Ch17: Pelvic Girdle Flashcards
What four bones make up the pelvic girdle?
- Sacrum
- Coccyx
- 2 Innominate Bones
Innominate bones are also known as the…
Hip bones or os coxae
Each irregularly shaped innominate bone is composed of…
The ilium, the ischium, and the pubis, which are fused together into one bone.
The joints or articulations in the pelvic girdle include the…
Right and left sacroiliac joints posterolaterally, the symphysis pubis anteriorly, and the lumbosacral joint superiorly
Functions of the pelvic girdle (pelvis)
- Most important to movement and posture: supports the weight of the body through the vertebral column and passes that force on to the innominate bones via the sacrum.
- Receives the ground forces generated when the foot contacts the ground and transmits them upward toward the vertebral column.
- During walking, the pelvic girdle moves as a unit in all three planes, allowing relatively smooth motion.
- Supports and protects the pelvic viscera
- Provides attachment for muscles
- Makes up the bony portion of the birth canal in females.
Joints of the Pelvic Girdle
Lumbosacral, Sacroiliac, Symphysis Pubis
False Pelvis
(Aka the greater or major pelvis)
- The bony area between the iliac crests and superior to the pelvic inlet.
- There are no pelvic organs within the false pelvis.
Pelvic Inlet
Can be seen by drawing a line between the sacral promontory posteriorly and the superior border of the symphysis pubis anteriorly
True Pelvis
(aka lesser or minor pelvis)
- Lies between the pelvic inlet and the pelvic outlet.
- Makes up the pelvic cavity
- Contains portions of the gastrointestinal (GI) tract, the urinary tract, and some reproductive organs
- In females, it forms the birth canal.
Pelvic Outlet
Can be seen by drawing a line from the tip of the coccyx to the inferior surface of the pubic symphysis
Differences in the Male and Female Pelvis
- Superior opening into pelvic cavity is more oval in females and more heart-shaped in males
- Pelvic cavity is shorter and less funnel-shaped in females, and sacrum is shorter and less curved
- Iliac walls are not as vertical, and the acetabula (plural of acetabulum) and ischial tuberosities are farther apart in females (makes the area within the female pelvic cavity greater than the longer, funnel-shaped cavity of the male pelvis)
- Pelvic arch is wider and more rounded in females
Pelvic Inlet and Outlet
True and False Pelvis
The bony area between the pelvic inlet and outlet is called…
True Pelvis
The bony area above the pelvic inlet is called…
False Pelvis
Male vs. Female Pelvic Arch
female is bigger than male
Sacroiliac Joint
(aka SI joint)
- Synovial, nonaxial joint between the sacrum and the ilium.
- Describes as a plane joint, but its articular surfaces are very irregular.
- Irregularity helps to lock the two surfaces together.
Function of the Sacroiliac Joint
To transmit weight from the upper body through the vertebral column to the innominate bones
- Designed for great stability and has very little mobility
- Like other synovial joints, its articular surface is lined with hyaline cartilage.
- Synovial membrane lines the nonarticular portions of the joint. It has a fibrous capsule reinforced by ligaments.
Function of the Sacroiliac Joint
To transmit weight from the upper body through the vertebral column to the innominate bones
- Designed for great stability and has very little mobility
- Like other synovial joints, its articular surface is lined with hyaline cartilage.
- Synovial membrane lines the nonarticular portions of the joint. It has a fibrous capsule reinforced by ligaments.
SI Joint Motion
The actual type and amount of movement occurring at the SI joint is the subject of considerable controversy
-It is generally accepted that the motions that do occur at the SI joint are nutation and counternutation
Sacroiliac Joint Motions
Nutation and Countermutation
Nutation
(aka sacral flexion)
- Occurs when the base of the sacrum (on the superior end) moves anteriorly and inferiorly which causes the inferior portion of the sacrum and the coccyx to move posteriorly.
