ANATOMY OF LOWER LIMB Lecture 1

General Introduction The lower limb is divided into the gluteal region, thigh, leg, and foot on the basis of major joints, component bones, and superficial landmarks.

Regions of the lower limb the gluteal region is posterolateral and between the iliac crest and the fold of skin (gluteal fold) that defines the lower limit of the buttocks. the thigh is between the inguinal ligament and the knee joint and the posterior thigh is between the gluteal fold and the knee. the leg is between the knee and ankle joint. the foot is distal to the ankle joint.

The bones of the lower limb The bones of the gluteal region are the pelvic bones. Thigh bone is the femur. it articulate with the patella (knee cap). Bone of leg are: The tibia is medial in position, is large bone, and is the weight bearing bone. The fibula is lateral bone, smaller than tibia, participate in ankle, no participation in the knee joint. *They articulate to each other by superior and inferior tibiofibular joints. *Between these two bones there is an interosseous membrane.

The bones of the lower limb The bones of the foot consist of the seven tarsal bones, the metatarsals, the phalanges. The ankle joint is formed by distal end of the tibia and part of one of the tarsal bones of the foot (talus) with small participation of fibula.

Bones of the Gluteal Region The ilium, ischium, and pubis form the hip bone. They meet one another at the acetabulum. The hip bones articulate with the sacrum at the sacroiliac joints. K They also articulate with one another anteriorlly at the symphysis pubis. Bones of the Gluteal Region

The ilium Iliac crest Ala Internal lip of iliac crest Anterior superior iliac spine Posterior superior iliac spine Anterior inferior iliac spine Posterior inferior iliac spine Greater sciatic notch.

The ischium The ischium is L shaped, possessing an upper thicker part, the body, and a lower thinner part, the ramus. The ischial spine projects from the posterior border of the ischium and intervenes between the greater and lesser sciatic notches. The ischial tuberosity forms the posterior aspect of the lower part of the body of the bone.

The pubis The pubis Divided into a body, a superior ramus, and an inferior ramus. The bodies of the two pubic bones articulate with each other in the midline anteriorlly at the symphysis pubis; the superior ramus joins the ilium and ischium at the acetabulum, the inferior ramus joins the ischial ramus below the obturator foramen.

Obturator canal The obturator foramen in life is filled in by the obturator membrane. The obturator membrane is a thin fibrous sheet, which almost completely closes the obturator foramen. Its fibers are arranged in interlacing bundles; the uppermost bundle completes the obturator canal for the passage of the obturator vessels and nerve.

the acetabulum On the outer surface of the hip bone is a deep depression, called the acetabulum, that articulates with the almost spherical head of the femur to form the hip joint. The inferior margin of the acetabulum is deficient and is marked by the acetabular notch. The articular surface of the acetabulum is limited to a horseshoe-shaped area (the lunate surface) and is covered with hyaline cartilage. The floor of the acetabulum is nonarticular and is called the acetabular fossa.

The Pubic Symphysis The Pubic Symphysis is the midline cartilaginous joint, uniting the bodies of the left and right pubic bones.  The cartilaginous disk is reinforced by a series of ligaments: The superior pubic ligament; The inferior pubic ligament (arcuate pubic ligament). Arcuate = مقوّس

The sacrum The sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity. It consists of usually five initially unfused vertebrae which begin to fuse between ages 16–18 years and are usually completely fused into a single bone by age 34.

sacroiliac joints The sacroiliac joints are two paired "kidney bean" or L-shaped synovial joints. having a small amount of movement (2–18 degrees, that are formed between the articular surfaces of the sacrum and the ilium bones. The two sacroiliac joints move together as a single unit and are considered bicondylar joints (where the two joint surfaces move correlatively together).

Ligaments of the sacroiliac joints   The sacroiliac joint’s stability is maintained mainly through a combination of only some bony structure and very strong intrinsic and extrinsic ligaments: The Anterior Sacroiliac ligament;  The Posterior Sacroiliac ligament;  The Sacrotuberous Ligament;  The Sacrospinous Ligament.

Ligaments of the sacroiliac joints The Sacrotuberous Ligament is situated at the lower and back part of the pelvis and runs from the sacrum to the tuberosity of the ischium.

Ligaments of the sacroiliac joints The Sacrospinous Ligament is a thin, triangular ligament attached by its apex to the ischial spine, and medially, by its broad base, to the lateral margins of the sacrum and coccyx. Together with the sacrotuberous ligament, it converts the greater sciatic notch into the greater sciatic foramen and the lesser sciatic notch into the lesser sciatic foramen.

The greater sciatic foramen is bounded as follows: anterolaterally by the greater sciatic notch of the illium; posteromedially by the sacrotuberous ligament; inferiorly by the sacrospinous ligament and the ischial spine; superiorly by the anterior sacroilliac ligament.

The lesser sciatic foramen has the following boundaries: Anterior: the tuberosity of the ischium. Superior: the spine of the ischium and sacrospinous ligament. Posterior: the sacrotuberous ligament.