Chapter 4: The Pelvic Girdle and Hip Joint

Movements of the pelvic girdle

Anterior tilt, posterior tilt, R/L lateral tilt, R/L rotation

Iliac fossa

internal surface of the ilium

Angle of femoral inclination

is an angle formed b/t the neck of the femur and the shaft of the femur when viewed from the front - 145°-150° in newborns; decreases to 125° to 130° in adults; 120° in old age - angle of inclination has an important influence on the mobility and stability of the femur, as well as knee and lower leg alignment

Tensor fasciae latae

— hip abduction, hip flexion, and hip internal rotation — Provides important lateral support for the knee joint - No distal attachment b/c inserts into the iliotibial band

Suction in the hip joint

• A vacuum is created due to a difference in atmospheric pressure that pulls the head of the femur into the socket—even if all the ligaments and muscles were cut; the joint will stay together, and large forces are required to separate the bones as long as the capsule is intact

How does a dancer perform a proper roll-down to lessen low back and knee stress?

• Apply lumbar-pelvic rhythm... first utilizing the abdominal-hamstring force couple to maintain a neutral pelvis while motion is isolated to spinal flexion... • To complete the spinal flexion, one should focus on rotating the pelvis about with the head of the femur staying in place as much as possible and the ischial tuberosities rapidly going upward to the ceiling

Bony factors that determine turnout include...

• Depth and shape of acetabulum — more shallow acetabulum that faces more laterally is more favorable to external rotation; deeper acetabulum that faces more anteriorly lessens the extent of external rotation • Angle of the shaft of the femur relative to the neck of the femur also affects the extent of turnout (retroversion) • Curvature and length of the femoral neck may also affect mobility— a more concave and longer neck will tend to facilitate abduction and external rotation

Muscular factors... adequate extensibility in

• Hip internal rotators • Hip adductors

Joint capsule and ligamental factors

• Iliofemoral ligament... if more extensible will allow greater turnout

Sacroiliac (SI) Joint Pain Syndrome

• Inflammation of the SI joints The SI joint undergoes great stresses as forces are translated to and from the torso and lower extremities. Slight motion does exist in the SI joint.... In some cases the os coxae can get "wedged" and "locked" with an anterior displacement of the os coxae on the sacrum. This occurs with exaggerated lumbar lordosis, spinal hyperextension, or hip extension • SI problems are more common in women due to pelvis structure and hormones Causes: • Falling on the buttocks • Partnering • Sudden twisting motion • Leaning forward • Repetitive standing on one leg • Excessive lumbar lordosis Symptoms: • Pain posteriorly over one or both SI joints • Sharp twinges of pain • ROM limited in specific motions of the hip • Weak gluteus medius • Tight piriformis Treatment: • With an anterior displacement, hip flexion stretches, ab strengthening, and limiting spinal hyperextension • With posterior displacement, back extensor strengthening • Avoidance of flexion • Hip ABD strength and pelvic stabilization restoration are key • Joint mobilization techniques and correction of leg length differences with the use of heel lifts

Osteoarthritis

• Involves a progressive thinning and wearing away of the articular cartilage of the hip joint and associated inflammation Symptoms: • Dull aching pain in the groin, outer thigh, or buttocks; - loss of ROM, particularly hip int rotation Treatment: • Modify activity and gentle non-weight bearing exercises • Medications to reduce inflammation and pain, as well as promote cartilage healing • Total hip replacement with severe degeneration

Ischial tuberosities

"sitz bones" The most inferior part of the ischium

Biceps femoris

(Hip extension, Hip external rotation, knee flexion) workhorse for hip extension—assist with knee external rotation or hip external rotation when the knee and hip are extended

Semitendinosus and semimembranosus

(Hip extension, hip internal rotation, knee flexion) -assist with knee internal rotation or hip internal rotation when the hip and knee are extended

Anterior pelvic tilt Posterior pelvic tilt

(increased inclination) - top of pelvis rotates forward; ASIS are forward relative to the symphysis decreased inclination) - the top of the pelvis rotates backward such that the ASIS are back relative to the pubic symphysis

Gluteus maximus

- Hip extension - Hip external rotation Most powerful hip extensor and is crucial for movements requiring large forces - Can produce hip external rotation and upper fibers can produce hip abduction against resistance

