Muscles of the Iliac and Gluteal Region Flashcards Preview

Lower Limb > Muscles of the Iliac and Gluteal Region > Flashcards

Flashcards in Muscles of the Iliac and Gluteal Region Deck (75):
1

Muscles of the iliac region

ALL take origin in the iliac region and insert onto the femur

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Three muscles of the iliac region

- Psoas major and minor
- Iliacus

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Muscles of the gluteal region

o Gluteus maximus
o Gluteus medius
o Gluteus minimus
o Tensor fasciae latae
o Piriformis
o Obturator internus
o Superior gemellus
o Inferior gemellus
o Quadratus femoris
o Obturator externus

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Psoas major origin

- Ventral surfaces of caudal borders and bases of the transverse processes of all lumbar vertebrae
- Lateral surfaces of intervertebral discs of the last thoracic vertebrae
- Tendinous arches which allow the passage of lumbar arteries, veins

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Psoas major insertion

Muscle passes distally across the brim of the true pelvis and deep to the inguinal ligament to insert into
- Apex of lesser trochanter of the femur (medial to insertion of iliacus)
NOTE: bursa separates the tendon from the pubis and hip joint capsule

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Psoas major nerve supply

Branches of the lumbar plexus containing fibers from L2 and L3

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Psoas major function

Flexor at the hip and flexor of the lumbar spine

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Psoas minor notes

The psoas minor is an inconstant muscle found on anterior surface of psoas major

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Psoas minor origin

12th thoracic and 1st lumbar vertebrae and intervertebral disc between them

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Psoas minor insertion

Via a long, thin tendon, psoas minor inserts into the iliopectineal eminence and iliac fascia

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Psoas minor nerve supply

1st lumbar nerve

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Psoas minor function

Flexion of lumbar spine

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Iliacus notes

Iliacus muscle fills the iliac fossa

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Iliacus origin

- Upper 2/3 of iliac fossa
- Iliac crest reaching the ASIS and AIIS
- Superolateral portion (ala) of the sacrum
- Anterior sacroiliac and iliolumbar ligaments

15

Iliacus insertion

The muscle becomes a tendon on the lateral side of the psoas major muscle and inserts into the base of the lesser trochanter of the femur

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Iliacus nerve supply

Femoral nerve

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Iliacus function

Flexion at the hip

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Iliacus minor is occasionally present

o A small muscle (sometimes considered to be a detached part of the iliacus) is occasionally present
o Arises from the anterior inferior iliac spine
o Inserts on the intertrochanteric line of the femur or into the iliofemoral ligament

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Fascia of the gluteal region

- Subcutaneous fascia of gluteal region is continuous with fascia of the thigh and back
- Made up of a superficial fatty layer and a deep membranous layer

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Deep layer of fasica of gluteal region

o Continuous with fascia lata of the thigh
o As fascia lata passes upward toward gluteal region, it surrounds gluteus maximus
o Tendon of gluteus maximus ends in the iliotibial tract, which is a strong tendon embedded in the fascia lata

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Gluteal aponeurosis

o Composed of vertical fibers which are present between the iliac crest and superior border of the gluteus maximus

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Muscles of gluteal region

o Gluteus maximus
o Gluteus medius
o Gluteus minimus
o Tensor fasciae latae
o Piriformis
o Obturator internus
o Superior gemellus
o Inferior gemellus
o Quadratus femoris
o Obturator externus

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Notes on gluteus maximus

Large thick muscle, composed of remarkably coarse parallel fibers and lies superficially on the buttock

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Origin of gluteus maximus

- Posterior gluteal line of the ilium (and bone superior and posterior to it)
- Posterior surface of the sacrum and coccyx
- Aponeurosis of the sacrospinalis muscle
- Sacrotuberous ligament
- Gluteal aponeurosis covering gluteus medius

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Insertion of gluteus maximus

Proximal and superficial fibers of distal muscle
- Iliotibial band

Deep fibers of distal portion
- Gluteal tuberosity

Bursae
- Generally, there are 3 bursae associated with gluteus maximus, which are all found on its deep surface
- 1st largest bursae - over the greater trochanter
- 2nd largest bursae - over the ischial tuberosity (most commonly missing)
- 3rd largest bursae - between tendon of gluteus maximus and tendon of vastus lateralis

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Nerve supply of gluteus maximus

Inferior gluteal nerve

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Function of gluteus maximus

Extend, laterally rotate and abduct the thigh at the hip

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Gluteus medius notes

Located on the outer surface of the pelvis, with its posterior ½ being covered by the gluteus maximus and its anterior ½ being covered by the gluteal aponeurosis

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Gluteus medius origin

- Outer surface of the ilium between the iliac crest and posterior gluteal line (posteriorly)
- Anterior gluteal line (anteriorly)

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Gluteus medius insertion

Oblique bony ridge on the lateral surface of the greater trochanter

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Gluteus medius nerve supply

Superior gluteal nerve

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Gluteus medius function

Abduction of the hip and medial rotation of an extended hip
- Anterior fibers  flex and medially rotate at the hip
- Posterior fibers  laterally rotates at the hip
***Most important = stabilization of the pelvis during locomotion

