Lower Limb Anatomy PDF

The lower limb Bones of the lower limb (fig6.1) Pelvic girdle Free lower extremity 1. Femur. 2. Tibia. 3. Fibula. 4. Patella. 5. Foot bones. Joints of the lower limb: Hip Joint. Knee joint Ankle joint. Foot joints. (...

The lower limb Bones of the lower limb (fig6.1) Pelvic girdle Free lower extremity 1. Femur. 2. Tibia. 3. Fibula. 4. Patella. 5. Foot bones. Joints of the lower limb: Hip Joint. Knee joint Ankle joint. Foot joints. (Fig5.1): A diagram shows the lower limb bones and joints. The bony pelvis: The pelvis is a bony ring consisting of paired innominate bones, the sacrum and coccyx. Each innominate (hip) bone is composed of three parts: the ilium, ischium and pubis. These meet at the triradiate cartilage, seen as a lucency within the acetabulum in the immature skeleton. The hip bones have three main articulations: Sacroiliac joint – articulation with the sacrum. Pubic symphysis – articulation between the left and right hip bones. Hip joint – articulation with the head of femur. Fig (5.2) pelvic bone The Ilium The ilium is the widest and largest of the three parts of the hip bone and is located superiorly. The body of the ilium forms the superior part of the acetabulum (acetabular roof). Immediately above the acetabulum, the ilium expands to form the wing (or ala). (Fig5.3&5.6) The wing of the ilium has two surfaces: Inner surface – has a concave shape, which produces the iliac fossa (site of origin of the iliacus muscle). External surface (gluteal surface) – has a convex shape and provides attachments to the gluteal muscles.  The superior margin of the wing is thickened, forming the iliac crest. It extends from the anterior superior iliac spine (ASIS) to the posterior superior iliac spine (PSIS). On the posterior aspect of the ilium there is an indentation known as the greater sciatic notch. Fig (5.3) bony landmarks of ilium The Pubis The pubis is the most anterior portion of the hip bone. It consists of a body, superior ramus and inferior ramus (ramus = branch). (fig5.4&5.6) Public body – located medially, it articulates with the opposite pubic body at the pubic symphysis. Its superior aspect is marked by a rounded thickening (the pubic crest), which extends laterally as the pubic tubercle. Superior pubic ramus – extends laterally from the body to form part of the acetabulum. Inferior pubic ramus – projects towards the ischium. Together, the superior and inferior rami enclose part of the obturator foramen – through which the obturator nerve, artery and vein pass through to reach the lower limb.  Fig (5.4) bony landmarks of pubis The Ischium The ischium forms the posteroinferior part of the hip bone. Much like the pubis, it is composed of a body, an inferior ramus and superior ramus. (Fig5.5&5.6) The inferior ischial ramus combines with the inferior pubic ramus forming the ischiopubic ramus, which encloses part of the obturator foramen. The postero-inferior aspect of the ischium forms the ischial tuberosities and when sitting, it is these tuberosities on which our body weight falls. Near the junction of the superior ramus and body is a posteromedial projection of bone, the ischial spine.  Fig (5.5) bony landmarks of ilium Fig (5.6) bony landmarks of pelvic bone X ray anatomy of pelvic bone (Fig 5.7&5.8)  Fig (5.7):x-ray pelvis A-p view Fig (5.8): x-ray anatomy of the pelvis A-p view The femur bone: Gross Anatomy:  The femur is the longest, most voluminous and strongest bone in the human body and It consists of a head, neck, shaft and expanded lower end. The head is more than half a sphere and is directed forwards, medially and upwards and has a central pit or fovea where the ligamentum teres is attached. It articulates with the acetabulum of the pelvis to create the hip joint The neck is about 5 cm long and makes an angle of 125–135° with the shaft and is also anteverted by 8°. Th e degree of anteversion is larger in neonates and reduces progressively with age. Between the greater and lesser trochanters, there is a rough intertrochanteric line anteriorly and a more rounded intertrochanteric crest posteriorly. The shaft of the femur is cylindrical angled medially so that the medial condyles at the knee are close to each other, but the heads are separated by the bony pelvis. The distal shaft is angled posteriorly and expanded into medial and lateral condyles separated posteriorly by the intercondylar fossa. The medial condyle is larger, and the inferior surface of the femur is nearly horizontal despite the shaft obliquity. The lateral condyle bears the majority of the patellar articulation and is grooved posterolaterally by popliteus tendon.  