FEMUR (osteology) OBJECTIVES At the end of the session, the students should be able to: Know different parts of the femur Determine the side of the bone Identify the surfaces and borders of the bone GENERAL Femur is the longest and largest bone in the body. forward convexity of the shaft and posterior concavity Has the linea aspera in its middle third. An angle of torsion of 30 with the shaft Femoral condyles rest horizontally on the plateau of the tibia . In the erect posture it is not vertical but inclined downward and medially The inlclination if the shaft depends on the length of the femur and the width of the pelvis. PARTS FEMUR A OF body and two extremities. Upper end has Head Neck Lesser trochanters Greater trochanters. Body is known as the shaft Lower end has lateral and medial condyles. It forms part of the hip joint and knee joint. There are four eminences: Head Greater trochanter Lesser trochanter Lower extremity. Upper end of the femur The upper extremity has a head, a neck, a greater and a lesser trochanter Head of the femur Capped with hyaline cartilage More than half a sphere. Directed upward, medially, and a little forward Medial convexity has the fovea capitis femoris. Anteriorly the articular cartilage extends to the neck. The synovial membrane of the hip joint, lines the capsule and covers the retinacular fibres on the neck which are attached to the articular margin of the head. Neck of the femur An upward extension of the shaft. The angle of the neck is strengthened internally by the calcar femorale Bounded above by the greater trochanter and below by the lesser trochanter It has anterior and posterior surface superior and inferior borders. The anterior surface of the neck with its adherent retinacular fibres is wholly intracapsular perforated by numerous vascular foramina Neck of the femur Posterior surface is smooth The back of the neck joins the greater trochanter at a prominent rounded ridge, the intertrochanteric crest Capsule is attached only halfway to the crest Superior border is short and thick Ends laterally at the greater trochanter its surface is perforated by large foramina Inferior border, long and narrow curves a little backward, to end at the lesser trochanter. TROCHANTERS These are epiphysis that ossify separately from the shaft and their purpose is for muscle attachment GREATER TROCHANTER A large, irregular, quadrilateral eminence, situated at the junction of the neck with the upper part of the shaft Directed a little laterally and backward About 1 cm. lower than the head in the adult It has two surfaces and four borders. Surfaces Of The Greater Trochanter Lateral surface, quadrilateral in form, broad, rough, convex, and marked by a diagonal impression Above and below the impression are triangular surfaces, for muscles and bursae attachment The medial surface has at its base a deep depression, the trochanteric fossa (digital fossa) Borders Of The Greater Trochanter Superior border is free; it is thick and irregular and marked near the center Inferior border corresponds to the line of junction of the base of the trochanter with the lateral surface of the body; it is marked by a rough, prominent, slightly curved ridge Anterior border is prominent and irregular Posterior border is very prominent and appears as a free, rounded edge, which bounds the back part of the trochanteric fossa. LESSER TROCHANTER A conical eminence Projects from the lower and back part of the base of the neck. Summit is rough. From its apex three borders extend Borders Of The Lesser Trochanter Medial border continuous with the lower border of the neck Lateral border with the intertrochanteric crest The inferior border with the middle division of the linea aspera. Running obliquely downward and medially from the tubercle is the intertrochanteric line (spiral line of the femur) Running obliquely downward and medially from the summit of the greater trochanter on the posterior surface of the neck is the intertrochanteric crest A slight ridge sometimes commences about the middle of the intertrochanteric crest, called the linea quadrata. THE BODY OR SHAFT (CORPUS FEMORIS) The body, almost cylindrical in form It is slightly arched, convex in front, and concave behind. The body has three borders, separating three surfaces. The linea aspera, is posterior, others are medial, and lateral. Borders Of The Shaft The linea aspera is a prominent longitudinal ridge or crest, on the middle third of the bone, presenting a medial and a lateral lip, and a narrow rough, intermediate line. The linea aspera is perforated by the nutrient canal, which is directed obliquely upward. Above, the linea aspera is prolonged by three ridges. The lateral ridge joins, at base of the greater trochanter, the gluteal tuberosity. Intermediate ridge or pectineal line is continued to the base of the lesser trochanter The medial ridge is lost in the intertrochanteric line The lateral border extends from the antero-inferior angle of the greater trochanter to the anterior extremity of the lateral condyle The medial border extends from the intertrochanteric line to the anterior extremity of the medial condyle Below, the linea aspera is prolonged into two ridges, enclosing between them a triangular area, the popliteal surface, upon which the popliteal artery rests. The lateral ridge descends to the summit of the lateral condyle. The medial ridge is less marked, where it is crossed by the femoral artery. It ends below at the summit of the medial condyle, in a small tubercle, the adductor tubercle. Surfaces Of The Shaft The anterior surface includes that portion of the shaft which is situated between the lateral and medial borders. The lateral surface includes the portion between the lateral border and the linea aspera It is continuous above with the corresponding surface of the greater trochanter, below with that of the lateral condyle The medial surface includes the portion between the medial border and the linea aspera It is continuous above with the lower border of the neck, below with the medial side of the medial condyle THE LOWER EXTREMITY (DISTAL END) It consists of two oblong eminences known as the condyles, lateral and medial An articular depression called the patellar surface separate them infront Behind, they form a deep notch, the intercondyloid fossa. The lateral condyle is the more prominent The medial condyle is the longer and projected lower than the lateral condyle in perpendicular position. The intercondyloid fossa is limited above by a ridge, the intercondyloid line, and below by the patellar surface Each condyle is surmounted by an elevation, the epicondyle The medial epicondyle is a large convex eminence with adductor tubercle at its upper part The lateral epicondyle is have and oblique and a horizontal groove arising from it Articular Surface The articular surface of the lower end of the femur occupies the anterior, inferior, and posterior surfaces of the condyles Its front part is named the patellar surface and articulates with the patella It presents a median groove which extends downward to the intercondyloid fossa and two convexities The lower and posterior parts of the articular surface constitute the tibial surfaces for articulation with the corresponding condyles of the tibia and menisci Blood supply of femur The primary blood supply to the head of the femur arises from the circumflex arteries at the base of the femur neck. LEARNING RESOURCES Gray’s Anatomy by Henry Gray Last’s Anatomy by R.J.Last Netter’s Atlas