Iliopsoas

- Hip flexion - Hip abduction (higher ranges) one of the most powerful muscles in the body —most important muscle for hip flexion above 90° 1. Assists with hip abduction 2. Only muscle that has attachments to the spine, pelvis, and femur which gives it the unique position not only to produce movement but also to stabilize the hip and effect the positioning of the lumbar spine 3. Posturally, prevents the torso from falling backward and may help maintain the lumbar curve • Only hip flexor which enables the leg to raise higher than 90 degrees b/c of its high origin at T12 • It has close contact with important structures within the abdomen: o The diaphragm o The kidneys o The colon • Poor functioning of these structures will have a negative effect on the iliopsoas muscle

How does a dancer improve his/her extension to the side?

- Strengthen the iliopsoas, DOR, and abductors, stretch the hamstrings - Strengthen the iliopsoas by working with a bent knee

Angle of femoral torsion

- The angle of the head and neck of the femur relative to the shaft of the femur and the femoral condyles when viewed from above ◦ 35° to 40° in newborns ◦ Decreases with age to 8° to 15° ◦ This angle can influence the extent of turnout allowed at the hip

Gluteus minimus

- hip abduction - anterior fibers are key for hip internal rotation - posterior fibers assist with extension

Pelvic rotation

- mvt of the whole pelvis in the transverse plan — involves a rotation of the pelvis such that one ASIS is anterior or posterior to the other • Rotation is named in terms of the direction toward which the front of the pelvis turns

Trochanteric bursitis

... Painful inflammation of the bursa located just superficial to the greater trochanter of the femur - bursa under IT band Causes: • Direct injury to the hip • Repetitive hip and knee flexion and extension Symptoms: • Pain on the outside of the hip and or buttocks • Point tender • Pain when walking or climbing stairs Treatment: • Meds • Heat application prior to class and ice after • Stretching of the IT band • Strengthening of hip ABD • Technique correction of excessive lateral tilt • Aspiration of fluid and an injection

Closed-Chain pelvic movements 1. Anterior pelvic tilt 2. Posterior tilt 3. R lateral tilt 4. R rotation

1. Associated mvt of spine: lumbar hyperextension Associated mvt of hip: hip flexion 2. lumbar flexion hip extension 3. L lateral spinal flexion R hip ABD, L hip ADD 4. L spinal rotation R hip internal rotation, L hip external rotation

The extent of turnout possible for a dancer is determined by...

1. Bony factors 2. Ligamental factors 3. Muscular factors

Hip External Rotation

1. DOR 2. Gluteus maximus

Hip Internal rotation

1. Gluteus medius 2. Gluteus minimus

Adductor magnus

1. Hip adduction 2. Hip extension (low ranges) (posterior fibers) - (3. hip flexion - anterior fibers)

Pectineus

1. Hip adduction 2. Hip flexion

Gracilis

1. Hip adduction 2. Hip flexion 3. Knee flexion

Adductor brevis

1. Hip adduction 2. Hip flexion (low ranges)

Adductor longus

1. Hip adduction 2. Hip flexion (low ranges)

How can a dancer optimize the height of the leg with less stress to the lumbar spine in an arabesque?

1. Max external rotation of the femur with the lower DOR muscles rather than rotate the pelvis 2. Think of "reaching the leg out" stretching across the front of the hip and utilizing the full possible range of hip extension, rather than immediately anteriorly tilting the pelvis 3. Focus on "lifting the leg from the knee" to encourage more use of the hamstrings trying to increase hip extension range and the height of the leg 4. When full range of hip extension is reached and the pelvis must tilt anteriorly, "pull the lower abs up and in" and "lift the upper back" to lessen the stress on the lumbar area and better distribute the necessary hyperextension throughout more of the spine 5. Delay the pelvic rotation 6. Strengthening the hip extensors and back extensors can enhance leg height in movements of the leg to the back.

