Tuesday, September 15, 2020

Parts of Appendicular Skeleton-Pectoral girdle -Pelvic girdle



 The skeleton of any vertebrates is divided into two categories :


  • Axial Skeleton 
  • Appendicular Skeleton



  • Appendicular Skeleton

The Appendicular Skeleton consists of girdle bines and the limb bones.


  1. Girdle Bones


  • Pectoral girdle 


It is made up of two bones viz Scapula Coracoids and clavicle.The Scapula is the universal character.The narrow and the flat end tha is present in the scapula is called as suprascaula.The other parts that can be considered are Neural Spine,Coracoid Border,Glenoid Border,Acromian and Metacromian process and Coracoid border with Glenoid cavity.
I have a question for you :
Which is the only part of the pectoral girdle that connects Axial and Appendicular Bones?
Comment the answer below.


  • Pelvic Girdle


The shape of the main part is 'W' shaped.And the each half is called as os-innominatum that consists of Ilium,Ischium,Pubis.The inner side of acetabulum between ilium and ischium is Cotyloid.Acetabulum is the structure formed by the fusion of Ilium and Ischium.This structure is the cavity for the articulation of head of femur.This Ilium joins the vertebral column by the jiint called Sacro-Iliac joint.The part Pubis has Pubic symphysis and Obturator Foramen.The two halves of the pelvic girdle are joined at pubic symphysis.

Interesting point :The largest foramen of the bidy is Obturator Foramen.

     2.Limb Bones


  • Upper Limbs

Humerus

Humerus is the bone of upper arm which consists of the uppervend and the lower end.The upper end consists of the Head,Bicipital Groove and the Tuberosities.Similarly talking about the lower end ,it consists of Supratrochlear foramen,Trochlea,Olecranon Fossa,Coronoid Fossa.Here the Tuberosities are the rough surface area of the long bones providing surface area for muscular attachment.The head fits in the glenoid cavity of the pectoral girdle forming ball and socket joints.Also the Trochlea fits in sigmoid notch and forms hinge joint.

Deltoid Ridge:It is present below the head of the humerus.Don't be confused with the deltoid ligament that is present in ankle joint.

Radio Ulna

These are the bone of lower  arm which are partly fused among which the Ulna is longer.The uppper end consists of Olecranon process and sigmoid notch while the lower end has Epiphyses.

Carpals

At the junction of the lower arm and the palm there are about 8bones present in the 2 rows .The first row has Radiale,Ulnare and intermedium while the second row consist of Trapezium ,Trapezoid,Centrale,Magnum,Unciform.Talking about the rabbit a 9th carpal can be fiund called as pisciform.

Pisciform is a sesamoid bone.

Metacarpals are the five elongated bones in the palm region.


Phalanges

There are 14 phalanges bone.On thus basis it is given Digital formula of fore limbs.
Human 23333   Rabbit 23333     Frog  02333


  • Lower limb

Femur


This is the bone of thigh region which is considered as the longest ,heaviest and the strongest bone of mammal.The upper end of the femur has greater,lesser and the 3rd trochanter for the muscular attachment.While the lower end has patellar grooves,condyles.The head if the femur fits to the Acetabulum of the pelvic girdle that form a ball and socket joint.The middle part of the femur is called as Shaft.
Patella
Commonly called as Knee cap formed byvthe ossification of tendon .Similarlybon the either side of the bone febullae is present.Semilunar cartilage called meniscus is present in knee joint aling with patella.

Tibio-Fibula

These are the bone of shank region which uooer end is Cnemial Crest and the lower end is epiphyses.

Tarsals

These are the six bines arranged in the three rows named Astragalus,Calcaneum,Navicular,Mesocuneiform,Ectocuneiform,Cuboid.

Metatarsals are the five bones forming the skeleton of sole.


Phalanges

There are12 bones after the metacarpals called the digits of lower limb.
Human  23333    Rabbit  03333  Frog 22343

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