KinesiologyQuiz3Weeks8-10 Flashcards
Inominate
union of ilium, pubis, and ischium; anterior connection is the pubic symphysis, posterior connection is the sacrum (SI joint)
What populations commonly injure the acetabular joint?
young (dislocation) and elderly (degenerative)
During standing, what is the alignment of the inominate?
ASIS to pubic tubercle (lateral view - sagittal plane view)
Where does the inguinal ligament attach?
pubic tubercle on the pubis
Pubic Symphysis
completes anterior pelvic ring, hyaline cartilage (synarthrosis - relatively immobile), stress relief - walking, childbirth (moves slightly)
What separates the greater sciatic and lesser sciatic notch?
ischial spine
Femur - Angle of Inclination
angle within the frontal plane for optimal alignment of joint surfaces, normal angle is 125 degrees, starts larger, in coxa valga, but decreases due to loading (SAID)
Femur
longest and strongest bone, convex head, natural valgus at knee, bowing effect - anterior convexity, linea aspera - prominent line muscular attachment of v. medialis & v. intermedius
Coxa Vara
angle of inclination markedly less than 125 degrees, stress fractures in neck in elderly, sharp angle causes femur to rotates medially in the frontal plane to compensate sharp angle (more fractures in femoral neck)
Coxa Valga
angle of inclination markedly greater than 125 degrees, arthritis common because acetabulum is not sharing forces, femur rotates laterally in the frontal plane to compensate large angle (more dislocations)
Femur - Torsion Angle
normal anteversion - 15 degrees, anything markedly greater is excessive anteversion and markedly less is retroversion
Femur Torsion Angle Compensatory Mechanisms
abnormal anteversion - in-toeing; retroversion - out-toeing
What type of bone primarily occupies the femoral head and why?
cancellous bone, absorbs stress
The femoral head contacts the acetabulum surface through what structure?
lunate surface - thickest cartilage is along the superior-anterior to the fovea
What is the primary function of the lunate surface?
flattens slightly as the acetabular notch widens slightly, thereby increasing contact area as a means to reduce peak pressure
What is the fovea?
pit that contains ligamentum teres & branch of the obturator artery (some vascularity), most vascularity is through the joint capsule
Why could avascular necrosis of the femoral neck and head occur?
because most of the vascularity in this region is in the joint capsule rather than the bone itself
Describe the change in the area of joint surface contact during swing phase to mid stance phase of walking.
20% of the lunate surface during the swing phase to about 98% during the mid stance phase
Acetabular Alignment
acetabulum projects laterally from the pelvis with a varying amount of inferior and anterior tilt
Center Edge Angle
extent to which acetabulum covers femoral head within frontal plane, 35-40 degrees is normal, lower angle = increased risk of dislocation
Acetabular Anteversion Angle
extent acetabulum surrounds femoral head in horizontal plane, normal is 20 degrees, high angle = anterior hip dislocation
Which ligaments reinforce the hip joint capsule?
iliofemoral, pubofemoral, ischiofemoral
Iliofemoral Ligament
Y ligament, thick and strong, taut in extension & lateral fibers with external rotation, femoral head rests on it during full extension
Pubofemoral Ligament
taut with hip abduction and extension
Ischiofemoral Ligament
superficial fibers - taut in internal rotation and extension, superior fibers - taut in adduction, inferior fibers - taut in flexion
What is closed pack position for the hip?
full extension, slight abduction, slight internal rotation (taut position of ligaments)
What is maximal joint congruency for the hip?
