π
RABBIT BONES AND SKELETON
β’ Introduction:
Table 1: Basic Terms
Term | Meaning |
|---|---|
Osteology | Study of bones |
Osteogenesis / Ossification | Process of bone formation |
Skeleton | Supportive framework of body |
β Types of Bones in Vertebrates:
- β’Exoskeleton
- β’Endoskeleton
β’ Exoskeleton:
β Origin: Derived from epidermis / dermis; ectodermal origin
β Examples:
- β’Scales
- β’Nails
- β’Hairs
- β’Hoof
- β’Horn
- β’Feathers
- β’Beak
- β’Claws
β’ Endoskeleton:
β Composition: Cartilage + bones
β Origin: Mesodermal origin
β Function: Internal support, protection, movement, muscle attachment
β’ Types of Bones in Vertebrates:
Table 1: Types Based on Formation
Bone Type | Formation | Examples |
|---|---|---|
Cartilaginous / replacing bone | Ossification of cartilage; endochondral ossification | Most long bones |
Membrane / investing / dermal bone | Ossification of fibrous connective tissue; intramembranous ossification | Lower jaw bones, clavicle, skull bones |
Sesamoid bone | Ossification of tendon | Patella, pisiform, fabella |
β Important Point: Fabella is present behind femur in many mammals but absent in humans
β’ Main Division of Skeleton:
Table 1: Skeleton Division
Skeleton | Components |
|---|---|
Axial skeleton | Skull, vertebral column, sternum, ribs, hyoid |
Appendicular skeleton | Pectoral girdle, pelvic girdle, forelimbs, hindlimbs |
β’ Axial Skeleton:
β Components:
- β’Skull
- β’Vertebral column
- β’Sternum
- β’Ribs
- β’Hyoid apparatus
β’ Skull:
β Rabbit Skull: Dicondylic and tropibasic
β Dicondylic Skull: Skull with two occipital condyles
β Monocondylic Skull: Single occipital condyle; found in fishes, reptiles and birds
β Dicondylic Found In: Amphibia and mammals
β Tropibasic Skull: Presence of interorbital septum
β Foramen Magnum: Opening in occipital bone through which brain joins spinal cord
β Skull Divisions:
- β’Cranium
- β’Sense capsules
- β’Visceral skeleton
β’ Cranium:
β Function: Protects brain
β Segments:
- Occipital segment
- Parietal segment
- Frontal segment
- Ethmoid segment
Table 1: Cranial Segments
Segment | Bones / Features |
|---|---|
Occipital segment | Four bones around foramen magnum: supraoccipital, exoccipitals, basioccipital |
Parietal segment | Basisphenoid, alisphenoids, parietals; sella turcica present in sphenoid |
Frontal segment | Frontals, orbitosphenoids, presphenoid |
Ethmoid segment | Single mesethmoid bone; cribriform plate closes anterior cranial cavity |
β Sella Turcica: Depression in sphenoid bone lodging pituitary gland
β Interparietal Bone: Present between two parietals
β’ Sense Capsules:
β Olfactory Capsule:
β Function: Smell
β Bones:
- β’Nasal bones β roof
- β’Vomers β floor
- β’Turbinal bones β ethmoturbinal, maxilloturbinal, nasoturbinal
β Auditory Capsule:
β Function: Hearing
β Bones:
- β’Periotic bone
- β’Tympanic bone
β Periotic Bone: Formed by fusion of prootic, epiotic and opisthotic bones
β Tympanic Bulla: Flask-shaped bony structure outside periotic; contains tympanic membrane and stapes
β’ Visceral Skeleton:
β Includes:
- β’Upper jaw
- β’Lower jaw
- β’Hyoid apparatus
β Upper Jaw Bones:
- β’Premaxilla
- β’Maxilla
- β’Palatine
- β’Pterygoid
- β’Squamosal
- β’Jugal
β Zygomatic Arch: Formed by jugal, maxilla and squamosal
β Important Point: In primates, zygomatic bone is present instead of zygomatic arch; zygomatic bone is also called cheek bone
β’ Lower Jaw / Mandible:
