the hip joint is a bol and socket joint that is formed uh between the acetabulum of the pelvic and the head of femur and uh between the acetabulum and the head of femur there's acetabulum laborum that serve as a shock absorber and also uh it increase the joints stability by increasing the depth of the acetabulum and the hip joint uh allow three degrees of freedom that um The Hip can move in the sagittal plan for a flexion extension and for frontal plan uh to perform abduction and adduction and in horizontal plan or transverse plan to do internal and external rotation the hip joint itself is secure by three uh major ligaments and the labram we talk about the laum earlier that increased The Joint stability and for the three major ligament uh from the anterior side we can um see there's a ligament that connect um the ilum and the femal bone called elop femoral uh ligaments and from uh the posterior side we can see there's isual femoral ligament um and then from the interior side we can see there's a pupil of FAL ligaments all three major ligaments uh limit uh hip extension so um it's not too hard to understand that the close pack position for the hip is actually when the hip is in full um extension and the opposite way for uh the open pack position of the hip is uh when the hip is in uh flexion from a surface uh we can um identify uh muscle groups um using the boning L Mark so in the back we can identify the PSIs and from the side we can identify uh the greater chander if you go back to the um uh the picture of the hit joint right here um this is the head of the femur this is the neck of the femur and then you can see uh there's a greater Cher right here and then the Lesser Cher right here so you can uh understand that we uh from the outside we can palpate the greater chanter um so on the surface we first identify the PSIs and the greater Cher right here and then we can draw a uh line um in this slide we uh we can divide uh grus Maximus and the grus Medias and also when we turned our Focus to the front we can identify the Asis combined with the greater Chanda we if we draw a line right there you can see on the uh anterior side we can locate the tensor fasia L and then on the other side we can see the IT band or elal um tbio band right here and also uh at the Asis connected to the mle side of the knee there's a muscle called sorus this sorus um happen to be able to separate the quadriceps and the hip adductors so this is something um from the surface um Anatomy that we can identify the muscle group so let's um look uh deeper on the muscles the muscles acting on the hip uh have several compartments so the anterior compartments are um major um hip flexors um here you can see there's uh idcus and the Solus major and when when they pass the inren ligament that the two muscles join as one and we name it a Oso so uh please um remember that Oso is is actually two muscles one from idcus and one from Source major and this is a a big hip flexor and uh and um another muscle that originated from Asis and U the medial side of the knee is sorious and um the muscle acting uh sorry the muscle of the quadriceps that's actually acting on the hip it's only uh re forus because you uh you can see there's attachment um um to the hip sorry to the pelvic um the posterior compartments are uh hip extensors um the major hip extensors is uh glus Maximus right here and the hamst streams so um so at the hamst streams the most superficial um layer is on the medial side is semiosis when we take this uh muscle out you can see the the another muscle line beneath that is semi membran nois on the lateral side uh there are uh biceps foror's long long head and then beneath it this uh bicep foror's uh short head so these muscle acting um as the hip extensors on the mle um side of the hip um it is hip doctor or uh ad doctors they are uh ptinus and uh aductor longus and beneath the longus you can see the bre sorry adductor breev right there and when we take all these out you can see a huge piece of adductors that's uh name as aductor Magnus on the far medior border uh that's a uh uh grassless so these muscle form uh the medle compartment of the hip and they function as hip adductors on the lateral side U they are hip AB doctors or AB doctors um they are um um glus medius when we take the glus medius out you can see the guus Minimus and also uh uh tenso fasal L is another hip abductors these three muscles acting as the hip St stabilizer because their function is to uh uh align the hip um so and also um by uh the tensor and there is IT band The IT band is separate from the testas Lata so they're not the same IT band is is actually a Bend of fcia and it kind of connect um to the tensor fascia lat to the knee uh right here there's another uh deep layer uh in the back of the hip um there's actually six muscles and they are external rotators um it's hard to remember so I'm I'm going to try my best to to help you um uh review uh these muscles so uh right beneath the uh glut Minimus there's a p forus right here um I uh I also use a p forus to identify the stic nerve because stic nerve kind of um Can through can under the Peri forus muscle and then the Border uh of this six muscles um the far end is that you know this uh uh rectangle shape it's quadratus Fus in between perus and quadratus aorus there are three muscles in a middle it is upor Inus above it that's uh Jus Superior and below it of course is uh the in inferior and it's from the posterior side that we cannot see the up terator externals so um in the pin tests um this muscle will not um be tested when we look at osteokinematics we also need to consider U the arth kinematics that's happening um within the joint space when the person is doing hip flection extension um um the Arro kinematics is uh uh primarily on spinning uh where uh when the person is doing ab uction uh uction or external rotation internal rotation on the arthro kinematics is doing rolling and gliding so now let look at the uh movement itself when a person is perform open chin um hip flexion um U we're actually recruiting the hip flexor to do concentric contraction um they are edios soos um and uh rectus Fus and Sartorius to do a hep flection when we are doing close chain uh hi flexion uh because the distal um part is fixed and what we see is this person is bending the trunk so uh the uh the situation when we do this is when we are doing we bearing right and the typical uh activity for us to do uh close CH he uh flection is when we are trying to sit up right from a suine position to do that when we bring our trunk up uh the hip flexors are Contracting uh concentrically to do that well uh and then to maintain balance the uh the gravity continue to pull us downward If the gravity is pull pulling us anteriorly and to prevent us from falling forward the hip extensors are Contracting eccentrically uh on the other hand when the gravity is pulling us uh posteriorly and the hip flexors will be recruited to cons uh contract eccentrically to prevent us from falling behind falling backward I'm sorry and the um the uh flexors and extensors are also have a role uh in control uh of trunk movement um the edos soas uh or hip flexors uh they can reinforce the lumbar curve and they have a part of anterior uh pelvic tilt the hamstring or the hip extensors um they have a whirl in posterior pelvic tilt um you can uh you can anticipate when a person who has uh tight hamstrings and very likely this person will develop a flat curve of the lumbar spine and that would limit the forward movement like uh when we when they're uh trying to touch their toad um and this is also uh commonly uh contributing to uh the back pan issue um for the hip AB duction and AD duction in Clos chain open chin movement um the M the two muscle groups are acting to maintain the lateral stability of the pelvics and the trunk we can see this as when a person is uh standing uh in one leg and the um the gravity pull the pelvic down the opposite um side of the hip abductor is recruited to uh pull uh the pelvic up to maintain the balance for external internal rotation is kind of tricky uh uh in some situation uh but overall in open chin movement of external rotation the Gus Maximus is actually a powerful lateral rotators and there are uh in the Deep layers there are six uh small Rotator muscles um they contributing to U external rotation when it's open chain movement when it's closed chain movement that um that doing Walk That kind of a closure movement um they are acting to balance the pelvic and the trunk over the lower extremity when a person is doing open open chain internal rotation like uh when we doing ski we are trying to stop uh we perform this internal rotation uh it is um the role of hip AB doctors specifically uh they are grus Minimus uh tensor falata and anterior fiber of the guus Medias