- Pelvic outlet becomes larger and can be visualized by drawing a line from the tip of the coccyx to the bottom surface of the pubic symphysis
Counternutation
(aka sacral extension)
- Base of the sacrum moves posteriorly and superiorly, causing the tip of the coccyx to move anteriorly
- Pelvic inlet becomes larger and can be visualized by drawing a line from the base of the sacrum across to the top of the symphysis pubis
How much motion occurs with nutation and countermutation?
Minimal (and it can occur only in conjunction with other joint motions)
Nutation occurs with…
Trunk flexion or hip extension
Counternutation occurs with…
Trunk extension or hip flexion
Why are movements of nutation and countermutation in conjunction with other joint motions important during childbirth?
When baby moves through pelvic inlet during early stages of labor, the anterior-posterior (A-P) diameter needs to be larger so SI joints are in counternutation
-In later stages of labor, when baby passes through the pelvic outlet, it is important that this A-P diameter has increased and putting the SI joints in nutation increases the A-P diameter.
The two bones of the SI joint are the…
The sacrum and the ilium (the latter of which is the superior portion of the innominate bone)
Sacrum
Wedge-shaped and consists of five fused sacral vertebrae
- Located btw the 2 innominate bones and makes up the posterior border of the bony pelvis
- Anterior surface, often called the pelvic surface, is concave
- Bc it is tilted, the sacrum articulates with the fifth lumbar vertebra at an angle referred to as the lumbosacral angle.
Base of Sacrum
Superior surface of S1
Promontory of Sacrum
Ridge projecting along the anterior edge of the body of S1
Parts of the Sacrum (lateral view)
.
Parts of Sacrum (posterior view)
.
Superior Articular Process of the Sacrum
Located posteriorly on the base, it articulates with the inferior articular process of L5
Ala of the Sacrum
Lateral flared wings that are actually fused transverse processes
Ala of the Sacrum
Lateral flared wings that are actually fused transverse processes
Foramina of the Sacrum
Located on the anterior (pelvic) and dorsal surfaces are four pairs of foramina. They serve as the exit for the anterior and posterior divisions of the sacral nerves. The anterior foramina are larger.
Foramina of the Sacrum
Located on the anterior (pelvic) and dorsal surfaces are four pairs of foramina. They serve as the exit for the anterior and posterior divisions of the sacral nerves. The anterior foramina are larger.
Auricular Surface of the Sacrum
Named because its shape is similar to the external ear (auricular is Latin for “earlike”). It is located on the lateral surface of the sacrum and articulates with the ilium. The irregular surface assists in locking the two surfaces together, providing greater stability.
Pelvic Surface of the Sacrum
Concave anterior surface
Ilium
Makes up the superior part of the innominate bone.
Iliac Tuberosity of the Ilium
Large, roughened area between the posterior portion of the iliac crest and the auricular surface. It serves as an attachment for the interosseous ligament.
Iliac Tuberosity of the Ilium
Large, roughened area between the posterior portion of the iliac crest and the auricular surface. It serves as an attachment for the interosseous ligament.
Auricular Surface of the Ilium
Named for its earlike shape, it is the articular surface of the ilium with the sacrum. It is located inferior and anterior to the iliac tuberosity.
Auricular Surface of the Ilium
Named for its earlike shape, it is the articular surface of the ilium with the sacrum. It is located inferior and anterior to the iliac tuberosity.
Iliac Crest of the Ilium
Superior ridge of the ilium, the bony area felt when you place your hands on your hips
Iliac Crest of the Ilium
Superior ridge of the ilium, the bony area felt when you place your hands on your hips
Posterior Superior Iliac Spine of the Ilium
(PSIS) The posterior projection of the iliac crest and serves as an attachment for the posterior sacroiliac ligaments.
Posterior Inferior Iliac Spine of the Ilium
Often abbreviated PIIS, it lies inferior to the PSIS and serves as an attachment for the sacrotuberous ligaments
Posterior Inferior Iliac Spine of the Ilium
Often abbreviated PIIS, it lies inferior to the PSIS and serves as an attachment for the sacrotuberous ligaments
Greater Sciatic Notch of the Ilium
Formed by the ilium superiorly and the ilium and ischium inferiorly
Greater Sciatic Foramen of the Ilium
Formed from the greater sciatic notch by ligamentous attachments. The sacrotuberous ligament forms the posterior medial border of the foramen, and the sacrospinous ligament forms the inferior border. The sciatic nerve passes through this opening.
