The linea aspera represents the posterior corticalthickening of the femoral diaphysis which working as a muscularattachement and buttressing theconcavity of the femoral shaft at the middle portion of the shaft , the femurhas smooth medial, lateral and posterior borders . In the proximal and distalportion of the femur , the linea aspera widens to create an additionalposterior surface . Muscle attachements :-The subtrochanteric region of the femur is completelycovered by mascular envelops.
The muscles of the thigh are arranged in threecompartements separated from each other by inter mascular septa .Figure (2) muscle attachement of the anterioraspect of the femur ( ) The anterior compartement of the thigh :-Is formed by the Sartorius and the four ,quadricepsfemors muscles (rectus femoris, vastus lateralis, vastus medialis, and vastusintermedius). Which is all are supplied by the femoral nerve . In addition theterminal ends of the muscles, psoas major and iliacus pass into the upper portionof the anterior compartement from its site of origin at the posterior abdominalwall .Vastus lateralis musclehas its linear attachement fromthe base of the greater trochanter to the proximal end of the glutealtuberosity and along the lateral margin of the proximal half of the lateraledge of the linea asperaFigure(3) anterior compartement of the thigh musclesFigure (4) Showing the vastus lateralis muscle The posterior compartement of the thigh :-It consists of three muscles (semitendinousus ,semimembranousuds and the biceps femoris muscle). all the three muscles are calledthe hamstring muscles. And all are supplied by the sciatic nerve .
Figure (5) showing muscleattachement of the posterior compartement of the thigh Figure (6) showing muscles of the posteriorcompartement of the thigh The medial compartement of the thigh :-It consists of six muscles (gracilis, pectineus,adductor longus, adductor brevis, adductor magnus and obturator externus) alltheses muscles are supplied by the femoral nerve except the pectineus muscleand part of the adductor magnus muscle which are supplied by the obturator nrve. adductor magnus is attached to the linea aspera and its aponeurosis isattached to the proximal part of the medial supracondylar ridge and its remainingfibers fuse to form alarge tendon which are attached to the adductor tubercle ,with an aponeurotic expansion is attached to the distal part of the medialsupracondylar ridge .figure (7) .Figure (7) muscles of the medial compartement of thethigh Pectineus and adductor brevis are attached to theposterior surface of the femur between the gluteal tuberosity and the spiralline ,the pectineal attachement is a rough line from the base of the lessertrochanter to the linea aspera . Adductor brevis attachement is lateral to thepectineus and behind this to the proximal part of the linea aspera , medial tothe adductor magnus .
adductor longus, intermascular septa and the short head ofthe biceps femoris areattached to the linea aspera .The proximal shaft of the femur can be exposed easilythrough the lateral approach with the dissection of the vastus lateralis andligation of the perforators vessels .The muscular attachements which are surrounding theproximal femur are the most common cause of the deformity following thesubtrochanteric fracture of the femur .hence as a result of these strongdeforming forces which are making the reduction is difficult to be achieved inyoung adult patients . and shortening of the femur resulting from the spastictone of the group of muscles which are spanning the proximal femur including the quadriceps and the hamstringmuscles .For the subtrochanteric fracture the proximal segmentis flexed & abducted and externally rotated by hip abductors, the externalrotators and the iliopsoas muscles. The adductors typically acting to medializethe distal component of the femur.
The subtrochanteric fracture that areassociated with fracture of the lesser trochanter the deformity may be less asthe flexion and the external rotation of the iliopsoas will be neutralized.Figure (8) Showing the deforming forces whichare acting on the proximal and distal segment of the femur. Vascular anatomy of the proximal femur:-The blood supply to the shaft of the femur is from thefemoral artery and its main branch the profunda femoris artery by nutrientvessels in combination with numerous periosteal vessels figure (9) .thenutrient artery entering the region of the linea aspera in the proximal thirdof the femur .hence the linea aspera should not be stripped out of its muscularattachement in order to maintain the blood supply to the shaft of the femur.
The situation of the medial femoral circumflex vesselswhich is mostly related to the surgical exposure of the hip especialy whenwe considering its location in close proximity to the nailentery point .Figure (9) blood supply and circulation of the hip andthe upper thigh ( ) The blood supply of the femoral head is originatingfrom an arterial ring around the neck , just outside the attachement of thefibrous capsule and there is continuation by the medial and lateral circumflexarteries with minimal contributions from the superior and inferior glutealarteries. also from this ring , ascending cervical branches piercing thecapsule to enter the neck beneath the reflected synovial membrane .all thesevessels becoming the retinacular arteries and form a synovial intra –articularring.Small medial epiphyseal supply, which is considered ofmuch importance in the early childhood, it reaching the head a long theligamentum teres. The regions of the trochanteric femur and the subtrochantericshaft of femur both are supplied by the trochanteric and the cruciate arterialanastomosis .at the most distal area of the shaft of femur ,nutrient foraminadirected proximally which are mostly founded in the linea aspera varying mostlyin site & number .
one of these nutrient arteries usually present near itsproximal end and the second one usually present near its distal end. The mainnutrient artery usually orginated from the second perforator . The Periostealvessels originating from the perforators and from the profunda femorisartery, and running in circumferential pattern.