β Structure: Each ramus is half of lower jaw; two halves unite to form mandible
β Main Bone: Dentary
β Processes:
- β’Angular process
- β’Condylar process
- β’Coronoid process
β Inferior Dental Foramen: For passage of nerve and vessels
β Diastema: Space between incisor and premolar, commonly present in rabbit
β Alveoli: Bony sockets of jaws into which teeth are implanted
β Jaw Suspensorium: Craniostylic in rabbit
β Mouth Opening: Limited jaw movement; lower jaw articulates with squamosal
β Teeth Type: Heterodont, thecodont and diphyodont
β’ Dental Formula:
Table 1: Dental Formula
Animal | Dental Formula | Total Teeth |
|---|---|---|
Man | 2123 / 2123 Γ 2 | 32 |
Rabbit | 2033 / 1023 Γ 2 | 28 |
β’ Orbits:
β Location: Sides of frontal segment of cranium
β Interorbital Septum: Bony septum separating two orbits
β Optic Foramen: For optic nerve
β Nasolacrimal Duct: From orbit to nasal bone for tear duct
β’ Hyoid Apparatus:
β Location: Floor of buccal cavity
β Function: Supports tongue and larynx
β Hyoid Bone: Only bone not attached to another bone directly
β Main Support: Basihyal supports root of tongue
Table 1: Parts of Hyoid Apparatus
Part | Components |
|---|---|
Anterior cornua | Ceratohyal, epihyal, stylohyal, tympanohyal |
Posterior cornua | Single thyrohyal bone |
β Human Facial Bones: Vomer, conchae, nasals, maxillae, mandible, palatines, zygomatic and lacrimals
β’ Vertebral Column:
β Rabbit Vertebrae: 45 or 47
β Human Vertebrae: 33 before fusion; 26 in adult after sacrum and coccyx fusion
β Human Vertebral Formula: C7 T12 L5 S5 Co4
β Centrum: Main body of vertebra
β Plural of Centrum: Centra
β Intervertebral Disc: Fibrocartilage between centra
β Annulus Fibrosus: Outer fibrous ring of disc
β Nucleus Pulposus: Central part of disc; vestigial part of notochord
β Modified Vertebrae:
- β’Atlas
- β’Axis
β’ Types of Vertebrae Based on Centrum:
Table 1: Centrum Types
Type | Feature | Example |
|---|---|---|
Acoelous / amphiplatyan | Centrum flat at both anterior and posterior ends | Mammals |
Procoelous | Anterior concave and posterior convex | Many reptiles |
Amphicoelous | Both ends concave | 8th vertebra of frog |
β’ Cervical Vertebrae:
β Location: Neck region
β Number: 7 in nearly all mammals
β Exception: Sloth has 6 cervical vertebrae
β Important Point: Long neck of camel and giraffe is due to length of cervical vertebrae, not increased number
β Special Feature: Vertebrarterial canals for passage of cervical blood vessels and nerves
β’ Atlas:
β Position: First cervical vertebra
β Shape: Ring-like
β Function: Supports skull and helps nodding of head
β Absent Structures:
- β’Centrum
- β’Zygapophyses
- β’Well-developed neural spine
β Transverse Process: Wing-like
β Occipital Condyles: Fit into atlas
β’ Axis:
β Position: Second cervical vertebra
β Function: Helps rotation of head
β Centrum: Short and flat
β Neural Spine: Flat
β Odontoid Process: Present; fits into odontoid facet of atlas
β Zygapophyses: Prezygapophysis absent but postzygapophysis present
β’ Typical Cervical Vertebra:
β Neural Spine: Short and pointed
β Neural Canal: Triangular
β Zygapophyses: Pre and post zygapophyses present
β Transverse Process: Bifurcated
β’ Thoracic Vertebrae:
β Number: 12 or 13 in rabbit; 12 in human
β Function: Articulate with ribs
β Metapophysis: Present
β Neural Spine: Usually long and backwardly directed
β Rib Articulation: First 9 thoracic vertebrae with ribs reaching sternum in rabbit
β’ Lumbar Vertebrae:
β Number: 6 or 7 in rabbit; 5 in human
β Location: Abdominal region
β Nature: Largest, heaviest, strongest and stout
β Hypapophysis: Median ventral process on centrum of anterior lumbar vertebrae; absent in posterior lumbar vertebrae
β’ Sacrum:
β Formation: Fusion of 4 sacral vertebrae in rabbit; 5 in humans
β Function: Strong support and articulation with pelvic girdle
β Largest Sacral Vertebra: First sacral vertebra
β Ilium Articulation: First sacral vertebra unites with ilium of pelvic girdle
β Neural Spines: Four and unidirectional in rabbit
β’ Caudal Vertebrae:
β Number: About 16 in rabbit
β Also Called: Coccyx
β Trend: Size decreases toward tip
β Neural Spine and Canal: Reduced toward tip
β Transverse Process: Absent toward tip
β’ Ribs:
β Rabbit Ribs: 12 or 13 pairs
β Human Ribs: 12 pairs
Table 1: Rib Types
Type | Rabbit | Human |
|---|---|---|
True ribs | 1stβ7th pairs | 1stβ7th pairs |
False ribs | 8thβ9th pairs | 8thβ10th pairs |
Floating ribs | 10thβ13th pairs | 11thβ12th pairs |
β Rib Parts:
- β’Vertebral part
- β’Sternal part
β Vertebral Part: Bony; has tuberculum and capitulum
β Sternal Part: Cartilaginous; articulates with sternum
β’ Sternum:
β Also Called: Breast bone
β Type: Flat bone
β Position: Ventral thoracic region
β Parts:
Table 1: Parts of Sternum
Part | Description |
|---|---|
Prosternum / manubrium | First sternebra |
Mesosternum / gladiolus | Five sternebrae |
Metasternum / xiphisternum | One sternebra |
Xiphoid cartilage | Terminal cartilaginous part |
β’ Appendicular Skeleton:
β Components:
- β’Pectoral girdle
- β’Pelvic girdle
- β’Forelimb bones
- β’Hindlimb bones
β’ Pectoral Girdle:
β Bones:
- β’Scapula
- β’Clavicle
β Scapula Features:
- β’Suprascapula at narrow flat end
- β’Coracoid process
- β’Glenoid border
- β’Glenoid cavity
- β’Acromion process
- β’Metacromion process
β Glenoid Cavity: Articulates with head of humerus
β Clavicle: Only bone that connects axial and appendicular skeleton
β’ Pelvic Girdle:
β Shape: W-shaped
β Each Half: Os innominatum
β Each Os Innominatum Consists Of:
- β’Ilium
- β’Ischium
- β’Pubis
β Acetabulum: Cavity for articulation with head of femur; formed by ilium, ischium and pubis
β Obturator Foramen: Large opening in pelvic girdle
β Pubic Symphysis: Joint between two halves on caudal side
β’ Forelimb Bones:
β Formula: Humerus + radio-ulna + carpals + metacarpals + phalanges
β Humerus:
β Location: Upper arm
β Upper End: Head, bicipital groove, tuberosities
β Lower End: Supratrochlear foramen, trochlea, olecranon fossa
β Head: Fits into glenoid cavity of pectoral girdle
β Deltoid Ridge: Prominent rough area for muscle attachment
β Trochlea: Fits into sigmoid notch and forms hinge joint
β Radio-Ulna:
β Location: Lower arm
β Nature: Compound bone, partly fused
β Ulna: Longer than radius
β Upper End: Olecranon process and sigmoid notch
β Carpals:
β Number: 8 bones in 2 rows
β First Row: Radiale, ulnare, intermedium
β Second Row: Trapezium, trapezoid, centrale, magnum, unciform
β Pisiform: May be present in rabbit as sesamoid carpal bone
β Metacarpals: Five elongated bones in palm region
β Phalanges: 14 bones
β Digital Formula:
Table 1: Digital Formula of Forelimb
Animal | Formula |
|---|---|
Human | 2-3-3-3-3 |
Rabbit | 2-3-3-3-3 |
Frog | 0-2-2-3-3 |
β’ Hindlimb Bones:
β Formula: Femur + patella + tibio-fibula + tarsals + metatarsals + phalanges
β Femur:
β Location: Thigh region
β Importance: Longest, heaviest and strongest bone of mammals