90 degrees of flexion, moderate abduction and external rotation (most contact area)
Which ligament of the hip would a quadraplegic rely on to stand?
iliofemoral ligament
Why would someone with capsular swelling in the hip walk hunched over?
attempting to achieve 60 degrees of hip flexion where intracapsular pressure is least (shortened and tight iliopsoas, erector spinae are stretched and weak)
Femoral-on-Pelvic Flexion/Extension
sagittal plane, 120 degrees flexion and 20 degrees extension, dependent on knee flexion/extension, extension stretches iliofemoral ligament & hip flexors when knee is straight but rectus femoris when knee bent
Femoral-on-Pelvic Abduction/Adduction
frontal plane, 40 degrees abduction limited by pubofemoral ligament, add. muscles, hamstrings and 25 degrees adduction limited by abd. muscles, IT band, superior fibers of the ischiofemoral ligament
Femoral-on-Pelvic Internal/External Rotation
horizontal plane, 35 degrees internal rotation limited by ischiofemoral ligament and ER muscles and 45 degrees external rotation limited by iliofemoral ligament
Describe ipsidirectional lumbopelvic rhythm.
lumbar spine and pelvis rotate in the same direction, amplifying overall trunk motion and maximizing angular displacement for extremity movement
Describe contradirectional lumbopelvic rhythm.
lumbar spine and pelvis rotate in opposite directions, important for postural reactions, used during walking
Would pelvic-on-femoral osteokinematics assume ipsidirectional or contradirectional lumbopelvic rhythm?
contradirectional lumbopelvic rhythm, in many cases the amount of pelvic-on-femoral rotation is restricted by natural limitations of movement within the lumbar spine
Pelvic-on-Femoral Sagittal Plane Movement
flexion - anterior pelvic tilt (taut biceps femoris), extension - posterior pelvic tilt (taut iliofemoral ligament and rectus femoris)
Pelvic-on-Femoral Frontal Plane Movement
abduction (taut intertransverse, pubofemoral ligaments and add. muscles) and adduction (taut intertransverse ligament, piriformis, TFL, IT)
Pelvic-on-Femoral Horizontal Plane Movement
internal and external rotation, about 15 degrees each way
Arthrokinematics of the Hip (Paths for Hip Motion)
abduction/adduction - longitudinal diameter of joint surfaces; internal/external rotation - transverse diameter of joint surfaces (with hip extended); flexion/extension - spin
Which muscles are innervated by the lumbar plexus?
anterior and medial thigh, including quadriceps femoris
Which muscles are innervated by the sacral plexus?
posterior and lateral hip, posterior thigh, and entire lower leg
Which roots form the lumbar plexus?
ventral rami of spinal nerve roots T12-L4
What are the two primary nerve branches from the lumbar plexus and what are their roots?
femoral nerve and obturator nerve, both nerves are formed from L2-L4 nerve roots
Which muscles receive motor innervation from the femoral nerve?
hip flexors, knee extensors, sartorius and part of pectineus
What is the sensory distribution of the femoral nerve?
anterior-medial thigh via anterior femoral cutaneous nerve and anterior-medial lower leg via saphenous cutaneous nerve
Describe the motor and sensory aspects of the obturator nerve.
motor - hip adductors; sensory - medial thigh
Where does the obturator nerve split into anterior and posterior branches?
obturator foramen
Which nerve roots form the sacral plexus?
ventral rami of L4-S4 spinal nerve roots
Through what do most nerves from the sacral plexus exit the pelvis and which muscles are innervated (in general)?
greater sciatic foramen, posterior hip musculature
What nerves make up the sacral plexus?
3 nerves that innervate ER musculature (nerve by name), superior gluteal nerve (glut. med. and min.), inferior gluteal nerve (glut. max.), sciatic nerve
Sciatic Nerve
widest and longest in the body, exits pelvis through greater sciatic foramen inferior to piriformis, consists of tibial nerve and common peroneal nerve (division can occur in different locations)
Why would children complaining of knee pain actually have a hip pathology?
hip capsule receives sensory innervation by the same nerve roots that supply the overlying muscles, anterior capsule receives fibers from femoral nerve while medial aspect of hip and knee receive fibers from obturator nerve
What are two considerations for muscular function at the hip?
