Muscles of the Iliac and Gluteal Region Flashcards
Muscles of the iliac region
ALL take origin in the iliac region and insert onto the femur
Three muscles of the iliac region
- Psoas major and minor
- Iliacus
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
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
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
Psoas major nerve supply
Branches of the lumbar plexus containing fibers from L2 and L3
Psoas major function
Flexor at the hip and flexor of the lumbar spine
Psoas minor notes
The psoas minor is an inconstant muscle found on anterior surface of psoas major
Psoas minor origin
12th thoracic and 1st lumbar vertebrae and intervertebral disc between them
Psoas minor insertion
Via a long, thin tendon, psoas minor inserts into the iliopectineal eminence and iliac fascia
Psoas minor nerve supply
1st lumbar nerve
Psoas minor function
Flexion of lumbar spine
Iliacus notes
Iliacus muscle fills the iliac fossa
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
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
Iliacus nerve supply
Femoral nerve
Iliacus function
Flexion at the hip
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
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
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
Gluteal aponeurosis
o Composed of vertical fibers which are present between the iliac crest and superior border of the gluteus maximus
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
Notes on gluteus maximus
Large thick muscle, composed of remarkably coarse parallel fibers and lies superficially on the buttock
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
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
Nerve supply of gluteus maximus
Inferior gluteal nerve
Function of gluteus maximus
Extend, laterally rotate and abduct the thigh at the hip
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
Gluteus medius origin
- Outer surface of the ilium between the iliac crest and posterior gluteal line (posteriorly)
- Anterior gluteal line (anteriorly)
Gluteus medius insertion
Oblique bony ridge on the lateral surface of the greater trochanter
Gluteus medius nerve supply
Superior gluteal nerve
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
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
Gluteus minimus origin
- Outer surface of the ilium between the anterior and inferior gluteal lines
- Edge of the greater sciatic notch
Gluteus minimus insertion
Anterior border of greater trochanter
- NOTE: a bursa is frequently found between its tendon and the greater trochanter
Gluteus minimus nerve supply
Superior gluteal nerve
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
Tensor fasciae latae notes
Entirely enclosed in the upper fibers of the iliotibial band
Tensor fasciae latae origin
- Anterior end of iliac crest near anterior superior iliac spine
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
Tensor fasciae latae nerve supply
Superior gluteal nerve
Tensor fasciae latae function
Hip flexor and medial rotator
Piriformis origin
Within the pelvis - anterior surface of the sacrum between the 1st, 2nd, 3rd and 4th sacral foramina
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
Piriformis nerve supply
2nd sacral nerve (or 1st and 2nd)
Piriformis function
Lateral rotation, abduction of a flexed hip and extension of the hip
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
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
Obturator internus nerve supply
Nerve to obturator internus (L5-S1, 2)
Obturator internus function
Lateral rotation of the hip, extension of the hip, abduction of a flexed hip
Superior gemelli notes
The superior and inferior gemelli are the two muscles that lie on either side of the tendon of the obturator internus
Superior gemelli origin
Outer surface of ischial spine
Superior gemelli insertion
After partial fusion with the tendon of the obturator internus, it inserts into
- Medial surface of the greater trochanter
Superior gemelli nerve supply
Nerve to obturator internus
Superior gemelli function
Lateral rotation of the hip
Inferior gemelli notes
Larger of the two gemelli muscles
Inferior gemelli origin
Upper (superomedial) part of the ischial tuberosity
Inferior gemelli insertion
After partial fusion with the tendon of the obturator internus, it inserts into
- Medial surface of the greater trochanter
Inferior gemelli nerve supply
Nerve to quadratus femoris
Inferior gemelli function
Lateral rotator at the hip
Quadratus femoris notes
Quadratus femoris is a muscle found between the inferior gemellus and the upper fibers of the adductor magnus
Quadratus femoris origin
External margin (lateral edge) of the ischial tuberosity
Quadratus femoris insertion
Linea quadrata and quadrate tubercle of the femur
Quadratus femoris nerve supply
Nerve to quadratus femoris (L4, L5, S1)
Quadratus femoris function
Abduction and lateral rotation of the hip
Obturator externus notes
Obturator externus covers the outer surface of the anterior pelvic wall
Obturator externus origin
- Those portions of the ischium and pubis which surround the medial margin of the obturator foramen
- Obturator membrane
Obturator externus insertion
Its tendon passes laterally to be inserted into the
- Trochanteric fossa of the femur
Obturator externus nerve supply
Posterior division of the obturator nerve
Obturator externus function
Adduction and lateral rotation of the hip
Muscle in the gluteal region that can vary
- Piriformis
- Superior gemellus
- Inferior gemellus
- Quadratus femoris
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
Superior gemellus variation
o May be absent
Inferior gemellus variation
o May be fused with quadratus femoris or obturator internus
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