β Patella: Sesamoid bone of knee
β Tibia and Fibula: Leg bones
β Tarsals: Ankle bones
β Metatarsals: Foot bones
β Phalanges: Toe bones
β’ Human Axial Skeleton:
β Total: 80 bones
Table 1: Axial Skeleton Count
Part | Number |
|---|---|
Skull | 28 |
Vertebral column | 26 |
Sternum | 1 |
Ribs | 24 |
Hyoid | 1 |
β Skull Count:
Table 1: Human Skull Bones
Group | Bones |
|---|---|
Cranium | 8 |
Facial bones | 14 |
Ear ossicles | 6 |
β Cranial Bones: Frontal 1, parietal 2, temporal 2, occipital 1, sphenoid 1, ethmoid 1
β Facial Bones: Nasal 2, vomer 1, zygomatic 2, mandible 1, lacrimal 2, palatine 2, inferior nasal conchae 2, maxilla 2
β’ Human Appendicular Skeleton:
β Total: 126 bones
Table 1: Appendicular Skeleton Count
Part | Number |
|---|---|
Pectoral girdle | 4 |
Forelimbs | 60 |
Pelvic girdle | 2 |
Hindlimbs | 60 |
Table 2: Forelimb Bones
Bone | Number |
|---|---|
Humerus | 2 |
Radius | 2 |
Ulna | 2 |
Carpals | 16 |
Metacarpals | 10 |
Phalanges | 28 |
Table 3: Hindlimb Bones
Bone | Number |
|---|---|
Femur | 2 |
Tibia | 2 |
Fibula | 2 |
Patella | 2 |
Tarsals | 14 |
Metatarsals | 10 |
Phalanges | 28 |
β’ High-Yield Competitive Points:
Table 1: Must Remember
Question Clue | Answer |
|---|---|
Study of bones | Osteology |
Bone formation | Osteogenesis / ossification |
Exoskeleton origin | Ectodermal |
Endoskeleton origin | Mesodermal |
Cartilaginous bone formation | Endochondral ossification |
Membrane bone formation | Intramembranous ossification |
Sesamoid bone example | Patella |
Rabbit skull | Dicondylic and tropibasic |
Dicondylic skull | Two occipital condyles |
Hyoid bone | Does not articulate with any other bone |
Human adult skeleton | 206 bones |
Axial skeleton | 80 bones |
Appendicular skeleton | 126 bones |
Human vertebral formula | C7 T12 L5 S5 Co4 |
First cervical vertebra | Atlas |
Second cervical vertebra | Axis |
Largest and strongest bone | Femur |
Clavicle | Connects axial and appendicular skeleton |
Rabbit dental formula | 2033 / 1023 Γ 2 = 28 |
Human dental formula | 2123 / 2123 Γ 2 = 32 |
Q1.
The smallest bone in human body is
π
MOE 2069β’IOM 1994
Q2.
Which one of the following is correct digital formula for the phalanges of rabbit? (The question most likely means the digital formula of forelimb)
π
MOE 2069
Q3.
Zygomatic process in mammals is a part of:
π
MOE 2069
Q4.
Cotyloid bone is a part of the
π
MOE 2068β’2069
Q5.
Which one of the following is correct digital formula for the Phalanges of rabbit?
π
MOE-2069
Q6.
Number of false ribs in human body is:
π
MOE-2068
Q7.
Sigmoid notch in rabbit is found in:
π
MOE-2068
Q8.
The largest joint of our body is:
π
IOM
Q9.
Compact bone is characterized by the presence of
π
IE 2012
Q10.
Lumbar vertebra is located in:
π
KU-2011
Q11.
Humerus differs from femur in having a:
π
MOE-2068
Q12.
The number of vertebrae in human body is:
π
IOM-2011
Q13.
Neural spine is reduced in
π
MOE 2010
Q14.
Acromian process is found in the bone of rabbit
π
MOE 2010
Q15.
Deltoid ridge is found in
π
MOE-2061β’2010
Q16.
The bone of mammals contains longitudinal Haversian canals, which are connected by transverse canals called
π
IOM 2010
Q17.
The cheek-bone in rabbit is the
π
MOE 2009
Q18.
Which of the following bone is not included under axial skeleton?
Q19.
Socket in pelvic girdle in which head of femur articulates is formed by the fusion of
π
KU 2009
Q20.
Joint pains in old person are mostly due to:
π
1.E-2009
Q21.