1) line-of-force of each muscle does not represent a force vector, only the overall direction of muscle force 2) line-of-force and subsequent lengths of the moment arms apply only to anatomic position
What are the primary hip flexor muscles?
iliopsoas - iliacus and psoas major; primary hip flexor both femoral-on-pelvic and pelvic-on-femoral; iliacus - anterior tilting pelvis and can accentuate lumbar lordosis without ab stabilizing; psoas major - vertical stability to the lumbar spine
Name the hip flexor muscles.
iliopsoas, sartorius, tensor fascia latae, rectus femoris, pectineus, adductor longus
Sartorius
originates at the ASIS, combined action of hip flexion, external rotation, abduction
Tensor Fascia Latae
attaches to the ilium just lateral to sartorius, short muscle that attaches distally to proximal IT band, primary flexor and abductor secondary internal rotator
Rectus Femoris
two joint muscle, 1/3 of total isometric flexor torque at hip, primary knee extensor
Describe the pelvic-on-femoral hip flexion resulting in anterior pelvic tilt.
force-couple between hip flexors and low back extensors, increase in lordosis at lumbar spine, increases compression on lumbar apophyseal joints (normal lordosis optimizes alignment of entire spine)
Which muscles are synergistic with hip flexors during femoral-on-pelvic hip flexion and what would result if these muscles were weak?
abdominal muscles, anterior pelvic tilt and then increased lumbar lordosis will occur if abdominals do not stabilize and initiate posterior pelvic tilt so hip flexors can initiate flexion
Which muscles would fire to prevent further hip flexion if the psoas major were tight (hip flexion contracture on biomechanics of standing)?
gluteus maximus, adductor magnus, hamstrings
List primary hip adductors.
pectineus, adductor longus, gracilis, adductor brevis, adductor magnus
List secondary hip adductors.
biceps femoris, gluteus maximus (inferior fibers), quadratus femoris
Which muscles compose the superficial, middle, and deep layers of hip adductors?
superficial - pectineus, gracilis, adductor longus; middle - adductor brevis; deep - adductor magnus (anterior and posterior heads)
What is unique about the adductor longus muscle?
can be extensor (when hip flexed) or flexor (when hip extended) based on the position of the hip in addition to its primary movement of adduction
Which muscles are primarily responsible for hip internal rotation (anatomic position)?
anterior fibers of gluteus med. and min., adductors, and TFL (no primary hip internal rotators exist)
How is internal rotation affected by flexing the hip to 90 degrees?
internal rotation torque potential of the internal rotator muscles dramatically increases (50%), several external rotator muscles switch (piriformis), angle of insertion changes to near 90 degrees
How do the hip internal rotators function while walking?
rotate the pelvis in the horizontal plane over a relatively fixed femur during stance phase
Name the primary hip extensor muscles.
gluteus maximus, hamstrings, posterior head of the adductor magnus
Name the secondary hip extensor muscles.
posterior fibers of gluteus medius, adductor muscles (only when hip is flexed beyond 50-60 degrees)
At 75 degrees of hip flexion, which muscles would account for 90% of the total extensor torque potential at the hip?
hamstrings and adductor magnus
Describe the motion involved with posterior pelvic tilt (which muscles function in the force-couple).
hip extensor and abdominal muscles act in force-couple (pelvic-on-femoral hip extension), causes a decreased lumbar lordosis
Function of Hip Extensors
control forward lean of the body, slightly flexed posture is minimal activation of glut. max. and hamstrings, flexed position has greater hamstring activation, glut. max. relatively low effort throughout
Femoral-on-Pelvic Hip Extension
large extensor torque to accelerate body forward and upward (when flexed hip), adductor muscles assist
List the primary hip abductors.
gluteus medius, gluteus minimus, TFL
List the secondary hip abductors.
piriformis and sartorius
Which muscle has the greatest abductor moment arm?
gluteus medius, 60% of total abductor CSA, anterior fibers internally rotate the hip (slight), posterior fibers extend and externally rotate
How does the function of gluteus minimus differ from medius?
similar but it has the potential for flexion and IR in the anterior fibers
Which muscle is the smallest of the three primary hip abductors?
