Clavicle

• Synopsis of clavicle

• Etymology
• Introduction
• Anatomical position
• Side determination
• Parts
• Attachments
• Clinical anatomy
• Pictures

Etymology

clavicle :-

• Derived word = Latin
• meaning = small key
• Synonym:-Collar bone , or beauty bone

Introduction

it is the bone of shoulder region.
It takes part in the formation of shoulder girdle.
It is only long bone that lies horizontal in the body.
It is first bone to ossify & last bone to complete ossification.

• Location:- Antero-superior to the thoracic cage
• Type:- Long bone
• Articulation:- Articulation between lateral end of c.bone & medial border of acromion process.

1) Sternoclavicular joint: articulation between clavicular notch of manubrium-sterni and medial end of clavicle.
2) Acromioclavicular joint :- articulation between lateral end of clavicle border of acromion process.

Anatomical position

1) ClavicleWhat is the function of the clavicle? should be held horizontally
2) The enlarged sternal end directed medially
3) The flattened acromial end directed laterally
4) The medial.2/3rd of the shaft convex forward
5) The lateral 1/3rd of the shaft concave forward
6) The conoid tubercle directed postero-inferiorly

Side determination

1) First of all bone hold in it’s anatomical position
2) Then lateral flattened end will determined the side

Parts

1) Medial end (sternal end)
2) Lateral end (acromial end)
3) Shaft

1) Medial end (sternal end)

• t is also known as sternal end.
• It is quadrangular in shape.
• It has a articular surface.
• which articulates with clavicular notch of manubrium sterni.
• This articulation form the sternoclavicular joint.

2) Lateral end (acromial end)

• It is also known as acromial end.
• It is flat in the shape.
• It has a facet. (small articular surface)
• The facet articulates with the medial border of acromion process.
• This articulation form the acromioclavicular joint.

3) Shaft

• For easiness of study shaft divided in to two parts.

1) Medial two-thirds (convex forward)

2) Lateral one-thirds (concave forward)

1) Medial two third (convex forward)

• It has following

I. Four surface:-

i. Anterior surface

• It is convex anteriorly.

ii. Posterior surface

• It is concave posteriorly.

iii. Superior surface

• It is subcutaneus.

iv. Inferior surface

• It is subclavian groove

2) Lateral one-thirds

• It has following.

I. Two border

i. Anterior borders

• It is concave and thin .
• It has a deltoid tubercle.

ii. Posterior border

• It is convex and thick.

II. Two surface

i. Superior surface

• It is rough & subcutaneus

ii. Inferior surface

• It has trapezoid ridge & conoid tubercle

Attachments

• Following structure are attached on clavicle .

1) Muscles = 06 (origin:-04 & insertion:-02)
2) Ligaments = 07
3) Capsule= 02
4) Disc= 02
5) Relations =05

Muscles:-06

Origin= 04

Following muscles are originates from clavicle.

1. Deltoid:- it has three fiber or head (origin point)

1. Anterior fiber:-anterior border of lateral one-third of clavicle
2. Lateral fiber :- lateral border of acromion process of scapula
3. Posterior fibers:- posterior border of spinous process of scapula (lower lip)

2. Pectoralis major:- it has two head

1. Clavicular head :- anterior surface of medial 2/3rd of clavicle
   II. Sternocostal head anterior surfaces of manubrium sterni & body of sternum (anterolateral aspect)

3. Sternocleidomastoid :- It has two head

I. Clavicular or lateral head: superior surface of medial 2/3rd of clavicle
II. Sternal or medial head :- anterior surface of manubrium sterni (anterosuperior aspect)

4. Sternohyoid :- posterior surface of medial two-third of clavicle

Insertion = 02

Following muscles inserted on clavicle.

1. Trapezius :-it has three fiber

I. Upper fiber: Posterior border of lateral 1/3rd of clavicle.
II. Middle fiber :-Medial border of acromion process & upper lip of Spinous process of scapula
III. Lower fiber :- Root of the spinous process of scapula.

2. Subclavius:- inferior surface of medial two-third of clavicle (subclavian groove)

Ligament = 07

Relations :-

Posterior surface of medial two-third from medial to lateral.

I. Internal jugular vein
II. Subclavian vein
III. Brachiocephalic vein
IV. Trunk of brachial plexus
V. Subclavian artery

Capsule = 02

I. Sternoclavicular joint: capsule :- around the margin of articular surface of medial end
II. Acromioclavicular joint capsule :- lateral end around the margin of articular facet of

Disc = 02

I. Sternoclavicular disc :- medial end of clavicle (posterosuperior aspect)
II. Acromioclavicular disc:- lateral end of clavicle (above the articulation)

Clinical anatomy

1) Fracture of clavicle

• Common Site: junction between medial 2/3rd & lateral 1/3rd (weakest point)
• Mechanism :- indirect injury (eg: fall on outstretched hand)
• Displacement :-

1. lateral fragment:- downward due to weight of upper limb
   2. medial fragment :- upward due to pull of sternocleidomastoid

2) Cleidocranial dysotosis

• cleido :-clavicle
• cranial:- skull
• dys:- abnormal
• ost :- bone
• osis:- disease condition

It is imperfect development or congenital absent condition of clavicle

THE END