Common muscular imbalances in dancers

1. Tightness and weakness of the abductor muscles 2. Imbalance in strength and mobility between the int/ext rotators 3. Tightness of the hip flexors 4. Imbalance in mobility between the medial and lateral hamstrings (- we work biceps femoris (most lateral hamstring) more than medial)

Deep Outward Rotators (DOR)

6 Small muscles located deep to the gluteus maximus 1. Piriformis 2. Quadratus femoris 3. Obturator internus 4. Obturator externus 5. Gemellus superior 6. Gemellus inferior

Angle of pelvic inclination

60° angle relative to the horizontal plane is the neutral position of the pelvis and roughly responds to a position in which both of the ASIS and pubic symphysis are in the same frontal plane

Iliotibial band (IT band)

A wide strip of fibrous tissue that extends down the outside of the upper leg. - Gluteus maximus, tensor fasciae latae insert into it - Extends from the iliac crest down the lateral part of the thigh to the lateral condyle of the tibia - Provides stability to the knee and assists with flexion and extension of the knee.

Hip Horizontal Adduction

Adductor group and pectineus

Medial muscles of the hip

Adductor longus Adductor brevis Adductor magnus Pectineus Gracilis

Hip Adduction

Angle b/t the medial surfaces of the articulating bones decrease 1. Adductor longus 2. Adductor brevis 3. Adductor magnus 4. Gracilis (1-3 = hip adductor group?)

Hip extension

Angle b/t the posterior surfaces of the articulating bones decrease 1. Gluteus maximus 2. Hamstrings (all 3)

Coxa valga

Angle is increased (greater than 125 degrees) • Increases load on femoral head but decreases the load on the neck of the femur • Increases the hip risk for subluxation or dislocation of the hip joint • Decreases the effectiveness of hip abductor muscles • Increases the ROM of hip abduction

Posterior superior iliac spine (PSIS)

Bony prominences on the back of the pelvis

Anterior superior iliac spine (ASIS)

Bony prominences on the front of the pelvis

Acetabular Labral Tear

Causes: Impingement between the femur and the acetabulum that compresses the labrum with extreme hip flexion and hip ABD Symptoms: • Clicking • Catching • Bulking sensation • Deep aching pain in the anterior hip or groin Treatment: • Reduce extreme hip movements • Optimize technique

Internal Snapping Hip

Causes: • Not maintaining external rotation and the iliopsoas snaps over the femoral head and hip capsule Treatment: • Meds • Stretching of the hip flexors • Correction of dance technique • Strengthening the hip external rotators, abductors, and iliopsoas to maintain turnout and minimize letting the femur rotate inward as the leg is lowered

Hip flexion

Decreases the angle b/t the anterior surfaces of the articulating bones 1. Iliopsoas 2. Rectus femoris 3. Sartorius

What kind of contraction is used to lower the leg in a controlled manner from being lifted to the front? What are the primary muscles?

Eccentric - Iliopsoas, rectus femoris, sartorius (hip flexors)

What kind of contraction occurs at the hip when one performs a flat back position? Why? What are the primary muscles?

Eccentric contraction. To control the lowering of the torso with gravity. (flexion joint action because you are creasing at the hip). Hamstrings and gluteus maximus

What kind of contraction is used to lower the leg in a controlled manner from being lifted to the side? What are the primary muscles?

Eccentric. Gluteus medius and gluteus minimus

Abdominal-hamstring force coupling

Engage abdominals and hamstrings to maintain neutral pelvis

Hip Horizontal Abduction

Glut group (gluteus medius, minimus and maximus) and DOR

Lateral muscles of the hip (Hip abductors)

Gluteus medius Gluteus minimus Tensor fasciae latae All lateral muscles play an important stabilizing role in standing and locomotion —when on one leg these muscles act to prevent the pelvis from dropping down on the opposite side or the support femur from excessively adducting "sitting in the hip" — called the abductor mechanism

Iliofemoral ligament limits

I. Hip extension II. Hip external rotation III. Hip adduction

Coxa vara

Inclination is decreased (less than 125°) • Decreases the load on the femoral head but increases load on neck of femur • Increases the risk of fracture of the neck of the femur • Increases the effectiveness of hip ABDuctor muscles • Decreases the ROM of hip ABDuction

Ischium

Irregular bone that is the strongest of the 3 pelvic bones

What kind of contraction is used to maintain an extended hip on the supporting leg?