Supratrochlear foramen is present in
π
MOE-2008
Q22.
In rabbit, yellow bone marrow is found especially in the medullary cavity of
Q23.
Adjoining bones of frontal in rabbit's skull are
π
MOE-2062
Q24.
The process found in axis vertebra is
π
MOE-2061
Q25.
Parietal bone is found in
π
MOE-2060
Q26.
Obturator foramen of rabbit is found in:
π
BP-2007
Q27.
In rabbit, the presence of the odontoid process in the centrum is the characteristic of:
π
BP-2005
Q28.
Saddle joint is present between the:
π
BP-2004
Q29.
Deltoid ligament is found in
π
IOM 2003
Q30.
The odontoid process of axis vertebrae in mammal fits with
π
MOE-2003
Q31.
Wrist bones are called:
π
MOE-2003
Q32.
A man broke his fibula, i.e. he broke his
π
MOE-2057
Q33.
One of the followings is not a part of mammalian bone:
π
BP-2003
Q34.
Which of the following is the first bone to start ossification?
π
IOM-2003
Q35.
Which of the following fits into deep sigmoid notch?
π
MOE-2002β’2054
Q36.
The number of lumbar vertebrae in human body is
π
IOM 2001
Q37.
The shoulder and hip joints are of type:
π
IOM-2001
Q38.
Which of the following is not the bone of hind limb or fore limb?
π
MOE-2000
Q39.
Hypapophysis is present in the
π
MOE-2058
Q40.
Which one is not a bone of a limb of the body?
π
MOE-2054
Q41.
Diastema is a gap between
π
MOE-2052
Q42.
The total number of thoracic vertebrae in human is:
π
IOM-1999
Q43.
The number of cervical vertebra in human is:
π
IOM-1998
Q44.
Pisiform bone is related to:
π
IOM-1998
Q45.
Removal of olecranon process from ulna of Rabbit will leave
π
IOM 1998
Q46.
The number of tarsals in the ankle (tarsus) of a rabbit is
π
IOM 1997
Q47.
Anticlinal vertebra is:
π
IOM-1997
Q48.
The process of bone formation is known as:
π
IOM-1997
Q49.
The thoracic cage in human is formed by
π
IOM 1992
Q50.
The smallest bone of our body is located in
π
IOM-1992
Q51.
Incus is found in:
π
IOM-1996
Q52.
Which bone is present in upper incisor?
π
IOM-2005
Q53.
Fracture is defined as:
π
IOM-1997
Q54.
Sternum is a:
π
IOM-1996
Q55.
Cholecalciferol is associated with:
π
IOM-1995
Q56.
Shoulder joint is aβ¦β¦.joint.
π
IOM
Q57.
Rickets can be treated by:
π
IOM-1994
Q58.
Navicular bone is related to:
π
IOM-1994
Q59.
Semilunar cartilage of the knee is called:
π
IOM-1995
Q60.
Which one of the following is sesamoid bone of our body?
Q61.
Deltoid ligament is found in:
π
IOM-2003
Q62.
Which is not a synovial joint?
π
IOM-1993
Q63.
An example of hinge joint is:
π
IOM-1994β’2000
Q64.
The second cervical vertebrae is characterized by the presence of
π
MOE 2014
Q65.
Illium, ischium and pubis of rabbit are fused to form:
π
MOE 2014
Q66.
Olecranon process is found in:
π
MOE 2014
Q67.
Supratrochlear foramen is present in
π
MOE 2014
Q68.
Which of the following piece of bone is not the part of rabbit cranium?
π
MOE 2014
Q69.
Number of false ribs in rabbit is:
π
MOE 2014
Q70.
Zygomatic process in mammals is a part of
π
MOE 2012
Q71.
Which one of the following is correct digital formula for the phalanges of rabbit?
π
MOE 2012
Q72.
The smallest bone in human body is:
π
MOE 2012
Q73.
Cotyloid bone is found in:
π
MOE 2012
Q74.
Trochanters occur in
π
KU 2014
Q75.
Hinge joint is present between:
π
KU 2014
Q76.
Each human hand contains:
π
KU 2014
Q77.
Scientific term for upper jaw bones is:
π
KU 2011
Q78.
Lumbar vertebrae are located in:
π
KU 2011