Gluteus region and pelvis

How many bones form the pelvis?

7

What bones make up the pelvis?

2 ischial

2 pubic

2 ilium bones form each half

Posterior border is formed by the sacrum

Pubis symphysis

a joint located at the front of the pelvis where the left and right pubic bones meet

Sacroiliac joints

where the sacrum connects to the iliac/illum bones

◦Coxofemoral joint

where the head of the femur meets acetabulum of the pelvis (standard hip joint)

Iliofemoral ligament

a fan-shaped ligament located a the front of the hip joint

What are the external hip ligaments?

iliofemoral ligament

pubofemoral ligament

ischiofemoral ligament

Ramus

branches of the pubic bone

Ligamentum teres

serves primarily as conduit for the passage of the artery of the ligamentum

Inguinal ligament

strong band that runs from the ASIS to the pubic tubercle

What are the superficial muscles in glute/hip?

gluteus medius

gluteus maximus

gluteus minimus

What is the main deep group muscles in the glute/hip?

piriformis

What is the origin and insertion of the gluteus maximus?

O: ilium posterior to the posterior gluteal line (femur), dorsal surface of the sacrum and coccyx

I: IT band and gluteal tuberosity of femur

What nerve innervates the gluteus maximus?

inferior gluteal nerve

What are the actions of the gluteus maximus?

extends the femur at the hip

assists with lateral rotation of femur at hip

assist with extending the trunk from a flexed position

What is the origin and insertion of the gluteus medius?

O: external surface of the ilium between anterior and posterior gluteal lines

I: lateral surface of the greater trochanter

What nerve innervates the gluteus medius?

superior gluteal nerve

What is the action of the gluteus medius?

abducts and medially rotates the femur at the hip

steadies the pelvis when contralateral leg is lifted off the ground

What is the origin and insertion of the piriformis?

O: anterolateral aspect of sacrum

I: apex of the greater trochanter

What nerve innervates the piriformis?

not required (sacral S1 & 2)

What is the action of the piriformis?

lateral rotation of the femur at the hip (ER)

What is the anterior musculature of the hip?

rectus femoris

sartorius

illopsoas group

What is the medial musculature of the hip?

adductor group

gracilis

What is the femoral triangle?

a hollow region located in the supero-medial part of the anterior thigh

What important structures make up the femoral triangle?

femoral nerve

femoral artery

femoral vein

How do we stretch the piriformis?

typically to stretch a muscle you would do the opposite motion it performs (internal rotation) but after the external rotation surpasses 90 degrees it stratches it

What muscles are the external rotators of the hip?

piriformis

obturator internus

superior gemellus'

inferior gemellus

quadratus femoris

What is the main purpose of the external rotators of the hip outside of external rotation?

prevent the hip from internally rotating too much during gait by eccentrically contracting

What muscles make up the iliopsoas group?

psoas minor and major

iliacus

What structures create the triangle of the femoral triangle?

sartorius

inguinal ligament

adductor longus

What plane does the sacroiliac joint move in?

sagittal plane motion about the medial to lateral axis of rotation

What are the movements of the sacrum and iliac at the sacroiliac joint?

nutation and counternutation

Nutation- sacrum

when the sacrum move anteriorly and down

Counternutation- sacrum

when the sacrum moves posteriorly and up

Nutation- iliac

posterior rotation of innominate

Counternutation

anterior rotation of innominate

Form closure

describes the ability if the joint from the design of the pelvis

Form closure explained

the sacrum and ilium each have one flat surface and one rigid surface which interlock together causing stability

Force closure

describe the other forces acting across the joint to create stability

Force closure explained

for mobility to occur, further joint compression and stabilization is required to withstand a vertical load

Pelvis girdle

closed osteoarticular ring

Pelvis girdle characteristics

force transference between the spine and lower extremity

SIJ joint acts as a stress reliever for the pelvic ring

requires mobile stability

What anatomical features prevent shear and contribute to the self-locking mechanism?

