Lecture 6 (test 2): Hip Musculature Flashcards
the lumbar plexus supplies what area of the body
anterior/medial thigh
the sacral plexus supplies what area of the body
posterior lateral hip and posterior thigh and entire lower leg
anterior capsule is innervated by
femoral and obturator nerves from the lumbar plexus
posterior capsule is innervated by what
sacral plexus
roots of femoral n
L2-4
the femoral n supplies what
most hip flexors
-psoas
-iliacus
-sartorious
-pectineus
-quads
all knee extensors
sensory to anterior medial thigh
obturator n roots
L2-4
obturator n supplies what
hipp adductirs
obturator externus
sensory to medial thigh
nerves that come of sacral plexus
superior gluteal n
inferior gluteal n
n to piriformis
scaitic n
n to obturator internus and gemellus sup
n to quadratus femoris and gemellus inf
primary muscles that flex the hip
iliopsoas
sartorius
tensor fascia latae
rectus femoris
adductor longus
pectineus
secondary muscles that flex the hip
adductor brevis
gracilis
anterior fibers glut min
describe iliopsoas and psoas major
large/long
iliacus= in iliacus fossa/over SI joint
psaos major = TP T12/discs (blends with diaphragm)
both muscles blend anterior to the femoral head before attaching to the lesser trochanter
what is “internal snapping hip”
distal abrasion at iliopubic eminence region
actions of iliopsoas
prominent femoral on hip flexor and flexor of trunk/pelvis over fixed thighs
swing phase of walk/run
frontal plane stability of lumbar spine (bilateral contraction) with unilateral leg SLR
where is psoas minor, where does it attach, and what does it do
directly anterior to major
present in 60-65%
attaches on T12/L1 bodies medial to acetabulum and iliac fascia
may help stabilize the position of the underlying psoas major (prevents “bowstring”)
describe the sartorius (location, characteristics, and actions)
longest muscle in body.
“tailor’s muscle”
runs form ASIS to medial proximal tibia at pes anserine
actions = hip flexion, ER, and abd
innervation of sartorious
femoral n (posterior division of L2 and L3)
attachment and action of tensor fascia latae
from ilium to IT band (short)
flexor/abd of hip
*IR from ER only
TFL innervation
superior gluteal n
L4, L5, S1
rectus femoris attachments and function
between sartorius and TFL
from AIIS and sup rim of acetabulum/capsule to the tibia
1/3 isometric torque at hip
primary knee extensor
innervation rectus femoris
femoral n
describe pelvic on femoral hip flexion: anterior tilt
a force couple with femurs fixed: hip flexors and trunk extensors (stretch flexors, contract extensors??)
lordosis increases
load on facets increase anterior shear force of L5/S1
describe femoral on plevic hip flexion
often simultaneous with knee flexion to shorten limb
mod to high power coactivation of hip flexors and abdominals
what happens if the core is not properly activated during activation of the hip flexors
reduced activation of core causes a marked anterior tilt of pelvis with contraction of hip flexors
primary muscles that adduct the hip
pectineus
adductor longus
gracilis
adductor brevis
adductor magnus
secondary muscles that adduct the hip
biceps femoris (long head)
glut max (inf fibers)
quadratus femoris
obturator externus
what are the 3 layers of muscles for hip adduction
superficial: pectineus, add longus, and gracilis
middle: adductor brevis
deep: add magnus- horizontal and oblique (60% mass)
describe the muscle function of hip add
produces force in all 3 planes
primarily in sagittal and frontal
frontal plane function of adductors
femoral on pelvis and pelvis on femoral
i.e. kicking a soccer ball
R leg is femoral on pelvis add and L is pelvis on femoral add
eccentric activation of the L glut med to help control the velocity and extent of the drop of the adducting L hip
sagittal plane function of the adductors
adductor magnus: post fibers are powerful hip extensors
outside 40-70 degrees flexion, adductors can be powerful flexors or extensors
hip near full flexion = add assist in ext
hip near full ext = add assist flexors
**important in high power cyclical motions like sprinting, cycling, deep squat, etc
what muscles IR the hip
anatomical position = no perfect positioned IRs
secondary rotators = ant fibers glut min/med, TFL, add longus/brevis, pectineus
