Pelvis Attachment Anatomy Flashcards
Gracillis
The gracilis is a long, thin muscle located in the medial compartment of the thigh, originating from the pubic bone and inserting on the medial surface of the tibia, contributing to hip adduction, knee flexion, and internal knee rotation
Origin: Inferior margin of pubic symphysis, inferior ramus of pubis, and adjacent ramus of ischium.
(anterior to adductor brevis)
Insertion: Medial surface of tibial shaft, just posterior to sartorius.
Innervation: Anterior branch of the obturator nerve.
Arterial Supply: Obturator artery, medial circumflex femoral artery, and muscular branches of profunda femoris artery.
Location: Superficial muscle on the medial aspect of the thigh.
Piriformis
The piriformis muscle (from Latin piriformis ‘pear-shaped’) is a flat, pyramidally-shaped muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group.
Origin:
Anterior surface of the sacrum between the second, third, and fourth anterior sacral foramina.
Insertion:
Superior border of the greater trochanter of the femur
Innervation:
Piriformis nerve (L5, S1, S2)
Action:
Lateral rotator of the hip joint
Helps abduct the hip if it is flexed
Sciatic Nerve:
The sciatic nerve, the longest nerve in the body, typically runs underneath or, in some people, through the piriformis muscle.
when irritated or inflamed, cause pain and numbness in the buttocks and down the back of the leg, a condition known as piriformis syndrome.
Runs through the sciatic foramen. above the piriformis: superior gluteal nerves and vessels. below the piriformis: sciatic nerve
Quadratus Femoris
Located on the posterior side of the hip joint, it is a strong external rotator and adductor of the thigh, but also acts to stabilize the femoral head in the acetabulum.
most inferior of the deep gluteal muscles
The quadratus femoris is bordered by the obturator externus muscle (superiorly), fat, and the sciatic nerve
Origin: lateral upper ischial tuberosity
insertion - quadrate line of femur
innervation: nerve to quadratus femoris L5S1
Insertion:
Obturator Internus
Deep gluteal muscle
Lateral rotator
Muscle belly originates on the medial side of the obturator foramen.
Tendon travels around the femur, between the ischial spine and ischial tuberosity, being 90 degrees to attach to the greater trochanter.
Innervation: nerve to obturator internus L5 S2
Lateral rotators hip
Piriformis
Obturator internus and externus
Gemelli superior and inferior
quadratus femoris
gluteus maximus
Abductors
gluteus medius
gluteus minimus
TFL
muscles attaching to GT
POGO
piriformis
obturator internus
gemelli
obturator externus
Gluteus maximus
origin: ilium, sacrum, coccyx. posterior gluteal line
insertion: gluteal tuberosoty and IT band
Innervation: Inferior gluteal nerve L5 S2
largest and most superficial
Obturator externus
Lateral rotator
often considered part of the medial compartment
origin ischiopubic rami - lateral side.
insertion troachanteric fossa
innervated by the obturator nerve L2-4
Gemelli
Lie either side of the obturator internus tendon
superior:
origin - ischial spine
insertion - medial GT
innervation - nerve to obturator internus L5 s2
Inferior:
origin - ischial tuberosity
insertion - medial GT
Innervation: nerve to quadratus femoris L5S1
Gluteus medius
Origin - lateral ilium between anterior and posterior gluteal lines
insertion - GT
Inneration: Superior gluteal nerve L4S1
action: abduction
when walking, stabilises the pelvis (stops dropping to one side - trendelenberg)
gluteus minimus
origin: ilium between anterior and inferior gluteal lines
insertion: lateral GT deep to medius
innervation: superior gluteal L4S1
supports medius with abduction and pelvis stabilisation
IT Tract
attached to the anterolateral tubercle on the iliac creast and the lateral condyle of the tibia
gluteus maximum and TFL attach to it
stabilises the knee in extension and partial flexion
Important in walking and running
Surface markings of the sciatic nerve
L4,5,S1,2,3
exits the peliv via greater sciatic foramen below the piriformis
surface marking is a curved line between 2 points. halfway between PSIS and ischial tuberosity to half way between ischila tuberosity and GT
safe injection point on the buttocks
upper lateral quadrant
variations of the sciaitic nerve exiting the pelvis
most go beneath piriformis
some go through the muscle
others may divide hight with one branch going through piriformis
What does the common femoral artery branch into
profunda and superficial femoral
profunda gives of lateral circumflex femoral
SFA gives off popliteal
Acetabular notch
inferior margin of acetabulum
The transverse acetabular ligament spans across the notch, converting it into a foramen
llows the passage of the acetabular branch of the obturator artery, which supplies blood to the hip joint, including the ligamentum teres
also involved in load distrbution
surface landmark iliac creast
L4
safe for LP
meausring leg length
ilio pubic eminence
where the ilium and pubis meet
anteruir inferior to the acetabulum
It is an important anatomical landmark for the obturator nerve and external iliac vessels, which pass nearby.
used in THR to avoid injury to these structures
obturator crest
The obturator canal, which transmits the obturator nerve, artery, and vein, runs just inferior to the obturator crest.
Tensor Fascia Lata
origin: anterior iliac crest
insertion: IT band
Nerve: superior gluteal 4-S1
what muscles insert into the IT tract
gluteus maximus
TFL