Parts of the Innominate Bone
.
Ligaments of the Pelvis
.
Cross Section of Sacroiliac joints
.
Ischial Body of the Ischium
Makes up all of the ischium superior to the tuberosity
Lesser Sciatic Notch of the Ischium
Smaller concavity located on the posterior body between the greater sciatic notch and the ischial tuberosity
Ischial Spine of the Ischium
Located on the posterior body and between the greater sciatic and lesser sciatic notches. It provides attachment for the sacrospinous ligament.
Ischial Tuberosity of the Ischium
The blunt, rough projection on the inferior part of the body. It is a weight-bearing surface when you are sitting.
Sacroiliac Joint
Meant to absorb a great deal of stress while providing great stability, it is heavily endowed with ligaments.
Anterior Sacroiliac Ligament
A broad, flat ligament on the anterior (pelvic) surface connecting the ala and pelvic surface of the sacrum to the auricular surface of the ilium. It holds together the anterior portion of the joint.
Interosseous Sacroiliac Ligament
The deepest, shortest, and strongest of the sacroiliac ligaments. It fills the roughened area immediately above and behind the auricular surfaces and the anterior sacroiliac ligament and it connects the tuberosities of the ilium to the sacrum.
Two Parts of the Posterior Sacroiliac Ligament
Short Posterior Sacroiliac Ligament and Long Posterior Sacroiliac Ligament
Short Posterior Sacroiliac Ligament
Runs more obliquely between the ilium and the upper portion of the sacrum on the dorsal surface. It prevents forward movement of the sacrum.
Long Posterior Sacroiliac Ligament
Runs more vertically between the posterior superior iliac spine and the lower portion of the sacrum. It prevents downward movement of the sacrum.
How many accessory ligaments further reinforce the sacroiliac joint
3 (sacrotuberous ligament, sacrospinous ligament, iliolumbar ligament)
Sacrotuberous Ligament
A very strong, triangular ligament running from between the PSIS and PIIS of the ilium, from the posterior and lateral side of the sacrum inferior to the auricular surface, and from the coccyx. These fibers come together to attach on the ischial tuberosity. It serves as an attachment for the gluteus maximus and prevents forward rotation of the sacrum.
Sacrospinous Ligament
Also a triangular and lies deep to the sacrotuberous ligament. It has a broad attachment from the lower lateral sacrum and coccyx on the posterior side. It then narrows to attach to the spine of the ischium.
Which two ligaments convert the greater sciatic notch into a foramen through which the sciatic nerve passes?
Sacrotuberous and Sacrospinous Ligaments.
Iliolumbar Ligament
Connects the transverse process of L5 with the iliac crest. It is described in more detail in the “Lumbosacral Joint” section.
Ligaments of the Pelvis (posterior view)
.
Pubic Symphysis Joint
Located in the midline of the body. The right and left pubic bones are joined anteriorly and form the pubic symphysis. A fibrocartilage disk lies between the two bones. Bc it is an amphiarthrodial joint, there is little movement but it becomes much more moveable in women during childbirth.
What two ligaments hold the pubic symphysis together?
Superior Pubic Ligament and Inferior Pubic Ligament
Superior Pubic Ligament
Attaches to the pubic tubercles on each side of the body and strengthens the superior and anterior portions of the joint.
Inferior Pubic Ligament
Attaches between the two inferior pubic rami. It strengthens the inferior portion of the joint.
Body of the Pubis
Main portion of the pubic bone, between the two projections (rami)—superior and inferior
Superior Ramus of the Pubis
Superior projection of the pubic body
Superior Ramus of the Pubis
Superior projection of the pubic body
Pubic Symphysis
.
