Bones of lower limb

Ossa membri inferioris

  • Latin synonym: Ossa extremitatis inferioris
  • Synonym: Bones of lower extremity

Definition

Bones of lower limb can be classified into two groups: those belonging to the pelvic girdle and those found in the free part of the lower limb.

A.      The pelvic girdle consists of two hip bones that connect anteriorly at the pubic symphysis and posteriorly to the sacrum at the sacroiliac joints.

B.      The bony structure of the free part of the lower limb includes several bones, such as:

  • The femur (thigh bone)

  • The patella (knee cap)

  • The tibia and fibula (leg bones)

  • The tarsal bones, metatarsals, and phalanges (foot bones) → The tarsal bones include the calcaneum, talus, navicular, cuboid, and three cuneiform bones (medial, intermediate, and lateral). There are five metatarsal bones. Each toe consists of three phalanges, except for the big toe, which has only two phalanges.

The bones of lower limb form various joints:

  • The head of the femur fits into the acetabular fossa of the pelvic bone, forming the hip joint. The hip joint is a synovial joint of ball and socket type, allowing a wide range of movements such as flexion, extension, adduction, abduction, medial and lateral rotation, and circumduction.

  • Distally, the femoral condyles articulate with the tibial condyles, forming the knee joint. The fibula, one of the leg bones, does not participate in the knee joint articulation.

  • The tibia and fibula are connected by the superior and inferior tibiofibular joints and interosseus membrane, but they allow limited movement between them.

  • Distally, both the tibia and fibula articulate with the talus, forming the ankle joint.

  • Both the knee and ankle joints are a hinge-type synovial joints, enabling flexion and extension movements.

  • The feet contain several small joints, including the intertarsal, tarsometatarsal, metatarsophalangeal, and interphalangeal joints.

  • Inversion and eversion (inwards and outward movement of the foot, respectively) occur at the intertarsal joints.

  • Muscles and ligaments support the tarsals and metatarsals, creating longitudinal and transverse arches and preventing them from lying flat on the ground. These arches play a crucial role in absorbing and transmitting forces during movement.

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Text written by Muhammad A. Javaid, MD, PhD © 2023 IMAIOS.

  • Drake, R.L., Vogl, A.W. and Mitchell, A.W.M. (2009). ‘Chapter 6: Lower Limb’ in Gray’s anatomy for Students. (2nd ed.) Philadelphia PA 19103-2899: Elsevier, pp.517-518.

  • Anderson, B.W., Ekblad, J. and Bordoni, B. Anatomy, Appendicular Skeleton. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK535397/


Comparative anatomy in animals

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