Comparative study of Hind limb bones of vertebrate

Hind Limb Bones of Frog

Hind limb constitute the femur, tibio-fibula, astragalus-calcaneum and bones of foot.

Comments

• Femur
  • It is thigh bone having expanded ends, covered with calcified cartilages.
  • Proximal end or head articulates with acetabulum while distal end with tibio-fibula.
• Tibio-fibula
  • These are shank bones and are elongated.
  • Tibia is inner and fibula is outer, both fused together to form a compound bone.
  • Proximally tibia contains a tibial crest.
  • At proximal end tibio-fibula articulates with femur, and at distal end with astragalus-calcaneum. Structures seen are proximal articular facet, groove, tibia, fibula, nutrient foramen, distal groove and distal articular facet.
• Astragalus-calcareum
  • These are proximal ankle bones united at both ends and covered by proximal and distal epiphyses of calcified cartilages at proximal and distal ends respectively.
  • Outer thicker straight bone is calcaneum of iibulare, while inner thinner and slightly curved bone is astragalus or tibiale.
• Bones of foot
  • Foot contains 5 long, slender bones, known as metatarsals, having five true toes.
  • First, second, third, fourth and fifth digits contain 2, 2, 3, 4 and 3 phalanges respectively.
  • Sixth toe is very small having 2 or 3 bones and is called as pre-hallux or calcar.

Hind Limb Bones of Varanus

Hind limb consists of femur, tibia, fibula and bones of hind foot.

Comments:

• Femur
  • It is thigh bone having two epiphyses.
  • Proximal end contains head, which fits into acetabulum, while distal end is pulley-shaped, having two tuberosities or for articulation with tibia and fibula,.
  • Femur condyles has lesser trochanter and greater trochanter on pre-axial and post-axial sides, respectively.
• Tibia and fibula and bones of hind foot
  • These are shank bones
  • Tibia is stout, curved and on pre-axial side, while fibula is slender and on post-axial side.
• Bones of hind-foot
  • It is made up of 5 tarsal bones.
  • First, second, third, fourth and fifth toes contain 2, 3, 4, 5 and 3 phalanges, respectively.
  • Each toe bears a terminal horny claw.

Hind Limb Bones of Fowl

Hind limb comprises of femur, tibio-tarsus and fibula, tarsals, tarso-metatarsus and phalanges. Hind is modified for bipedal locomotion.

Comments:

• Femur (Anterior view)
  • It is cylindrical, short and curved thigh bone.
  • Head fits into acetabulum and outwardly it contains greater trochanter.
  • Distal end is pulley-shaped for patella bone and bounded by two condyles to articulate with tibia namely outer condyles and inner condyle with inter condylar fossa.
• Femur (Posterior view)
  • Contains nutrient foramen, head, inter condylar fossa, outer condyle and inner condyle.
• Tibio-tarsus and fibula (Anterior view)
  • Tibio-tarsus and fibula form shank bones.
  • Tibio-tarsus is a straight and long bone formed by fusion of tibia with proximal row of tarsals (astragalus and calcaneum).
  • Proximally, it articulates with femur and distally with tarso-metatarsus.
  • Fibula is reduced to a small slender bone. Other structures are tibial crest distal lateral tubercle, distal groove.
• Tarso-metatarsus female (Posterior view).
  • It is a compound bone formed by fusion of distal row of tarsals with second, third and fourth metatarsals. Other structures seen at proximal end are articular facets for tibiotarsus, nodule of I metatarsal, II metatarsal, III metatarsal and IV metatarsal.
• Tarso-metatarsus. Male (Anterior view). In males tarsometatarsus contains a spur. Phalanges.
  • Four toes.
  • First or hallux is directed backwards and remaining three forwards.
  • First, second, third and fourth toes have 2, 3, 4 and 5 phalanges respectively; each one is clawed.

Hind Limb Bones of Rabbit

Hind limb is formed by femur, tibio-fibula and bones of hindfoot.

Comments :

• Right femur (Back view)
  • It is thigh bone.
  • Proximal head articulates with acetabulum.
  • Lesser, greater and third trochanters present for muscle attachment.
  • Distally it has pulley-shaped structure, having two lateral condyles which enclose an intercondylar groove.
• Right femur (Front view) :- It shows head, greater trochanter, lesser trochanter, shaft, patellar groove and condyles.
• Bones of hind foot :
  • It contains tarsal bones in two rows.
  • Tibiale and intermedium of the proximal row are fused to form astragalus on pre-axial side, while fibulare or calcaneum is the largest tarsal bone produced into a spur on post-axial side.
  • Distal row contains three bones mesocuneiform, ectocuneiform and cuboid.
  • Only four toes each having three phalanges, the terminal one bearing a claw.