Inferior Ramus of the Pubis
Inferior projection of the pubic body that provides attachment for the inferior pubic ligament
Tubercle of the Pubis
Projects anteriorly on the superior ramus near the midline and provides attachment for the superior pubic ligament
Lumbosacral Joint
Made up of the 5th lumbar vertebra and the 1st sacral vertebra. The articulation between these vertebrae is the same as that for all other vertebrae. The bodies of these 2 bones are separated by an intervertebral disk and are held together at the bodies by the anterior and posterior longitudinal ligaments. The vertebrae articulate at the articular processes (inferior articular process of L5 and superior articular process of S1). The ligaments holding together this portion of the joint are the supraspinal and interspinal ligaments and the ligamentum flava.
Lumbosacral Joint
Made up of the 5th lumbar vertebra and the 1st sacral vertebra. The articulation between these vertebrae is the same as that for all other vertebrae. The bodies of these 2 bones are separated by an intervertebral disk and are held together at the bodies by the anterior and posterior longitudinal ligaments. The vertebrae articulate at the articular processes (inferior articular process of L5 and superior articular process of S1). The ligaments holding together this portion of the joint are the supraspinal and interspinal ligaments and the ligamentum flava.
Two additional ligaments that specifically hold the lumbosacral joint together
Iliolumbar Ligament and Lumbosacral Ligament
Iliolumbar Ligament
Attaches on the transverse process of L5 and runs inferiorly and laterally to the posterior portion of the inner lip of the iliac crest. This ligament limits the rotation of L5 on S1, and it assists the articular processes in preventing L5 from moving anteriorly on S1
Iliolumbar Ligament
Attaches on the transverse process of L5 and runs inferiorly and laterally to the posterior portion of the inner lip of the iliac crest. This ligament limits the rotation of L5 on S1, and it assists the articular processes in preventing L5 from moving anteriorly on S1
Lumbosacral Ligament
Attaches on the transverse process of L5. It runs inferiorly and laterally to attach on the ala of the sacrum, where its fibers intermingle with the fibers of the anterior sacroiliac ligament
Lumbosacral Angle
Responsible for creating the lumbar lordosis, and indirectly for creating the rest of the spinal curve. Having optimal lumbosacral angle generates the optimal degree of curvature throughout the rest of the spine. The angle is determined by drawing one line parallel to the ground and another line along the base of the sacrum. This angle will increase as the pelvis tilts anteriorly and will decrease as the pelvis tilts posteriorly
The optimal lumbosacral angle is…
Approximately 30 degrees
As the lumbar lordosis increases…
The angle increases. This causes the shearing stresses of L5 on S1 to increase.
Forward movement of L5 on S1 is prevented by…
Ligamentous restraint, and the shape and fit of the inferior articular process of L5 is seated inside and behind the superior articular process of S1. Conversely, as the lumbar lordosis decreases, lumbosacral angle decreases.
Lumbosacral Angle and Lordosis
.
Lumbosacral Angle and Lordosis
.
The joints directly involved in pelvic girdle movement include the two hip joints and the lumbar joints, particularly the…
Lumbosacral articulation between L5 and S1.
Pelvic motions occur in how many planes?
All three planes
When you stand in an upright position, the pelvis should be…
Level; in the sagittal plane, the anterior superior iliac spine (ASIS) and the pubic symphysis should be in the same vertical plane
Anterior Tilt of the Pelvic Girdle
Occurs when the pelvis tilts forward, moving the ASIS anterior to the pubic symphysis.
Posterior Tilt of the Pelvic Girdle
Occurs when the pelvis tilts backward, moving the ASIS posterior to the pubic symphysis
Keeping the body upright when the pelvis tilts forward requires the joints above and below the pelvis to move in what direction?
The opposite direction.
When the pelvis tilts anteriorly, the lumbar portion of the vertebral column goes into…
Hyperextension and the hip joints flex.
When a person with a hip flexion contracture stands in the upright position, the pelvis…
Tilts anteriorly and the lumbar region hyperextends.
A person with tight hamstrings may stand with the pelvis tilted…
Posteriorly and the lumbar curve flattened.
