-CLAVICAL (THE COLLOR BONE) is a long bone . It is also known as collor bone/ beauty bone.

-It is the only bone in the body that lies horizontally.

-It is a bone of upper extremity.

– It has ;

1) Shaft

2) Two ends – lateral and medial.


• Side determination


√  Lateral End – flat

Medial end – quadrilateral


√ Shaft – slightly curved

* Medial 2/3 rd  – convex forwards

* Lateral 1/3 rd – concave forwards.

✓ Clavicle is the only long bone which lies horizontally.

✓ It is the first bone which starts ossifying.

✓ It receives weight of upperlimb  via lateral 1/3 rd through coracoclavicular ligament and transmits to axial skeleton via the medial 2/3 rd.

• Features

1) Shaft


– It is divided into lateral 1/3 rd and medial 2/3 rd.


* Lateral 1/3 rd

√ Flattened from above downward

√ 2 borders – Anterior and posterior


Anterior – concave forwards

Posterior – convex backwards


√ 2 Surfaces – Superior and Inferior

Superior – It is subcutaneous.

Inferior – Presents an elevation called conoid tubercle and a ridge called trapezoid ridge.

* Medial 2/3 rd

√ It is rounde

√ 4 surfaces :

Anterior surface – convex forwards

Posterior surface – smooth

Inferior surface – has a rough oval impression at the medial end

Lateral half of the surface has a longitudinal subclavian groove.

There is a nutrient foramen present at the lateral end of the groove.

2) Lateral End / Acromial end


– Flattened from above downwards .

– It has a facet that articulates with acromion process of the scapula and form Acromioclavicular joint.


3) Medial / Sternal end


– It is quadrangular

– Articulates with clavicular notch of manubrium sterni and forms sternoclavicular joint.


• Attachments

1) At Lateral End ;


– The margin of articular surface for its Acromioclavicular joint gives attachment to joint Capsule.


2) At medial end ;


– Margin of articular surface for the sternum gives attachment to ,

(a) Fibrous capsule of sternoclavicular joint

(b) Articular disc ( posterosuperiorly )

(c) Interclavicular ligament ( superiorly )


3) Lateral 1/3 rd of shaft


(a) Anterior border – it gives origin to deltoid .

(b) Posterior border – It provides insertion to trapezius.

(c) Conoid tubercle and trapezoid ridge – Gives attachment to Conoid and trapezoid parts of coracoclavicular ligament.


4) Medial 2/3 rd of shaft


(a) Anterior surface : gives origin to pectoralis major

(b) Half of the superior surface : gives origin to Clavicular head of Sternocleidomastoid muscle .

(c) The oval impression on inferior surface ( at the medial end ) : It gives attachment to costoclavicular ligament.

(d) The subclavian groove : It gives insertion to subclavius muscle

(e) Posterior surface close to medial end : it gives attachment to sternohyoid muscle.

(f) Subclavian vessels and cords of brachial plexus passes towards axilla which lies between inferior surface of clavicle and upper surface of 1st rib .

– The nutrient foramen : transmits a branch of suprascapular artery.


• Ossification of clavicle

– It is the first bone to ossify

– It ossifies in membrane ,except for its medial end.

– Ossification starts from 2 primary centres and 1 secondary centre.


* Two primary centres :


– Appears in shaft

– Between 5th and 6 th week of intrauterine life.

– And fuse about the 45th day..

* The secondary centre


– Appears during 15-17 years

– Fuses with shaft during 21-22 years.


• Clinical anatomy

1) Clavicle fracture

– Clavicle is most commanly fractured.

– This fracture can occur by falling on outstretched hand .

– Most common site : junction between two curvatures of the bone.

2) Cleidocranial dysostosis

– Congenital absence of clavicle or imperfectly developed clavicle in a disease is called as Cleidocranial dysostosis.





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