Posterior Abdominal Wall/lumbosacral plexus/Pelvice Floor

• Superior Attachment: TPs of lumbar vertabrae; sides of bodies of T12-L5 vertebrae and intervening IV discs
• Inferior Attachment: Lesser trochanter of femur via iliopsoas tendon
• Innervation: anterior rami of L1, L2, L3
• Main Actions: Acting inferiorly with the iliacus, it flexes the thigh; acting superiorly it flexes the vertebral column laterally and anteriorly tilts pelvis; it is used to balance the trunk; when sitting it acts inferiorly with iliacus to flex trunk

• Superior Attachment: Sides of T12-L1 vertebrae and IV discs
• Inferior Attachment: Pectineal line, iliopectineal eminence via iliopectineal arch
• Innervation: anterior rami of L1, L2
• Main Actions: Flexes and stabilises hip joint; tilts pelvis posteriorly

• Superior Attachment: Superior two thirds of iliac fossa, ala of sacrum, and anterior sacroiliac ligaments
• Interior Attachment: Lesser trochanter of femur and shaft inferior to it and to iliopsoas tendon
• Innervation: Femoral nerve (L2-L3)
• Main Actions: Flexes thigh and stabilises hip joint; acts with psoas major

• Superior Attachment: Medial half of inferior border of 12th ribs and tips of lumbar TPs
• Inferior Attachment: Iliolumbar ligament and internal lip of iliac crest
• Innervation: Anterior branches of T12 and L1-L4
• Main Actions: Extends and laterally flexes vertebral column; fixes 12th rib during inspiration
• Reverse Action: "hip hiker" muscle: pulls hip up toward vertebral column

Can be palpated posteriorly

• Proximal Attachment: Body of pubis; tendinous arch of obturator fascia; ischial spine
• Distal Attachment: Sacrum, perineal body, anococcygeal ligament, walls of prostate or vagina, rectum, anal canal, and a little of the coccyx
• Innervation: Nerve to levator ani (branches of S4), inferior anal (rectal) nerve, and coccygeal plexus
• Main Actions: Forms most of the pelvic diaphragm the helps support pelvic viscera and resists increases in intra-abdominal pressure; elevates anus; stops urine flow

• Proximal Attachment: Pelvic surface of S2-S4 secments; superior margin of greater sciatic notch and sacrotuberous ligament
• Distal Attachment: Superior surface of greater trochanter
• Innervation: anterior rami of S1 and S2
• Main Actions: Rotates thigh laterally; ABducts thigh; assists in holding head of femur in acetabulum

• Proximal Attachment: Ischial spine
• Distal Attachment: Inferior end of sacrum and coccyx
• Innervation: Branches of S4 and S5 spinal nerves
• Main Actions: Forms small part of pelvic diaphragm that supports pelvic viscera; flexes coccyx; elevates anus; stops urine flow

• Proximal Attachment: Pelvic surfaces of ilium and ischium; obturator membrane
• Distal Attachment: Medial apsect of greater trochanter
• Innervation: Nerve to obturator internus (L5, S1, S2)
• Main Actions: Rotates thigh laterally; ABducts flexed thigh; assists in holding head of femur in acetabulum

• Imaginary plane from front of sacrum around pelvic brim to pubic symphysis
• more open on female
• heart shaped on males

From coccyx around ischial tuberosities

• Passes from the TPs of L5 to the posterior part of the inner lip of the iliac crest
• Strengthens lumbosacral joint

• Bounded by greater sciatic notch, sacrospinous ligament, and sacrotuberous ligament
• Sciatic n., piriformis, superior and inferior gluteal aa., vv. and nn. pass through it

• Bounded by ischial spine and lesser sciatic notch, and sacrotuberous ligament
• Tendon of obturator internus passes through it

• Goes from ischial spine to lower portion of sacrum and upper coccyx
• Forms inferior boundary of greater sciatic foramen

• Muscles Innervated: Anterior, medial, and lateral thigh
• Cutaneous Innervation: Lower abdomen; anterior, medial, and lateral thigh; medial lower leg

• Muscles Innervated: Gluteal, posterior thigh, below knee
• Cutaneous Innervation: Gluteal, posterior thigh, below knee (except medial lower leg)

• Not part of lumbar plexus
• Comes from just below 12th rib
• Innervates skin over ASIS

• Iliohypogastric (L1)
• Ilioinguinal (L1)
• Genitofemoral (L1-L2)
• Lateral Femoral Cutaneous (L2-L3)
• Femoral (L2-L4)
• Obturator (L2-L4)
• Lumbosacral trunk (L4-L5)

• Mnemonic: In Indiana Girls Like Fat Old Losers
• L1, L1, L1-L2, L2-L3, L2-L4, L2-L4, L4-L5

Innervates: Internal oblique, transverse abdominus, external oblique, rectus abdominus; Skin over hypogastric region and over iliac crests

Innervates: Internal oblique, tranverse abdominus, external oblique, rectus abdominus; Skin of external genitalia

Innervations: cremaster muscles (males); skin of superior medial thigh and external genitalia

• Innervates: skin on lateral thigh
• pierces skin just medial to ASIS

• Innervates: muscles of anterior thigh: hip flexors (quadriceps), knee extensors (sartorious)
• Anterior femoral cutaneous branch: innervates skin of anterior thigh
• Saphenous branch: medial leg

Innervates: ADductors, skin of medial thigh

Comes off lumbar plexus and down to sacral plexus

• Branch of the internal iliac a.
• Supplies: Gluteus maximus, gluteus minimus, gluteus medius, TFL
• Exits through greater sciatic notch above piriformis

• Branch of the internal iliac a.
• Supplies: Gluteus maximus, obturator internus, quadratus femoris, superior hamstrings
• Exits through greater sciatic notch below piriformis