TFL, 11% of total abductor CSA
What role does hip abduction play in walking?
control of frontal plane stability of the pelvis during walking, stance phase of gait, primarily glut. med., this is case for all WB activities
Approximate Joint Reaction Force Through Hip During Walking
2.4 times BW (up to 5.5 times during running)
In what position would the hip abductors be able to produce the greatest torque?
slight adduction
List the primary hip external rotators.
piriformis, obturator internus, gemellus superior, gemellus inferior, quadratus femoris, gluteus maximus, sartorius
List the secondary hip external rotators.
posterior fibers of the gluteus medius, biceps femoris, obturator externus
Which muscle of the six “short external rotators” is not considered to be a PRIMARY external rotator?
obturator externus, very close to the axis of rotation
How would you stretch the piriformis if the hip were not flexed?
adduction and internal rotation
In which plane of motion is the average maximal-effort torque produced by the muscles of the hip greatest? The least?
greatest in the sagittal plane (extension and flexion), least in the horizontal plane (internal and external rotation)
What two primary factors contribute to hip fractures in elderly?
osteoporosis and increased risk of falling
What are some signs and symptoms of hip osteoarthritis?
pain, synovitis, loss of joint space, muscle atrophy, hypertrophic bone formation, reduced range of motion, abnormal gate
Why would you want a patient with hip issues to use a cane contralateral but carry a load ipsilateral?
this reduces joint forces caused by hip abductor force on the affected hip
Why would a coxa vara or valga procedure be performed?
to improve the congruency of the weight-bearing surfaces of the hip
What are the positive and negative effects of coxa vara?
positive - increased moment arm for hip abductor force, alignment may improve joint stability; negative - increased shear force across femoral neck, decreased functional length of hip abductor muscles
What are the positive and negative effects of coxa valga?
positive - decreases shear force across femoral neck, increased functional length of hip abductor muscles; negative - decreased moment arm for hip abductor force, alignment may favor joint dislocation
The knee consists of which joints?
lateral and medial compartments of the tibiofemoral joint and the patellofemoral joint
What is more responsible for the stability of the knee: soft-tissue constraints or bony configuration?
soft-tissue constraints (ligaments, joint capsule and menisci, large muscles)
What forms the passageway for the cruciate ligaments of the knee?
intercondylar notch
What structures attach to the head of the fibula?
LCL and biceps femoris
Why is a fracture of the fibula not as problematic?
fibula has no direct function at the knee, only accepts minimal weight (10%)
Describe the surface of the tibia plateau (medial and lateral condyles).
medial slightly concave and lateral slightly convex BUT menisci make both surfaces concave
What attaches to the apex of the patella?
patella tendon (distal point)
What does the articular surface of the patella contact?
intercondylar groove of the femur (patellofemoral joint)
Describe normal genu valgum.
knee forms an angle on its lateral side of about 170 to 175 degrees due to medial angulation of the femur (125 degree angle of inclination of the femur)
Composition of the Anterior Capsule of the Knee
quadriceps muscle, patellar tendon, patellar retinacular fibers
Composition of the Lateral Capsule of the Knee
LCL (outside joint), lateral patellar retinacular fibers, iliotibial tract, biceps femoris, popliteus, lateral head of the gastrocnemius
Composition of the Posterior Capsule of the Knee
oblique popliteal ligament, arcuate popliteal ligament, popliteus, gastrocnemius, hamstring muscles especially through tendon of semimembranosus tendon (muscles and the posterior capsule ligament hyperextension)
Describe excessive frontal plane deviation of the knee.
excessive genu valgum - knock-knee (180 degrees)
Composition of the Posterior-Lateral Knee Capsule
arcuate ligament, LCL, tendon of the popliteus muscle (often referred to as a whole as the arcuate complex)
Composition of the Medial Capsule of the Knee
MCL, medial patellar retinacular fibers, expansions from the tendon of the semimembranosus, further reinforced by the tendons of the sartorius, gracilis, and semitendinosus (pes anserinus)