Manubrium, body, xiphoid process

Skeletal system | CEE Academy

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AXIAL SKELETON

▢ Human Skull :

❖ Total Bones: 29

❖ Skull Bones:

Table 1: Human Skull Bones

Division	Bones	Number
Cranial bones	Frontal, Parietal, Temporal, Occipital, Ethmoid, Sphenoid	8
Facial bones	Mandible, Maxilla, Zygomatic, Nasal, Lacrimal, Palatine, Vomer, Inferior nasal conchae	14
Ear ossicles	Malleus, Incus, Stapes	6
Hyoid	Hyoid bone	1

❖ Cranial Bones:

Table 1: Cranial Bones

Bone	Number	Note
Frontal	1	Anterior skull
Parietal	2	Roof + side
Temporal	2	Lateral skull
Occipital	1	Posterior skull
Ethmoid	1	Cranial base + nasal cavity
Sphenoid	1	Sella turcica depression

❖ Facial Bones:

Table 1: Facial Bones

Bone	Number
Mandible	1
Maxilla	2
Zygomatic bone	2
Nasal bone	2
Lacrimal bone	2
Palatine bone	2
Vomer	1
Inferior nasal conchae	2

❖ Ear Ossicles:

Table 1: Ear Ossicles

Bone	Number	Shape
Malleus	2	Hammer 🛠
Incus	2	Anvil
Stapes	2	Stirrup

▢ Human Vertebral Column:

❖ Total: 33 bones → 26 after fusion

Table 1: Human Vertebrae

Region	Original number	Adult fused number
Cervical	7	7
Thoracic	12	12
Lumbar	5	5
Sacral	5	1 sacrum
Coccygeal	4	1 coccyx

▢ Human Rib Cage:

❖ Total Bones: 25

Table 1: Human Rib Cage

Bone	Number	Type
Ribs	12 pairs / 24	Curved thoracic bones
True ribs	7 pairs / 14	Direct sternum attachment
False ribs	3 pairs / 6	Indirect sternum attachment
Floating ribs	2 pairs / 4	No anterior sternum attachment
Sternum	1	Breast bone

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APPENDICULAR SKELETON

▢ Human Thoracic / Pectoral Girdle:

•
Clavicle
•
Scapula

▢ Human Forelimb / Hand:

Table 1: Forelimb Bones

Region	Bones
Arm	Humerus
Forearm	Ulna + Radius
Wrist	Carpals
Palm	Metacarpals
Digits	Phalanges

❖ Digital Formula: Forelimb = 2, 3, 3, 3, 3

▢ Human Pelvic Girdle:

Table 1: Pelvic Girdle

Bone	Number	Components
Innominate bone	2	Ilium + Ischium + Pubis

▢ Human Hind Limb / Leg:

Table 1: Hind Limb Bones

Region	Bones
Thigh	Femur
Knee	Patella / knee cap
Leg	Tibia + Fibula
Ankle	Tarsals
Foot	Metatarsals
Digits	Phalanges

❖ Digital Formula: Hind limb = 2, 3, 3, 3, 3

📚

RABBIT SKULL 💀

▢ Type:

•
Dicondylic → 2 occipital condyles
•
Tropibasic → interorbital septum

▢ Foramen Magnum: Opening of skull; formed by 2 exoccipitals

▢ Cranium:

Table 1: Rabbit Cranium Segments

Segment	Bones	Number / Note
Occipital segment	Supraoccipital	1
Occipital segment	Exoccipital	2; forms foramen magnum
Occipital segment	Basioccipital	1
Parietal segment	Basisphenoid	1; sella turcica depression
Parietal segment	Alisphenoid	2
Parietal segment	Parietal	2; interparietal between parietals
Frontal segment	Frontal	2
Frontal segment	Orbitosphenoid	2
Frontal segment	Presphenoid	1
Ethmoid segment	Mesethmoid / cribriform plate	Closes cranial cavity anteriorly

▢ Sense Capsules:

Table 1: Sense Capsules

Capsule	Bones / Parts	Note
Olfactory capsule	Nasal bones	2
Olfactory capsule	Vomer	2
Olfactory capsule	Scroll / turbinal bones	3
Auditory capsule	Periotic	Ear capsule bone
Auditory capsule	Tympanic bulla	Contains tympanic membrane + 3 ear ossicles

❖ Ear Ossicles:

•
Malleus
•
Incus
•
Stapes

▢ Visceral Skeleton:

❖ Upper Jaw:

