Lecture 12 Appendicular Skeleton II: Pelvic Girdle, Lower Limb, and Foot

A comprehensive vocabulary review of the anatomical structures, bony landmarks, joints, and clinical concepts of the pelvic girdle, femur, tibia, fibula, and foot.

Pelvic Girdle

A structure consisting of the paired hipbones and sacrum that attaches the lower limbs to the axial skeleton, supports pelvic organs, and transmits body weight from the upper body to the lower limbs.

Acetabulum

The deep, cuplike socket in the pelvis formed by the fusion of the ilium, ischium, and pubis that connects the head of the femur to the hip joint.

Iliac Crest

The thickened superior margin of the ala (superior winglike portion of the ilium) that serves as an attachment site for muscles.

Anterior Superior Iliac Spine (ASIS)

A blunt projection located at the anterior end of the iliac crest that functions as an attachment site for muscles and ligaments.

Posterior Superior Iliac Spine (PSIS)

A sharp projection marking the posterior end of the iliac crest that functions as an attachment site for muscles and ligaments.

Greater Sciatic Notch

A deep indentation in the ilium located inferior to the posterior inferior iliac spine that allows passage for the sciatic nerve.

Iliac Fossa

The large, smooth concavity or depression located on the inner surface of the ala of the ilium.

Arcuate Line

A bony ridge on the inner surface of the ilium that projects anteriorly and inferiorly from the auricular surface toward the pubis, helping define the pelvic brim.

Pelvic Brim (Inlet)

An opening in the pelvis that marks the continuous boundary separating the false (greater superior) pelvis from the true (lesser superior) pelvis.

Ischial Spine

A pointed triangular process that projects medially from the ischium, serving as an attachment point for the sacrospinous ligament.

Ischial Tuberosity

The thickened, rough inferior surface of the ischial body that bears the body's weight when seated.

Lesser Sciatic Notch

A small indentation situated inferior to the ischial spine that transmits nerves and blood vessels.

Pubic Symphysis

A cartilaginous joint formed between the bodies of the two pubic bones that contains a fibrocartilage disc.

Pubic Crest

A prominent, thickened anterior border ridge of the pubis that provides attachment sites for muscles and ligaments.

Pubic Tubercle

A rounded projection located lateral to the pubic crest.

Pelvic Outlet

The inferior space of the pelvis bounded by the pubic arch, ischia, sacrum, and coccyx.

Femur

The longest and strongest bone in the body, accounting for $\frac{1}{4}$ of a person's height; it articulates proximally with the acetabulum and distally with the tibia and patella.

Fovea Capitis

A small pit located in the ball-like head of the femur that assists with weight-bearing function.

Intertrochanteric Line

A bony ridge that connects the greater and lesser trochanters of the femur anteriorly.

Intertrochanteric Crest

A bony ridge connecting the greater and lesser trochanters of the femur posteriorly.

Linea Aspera

A roughened ridge on the posterior surface of the femur shaft that serves as an attachment site for several muscles that move the thigh.

Adductor Tubercle

A bump located on the medial epicondyle of the femur that serves as an attachment site for the adductor magnus muscle.

Patellar Surface

A smooth anterior surface on the distal end of the femur that articulates with the patella.

Intercondylar Fossa

A deep groove situated between the medial and lateral condyles on the posterior aspect of the distal femur.

Tibia

The medial leg bone that receives body weight directly from the femur and transmits it down to the foot.

Fibula

The lateral bone of the leg that is non-weight-bearing, does not articulate with the femur, and articulates proximally and distally with the tibia.

Tibial Tuberosity

A large, rounded projection located on the anterior surface of the proximal tibia that serves as the attachment site for the patellar ligament.

Anterior Border of the Tibia

A sharp ridge running along the anterior shaft of the tibia, commonly known as the shin.

Medial Malleolus

A large process at the medial border of the distal tibia that can be felt as the medial bulge of the ankle.

Lateral Malleolus

The process at the distal end of the fibula that forms the lateral ankle bulge and articulates with the talus bone.

Bimalleolar Fracture

A common sports injury involving a break in the distal ends of both the tibia and the fibula, affecting ankle stabilization and weight-bearing.

Calcaneus

One of the two primary weight-transmitting tarsal bones; it forms the heel and makes direct contact with the ground.

Talus

One of the two primary weight-transmitting tarsal bones that articulates with the leg bones to distribute body weight.

Hallux

The great toe, which differs from digits 2 through 5 by having only two phalangeal bones (proximal and distal) and no middle phalanx.

Medial Longitudinal Arch

The highest foot arch that curves upward along the medial side of the foot to assist in weight distribution and shock absorption.

Lateral Longitudinal Arch

A low curve that elevates the lateral part of the foot.

Transverse Arch

An arch that runs obliquely from one side of the foot to the other, spanning across the metatarsal heads.

Flat Feet (Fallen Arches)

A condition resulting from collapsed foot arches that alters lower extremity alignment and increases stress and joint wear at the ankle, knee, hip, and back.