Isometric

Pubofemoral ligament

Its inferior location makes it particularly effective for limiting... I. Hip abduction II. Hip extension III. Hip external rotation

All hamstrings work as

Knee flexors as well as hip extensors

Iliofemoral ligament

Located on the front of the hip joint "Y" ligament - One of the strongest ligaments in the body and plays a very important role in standing posture - Becomes taut with hip extension... passively allows stance to be maintained and prevents the trunk from falling backward or the head of the femur from displacing anteriorly with little hip muscular activity required

Sartorius

Longest muscle in the body Assists in hip flexion, abducts and externally rotates hip - designed for speed rather than strength which it is a common site for strain (can produce internal rotation and flexion on the knee) - Passé muscle

Lateral pelvic tilt

Movement of the whole pelvis in the frontal plane • Named in terms of which side of the pelvis is low, so a right lateral tilt the iliac crest, ASIS, and PSIS are lower of the right side

Muscle strains

Muscles involved: Hamstrings, adductor longus, gracilis, sartorius, rectus femoris and iliopsoas • Mechanism of injury is usually associated with a muscle being passively stretched or working eccentrically Possible causes: • Inadequate strength between right and left sides • Imbalanced strength with antagonists • Muscle fatigue • Electrolyte imbalance • Inadequate flexibility • Inadequate warm up • Poor coordination and technique Symptoms: • Tenderness over specific area • Swelling • Muscle spasms • Pain with stretching or forceful contraction of muscle Treatment: varies with degree of strain • Relative rest • Meds (anti-inflammatory) • Physical therapy modalities • Modification of activity to be pain free • Ice following class/rehearsal • Strengthening exercises

Lumbar-Pelvic Rhythm

Occurs when the distal end of the chain is fixed (feet) by standing but the proximal end of the chain (head) is free to move ◦ Ex. Roll-down (all the way down) - when you move your spine, your pelvis has to move

Rectus femoris

Only quadriceps muscle that crosses the hip joint —flexes the hip & extends the knee— known as the "kicking muscle"

Abductor Mechanism

Postural function of the hip abductors to maintain a level pelvis with the body weight appropriately positioned over the support foot - if not working properly, person will sit in hip - laterally tilt pelvis to unsupported side

Pelvic Stabilization

Process of keeping the pelvis relatively stationary during movements ◦ Co-contraction of the abs and back extensors

Ischiofemoral ligament

Provides protection from posterior displacement the femur Prevents... I. Hip internal rotation II. Horizontal adduction

Pelvic-Femoral Rhythm

Refers to the characteristic linking of the movements of the pelvis to the fundamental movements of the femur at the hip joint Ex. Hight battement to the front on forced-arch (hinged knee)

Os coxae

Sides of pelvis/ pelvic girdle -each side is made up of 3 bones—the ilium, ischium, and pubis...becomes fused together by the age of 15 or 16

Iliac crest

Superior convex border of ilium - top of iliac is level with the space between the spines of L4 & L5

Hip Abduction

The angle b/t the lateral surfaces of the articulating bones decrease 1. Gluteus medius 2. Gluteus minimus

Acetabulum

The concave surface of the pelvis (The hip socket) the head of the femur fits into this hip socket

Acetabulofemoral joint

The hip joint - Ball and socket joint formed between the acetabulum and the femoral head - 70% of head of femur articulates with the acetabulum - 3° of freedom of motion: Flexion-extension in sagittal Adduction-abduction in frontal External-internal rotation in transverse

Obturator foramen

The largest foramen in the body and is covered by a membrane and the surrounding bones form attachments for muscles that are key for effecting turnout (DOR)

Femur

The strongest and heaviest bone in the body —Head tapers into the Neck of the femur —angles to join the shaft of the femur —Greater trochanter faces laterally —Lesser trochanter faces medially — Shaft - diaphysis — Femoral condyles - Medial, lateral epicondyle

Why is it more difficult to maintain external rotation to the front as the leg height increased?

