Chapter 11
Pelvic Girdle and Hip Joint
Learning Outcomes: Students will be able to:
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The pelvic girdle is located between the trunk (lumbar area) and the thighs (femurs). The pelvic girdle functions primarily to provide stability and support for the upper body and transmits upper body weight to the lower limbs when standing (or to the ischial tuberosity when sitting). It also contributes to walking by providing a sturdy base for trunk and lower extremity muscles to move the more distal segments (distal mobility and proximal stability).
Figure 1 | The bones of the pelvic girdle consist of two os coxae, or innominates, formed by the embryonic fusion of the ilium, ischium, and pubis. The os coxae (innominates) are joined to the sacrum posteriorly at the sacroiliac joints, and to one another anteriorly at the pubic symphysis.. The pelvic girdle articulates with the fifth lumbar vertebra superiorly at the lumbosacral joint and inferiorly to the two femurs at the acetabulofemoral (hip) joints. |
Pubis Symphysis (amphiarthrodial) – the junction between the two pubic bones.
two pubic bones and during childbirth becomes softer allowing more movement at the joint.
on each side, strengthening the superior and anterior portions of the joint.
Attaches to the two inferior pubic rami, strengthening the inferior portion of the joint.
also help strengthen and stabilize this joint. | Figure 2 |
Sacroiliac (SI) Joints (arthrodial) – the junction between the “auricular” surfaces of the sacrum and the “auricular” surfaces of the ilium. The function of the sacroiliac joint is to transmit weight from the upper body through the vertebral column to the hips and femurs. The sacroiliac ligaments support the SI joint on the anterior and posterior surfaces of the joint.
posterior surface of the upper sacrum to the posterior surface of the ilium.
from the posterior superior iliac spine to the lower sacrum.
surface of the sacrum and ala to the auricular surface of ilium, stabilizing the anterior surface of the joint.
attaches from the sacrum to the ischial tuberosity.
attaches from the sacrum to the ischial spine. |
Figure 3 |
Sacroiliac Joint Motion |
The actual type and amount of movement occurring at the SI joint is controversial. However, it is generally accepted that only a very small amount of movement (1-3 mm) occurs, it must be in conjunction with other motions, and is described as nutation or counternutation. | |
Note: In the initial moments of these movements the sacrum actually moves opposite of what is stated, but as soon as the joint ligaments become taut the sacrum follows the pelvis and spine. |
Lumbosacral Joint | |
The lumbosacral joint is the articulation between the sacrum and L5 vertebra (L5-S1 spinal segment). Movement of the pelvis at the lumbosacral joint is limited. When the pelvis moves at the lumbosacral joint, the rest of the spine will begin to move once the motion at the lumbosacral joint has reached its limit. In addition to the spinal ligaments, this joint is also supported by:
| Figure 5 |
Pelvic Girdle Movements |
The joints directly involved in pelvic girdle movement include the two hip joints and the lumbosacral joint. Because the axial skeleton attaches to the pelvis through the sacroiliac joint, movement of the pelvis in relationship to the hip also influences spinal movements. |
In good posture the anterior superior iliac spine (ASIS) and the pubic symphysis are in the same vertical plane, known as spine neutral or neutral spine. | Figure 6 |
Sagittal Plane Movement | ||
Anterior Pelvic Rotation: occurs when the pelvis rotates forward, moving the ASIS anterior to the pubic synthesis, decreasing the angle between the pelvis and the femoral shafts, resulting in closed chain hip flexion. A force couple is creating by the simultaneous contraction of the hip flexors and trunk extensors.
Anterior Pelvic Tilt: Tilt reflects a postural fault due to muscular imbalance: tight hip flexors and low back extensors, weak trunk flexors and hip extensors. | Posterior Pelvic Rotation: occurs when the pelvis rotates backward, moving the ASIS posterior to the pubic synthesis, increasing the angle between the pelvis and the femoral shafts, resulting in closed chain hip extension. A force couple is created by the simultaneous contraction of the hip extensors and trunk flexors.
Posterior Pelvic Tilt: Tilt reflects a postural fault due to muscular imbalance: tight hip extensors and trunk flexors, weak hip flexors and low back extensors. | |
Frontal Plane Movement | ||
Left Lateral Pelvic Rotation: the right pelvis is elevated while the left moves inferiorly, resulting in left hip abduction and right hip adduction.
Figure 9 Front View | Right Lateral Pelvic Rotation: the left pelvis is elevated/hiked rotating the pelvis toward the right as it moves inferiorly, resulting in right hip abduction and left hip adduction.
Figure 10 Front View |
Transverse Plane Movement | ||
Left Transverse Pelvic Rotation: With rotation of the pelvis to the body’s left, the right iliac crest moves anteriorly in relation to the left iliac crest, which moves posteriorly. Closed chain right hip external rotation and left hip internal rotation occur during left transverse pelvic rotation.
Figure 11 | Right Transverse Pelvic Rotation: With rotation of the pelvis to the body’s right, the left iliac crest moves anteriorly in relation to the right iliac crest, which moves posteriorly. Closed chain right hip external rotation and left hip internal rotation occur during left transverse pelvic rotation.
Figure 12 |
Open Chain Pelvofemoral Motions
Hip Flexion: will be accompanied by ipsilateral posterior pelvic rotation to allow further hip flexion ROM, and contralateral anterior pelvic rotation.
Hip Extension: will be accompanied by ipsilateral anterior pelvic rotation to allow further hip extension ROM, and contralateral posterior pelvic rotation.