In the frontal plane, the iliac crests should be
Level (You can assess this by placing your thumbs on the ASISs and determining whether your thumbs are at the same level)
Lateral Tilt
Occurs when the two iliac crests are not level. Because the pelvis moves as a unit, one side moves up as the other side moves down. Therefore, a point of reference must be used. (The side that is unsupported (or non–weight-bearing) will be the point of reference)
When you walk, the pelvis is
Level when both legs are in contact with the ground. When one leg leaves the ground (swing phase), it becomes unsupported and the pelvis on that side drops slightly. It is impossible to drop the pelvis on the weight-bearing side (the point of reference for lateral tilt is the unsupported, or less supported, side) The person bears weight on the right leg while lifting the left leg from the ground. The left side of the pelvis becomes unsupported and drops, or laterally tilts to the left.
Pelvic Movement in the Sagittal Plane
(A) The anterior superior iliac spine (ASIS) and the pubic symphysis should be in the same vertical plane.
(B) Anterior tilt occurs when the pelvis tilts forward, moving the ASIS anterior to the pubic symphysis.
(C) Posterior tilt occurs when the pelvis tilts backward, moving the ASIS posterior to the pubic symphysis.
To keep the body balanced, joints directly above and below will shift in the…
Opposite Direction
As the pelvis tilts (drops) to the right, the vertebral column…
Laterally bends to the left.
While the weight-bearing hip joint (left) adducts, the unsupported hip joint (right) becomes…
More abducted.
Pelvic movement in the frontal plane.
When standing upright on both feet, the iliac crests and the ASISs should be level.
Left lateral tilt of the Pelvis (anterior view)
One side of the pelvis moves up while the other side moves down.
Hip Hiking
(More accurately, it should be called pelvic hiking) It is possible to raise the pelvis on the unsupported side. When a person walks with a long leg cast or a brace, hip hiking helps the foot clear the floor during the swing phase. Shifting from one ischial tuberosity to the other while sitting also involves raising the pelvis on one side. This motion is useful in allowing some pressure relief.
Left lateral tilt of the Pelvis (anterior view).
When one leg leaves the ground, the pelvis on that side becomes unsupported. This causes the pelvis on that side to drop slightly. Therefore, lateral tilt is named by the unsupported side.
Other joint motions affected by pelvic tilting
As the pelvis tilts to the right, the vertebral column laterally bends to the left. The left hip joint (the weight-bearing side) adducts and the right hip joint (the non-weight-bearing side) abducts.
Other joint motions affected by pelvic tilting
As the pelvis tilts to the right, the vertebral column laterally bends to the left. The left hip joint (the weight-bearing side) adducts and the right hip joint (the non-weight-bearing side) abducts.
Pelvic Rotation
Occurs in the transverse plane around a vertical axis when one side of the pelvis moves forward or backward in relation to the other side. Looking down on the pelvis, the significant landmarks again are the left and right ASISs.
In the anatomical (neutral) position, the left and right ASISs should be in the…
Same Plane
The left leg is weight-bearing and the right leg is swinging forward
In this example, the right side of the pelvis rotates forward, moving the right ASIS in front of the left ASIS. Right forward pelvic rotation is the result of the left acetabulum rotating medially on the stationary left femoral head in a closed-chain motion. This is actually left hip rotation in a reverse muscle action
If the right leg swings backward…
the left acetabulum rotates laterally on the stationary left femoral head in a closed-chain motion. This results in right backward pelvic rotation (left hip rotation in a reverse muscle action) so that the right ASIS is now behind the left ASIS.
Pelvic rotation in the transverse plane (superior view)
(the red dot represents the femoral head and the red circle around it is the acetabulum)
(A) In the anatomical (neutral) position, both ASISs are in the same plane (shown as black line)
(B) With forward rotation, the right side of the pelvis moves forward. This causes the left side of the pelvis to rotate around the femoral head, resulting in left hip medial rotation
(C) With backward rotation, the right side of the pelvis moves backward. This causes the left side of the pelvis to rotate on the femoral head, resulting in left hip lateral rotation.
