Skeletal system - Entrance preparation zoology

 Skeletal system relates to bones and joints in human body. It provides basic structure to the body. In entrance exams bone of Rabbit is more important. Comparative study of bones in frog, rabbit and human would be easier to remember and score high in MCQs.

 


Video Notes:

SKELETAL SYSTEM


Axial

• Skull-22
• Ribs-12 pairs
• Sternum-1
• Vertebrae- 26
• Hyoid bone-6

Skull

• Cranial-8
• Facial-14

Cranial bone

Virus Can Not Make My Pet Zebra Laugh.

V and M------------>Vomer and Mandibular are only unpaired bones in face.

Vertebrae

• C7H12L5S5Co4  (Baby)
• C7H12L5S1Co1    (Adult)

Dentary------------>Lower jaw (Half of lower jaw – Ramous)

Diastema-------------> Gap between incisor and premolar

Rodenia(Rat order) and Lagomorpha(Rabbit order)---------------> Have diastema

Suspensorium (Lower jaw join to upper jaw)

• Craniostyllic-Rabbit
• Autostylic-Frog

Rabbit vertebrae-------------> C7H12-13L6-7S4Co16

Dental formula------------->  2033/1023 (Rabbit), 2123/2123(Man)

Acoelous--->  Bone, Flat posterior and anterior

Procoelous----> Bone, front concave, rear convex

Amphicoelous----> Both surface concave

Vertebrae-----------> Man(26), Rabbit(45 to 47) , Frog(10)

Atlas--------> No prezygapophysis

Typical vertebrae of frog (2-7)---------> Acoelous  +  9th vertebrae

8th vertebrae of frog is Amphicoelous.


Cervical vertebrae-------------> 7 in all mammals except Sea cow (6), Sloth(8)




Atlas--------------->Neural spine reduced, No centrum, both zygapophysis

Axis------------------> Odontoid process(Dens), Post zygapophysis only present

Typical cervical-----------------> Transverse process + Short pointed neural spine, both zygapophysis

Thoracic vertebrae----------------> 1st has long backwardly directed  neural spine

Lumbar vertebrae-------------------> Anterior lumbar has hypapophysis

Sternum--------------> Breast bone

Xiphoid cartilage

• Manubrium(1)
• Gladiolus(2-6)
• Xiphisternum (7)  bear xiphoid cartilage

Ribs and thoracic vertebrae

• C to C Centrum to Capitulum)
• T to t (tuberculum to transverse process)

Pectorial girdle

• Coracoid process
• Acromian process
• Metacromian process

Pelvic girdle ---------------> Ilium + Ischium = Acetabulum

Only pubis doesnot form acetabularia.

Largest foramen of body(between pubis and ischium)---------------------> Obturator foramen

Cotyloid between ilium and ischium.

Digital formula

  Rabbit Frog Human
Fore limb 2,3,3,3,3 0,2,2,3,3 2,3,3,3,3
Hind limb 0,3,3,3,3 2,2,3,4,3 2,3,3,3,3

Humerus

Olecranon fossa, Coronoid fossa, Deltoid ridge

Radio-ulna-------> Epiphysis (Tibia-fibula)

Tibia------------> Cnemial crest

Deltoid ligament------------> Ankle joint

Stiffness of joint in old age is due to decrease in synovial fluid

Sprain-------------> Excessive stretching causing twis of pull of ligament.

Bone to bone joining is done by ligament.


Ball and socket joint---------------->Shoulder and hip

Hinge joint---------------->Elbow and phalangeal joint

Pivot joint---------------->Atlas and skull

Saddle joint---------------->Thumb joint

Gliding joint---------------->Radius and ulna

Angular joint---------------->Wrist joint


Knee joint is largest in body

Floating ribs, 2 in human, 3 in rabbit.

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