Study of Skeleton of Frog

         Skull of Frog 

                 Dorsal View

1.         Pair of pre-maxillae at the tip of upper jaw.

2.         Pair of maxillae forming the sides of the upper jaw.

3.         Ventral row of maxillary and pre-maxillary teeth are present.

4.         Pair of nasals present at the centre.

5.         Single long and flail frorp-parietal.

6.         Pair of prootic and squamosals.

7.         Posterior view shows foramen magnum, occipital corndyles, exoccipitals and columella.

 

                           Ventral View

                            1.         Pair of vomers with triangniarvomerine teeth.

2.         Pair of palatine are simple and slender bones.

3.         Single inverted T shaped parasphenoid.

4.         Pair of Y shaped pterygoids.

5.         Quadratojugals are sort which forms posterior part.

  b. LOWER JAW

  D. VERTEBRAE

1. Atlas vertebra 

1.         It is the first vertebra of frog.

2.         Centrum is reduced.

3.         Pre-zygapophyses are absent.

4.         Pos-zygapophyses are present but small.

5.         A pair of anterior concave facets articulates with the occipital condyles of skull.

TYPICAL VERTEBRA

1.         From third vertebra to seventh all vertebrae of frog are considered as typical vertebrae which show following characters.

2.         Centrum shows concavity on anterior side and hence typical vertebra is procoelous. . Transverse processes are tong and tapering.

3.         Pre-zygapophyses are directed upward and inwards.

4.         Post-zygapophysis of one articulates with the post-zygapophyses of the receding vertebra.

5.         Neural spine pointed and directed backward.

6.         Neural canal protects the spinal cord.

7.         Through internal foramen spinal nerves come out of the vertebral column.

EIGTH VERTEBRA     

1.         It is the amphicoelous vertebra.

2.         Centrum has concavity on both the ends.

3.         The remaining all other structural features are same that of typical vertebra.

NINTH VERTEBRA

1.         It is. the acoelous vertebra.

2.         Centrum has no concavity.

3.         Centrum has two convexities at the posterior end.4.         Anterior convexity fits into the concavity of 8^th vertebra.

5.         Posterior doubld convexities fit into corresponding concavities of urostyle.

6.         Transverse processes are stout and bent backward.

7.         Transverse processes articulate with the iliac of pelvic girdle.

  UROSTYLE BONE

1.         It is the last part of vertebral column.

2.         It has rod like centrurn and blade like neural crest.

3.         Small neural canal is also presents for filamentous terminally. (Last part of  
         spinal cord)

4.         Anterior double concavities articulate with the 9^th vertebra.

x. APPENDICULAR  SKELETON

  a. PECTORAL GIRDLE

1.         It is the anteriorgirclle that provides surface for articulation of fore limbs and also protects the irktal organs.

2.         It shows mid venal sternum.

3.         Sternum is distinguished into episteinum, omostemum, mesosternum and xiphiSterntnn.

4.         On lateral sides of sternurntere are two slender clavicle bones.

5.         Axe shaped colacoids are flat bones arising laterally from sternum.

6.         Scapula and supra scapula are the most promitieni parts of this sternum girdle.

7.         Scapula shows anterioily directed acromion process..

8.         Supra scapula turns on the back of fidgaiid it is a broad structure.

9.         Glenold cavity is at the junction of a clavicle, a coracoids and a scapula.

10.     Glenoid cavity receives the head of hitinerus bone.

11.     Thus, pectoral girdle shows sternum, clavicle, coracoids scapula and supra scapula and glenoid cavity.

b. PELVIC GIRDLE

1.         It is the posterior girdle.

2.         Two haves are joined to form V shaped structure.

3.         Each half constitutes ilium, ischium, pubis, and acetabulum.

4.         Ilium is rod like bone located at anterior part of girdle. It has dorsal iliac crest.

5.         Ischium is the posterior part of the girdle distinguished by its somewhat triangular shape.

6.         Pubis is the posterior and ventral part of the gird It is transparent and calcified cartilage, Two .halves of pubis form pubic symphysis.

7.         Acetahulaum is cup shaped cavity. It gives articulation to the head of femur,

c. FORE LIMB BONES

1.         Humerus, radio-ulna and hand bones are the bones of fore limbs.

2.         Humerus is the bone of upper arm. It's Proxima! with enlarged head; condole is at distal end and deltoid ridge at shaft.

3.         Radio- ulna is fore arm boric formed by lateral fusion of radius and ulna.

4.         Bones of hands are distinguished into three parts.

5.         Carpals — these form the skeleton of wrist. These are six in number and fused.

6.         Metacarpals - these are five in number, elongated and form skeleton of palm.

7.         Phalanges — bones of fingers are called phalanges. Their formula is 02233.

d. HIND LIMB BONES

1.         Hind limb bones are distinguished into femur, tibia fibula and bones of foot.

2.         Femur is .the thigh bone_ it’s proxfmal end is round and distal end is expanded.

3.         Tibiofabula is the bone of shank. It is longest and expanded bone, It is formed by the lateral fusion. Of tibia and fibula. Inner tibia has a tibial crest, Tibia-fibuta shows a foramen for blood vessel.

4.         Bones of foot are tarsals, metatarsals and phalanges.