“keystone-like“ bony anatomy of sacrum

ridges and depressions of SIJ surface

ligament support

efficient neuromuscular/fascial slings

Thoracolumbar fascia

a large diamond of connective tissue in the lower back that acts as a separation between the paraspinal muscles and posterior abdominal wall

Thoracolumbar fascia function

key structure for transfer of load from the trunk to lower extremity

contract muscles tighten TLF which stabilizes SIJ

Ankle of inclination

the angle formed by the femoral neck and femoral shaft within the frontal plane

What is the normal angle of the femoral neck and femoral shaft?

125 degrees

Coxa vara

when the angle between the femoral neck and femoral shaft is 105 degrees

Coxa valga

when the angle between the femoral neck and femoral shaft is 140 degrees

Torsion angle

the amount of twisting between the femoral neck and femoral shaft within the transverse plane

What is normal torsion angle?

neck faces 15 degrees anterior to the medial lateral axis through the femoral condyle

Torsion angle: excessive anteversion

> 15 degrees (toeing in)

Torsion angle: retroversion

< 15 degrees (toeing out)

What are the muscles of the posterior thigh (hamstrings)?

semimembranosus

semitendinosus

biceps femoris

Where do the hamstrings originate and insert?

O: ischial tuberosity

I:

medial hamstring

• semimembranosus: proximal tibia

• semitendinosus: pes anserine

lateral hamstring:

• bicep femoris: fibular head

What nerve innervates the hamstring muscles?

tibial portion of the sciatic nerve

What are the actions of the hamstrings?

hip extension

knee flexion

eversion and inversion of tibia at knee

What are the muscles of the anterior thigh?

psoas major

iliacus

sartorius

vastus lateralis

vastus medialis

vastus intermedius

rectus femoris

Where does the psoas major originate and insert?

O: lateral aspect of T12-T15 and transverse process of L1-L5

I: lesser trochanter of femur

What is the action of the psoas major?

hip flexion

Where does the iliacus originate and insert?

O: iliac fossa, iliac crest, ala of sacrum'

I: lesser trochanter of femur

What nerve innervates the iliacus?

femoral nerve

What is the action of the iliacus?

hip flexion

Where does the sartorius originate and insert?

O: ASIS

I: pes anserinus

What nerve innervates the sartorius?

femoral nerve

What are the actions of the sartorius?

hip flexion, abduction, and external rotation

knee flexion

Where does the rectus femoris originate and insert?

O: 2 heads

• straight head: ASIS

• reflected head: ilium

I: tibial tuberosity

What nerve innervates the rectus femoris?

femoral nerve

What are the actions of the rectus femoris?

knee extension

hip and pelvis flexion

Where does the vastus muscle group originate and insert?

O: superior surface of the femur

I: tibial tuberosity

What nerve innervates the vastus muscle group?

femoral nerve

What is the function of the vastus muscle group?

knee extension

What are the important muscles of the medial thigh?

adductor longus

gracilis

adductor magnus

Where does the adductor longus originate and insert?

O: body of pubis inferior to pubic crest

I: linea aspera/ mid medial femur

What nerve innervates the adductor longus?

obturator nerve

What is the action of the adductor longus?

adduction at the hip

What muscle is associated with a groin strain?

“groin strain“

What ligaments are located in the hip joint capsule & synovial membrane?

iliofemoral ligament

ischiofemoral ligament

pubofemoral ligament

• they spiral around the joint

Iliofemoral ligament characteristics

strongest and stiffest ligament in the hip

taut in full extension

Ischiofemoral ligament characteristics

taut in full internal rotation and extension

Pubofemoral ligament characteristics

taut in abduction and extreme extension

What is the closed-pack position of the hip?

full extension, slight internal rotation, and abduction

What kind of joint is the hip joint?

multiaxial ball and socket joint

What kind of surface does the femur have?

convex

What kind of surface does the pelvis have (acetabulum)?

concave

What are our hip flexors?

iliopsoas

rectus femoris

sartorius

adductor longus

What other action does the adductor magnus perform?

hip extension

At what degree of hip flexion does the adductor magnus also become an extensor?

> 70 degrees of flexion

What are our hip abductors?

gluteus medius

gluteus minimus

TFL (tensor fascia latae)

What is the most important abductor?

gluteus medius