fig (5.9): diagram showing femur. Fig(5.10) diagrams show upper femur  Fig. (5.11): A diagram shows the distal end of the femur. Radiographic anatomy: Plain X-ray: The anterio-posterior (A-P) view and lateral view are the standard series examining the femur in its entirety, including the hip and knee joint. Due to the limitations of the image detector, these projections are often performed in two images per view to ensure inclusion of both knee and hip joints (Fig.5.12-5.14). Fig. (5.12): x-ray femur (Ap and lateral views)  Fig. (5.13): labelled Xray of upper femur (Ap view) Fig. (5.14): labelled x-ray of distal femur and Knee joint (AP view)  Tibia The tibia is the largest bone of the leg and contributes to the knee and ankle joints. (fig 5.15&5.16) It is medial to and much stronger than the fibula, exceeded in length only by the femur (Fig.5.15). The broad weight-bearing surface of the proximal tibia consists of a larger medial and smaller lateral condyle as well as intercondylar fossa. The intercondylar area has a raised intercondylar eminence, with medial and lateral tubercles, separating the articular surfaces. The tibial tuberosity is a rough prominence onto which the patella tendon inserts and may be fragmented and irregular in the immature skeleton. The shaft is triangular in cross section and its anteromedial surface and anterior edge are subcutaneous. It is thinnest at the junction of middle and distal thirds. The lateral surface gives rise to the interosseous membrane and he posterior surface is crossed by the soleal line, which descends medially, giving rise to the soleus muscle. The distal end of the tibia is expanded and wider anteriorly, with a short medial and inferior projection, the medial malleolus. Fig (5.15): Diagram shows tibia and fibula.  Fig (5.16): Diagram shows upper and lower ends of tibia. Fibula o The fibula is the smaller of the two bones of the leg. It runs posterolateral to the tibia and consists of a head, neck, shaft and distal malleolus. (fig 5.17&5.18) o It is not directly involved in the transmission of weight but is important for ankle stability and acts as a source for numerous muscle attachments (Fig.17) o The fibula is slender and is mainly a site of attachment for muscles. o The common peroneal nerve winds around the neck where it is liable to injury. o The expanded distal end forms the lateral malleolus which is more inferior and posterior than its medial malleolus. Fig (5.17) diagarm of tibia and fibula Fig (5.18) diagarm of upper end of fibula Radiographic anatomy: Plain X-ray The tibia/fibula is comprised of an anteroposterior (AP), and lateral radiograph. The series is often used in emergency departments to evaluate the entirety of the tibia and fibula after trauma (Fig.5.19 &5.20). Fig (5.19):Antero-posterior and lateral views of leg both bones Fig (5.20): Ap and lateral views of leg both bones Patella The patella is the largest sesamoid bone in the human body. It lies within the quadriceps tendon/patellar tendon and forms part of the knee joint and extensor mechanism of the knee. (fig 5.21) The patella is triangular in shape with a superior base and inferior apex. The proximal three-quarters of the posterior surface are smooth, composed of articular cartilage, which is the thickest in the body, as much as 5 mm in some adults. The distal pole of the posterior surface of the patella does not functionally form part of the joint and is denuded of cartilage. The posterior surface is divided into medial and lateral facets by a vertical ridge. Several ossification centers appear at 3 years and fuse at puberty These may give rise to an irregular appearance of the normal unfused patella. A bipartite (or multipartite) patella is a common variant when the superolateral corner fails to fuse. Fig (5.21) A diagram shows patellar surfaces. Radiographic anatomy: will be discussed on knee joint. Fig (5.22) knee series Foot The foot is the most distal part of the lower limb below the leg and ankle. It is a complex anatomical structure and can be subdivided into the hindfoot, the midfoot, and the forefoot. The bones of the foot are (Fig.5.23&5.24): 1. Tarsal bones The tarsus is composed of seven bones arranged in three rows:  proximal row: talus, calcaneus  middle row: the navicular  distal row: three cuneiforms medially and the cuboid laterally. 2. Metatarsal bones The five metatarsal bones have a base, for articulation with the tarsal bones, a shaft, a neck, and a head for articulation with the proximal phalanges. 