The upper DOR (piriformis - most superior) become less effective (are unable to ext rotate/switch to int rotation) above 90°. Improve: Strengthen lower DOR

Pelvic alignment and movements

When identifying pelvic alignment or movement, the relative position of bony landmarks such as the ASIS, PSIS, pubic symphysis are used

Pubic symphysis

Where os coxae are joined to each other anteriorly - Cartilaginous joint that is heavily reinforced by ligaments on all sides —only allows slight movement that is important for shock absorbency—during pregnancy the width of the cartilage increases and the ligaments become more lax to allow the slight spreading of the os coxae

Sacroiliac joints (SI joints)

Where the paired os coxae of the pelvic girdle are joined posteriorly to each other/ the sacrum - Quite stable due to the restraints offered by the fibrocartilage and fibrous tissue with the joints, the presence of very strong ligaments that tether the bones together, expansions from surrounding muscles, and the shape of the involved bones - Very small movements of the SI joint can occur - forward and back usually

Ilium

a flat bone that is the largest—forms the upper and side "winged" portion of the pelvis

Hamstrings

more postural and fine-tuning in contrast to the power junction of the gluts

Gluteus medius

most fundamental hip abductor — prime mover for hip internal rotation

External Snapping Hip

• Involves the iliotibial band's movement over the greater trochanter Causes: • Wide pelvis • Prominent trochanter • Ligamental laxity • Weakness of the hip ABD • Sitting in the hip • IT band tightness Treatment: • Stretching the hip ABD and IT band • Strengthening the hip ABD • Meds • Positioning the pelvis properly over the support foot will often reduce snapping and pain

Piriformis Syndrome

• Pain in the buttocks with or without pain radiating down the back of the ipsilateral thigh due to piriformis spasm that compresses the sciatic nerve and mimics sciatica Causes: • Extensive use of ext rotators with associated risk of strain, tightness, or imbalance with int rotator strength and flexibility • Technical errors • Posture • More common in females Symptoms: • Point tender and muscles spasms • Dull aching pain • Weakness of hip ABD and tight hamstrings Treatment: • Meds • US - ultrasound • Passive stretching • Ice massage • Balanced strength and flexibility program for both ext/int rotators • Strengthen hip ABD • Technique corrections

Iliopsoas Tendinitis

• Repetitive use of lifting the leg above 90°; particularly vulnerable when the hip is flexed, abducted, and externally rotated (More common in females) Symptoms: • Crepitus (crunching) • Pain • Stiffness in the groin • Increased pain when lifting to the front or side Treatment: • Meds • Hip flexor stretching • Technique evaluation

Acetabular labrum

• Rim of fibrocartilage that is thicker at the circumference than at the center, thus increasing the effective depth of the acetabulum and helping to hold the femoral head in place • Helps provide cushioning for the top and back of the acetabulum against the large compression forces of the head of the femur during erect stance and movements • Helps improve joint stability and protects the bone

Pelvic floor

• Stabilizes the pelvis from below, thus giving the pelvis both stability and mobility • Pelvic floor extends from the coccyx along the "sitz" bones to the pubic bones • When weight bearing, the pelvic floor contracts concentrically, while it eccentrically contracts on the side of the working leg • Pre-requisite to this is a neutral pelvis which allows the pelvic floor to actually work as the floor of the pelvis

To reduce injury risk, how is a flat-back position recommended to be performed?

• Strong co-contraction of the abdominals and spinal extensors to prevent undesired action of spinal flexion... strong eccentric contraction of the hamstrings to control the flexion of the hip

Extensions to the front

• The iliopsoas is the most important hip flexor above 90° of hip flexion, improving the strength Have to improve strength and ability to activate the iliopsoas can help the dancer achieve more height - In addition to hip flexor and iliopsoas activation, the height to which the leg can be lifted can be influenced by hamstring flexibility.

DOR function as a group

• To help hold the head of the femur in the acetabulum and can help prevent upward jamming of the femur with hip abduction - hip external rotation - at 90 degrees some of the muscles are able to produce hip horizontal abduction

Why do dancers turn-out?

• To increase ROM sideways (proscenium stage) • Move with equal ease in any direction • Increase ROM for the legs • Stability is increased • Develops long, slender muscles

Bursae of the hip

• Trochanteric bursa - bursitis - tight in IT band • Iliopsoas bursa - deeper than iliopsoas

Femoral anteversion

◦ Abnormal increase in the angle of femoral torsion - Excessive anteversion results in greater internal rotation of the femur - Associated with decreased external rotation - Associated with lumbar lordosis, an increased Q angle, patellar problems, and excessive pronation

Femoral retroversion

◦ Decrease in the angle of femoral torsion - Results in greater hip external rotation