L7 -Gluteal Region Flashcards
Describe the surface anatomy of the gluteal region
Located posterior to the pelvis
Superior border: iliac crest
Inferior border: gluteal sulcus (groove beneath gluteal fold)
What exits the greater sciatic foramen?
Gluteal neurovascular bundle, piriformis muscle, sciatic nerve, posterior femoral cutaneous nerve, pudendal and internal pudendal artery, obturator internus/superior gemellus nerve
What structures enter the lesser sciatic foramen?
Pudendal nerve and internal pudendal artery
Obturator internus/superior gemellus nerve
What structure exits the lesser sciatic foramen?
Obturator internus
Which two ligaments form the greater and lesser sciatic foramen?
Sacrotuberous and sacrospinous ligament
Describe the cluneal nerves
Cutaneous innervation to the buttock region
Describe the course of the superior gluteal nerve
Leaves pelvis via greater sciatic foramen superior to the piriformis with the superior gluteal artery
Runs b/w gluteus medius and gluteus minimus
Supplies gluteus medius, minimus and tensor fascia latae
Describe the inferior gluteal nerve
Leaves pelvis inferior to the piriformis with inferior gluteal artery
Supplies gluteus Maximus
Describe the sciatic nerve
L4-S2 Leaves pelvis inferior to piriformis Runs inferiorly deep to gluteus Maximus Divides half way down the thigh into tibial and common fibular nerves Does not supply any gluteal structures
Which nerve supplies more skin than any other cutaneous nerve?
Posterior femoral cutaneous nerve
Describe the nerves of small rotators
Obturator internus/superior gemellus: leaves pelvis via greater sciatic foramen and re-enters pelvis via lesser sciatic foramen
Quadratus femoris/inferior gemellus nerve
Describe the pudendal nerve
Most medial structure exiting greater sciatic foramen
Re-enters pelvis via lesser sciatic foramen to supply perineal structures
Anterior division of S2-4 ventral rami
What are the arteries of the gluteal region that arise from the internal iliac artery?
Superior and inferior gluteal artery
Internal pudendal artery
Describe the superior gluteal artery
Largest internal iliac artery branch
Superficial branch supplies gluteus maximus
Deep branch supplies gluteus medius + minimus and tensor fascia latae
What does the inferior gluteal artery supply?
Gluteus maximus, small lateral rotators and superior hamstrings
Describe the cruciate anastomosis of the thigh
Arteries involved: transverse branch of the medial circumflex femoral artery, terminal part of the transverse branch of the lateral circumflex femoral artery and the inferior gluteal artery
May provide blood to the leg if the femoral artery is occluded or severed
Describe the internal pudendal artery
Re-enters the pelvis via lesser sciatic foramen with pudendal nerve
Supplies perineal muscles and external genitalia
Does not supply any gluteal structures
What are the origin and insertion of the gluteus maximus?
O: external aspect of ilium, sacrotuberous ligament and dorsal surface of sacrum and coccyx
I: IT band, gluteal tuberosity on femur
What innervates the gluteus maximus?
Inferior gluteal nerve
What is the arterial supply for the gluteus maximus?
Superior and inferior gluteal arteries
What is the action of the gluteus maximus?
Extend and laterally rotate the thigh
What are the attachments of gluteus medius and minimus?
O: ilium between anterior and posterior gluteal lines
I: greater trochanter of femur
Minimus is deep to medius
What innervates and provides blood supply to gluteus medius and minimus?
Superior gluteal nerve and artery
What is the action of gluteus minimus and medius?
Abduct and medially rotate the thigh
What innervates the tensor fascia latae?
Superior gluteal nerve
What is the function of the tensor fascia latae?
Abducts, medially rotates and flexes thigh
Maintains extended leg
What are the attachments of the tensor fascia latae muscle?
O: outer lip of ASIS
I: IT band
What are the actions of the IT band?
Abduct, medially rotate and flex the thigh
Extend and flexes the knee
Extends leg, compensates for quadriceps paralysis via gluteus maximus flexion
Pulls patella laterally, antagonist of vastus medialis and synergist with flexing vastus lateralis for this action
If the center of rotation is within the boundaries of the IT band, then the band acts as what?
An extensor of the knee when the gluteus maximus contracts
If the center of rotation of anterior to the boundaries of the IT band, then the band acts as what?
As a flexor at the knee when the gluteus maximus contracts
What are the attachments of the piriformis muscle?
O: anterior sacrum and sacrotuberous ligament
I: greater trochanter of femur
What innervates the piriformis?
Nerve to piriformis
What is the arterial supply for the piriformis muscle?
Superior and inferior gluteal arteries
What is the collective action of the piriformis, obturator internus, superior and inferior gemellus?
Lateral rotation of the thigh when thigh is extended and abduction when thigh is flexed
Stabilize femoral head in acetabulum
What are the attachments for obturator internus?
O: internal surface of obturator foramen
I: greater trochanter of femur
Which muscles are innervated by the nerve to obturator internus?
Obturator internus + superior gemellus
Which muscles does the inferior gluteal artery provide blood supply to?
Obturator internus, superior gemellus and inferior gemellus
What are the attachments for superior and inferior gemellus?
O: ischial spine and ischial tuberosity
I: tendon of obturator internus muscle to greater trochanter
Which muscles are innervated by nerve to quadratus femoris?
Inferior gemellus and quadratus femoris
What are the attachments for the quadratus femoris muscle?
O: ischial tuberosity
I: intertrochanteric crest of femur
Which artery provides blood supply to the quadratus femoris muscle?
Medial femoral circumflex artery
What is the action of the quadratus femoris muscle?
Laterally rotate the hip
What are the attachments for obturator externus?
O: external margins of obturator foramen
I: trochanteric fossa
Which muscles of the gluteal region are considered to be in the vertically orientated group?
Gluteus maximus, medius and minimus , piriformis, and tensor fascia latae
Which gluteal region muscles are considered to be in the horizontally orientated group
Both gemelli, obturator internus and quadratus femoris
What are the bursa of the gluteal region?
Ischial bursa, trochanteric bursa and gluteofemoral bursa
Which muscles are innervated by the obturator nerve?
Quadratus femoris and obturator externus
