
- Posterior surface of abdominal aorta
- Descends along midline of lower lumbar and sacrum
Collateral circulation in pelvis, gluteal, and hip regions
- Allows for continued perfusion if external iliac or femoral becomes occluded
Anastomoses of pelvis, gluteal, and hip regions
- Gluteal and branches of profunda femoris (trochanteric and cruciate anastomoses
- External iliac (inferior epigastric) and obturator artery
- Obturator with medial circumflex femoral and inferior gluteal
- Deep and superficial circumflex iliacs, iliac branch of iliolumbar and ascending branch of lateral circumflex femoral (ASIS anastomosis)
Sacral plexus
- Ventral rami S1-S4
- Loacated anterior to piriformis
- Lumbosacral trunk contributes ventral rami from L4 and L5
- Most branches exit pelvis through GSF
Branches of sacral plexus
- Superior gluteal
- Inferior gluteal
- Nerve to piriformis
- Perforating cutaneous nerve
- Sciatic
- Posterior cutaneous nerve of thigh
- Nerve to quadratus femoris
- Nerve to obturator internus
- Pudendal
Superior gluteal nerve (dorsal divisions of L4-S1)
- Passes superior to piriformis
- Motor to gluteus medius, gluteus minimus and TFL
- Sensory to hip joint
Inferior gluteal nerve (dorsal divisions of L5-S2)
- Passes inferior to piriformis
- Motor to gluteus maximus
Nerve to piriformis (dorsal divisions of S1,2)
- Motor to piriformis
- Doesn’t exit pelvic cavity
Perforating cutaneous nerve (dorsal divisions of S2,3)
- Pierces sacrotuberous ligament
- Sensory to skin over medial gluteal region
Superior gluteal nerve root
- Dorsal divisions of L4-S1
Inferior gluteal nerve root
- Dorsal divisions of L5-S2
Nerve to piriformis root
- Dorsal divisions of S1,2
Perforating cutaneous nerve root
- Dorsal divisions of S2,3
Sciatic (dorsal divisions of L4-S2 and ventral divisions of L4-S3)
- Sensory to hip joint
- Will divide into the common fibular and tibial nerves
- Major sensorimotor supplier to leg and foot
Posterior cutaneous nerve of thigh (dorsal divisions of S1,2 and ventral divisions of S2,3)
- Sensory to skin posterior thigh, popliteal fossa, upper calf
- Gives of inferior cluneal nerves that curve around lower border of glut max to supply skin over lower gluteal region
Nerve to quadratus femoris (ventral divisions of L4-S1)
- Motor to quadratus femoris and inferior gemellus muscles
- Sensory to hip joint
Nerve to obturator internus (ventral divisions of L5-S2)
- Motor to obturator internus and superior gemellus muscles
Pudendal (ventral divisions of S2-4)
- Major motor and sensory innervation of the perineum
Pelvic splanchnic (S2-4)
- Parasympathetic
Sciatic nerve root
- Dorsal divisions of L4-S2
- Ventral divisions of L4-S3
Posterior cutaneous nerve of thigh root
- Dorsal divisions of S1,2
- Ventral divisions of S2,3
Nerve to quadratus femoris root
- Ventral divisions of L4-S1
Nerve to obturator internus root
- Ventral divisions of L5-S2
Pudendal nerve root
- Ventral divisions of S2-4
Lumbosacral plexus roots
- Ventral rami of L1-S4
Subcostal nerve root
- T12
Iliohypogastric nerve root
- Ventral division of L1
Ilioinguinal nerve root
- Ventral division of L1
Genitofemoral nerve root
- Ventral divisions of L1,2
Lateral femoral cutaneous nerve root
- Dorsal divisions of L2,3
Nerve to psoas root
- Dorsal divisions of L2-4
- Also L1
Nerve to iliacus root
- Dorsal divisions of L2-4
- Branch of femoral
Femoral nerve root
- Dorsal divisions of L2-4
Obturator nerve root
- Ventral divisions of L2-4
Accessory obturator nerve root
- Ventral divisions of L3,4
Lumbosacral trunk root
- L4,5