Pelvic Girdle: Anterior Tilt (Associated Motions of the Pelvic Girdle, Vertebral Column, and Hip Joints)
Vertebral Column: Hyperextension
Hip: Flexion
Pelvic Girdle: Posterior Tilt (Associated Motions of the Pelvic Girdle, Vertebral Column, and Hip Joints)
Vertebral Column: Flexion
Hip: Extension
Pelvic Girdle: Lateral Tilt, unsupported side (Associated Motions of the Pelvic Girdle, Vertebral Column, and Hip Joints)
Vertebral Column: Lateral bending (to supported side)
Hip:
Adduction: weight-bearing side
Abduction: non-weight-bearing side
Pelvic Girdle: Roation Forward (Associated Motions of the Pelvic Girdle, Vertebral Column, and Hip Joints)
Vertebral Column: Rotation (to opposite side)
Hip: Medial rotation (weight-bearing side)
Pelvic Girdle: Rotation Backward (Associated Motions of the Pelvic Girdle, Vertebral Column, and Hip Joints)
Vertebral Column: Rotation (to opposite side)
Hip: Lateral Rotation (weight-bearing side)
The pelvis is moved and controlled by groups of muscles acting as…
Force Couples
As the pelvis tilts in the anterior-posterior direction, the opposing muscle groups provide…
Movement and Control
To tilt the pelvis anteriorly, the lumbar trunk extensors, primarily the…
Erector spinae, pull up posteriorly while the hip flexors pull down anteriorly.
To tilt the pelvis posteriorly, the trunk flexors…
(primarily the abdominals) Pull up anteriorly while the hip extensors (gluteus maximus and hamstrings) pull down posteriorly
How are muscle groups acting for both anterior and posterior pelvic tilt?
These muscle groups are acting as a force couple by pulling in opposite directions and causing the pelvis to tilt.
Force couple causing anterior pelvic tilt (lateral view)
The trunk extensors pulling up (posteriorly) and the hip flexors pulling down (anteriorly) cause the pelvis to tilt anteriorly.
Force couple causing posterior pelvic tilt (lateral view)
The trunk flexors pulling up (anteriorly) and the hip extensors pulling down (posteriorly) cause the pelvis to tilt posteriorly.
Force couple causing posterior pelvic tilt (lateral view)
The trunk flexors pulling up (anteriorly) and the hip extensors pulling down (posteriorly) cause the pelvis to tilt posteriorly.
Without any muscle action, the force of gravity can…
Tilt the pelvis laterally when that leg becomes unsupported. However, to control or limit the amount of lateral tilting, muscle groups on opposite sides of the body also work as a force couple.
In a reversal of muscle action, the left trunk lateral benders…
(primarily the erector spinae and quadratus lumborum) Pull up on the left side of the pelvis while the right hip abductors (gluteus medius and minimus) pull down on the right side to keep the pelvis fairly level.
By preventing pelvic motion, the trunk lateral benders (primarily the erector spinae and quadratus lumborum) and the hip abductors (gluteus medius and minimus) can work together to provide…
Stability
-Pelvic and trunk control are necessary to provide the stable foundation upon which the head and extremities can move.
By preventing pelvic motion, the trunk lateral benders (primarily the erector spinae and quadratus lumborum) and the hip abductors (gluteus medius and minimus) can work together to provide…
Stability
-Pelvic and trunk control are necessary to provide the stable foundation upon which the head and extremities can move.
Habitual Anterior Tilt (Muscular Implications of Chronic Poor Posture)
- An individual who stands with this puts the lumbar vertebral column in hyperextension and the hips in flexion. Over time, the trunk extensor and hip flexor muscles adaptively shorten and become tight
- The opposite happens to the trunk flexors and hip extensors. The trunk flexors are lengthened over the abdomen and the hip extensors are lengthened over the gluteal region. As a result, they become overstretched and weakened.
Habitual Posterior Tilt (Muscular Implications of Chronic Poor Posture)
The normal lumbar curve is reduced and the hips become slightly hyperextended. In this position, the hip extensors are shortened while the trunk extensors are lengthened. An individual with a habitual posterior tilt posture will have hip extensor and trunk flexor tightness. The trunk extensors and hip flexors will be overstretched and weakened.
