Download The Lower Limbs

The Lower Limbs
• Formed by the two coxal bones (a.k.a. ossa
coxae) that form the hip bones
• Coxal bones are attached to the sacrum to form
the bony pelvis
• The bony pelvis holds the entire weight of the
upper body and protects the organs of the lower
abdomen
• The pelvis is divided into two sections—false
pelvis and true pelvis
– False pelvis is area between wings of hip
– True pelvis is open space between the bones,
anterior to sacrum and coccyx
• Each hip bone is made by the fusion of three
bones—ilium, ischium, and pubis
• Ilium is the largest bone of the coxa
– Connects to the alae of the sacrum
– Form the superior, winged section of hip bone and
the superior part of the acetabulum
– Iliac crest is edge of the ilium that stretches from
the anterior superior spine to the posterior superior
spine
• The ischium is also called the “sitdown bone”
– Forms the most inferior part of the coxa
– Ischial tuberosity is roughened area of most inferior
point that receives the body weight when sitting
– Ischial spine is a projection on the posterior side of
the ischium, above the ischial tuberosity
– Greater sciatic notch is above the ischium, below
the posterior inferior iliac spine that allows nerves
and blood vessels to pass from the back of the
pelvis to the thigh
• The pubis is the most anterior part of the pelvis
– The ramus of each pubic bone forms the anterior
side of the obturator foramen (the ischial ramus
forms the posterior), which allows blood vessels
and nerves to pass into the anterior part of the
thigh
– The pubic symphysis is the cartilaginous point of
fusion for the pubic bones in the front
• The acetabulum is the socket formed by the three
bones where the thigh bone articulates with the
hip
• Thigh consists of one bone—the femur—that is
the heaviest, strongest bone in the body
• The proximal end of the femur includes a head,
neck, and trochanters
– The head is rounded and fits deep into the
acetabulum of the hip
– The neck is the constricted part of bone just
inferior/lateral to the head
– The greater trochanter is a projection on the top of
the bone for muscle attachment
– The less trochanter is a projection inferior to the
neck that allows for muscle attachment
• The gluteal tuberosity is a ridge on the posterior
that runs the length of the shaft and attaches to
the gluteal muscles
• The distal end of the femur includes the lateral
and medial condyles, separated by the
intercondylar notch
• The leg consists of two bones—the tibia and fibula
– The tibia and fibula are connected by an
interosseous membrane
– The tibia is also called the shinbone
• Larger, more medial bone of the leg
• Articulates with femur at the medial and lateral
condyles (separated by the intercondylar eminence)
• Tibial tuberosity is roughened surface on anterior
side of tibia that serves as a point of attachment for
the patellar ligament
• Anterior crest runs the length of the anterior side of
the tibia
• Medial malleolus is process on distal, medial end of
tibia that forms inner bulge of ankle
– The fibula is the smaller, lateral bone of the leg
• Does not articulate with the femur
• Sticklike structure that forms joints with the tibia
proximally and distally
• Lateral malleolus forms the outer part of the ankle
• Foot has three sections (like the hand) with the
tarsals, metatarsals, and phalanges
– There are 7 tarsal bones that form the inner ankle
and the heel
– 5 metatarsals form the sole of the foot
– 14 phalanges form the toes; labeled proximal,
middle, and distal like the fingers
• Ligaments within the tarsals and metatarsals
cause the arch of the foot (two longitudinal
arches, 1 transverse arch)