Lower Limb Anatomy: Regions and Bones

• Lower limb can be described as free flowing
• Pelvic girdle is the hip bones

Regions of the Lower Limb

• Gluteal region: posterior buttocks and hip region, articulating with axial skeleton via joint
• Femoral region: thigh, located between the hip and knee joint
• Knee region
• Leg region: between knee and ankle
• Ankle region: connects leg and foot
• Foot region

Bones of the Lower Limb

• Hip bone connects at the pelvic girdle to the femur (femoral region)

• Femur articulates with patella and tibia at the knee

• Tibia articulates with fibula in the leg

• Fibula articulates with 7 tarsal bones: calcaneus, talus navicular, cuboid, and 3 cuneiforms (medial, intermediate, lateral)

• Tarsal bones articulate with foot bones called metatarsals, of which there are typically 5

• Metatarsals articulate with 5 phalanges

• Pelvic girdle consists of 2 hip bones, the sacrum bone, and the coccyx bone, fused together

• Hip bone is also referred to as the innominate bone

• Ilium is the superior, large part of the hip bone

• Ilium, ischium, and pubis fuse at the acetabulum

• Medial part of the ilium is thicker to articulate with the sacrum, forming the sacroiliac joint

• Lateral part thins for muscle attachment

• Iliac crest is a thickened superior margin

• Iliac tubercle: bony protrusion from the iliac crest

• Iliac fossa: concave groove attaching muscle

• Iliac crest terminates in the Anterior Superior Iliac Spine (ASIS) protuberance

• Below ASIS is the Anterior Inferior Iliac Spine (AIIS) protuberance

Posterior of the Ilium

• Iliac crest has a protuberance called the Posterior Superior Iliac Spine (PSIS)

• Below PSIS is the Posterior Inferior Iliac Spine (PIIS) protuberance

• PIIS forms the upper part of the Greater Sciatic Notch

• Posterior side has 3 gluteal lines: posterior, anterior, inferior

• These lines facilitate attachment of gluteal muscles

• Ischium is the posteroinferior part of the hip bone

• Ischial spine: medial protuberance forming the lower border of the Greater Sciatic Notch

• Inferior to the greater sciatic notch is the lesser sciatic notch (formed by the ischium)

• Ischial tuberosity: rough surface inferiorly for hamstring muscle attachment, involved in posterior thigh muscle function

• Ischael ramus, a limb of the ischium, joins the inferior pubic ramus to form the ischiopubic ramus

• Pubis refers to the anterior inferior section of the hip bone

• Pubis features two limbs: the superior and inferior pubic ramus on each pubis body

• The middle of the body fuses anteriorly at the pubic symphysis

• On the superior medial border of the superior ramus is a protuberance called the pubic tubercle

• Superior pubic ramus, ischiopubic ramus, and the body of the pubis form the obturator foramen, which is lined by an obturator membrane

• The foramen allows passage of obturator vessels and nerves while also lightening the pelvic girdle's weight

• Pectineal line runs on the superior pubic ramus and continues around the ileum and sacrum, forming the pelvic ring

• Lunate surface articulates with the head of the femur

• Acetabular fossa does not articulate with the head of the femur

• Femur is the long bone of the thigh and the longest bone in the human body

• It articulates with the hip bone to form the hip joint and with the tibia and patella to form the knee joint

Femur Anatomy

• Head of femur: contains the fovea (pit)

• Neck: trapezoid shape joining head and neck

• Shaft features a superior, lateral protuberance called the greater trochanter and an inferior, medial protuberance called the lesser trochanter

• Intertrochanteric crest joins the greater and lesser trochanters posteriorly

• Quadrrate tubercle: found posteriorly under the greater trochanter

• Intertrochanteric line joins the greater/lesser trochanters anteriorly

• This line continues posteriorly as the pectineal line, eventually creates a groove called the linea aspera (lip shape)

• Linea aspera has medial and lateral lips

• Lateral lip continues superiorly and laterally borders the gluteal tuberosity, a rough triangular surface

• Gluteal tuberosity border is on the pectinate line

• The linea aspera separates (posteriorly and distally) into medial and lateral supracondylar lines

• Distal end of the femur includes the adductor tubercle, an attachment point for adductor muscles of the thigh

• Condyles at the distal end of the femur:

  • Medial condyle
  • Lateral condyle

• Condyles articulate with the tibia to form the knee joint

• Patella (kneecap): largest sesamoid bone (bone embedded in a tendon) embedded within the quadriceps femoris muscle

  • Muscle crosses anterior to the knee joint to insert on the tibia
  • Bone is triangular

• Apex of the patella is inferior for attachment of the patellar ligament connecting the patella to the tibia

• Base is broad and thick for attachment of the quadriceps tendon from above

• Posterior surface articulates with the femur: includes medial and lateral facets

• The lateral facet is larger to allow articulation of the lateral condyle of the femur

• Tibia is a triangular bone in cross section

• Tibia has 2 articular surfaces: superior articular surfaces articulate with the femur, whereas the inferior articular surface joins the tarsal bone

• It features 3 surfaces: medial, lateral, and posterior

• Three edges: anterior margin, medial margin, interosseus margin (lateral)

• A line runs from lateral to medial on the posterior side, called the soleal line used for attachment of the soleus muscle

• Condyles: lateral and medial articulate with the lateral and medial condyles of the femur

• Intercondylar eminence: protuberance between the two tibia condyles

  • Ends split into the medial and lateral intercondylar tubercles
  • The eminence contributes to the anterior and posterior intercondylar areas

• Medially-located medial malleolus

• Malleolus articulates with the talus bones of the ankle

• Fibula is a triangular bone with 3 sides: medial, posterior, and lateral and has 3 margins: posterior margin, anterior margin, and interosseus margin

• Head of fibula doesn't articulate with the femur: it is not part of the knee joint

• There is a neck of fibula (nerves around)

• Shaft

• Lateral malleolus is part of the ankle which allows for palpation

Ankle and Foot Bones

• 7 tarsal bones are found in the ankle
  • Talus: forms ankle joint
  • Calcaneus
  • Navicular
  • Cuboid
  • Cuneiforms (medial, intermediate, and lateral)
• Foot
• Metatarsals
• Phalanges- big toe includes distal and proximal bones

Hip Joint

• This is a ball and socket-type synovial joint
• The hip joint is an articulation between the head of the femur and the acetabulum
• It functions to bear weight and allow for bipedal locomotion
• Movements: flexion, extension, abduction, adduction, internal/external rotation, and circumduction
• Joint is strengthened ligaments and muscles

Knee Joint

• Hinge type synovial joint
• Articulation between:
  • Condyles of the femur and tibia (femorotibial)
  • Posterior surface of the patella with the patellar surface of the femur (femoropatella)
• Crescent-shaped cartilages (menisci) act as shock absorbers
• Movements: flexion, extension, and rotation
• Strengthened by ligaments and muscles

Tibiofibular Joint

• Proximal tibiofibular joint is synovial
  • Articulation between the lateral condyle of the tibia and the superomedial surface of the head of the fibula
  • Membrane closes distally at the contact surface
  • Bone is strengthened by ligaments

Overview of the lower limb, including the gluteal, femoral, knee, leg, ankle, and foot regions. Examination of the bones, including the hip bone, femur, tibia, fibula, tarsal bones, metatarsals, and phalanges. The pelvic girdle consists of the hip bones, sacrum, and coccyx.