how does flexion affect the IRs torque
60-90 degrees hip flexion the IRs torque changes due to angle
i.e. piriformis becomes IR past 60 degrees
function of IRs during gait
durign stance they RT the pelvis on femur
what is the clinical significance of an IR torque bias with greater hip flexion
related to excessively internally roatates and flexed crouched gait pattern in some people
poor control/weakness of hip extensors= typically flexed posture of the hip exaggerates the IT torque potential of many muscles of the hip
primary hip extensor muscles
glut max
hamstrings
post head of adductor magnus
secondary hip extensor muscles
middle and post fibers of glut med and ant fibers of adductor magnus
after 70 degrees of hip flexion mist adductor muscles can assist with what
hip extension
glut max innervation
inferior gluteal n
hamstrings innervation
sciatic n (tibial L5-S2)
post head of adductor magnus innervation
obturator n (posterior division; L2, 3, 4)
attachments of glut max
illium
sacrum
coccyx
ST and post SIJ lig
TL fascia
runs to
ITB, TFL, and gluteal tuberosity on femur
functions of glut max
EXT
ER
stabilizes SIJ
attachments and functions of hamstrings
IT to tibia and fibula
extend hip and flex knee
what happens with pelvic on femoral hip ext: posterior pelvic tilt
force couple with femurs fixed
hip extensors and abdominal muscles
lordosis reduced
forward lean of body
2 phases of forward lean of body
primarily uses hamstrings; forward lean increases the moment arm of HS which increases passive tension in HS
1: slight: COG still in pelvic girdle; minimum activation from glut max and HS
2: significant lean: COG out from hips; increase HS use but not glut max
describe femoral on pelvic hip ext
typically a large and powerful ext torque
rapid accelerations
why is a large knee ext torque needed by RF during femoral on pelvis hip ext
1: external load and BW cause knee flexion torque
2: to counter string knee flexion torques creased by HS and gastroc
large muscle contribution also creates an anterior tilt/hip flexion and the glut max/adductor magnus must match and exceed that torque to create hip ext and climb the hill
primary adbuctors of the hip
glut med
glut min
TFL
characteristics of glut med
goes from ilium to greater trochanter
largest at 60-65% of abdcutirs
excellent leverage
has anterior/middle/posterior portions
characteristics of glut min
deep and anterior to medius
from ilium to greater trochanter
blends with capusle hip joint (may prevent impingement)
secondary abductors of hip
piriformis
sartorius
rectus femoris
ant/sup fibers of glut max
why might abductors of the hip require neutralization to get pure abduction
all have either IR or ER actions and thus require neutralization to get pure abd
how do hip abductors provide frontal plane stability with walking
stance phase abductors stabilize pelvis over a fixed femur to keep pelvis from dropping
how do hip abductors produce compression force at the hip
seesaw with femoral head as a fulcrum
need static rotatory equiliibrium
every step = force of joint is combined forces of abd muscles and body weight with an equal and opposite JRF
when does max (torque) capacity of hip abductors occur? weakest?
when adducted just beyond neutral which is the position of unilateral stance
also where ITB has some passive tension due to a slight stretch (femur on pelvis adduction)
weakest is at 40 deg
primary ERs of hip
glut max
5 of the 6 short external rotators
secondary ERs of hip
post fibers of glut med and min
obturator externus
sartorius
LH biceps femoris
nerves of the ERs of hip
superior gluteal
obturator n
n to piriformis
n to obturator internus
n to obturator externus
what are the 6 short external rotators
piriformis
obturator internus
gemellus superior
gemellus inferior
quadratus femoris
obturator externus
how does pelvic on femoral RT occur
ER muscles RT pelvis over the femur
R LE planted and ER contraction will RT the anterior side of the pelvis and trunk to the L (contralateral to the rotators)
what muscle actions may occur with “planting and cutting” in sports
ex: glut max can ER and ext for turn and push off
adductors/IRs can eccentrically decelerate but can be subject to strain