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Gluteus minimus notes

Third and smallest of the gluteal muscles
- Lies deep to gluteus medius
- Between medius and minimus is the superior gluteal nerve and the deep branches of the superior gluteal artery and vein

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Gluteus minimus origin

- Outer surface of the ilium between the anterior and inferior gluteal lines
- Edge of the greater sciatic notch

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Gluteus minimus insertion

Anterior border of greater trochanter
- NOTE: a bursa is frequently found between its tendon and the greater trochanter

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Gluteus minimus nerve supply

Superior gluteal nerve

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Gluteus minimus function

Abduction of the hip, medial rotation of an extended hip, weak hip flexor
- Like gluteus medius, it stabilizes the pelvis during locomotion

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Tensor fasciae latae notes

Entirely enclosed in the upper fibers of the iliotibial band

39

Tensor fasciae latae origin

- Anterior end of iliac crest near anterior superior iliac spine

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Tensor fasciae latae insertion

This short, bulky muscle has fibers which pass inferiorly to insert into the iliotibial tract, usually slightly distal to the level of the greater trochanter
- The iliotibial tract attaches inferiorly on the lateral tibial condyle and also forms part of the capsule of the knee joint

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Tensor fasciae latae nerve supply

Superior gluteal nerve

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Tensor fasciae latae function

Hip flexor and medial rotator

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Piriformis origin

Within the pelvis - anterior surface of the sacrum between the 1st, 2nd, 3rd and 4th sacral foramina

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Piriformis insertion

The muscle passes through the greater sciatic foramen to be inserted on the
- Superior border of the greater trochanter posterior to the common tendon of the obturator internus and gemelli

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Piriformis nerve supply

2nd sacral nerve (or 1st and 2nd)

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Piriformis function

Lateral rotation, abduction of a flexed hip and extension of the hip

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Obturator internus origin

- Inside surface of the superior and inferior pubic rami
- Inside surface of ischial ramus
- Ilial and ischial contributions to the wall of the true pelvis
- Obturator membrane

48

Obturator internus insertion

Fibers of the obturator internus are directed toward the lesser sciatic foramen where they pass at a right angle over the bone between the spine and tuberosity of the ischium – the tendon receives fibers fo the gemelli muscle and is then inserted into:
- Medial surface of greater trochanter, anterior to trochanteric fossa
NOTE: a bursa is found as the tendon passes through the lesser sciatic foramen, another is found between the tendon and the hip joint capsule

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Obturator internus nerve supply

Nerve to obturator internus (L5-S1, 2)

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Obturator internus function

Lateral rotation of the hip, extension of the hip, abduction of a flexed hip

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Superior gemelli notes

The superior and inferior gemelli are the two muscles that lie on either side of the tendon of the obturator internus

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Superior gemelli origin

Outer surface of ischial spine

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Superior gemelli insertion

After partial fusion with the tendon of the obturator internus, it inserts into
- Medial surface of the greater trochanter

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Superior gemelli nerve supply

Nerve to obturator internus

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Superior gemelli function

Lateral rotation of the hip

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Inferior gemelli notes

Larger of the two gemelli muscles

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Inferior gemelli origin

Upper (superomedial) part of the ischial tuberosity

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Inferior gemelli insertion

After partial fusion with the tendon of the obturator internus, it inserts into
- Medial surface of the greater trochanter

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Inferior gemelli nerve supply

Nerve to quadratus femoris

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Inferior gemelli function

Lateral rotator at the hip

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Quadratus femoris notes

Quadratus femoris is a muscle found between the inferior gemellus and the upper fibers of the adductor magnus

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Quadratus femoris origin

External margin (lateral edge) of the ischial tuberosity

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Quadratus femoris insertion

Linea quadrata and quadrate tubercle of the femur

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Quadratus femoris nerve supply

Nerve to quadratus femoris (L4, L5, S1)

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Quadratus femoris function

Abduction and lateral rotation of the hip

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Obturator externus notes

Obturator externus covers the outer surface of the anterior pelvic wall

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Obturator externus origin

- Those portions of the ischium and pubis which surround the medial margin of the obturator foramen
- Obturator membrane

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Obturator externus insertion

Its tendon passes laterally to be inserted into the
- Trochanteric fossa of the femur

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Obturator externus nerve supply

Posterior division of the obturator nerve

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Obturator externus function

Adduction and lateral rotation of the hip

71

Muscle in the gluteal region that can vary

- Piriformis
- Superior gemellus
- Inferior gemellus
- Quadratus femoris

72

Piriformis variation

o May be divided into 2 parts by the passage of the fibular portion of sciatic nerve
o May be fused with gluteus medius
o May also receive fibers from superior gemellus
o May be absent

73

Superior gemellus variation

o May be absent

74

Inferior gemellus variation

o May be fused with quadratus femoris or obturator internus

75

Quadratus femoris variation

o May be absent
o May be fused with adductor magnus or inferior gemellus
o May have 2 separate tendons of insertion, with the anterior tendon attaching to the intertrochanteric crest of the femur