3. phalanges (14) Hallux (great toe): proximal and distal phalanges 2nd to 5th toes: Proximal, middle, and distal phalanges. Fig (5.23) Bones of foot (dorsal view) ✓ The hind foot =calcaneus and talus ✓ The mid foot=navicular +cubdoid+cuniforms ✓ The forefoot =metatarsal +phalanges Fig (5.24) bones of foot Radiographic Anatomy: Plain X-ray: The foot series is comprised of a dorsoplantar (DP), medial oblique, and a lateral projection. The series is often utilized in emergency departments after trauma or sports related injuries (Fig.5.25-5.27) fig (5.25 ) x ray foot (oblique view ) fig (5.26 ) x ray foot ( anteroposterior view ) fig (5.27 ) x ray foot ( lateral view) Hip Joint The hip joint is a synovial ball and socket joint between the femoral head and the acetabulum of the pelvis. Standard views are A-P and Lateral (Fig.29-31). Fig (5.28) hip x ray (anteroposterior view) Fig (5.29) hip x ray (lateral view)  Fig (5.30) pelvis x ray (anteroposterior view) The Knee Joint The knee joint is a modified hinge joint between the femur, tibia, and patella. It is the largest synovial joint in the body and allows flexion and extension of the leg as well as some rotation in the flexed position. Gross anatomy Articulations 1. Tibiofemoral Articulation There are two condylar joints between the femur and tibia (tibiofemoral). There are medial and lateral articular facets on the tibial plateau and medial and lateral femoral condyles on the distal femur which are convex and circular shaped (Fig.5.31 &5.32). Medially: between a narrow and curved femoral condyle, and an oval tibial articular surface with a long anteroposterior length  laterally: between a wide and flat femoral condyle; and a circular tibial articular surface which overhangs the shaft posterolaterally The knee menisci are shaped accordingly. 2. Patello-femoral articulation Saddle joint between the patella and femoral condyles: Medial, lateral and odd facet on the posterior surface of the patella articulate with the medial and lateral condyles of the femur. (Fig.32): A diagram showing the anatomy of the knee joint (anterior view).  Fig. (5.32): A diagram showing the anatomy of the knee joint (lateral view). Radiographic anatomy: Plain X-ray: The standard views are A-P, Lateral and skyline views (Fig. 5.33-5.35). Skyline view: is a superior-inferior projection of the patella. It is one of many different methods to obtain an axial projection of the patella. This view is used in trauma patients to assess for a patellar fracture or subluxation and in orthopedics for patellofemoral joint disease. This is an ideal projection for patients that are better suited to the supine. patient is supine on the table with both knees flexed at roughly 45°. Fig. (5.33): x ray of knee joint (A-P view). Fig. (5.34): x ray of knee joint (lateral view).  Fig. (5.35): x ray of knee joint (skyline view). Ankle joint The ankle joint (also known as the tibiotalar joint or talocrural joint) forms the articulation between the foot and the leg. It is a primary hinge synovial joint lined with hyaline cartilage. Gross anatomy The ankle joint is comprised of the tibia, fibula and talus as well as the supporting ligaments, muscles and neurovascular bundles. It carries the weight of the body and can undergo a myriad of pathology, most commonly traumatic injuries of the medial and lateral malleoli. (Fig5.36) The tibia extends inferiorly to articulate with the talus on its medial aspect which has an inferior projection at its medial aspect, the medial malleolus. The fibula has a similar inferior projection laterally, the lateral malleolus. The tibia has a partially curved surface to articulate with the talar dome which is wide anteriorly and narrows posteriorly.  The talus lies superior to the calcaneus and articulates with the navicular anteriorly. Fig. (5.36): A diagram showing bones of ankle joint. Radiographic Anatomy: Plain X-ray: The ankle series comprised of an anteroposterior (AP), mortise and lateral radiograph. The series is often used in emergency departments to evaluate the distal tibia, distal fibula, and the talus, forming the ankle joint (Fig.5.37-5.39). Mortise View: is not a true Anterior-Posterior projection but rather at an angle to optimize visualization of the ankle joint without being overlapped by the fibula.  Fig (5.37) Ankle series Fig(5.38) Ankle series Fig (5.39) Ankle x ray (lateral view) Foot Joints (Fig.5.40 &5.41) Fig(5.40) diagram showing foot joints Fig (5.41) x ray foot