Force couple keeps the pelvis level in the frontal plane. In a reversal of muscle action…
The left trunk lateral benders pull up while the right hip abductors pull down. This keeps the pelvis fairly level as opposed to letting the pelvis drop on the unsupported side.
What pelvic girdle motions occur in the sagittal plane around the frontal axis?
Anterior/posterior pelvic tilt
What pelvic girdle motions occur in the frontal plane around the sagittal axis?
Lateral Tilt
What pelvic girdle motions occur in the transverse plane around the vertical axis?
Pelvic Rotation
Concentric contraction of the right quadratus lumborum would cause the pelvis to laterally tilt to which side? Another term for this motion is ___.
To the Left, aka Right Hip Hiking
Motion occurs at the lumbosacral joint when the pelvis tilts anteriorly and posteriorly and at what other distal joint?
The Hip Joints
What associated hip joint motion occurs when the pelvis tilts: Anteriorly
Hip Flexion
What associated hip joint motion occurs when the pelvis tilts: Posteriorly
Hip Extension
What associated hip joint motion occurs when the pelvis tilts: Laterally
Hip abduction on the unsupported side and hip adduction on the weight-bearing side
What associated hip joint motions occur when the left side of the pelvis rotates: Forward
Right Hip Medial Rotation
What associated hip joint motions occur when the left side of the pelvis rotates: Backward
Right Hip Lateral Rotation
What associated lumbar motion occurs when the pelvis tilts: Anteriorly
Hyperextension
What associated lumbar motion occurs when the pelvis tilts: Posteriorly
Flexion
What associated lumbar motion occurs when the pelvis tilts: Laterally
Lateral bending to opposite side
If a person maintained a posture in which the pelvis was tilted excessively in an anterior position: What muscle groups would tend to be tight?
Trunk extensors, hip flexors
If a person maintained a posture in which the pelvis was tilted excessively in an anterior position: What muscle groups would tend to be weak?
Trunk flexors and hip extensors
If an individual has a scoliotic curve that is convex to the left, and assuming the scoliosis was caused by a true leg length discrepancy, which would be the short leg?
Left Leg
A decreased lumbosacral angle causes the anterior shearing force of L5 on S1 to increase/decrease ________.
Decrease
Name two ligaments that help prevent anterior shearing of L5 on S1.
Iliolumbar and lumbosacral ligaments
Identify the position of the pelvis: Lying supine, bring your right leg up to your chest.
Posterior Pelvic Tilt
Identify the position of the pelvis: Kneeling on your hands and knees, let your trunk sag downward.
Anterior Pelvic Tilt
Identify the position of the pelvis: Kneeling on your hands and knees, arch your back.
Posterior Pelvic Tilt
Identify the position of the pelvis: Stand with your left foot on a telephone book and your right foot on the floor with weight on both feet. Identify the position of right and left hip joints in terms of abducted or adducted positions
Left hip adducted and right hip abducted
During an anterior pelvic tilt: What hip muscle group helps to generate this motion?
Hip Flexors
During an anterior pelvic tilt: What hip muscle needs to contract as a stabilizer while the muscle group in (a) is contracting?
Hip Extensors
During an anterior pelvic tilt: What trunk muscle group helps to generate this motion?
Trunk extensors
During an anterior pelvic tilt: What trunk muscle group needs to contract as a stabilizer while the muscle group in (c) is contracting?
Trunk Flexors
Lie supine with your knees flexed and the soles of your feet flat on the mat. Place your hand in the small of your back (lumbar curve). Push your back against your hand. Identify the main trunk, pelvic, and hip joint motions. Which muscles contribute to this force couple action?
Motions:
Muscles:
Motions: Posterior Pelvic Tilt, Trunk Flexion, Hip Extension
Muscles: Gluteus Maximus and trunk flexors
Standing in anatomical position, lift your left foot off the ground while keeping your hip and knee joints extended. Identify the main pelvic and hip joint motions. Which muscles contribute to this force couple action?
Motions:
Muscles:
Motions: Left Lateral Pelvic Tilt; Left Hip Adduction and Right Hip Abduction
Muscles: Right Hip Abductors (gluteus medius and minimus) and left quadratus lumborum
