Question

What is the lower limb? Explain briefly the anatomy of the lower limb.

 

Answer 1

THE LOWER LIMB:

Hip bone or os coxae:

• It is a large, irregular bone comprising three parts - namely, the ilium, the ischium and the pubis.
• The ilium is the expanded, fan-shaped upper part. It includes the upper part of the acetabulum.
• The part of the bone below and behind along with the lower part of the acetabulum is termed the ischium.
• The pubis forms the rest of the bone.
• The ilium and the ischium enclose a large foramen termed the obturator foramen.

Side identification.

• • (a) The iliac crest forms the upper border of the bone,
  • (b) the acetabulum lies on the lateral surface,
  • (c) the obturator foramen is placed below and in front of the acetabulum.

Femur:

• The femur or thigh bone is the largest and strongest bone in the skeleton.
• The bone articulates with acetabulum of hip-bone above and with the tibia below.
• It consists of a shaft, an upper end and a lower end.
• The upper end includes a head, a neck, two trochanters-greater and lesser.
• It presents trochanteric crest, trochanteric fossa and quadrate tubercle.
• The posterior border of the middle-third of the shaft is formed by a rough ridge, termed the linea aspera.
• The posterior surface of the lower a third presents a flattened triangular area termed the popliteal surface.
• At its posterior surface of the upper third the shaft shows a spiral line
• The lower end bears two condyles. medial and a lateral and an inter-condyler notch which separates the two condyles; lateral epicondyle: medial epicon dyle: patellar surface, tibial surface etc.

Side identification:

• • (a) The rounded head is the upper end,
  • (b) the head is placed medially,
  • (c) the shaft shows a forward convexity.

Patella:

• The patella bone is placed in front of the knee joint, It is somewhat triangular in shape with rounded margins and an apex directing downwards.

Tibia:

• The tibia is the medial and larger of the two leg bones. I
• t has an expanded upper end or head bearing two condyles, medial and lateral, the tubercle of the tibia, the intercondyler area and the intercondyler eminence.
• The shaft, which is tri angular in cross-section presents medial, lateral and posterior surface and anterior, interosseous and medial borders.
• The anterior border forms a sharp crest, termed the 'shin'.
• The lateral border of the lower end is formed by a notch, termed the fibular notch.
• The projected short process of the lower end is called the medial malleolus.

Side identification:

• • (a) The upper end is much larger than the lower end,
  • (b) the medial malleolus lies on the medial side,
  • (c) the anterior border is the most prominent of the three borders.

Fibula:

• The fibula is very slender and is the lateral bone of the leg.
• It has an upper end- or head, a shaft and a lower end which forms the lateral malleolus.

Skeleton of the foot:

• The skeleton of the foot consists of unree sets of bones namely, the tarsus, the metatarsus and the phalanges.
• The Tarsus comprises seven bones.
• They are the talus and the calcaneum on the proximal row, the three cuneiforms Imedial, intermediate and laterall and the cuboid on the distal row, and the navicular which is placed between the talus and the medial three bones of the distal row.
• The metatarsal bones are five, in number.
• Each bone presents a head, a shaft and a base. As in the hand, the Phalanges are three in number in the toes other than the big toe where the number istwo.

The lower limb:

• It is divided into three regions.
• These are the thigh, located between the hipand knee joints; the leg, located between the knee and ankle joints; and distal to the ankle, the foot.
• There are 30 bones in each lower limb.