•
Premaxilla
•
Maxilla
•
Palatine
•
Pterygoid
•
Squamosal
•
Jugal

❖ Zygomatic Arch: Jugal + Maxilla + Squamosal

❖ Lower Jaw / Mandible:

◉ Half Mandible: Dentary

◉ Parts:

•
Angular process
•
Condyle
•
Coronoid process
•
Inferior dental foramen
•
Diastema

❖ Hyoid Apparatus: Present

▢ Ear Ossicles & Hyoid:

Table 1: Rabbit Ear Ossicles

Bone	Number	Shape
Malleus	2	Hammer 🛠
Incus	2	Anvil
Stapes	2	Stirrup
Hyoid	1	Hyoid apparatus

📚

RABBIT VERTEBRAL COLUMN

▢ Cervical Vertebrae:

❖ Number: 7

Table 1: Rabbit Cervical Vertebrae

Vertebra	Centrum	Transverse process	Neural spine	Post-zygapophysis	Special feature
Atlas	Absent / reduced	Wing-like	Reduced	Well developed	Odontoid facet
Axis	Short, flat	Present	Flat	Present	Odontoid process
Typical cervical	Present	Bifurcated	Short + pointed	Present	5 vertebrae

▢ Thoracic Vertebrae:

❖ Number: 12 / 13

Table 1: Rabbit Thoracic Vertebrae

Type	Number	Centrum	Neural spine
Anterior thoracic	6 / 7	Short + thick	Tall, slender, backwardly directed
1st thoracic	1	Short + thick	Very long backwardly directed neural spine
Posterior thoracic	6	Long + stout	Short

▢ Lumbar Vertebrae:

❖ Number: 6 / 7

Table 1: Rabbit Lumbar Vertebrae

Type	Number	Feature
Anterior lumbar	2	Hypapophysis present
Posterior lumbar	Remaining	Hypapophysis variable / absent

▢ Sacral Vertebrae: 5 fused → 1 sacrum

▢ Coccygeal Vertebrae: 16 caudal vertebrae

📚

RABBIT RIB CAGE

▢ Total Bones: 25

▢ Rib Parts:

Table 1: Rib Parts

Part	Feature
Vertebral part	Biramous / bicephalous
Capitulum	Articulates with centrum
Tuberculum	Articulates with transverse process
Sternal part	Anterior part toward sternum

▢ Ribs:

Table 1: Rabbit Ribs

Type	Number
Total ribs	12 pairs / 24
True ribs	7 pairs / 14
False ribs	2–3 pairs
Floating ribs	3–2 pairs
Sternum	1

📚

RABBIT APPENDICULAR SKELETON

▢ Pectoral Girdle:

Table 1: Pectoral Girdle

Bone	Parts / Features
Clavicle	Present
Scapula	Acromion process, metacromion process, coracoid process, glenoid cavity

▢ Forelimb:

❖ Humerus:

Table 1: Humerus

End	Parts
Upper end	Head, deltoid ridge below head, bicipital groove, greater tuberosity, lesser tuberosity
Lower end	Supratrochlear foramen, pulley-like trochlea, olecranon fossa, coronoid fossa

◉ Note: Deltoid ligament → ankle joint

❖ Radio-Ulna:

◉ Nature: Compound bone; partly fused

Table 1: Radio-ulna

End	Parts
Upper end	Olecranon process, sigmoid notch
Lower end	Epiphyses

❖ Carpals:

Table 1: Carpal Bones

Row	Bones
1st row	Radiale, Ulnare, Intermedium
2nd row	Trapezium, Trapezoid, Centrale, Magnum, Unciform

❖ Other Bones:

•
Metacarpals
•
Phalanges

❖ Digital Formula: Forelimb = 2, 3, 3, 3, 3

▢ Pelvic Girdle:

Table 1: Pelvic Girdle

Structure	Feature
Innominate bone	2
Ilium	Part of innominate
Ischium	Part of innominate
Pubis	Part of innominate
Acetabulum	Formed by ilium + ischium
Pubic symphysis	Joins 2 pubic halves
Obturator foramen	Largest foramen of body

▢ Hind Limb:

❖ Femur:

Table 1: Femur

End	Parts
Upper end	Head, greater trochanter, lesser trochanter, third trochanter
Lower end	Patellar grooves, condyles

◉ Head: Fixed to acetabulum → ball-and-socket joint

❖ Patella: Knee cap; sesamoid bone

❖ Tibia-Fibula:

◉ Nature: Compound bone

Table 1: Tibia-Fibula

End	Parts
Upper end	Cnemial crest of tibia
Lower end	Epiphyses

❖ Tarsals:

Table 1: Tarsal Bones

Row	Bones
1st row	Astragalus, Calcaneum
2nd row	Central / Navicular
3rd row	Mesocuneiform, Ectocuneiform, Cuboid

❖ Other Bones:

•
Metatarsals
•
Phalanges

❖ Digital Formula: Hind limb = 0, 3, 3, 3, 3

📚

HIGH-YIELD RECALL

Table 1: Skeleton One-Liners

Fact	Answer
Human skull bones	29
Human skull proper	22
Human cranial bones	8
Human facial bones	14
Ear ossicles	6
Hyoid	1
Sella turcica in human	Sphenoid
Sella turcica in rabbit	Basisphenoid
Human vertebrae	33 → 26 after fusion
Human ribs	12 pairs
True ribs	7 pairs
Floating ribs	2 pairs in human
Rabbit skull	Dicondylic + tropibasic
Dicondylic	2 occipital condyles
Tropibasic	Interorbital septum
Foramen magnum formed by	2 exoccipitals
Rabbit zygomatic arch	Jugal + maxilla + squamosal
Rabbit mandible half	Dentary
Atlas special feature	Odontoid facet
Axis special feature	Odontoid process
Rib capitulum	Articulates with centrum
Rib tuberculum	Articulates with transverse process
Scapula cavity	Glenoid cavity
Rabbit radio-ulna	Partly fused compound bone
Rabbit tibia-fibula	Compound bone
Patella	Sesamoid bone
Obturator foramen	Largest foramen of body
Rabbit forelimb digital formula	2, 3, 3, 3, 3
Rabbit hind limb digital formula	0, 3, 3, 3, 3

Q1.

Total number of bones in adult human skeleton is

Q2.

Total number of bones in axial skeleton is

Q3.

Appendicular skeleton consists of

Q4.

Number of bones in appendicular skeleton is

Q5.

The smallest bone of human body is

Q6.

The longest and strongest bone of human body is

Q7.

The only bone in human body that does not articulate with any other bone is

Q8.

The only movable bone of skull is

Q9.

Number of cranial bones in human skull is

Q10.

Number of facial bones is

Q11.

Total number of bones in skull including ear ossicles and hyoid is

Q12.

Cribriform plate is present in

Q13.

Foramen magnum is present in

Q14.

Sella turcica is found in

Q15.

Number of cervical vertebrae in humans is

Q16.

Vertebral formula of adult human is

Q17.

Atlas vertebra is characterized by absence of

Q18.

Odontoid process is found in

Q19.

Number of thoracic vertebrae is

Q20.

Number of pairs of ribs in human is

Q21.

True ribs are

Q22.

Floating ribs are

Q23.

Sternum consists of

Q24.

Sternal angle is important because it articulates with

Q25.

Pectoral girdle consists of

Q26.

Glenoid cavity is present in

Q27.

Acetabulum is formed by fusion of

Q28.

Bone of upper arm is

Q29.

Bones of forearm are

Q30.

The bone present on thumb side of forearm is

Q31.

Number of carpal bones in each wrist is

Q32.

Number of phalanges in each hand is

Q33.

Bone of thigh is

Q34.

Patella is an example of

Q35.

Shin bone is

Q36.

Number of tarsal bones in each foot is

Q37.

Heel bone is

Q38.

Which bone is commonly called collar bone?

Q39.

Which bone is the first bone to start ossification in embryo?

38Skeletal system

Table 1: Human Skull Bones

Table 1: Cranial Bones

Table 1: Facial Bones

Table 1: Ear Ossicles

Table 1: Human Vertebrae

Table 1: Human Rib Cage

Table 1: Forelimb Bones

Table 1: Pelvic Girdle

Table 1: Hind Limb Bones

Table 1: Rabbit Cranium Segments

Table 1: Sense Capsules

Table 1: Rabbit Ear Ossicles

Table 1: Rabbit Cervical Vertebrae

Table 1: Rabbit Thoracic Vertebrae

Table 1: Rabbit Lumbar Vertebrae

Table 1: Rib Parts

Table 1: Rabbit Ribs

Table 1: Pectoral Girdle

Table 1: Humerus

Table 1: Radio-ulna

Table 1: Carpal Bones

Table 1: Pelvic Girdle

Table 1: Femur

Table 1: Tibia-Fibula

Table 1: Tarsal Bones

Table 1: Skeleton One-Liners

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