Acetabulofemoral (enarthrodial- triaxial) Closed Pack Position: Fully extended, internally rotated, and abducted Open Pack Position: Flexed 30º and abducted 30º |
The acetabulofemoral joint is the articulation between the acetabulum of the os coxa/innominate and the head of the femur. Being an enarthrodial joint, it is surrounded by a fibrous joint capsule that provides significant stability for the joint. To help further strengthen this joint the capsule contains strong circular deep fibers called the zona orbicularis that surround the neck of the femur. In addition, three strong capsular ligaments reinforce the hip joint anteriorly.
Hip Joint Movements | |
Hip Flexion: Anterior movement of the femur in the sagittal plane | Hip Extension: movement of the femur straight posteriorly from any point in the sagittal plane away from the pelvis |
Hip Abduction: Lateral movement of the femur in the frontal plane away from the body midline | Hip Adduction: Medial movement of the femur in the frontal plane toward the body midline |
Hip External Rotation: Lateral rotary movement of the femur in the transverse plane around its longitudinal axis away from the body midline | Hip Internal Rotation: Medial rotary movement of the femur in the transverse plane around its longitudinal axis toward the body midline |
Hip Joint Range of Motion | |
Flexion: 120° (knee flexed) 90° (knee extended) Extension: 30° Abduction: 45° Adduction: 30° | Internal Rotation: 45° External Rotation: 45° |
Femoral Angle of Inclination |
The angle between the femoral neck and femoral shaft. In infants this angle may be around 160º, but by adulthood normally averages 125º.
- Coxa Vara: describes an abnormal decrease in the angle of inclination (<120 degrees).
- Coxa Valga: describes an abnormal increase in the angle of inclination (>135 degrees
Figure 16
These changes alter the alignment of a muscle’s line of pull and can lead to decreased muscle strength due to changes in the length of the muscular force arm. This malalignment can also increase joint stress and lead to joint dysfunction. Specifically:
- Coxa Vara is associated with femoral growth plate changes and adolescent hip disorders. May be seen in older adults with osteoarthritis (OA) and/or osteoporosis. Often leads to genuvalgum and overpronation of the foot/ankle.
- Coxa Valga reduces the femoral joint congruency resulting in joint instability and an increased risk of hip dislocations. Often associated with genuvarum and overpronation of the foot/ankle.
Femoral Angle of Torsion | |||
The angle between the shaft of the femur and the neck of the femur in the transverse plane. Normally the head is rotated anteriorly (anteverted) from the shaft approximately 15º.
Figure 17 |
Muscle Innervation & Cutaneous Distribution | |
Figures 18, 19, 20, 21
Muscles of the Hip Joint | |
Anterior – primarily hip flexion
| Posterior – primarily hip extension
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Lateral – primarily hip abduction
| Medial – primarily hip adduction
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Muscles of the Anterior Hip | ||||||
| Figure 22
Figure 23
Figure 24 |
Muscles of the Lateral Hip | ||||
| Figure 26 |
Deep 6 External Rotators | |
Origin: Anterior sacrum, posterior portions of the ischium and obturator foreman Insertion: Superior and posterior aspect of the greater trochanter of the femur Action: Hip external rotation Nerve: Branches of the sacral plexus and the obturator nerve | Figure 27 |
Piriformis Syndrome | |
Description: Compression of the sciatic nerve (L4-S2) as it passes under (or through) the Piriformis causing pain to radiate into the buttock and distally along the course of the sciatic nerve. How to locate Piriformis: ½ distance between PSIS & sacral apex. Drop off edge of sacrum → lies between edge and greater trochanter. | Figure 28 |
Muscles of the Posterior Hip | |||||
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Figure 29 Figure 30 |
Muscles of the Medial Hip | |||||
| Figure 31
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Hip Flexion & IT Band Tightness Tests |
- Thomas Test (tight hip flexors, non-specific): Patient in supine position. While leaving the test leg on the table the opposite leg is flexed towards chest and held there with hands.
- Positive Test: If test knee/leg raises off table.
- Modified Thomas Test (distinguishing between Iliopsoas complex and Rectus Femoris tightness): Perform Thomas Test at the end of the table with test leg hanging off the edge.
- Positive Test: If when the non-test knee is brought to the chest the test knee extends, then Rectus Femoris tightness is present.
Figure 33
- Ober’s Test (tight Tensor Fascia Latae): Patient is side-lying with back close to table’s edge. Down leg hip and knee are flexed approx. 45°. Examiner passively abducts and extends leg so the TFL is over the greater trochanter.
- Positive Test: If leg does not drop down to anatomic position or adduction, but is restricted in abducted position.
Tight Hamstrings |
- 90-90 Straight Leg Raise Test (hamstring tightness): Patient is positioned supine. Leg to be tested is brought to 90° hip flexion with knee in flexed position. Then the knee is extended as far as possible.
- Positive Test: At end point the knee is more than 20° flexed.
Pelvis and Hip Joint Review Questions |
- What is the difference between a pelvic rotation and a pelvic tilt in the sagittal plane?
- What is the relationship between the ASIS and pubic symphysis in spine neutral? In anterior pelvic tilt?
- What is the difference between stretching the rectus femoris in the prone vs supine position?
- You stand on a step with your right foot positioned “parallel” on the step and your other foot is hanging off the
Step. You then hike or elevate your hip on the side hanging off the side of the step. When doing this movement,
what hip movement is being performed on the side that is hanging off and what hip movement is being performed on
the opposite side?
- What three muscles attach on the medial border of the tibia just below the medial tibial condyle?
- In what direction is the arthrokinematic roll during hip extension?
- During walking, in which direction, right or left, will your pelvic rotate when your right leg swings forward?
- A posterior pelvic rotation is a force couple movement involving which two muscle groups?
- What is the prime mover for hip abduction?
- Describe the movement of the sacrum during sacral nutation?