Clavicle Bone Anatomy Animation : Bony landmarks and Development

Summary

The clavicle, or collarbone, is a unique horizontal long bone located at the neck's root, forming part of the shoulder girdle. It's the first bone to ossify and has no medullary cavity. The clavicle's functions include keeping the arm away from the trunk for free movement and transmitting weight from the upper limb to the trunk. It features the sternal and acromial ends, with the latter articulating with the scapula. The bone develops from three centers of ossification, fusing by the mid-twenties.

Takeaways

• 🦴 The clavicle, also known as the collar bone, is a long bone that lies horizontally in front of the neck.
• 🔒 It plays a crucial role in the formation of the shoulder girdle and is the only long bone in the body that is subcutaneous.
• 🌀 The clavicle's unique feature is the absence of a medullary cavity.
• 🚫 It prevents the arm from swinging into the trunk, allowing free movement without contact.
• 🏋️‍♂️ It helps transmit weight from the upper limb to the trunk and assists in arm movement above shoulder level.
• 📏 The clavicle is divided into the shaft, acromial end, and sternal end, with the shaft further divided into lateral and medial thirds.
• 🔍 The lateral third has two surfaces and two borders, with the superior surface being subcutaneous and the inferior surface rough.
• 🔗 The medial two-thirds have four surfaces, including a rough and convex anterior surface and a smooth and concave posterior surface.
• 🔑 The acromial end is flat with an oval facet that articulates with the acromium process of the scapula.
• 📐 The sternal end is quadrangular, articulating with the clavicular notch of the manubrium sterni.
• 📈 The clavicle ossifies from three centers: two primary centers in the shaft and one secondary center, with fusion complete by the 25th year.

Q & A

What is the clavicle also known as?

The clavicle is also known as the collar bone.

What is the primary function of the clavicle?

The clavicle's primary function is to keep the arm away from the trunk, allowing it to swing freely without coming into contact with the trunk, and to transmit weight from the upper limb to the trunk.

How is the clavicle positioned in the body?

The clavicle lies horizontally in front of the root of the neck and is part of the shoulder girdle.

What makes the clavicle unique among long bones?

The clavicle is unique because it has no medullary cavity and is the only long bone in the body that lies horizontally.

What are the three main parts of the clavicle?

The clavicle consists of the shaft, the acromial end, and the sternal end.

How is the lateral 1/3 of the clavicle's shaft described?

The lateral 1/3 of the clavicle's shaft presents with two surfaces and two borders, with a subcutaneous superior surface, a rough inferior surface with the conoid tubercle, and a concave anterior border bearing the deltoid tubercle.

What is the significance of the trapezoid line on the clavicle?

The trapezoid line is an oblique ridge on the clavicle that runs forwards and laterally towards the acromial end, giving attachment to the trapezoid part of the coracoclavicular ligament.

What does the medial 2/3 of the clavicle's shaft present?

The medial 2/3 of the clavicle's shaft presents with four surfaces, including a rough and convex anterior surface, a smooth and concave posterior surface, and an inferior surface with the costal impression.

How does the acromial end of the clavicle articulate with the scapula?

The acromial end of the clavicle is flat and has an oval facet that articulates with the clavicular facet on the acromion process of the scapula.

What is the shape of the sternal end of the clavicle?

The sternal end of the clavicle is quadrangular and articulates with the clavicular notch of the manubrium sterni.

How can you determine the side of the clavicle?

The flattened acromial end is on the lateral side, the rounded sternal end is on the medial side, and the shaft is convex forwards in the medial 2/3 and concave forwards in the lateral 1/3.

How does the clavicle grow and develop during intrauterine life?

The clavicle starts to ossify from three centers: two primary centers in the medial and lateral regions of the shaft that begin to ossify by the fifth to sixth week of intrauterine life and fuse by the 45th day, and one secondary center that starts to ossify by 18 to 20 weeks of intrauterine life and fuses by the 25th year.

Outlines

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🦴 Anatomy of the Clavicle

The clavicle, also known as the collar bone, is a unique long bone situated at the front of the neck's base, forming part of the shoulder girdle. It is horizontally positioned and is the only long bone in the body without a medullary cavity. The clavicle's function is to keep the arm away from the trunk, allowing free movement without contact. It also transmits weight from the upper limb to the trunk and aids in arm movement above shoulder level. The bone is divided into the shaft, acromial end, and sternal end. The shaft is further divided into lateral and medial thirds, each with distinct features such as the conoid tubercle, trapezoid line, deltoid tubercle, and coastal impression. The acromial end is flat with an oval facet for articulation with the acromium process of the scapula, while the sternal end is quadrangular, articulating with the manubrium sterni. The clavicle develops from three centers of ossification: two primary centers in the shaft and one secondary center, with the process starting in utero and completing by the mid-twenties.

Keywords

💡Clavicle

The clavicle, also known as the collar bone, is a long bone that plays a crucial role in the formation of the shoulder girdle. It is the only long bone in the body that lies horizontally and is subcutaneous, meaning it is close to the surface of the skin. The clavicle is unique in that it lacks a medullary cavity. In the video, the clavicle is described as being the first bone to start the process of ossification and is essential for allowing the arm to swing freely without contacting the trunk.

💡Shoulder Girdle

The shoulder girdle is a complex structure that connects the upper limbs to the axial skeleton. It consists of the clavicle, scapula, and the associated joints. The clavicle is a key component of this girdle, as it articulates with the scapula and the sternum, providing stability and facilitating movement of the arm.

💡Subcutaneous

Subcutaneous refers to the position of the clavicle, which lies just beneath the skin. This term is used in the script to emphasize the superficial location of the clavicle, making it easily palpable and visible on the surface of the body.

💡Medullary Cavity

The medullary cavity is a hollow space found within the shafts of long bones, containing bone marrow. The script highlights the peculiarity of the clavicle by stating that it is the only long bone without a medullary cavity, indicating a difference in its structure compared to other long bones.

💡Shaft

The shaft of the clavicle is the long, slender part that connects the two ends. The script divides the shaft into the lateral 1/3 and medial 2/3, each with distinct surfaces and borders. This division is important for understanding the anatomical landmarks and the attachments of various muscles and ligaments.

💡Acromial End

The acromial end of the clavicle is the flat end that articulates with the acromion process of the scapula. This joint, known as the acromioclavicular joint, is mentioned in the script as one of the areas where ligaments attach, contributing to the stability and movement of the shoulder.

💡Sternal End

The sternal end of the clavicle is quadrangular and articulates with the clavicular notch of the manubrium of the sternum. This end is highlighted in the script as another key area for ligament attachment, specifically the capsular ligament of the sternoclavicular joint.

💡Conoid Tubercle

The conoid tubercle is a roughened area on the inferior surface of the clavicle near the posterior border. As described in the script, it provides attachment for the conoid part of the coracoclavicular ligament, which plays a role in the stability of the shoulder.

💡Trapezoid Line

The trapezoid line is an oblique ridge on the clavicle that runs forwards and laterally towards the acromial end. The script mentions that it gives attachment to the trapezoid part of the coracoclavicular ligament, which is crucial for the support and stability of the shoulder joint.

💡Ossification

Ossification is the process of bone formation. The script states that the clavicle is the first bone to start ossification, which is a critical step in skeletal development. This process begins with the formation of bone tissue from the cartilage model during embryonic development.

💡Intra Utrine Life

Intra utrnine life refers to the developmental period within the womb. The script mentions that the clavicle begins to ossify from three centers during this period, with two primary centers starting in the fifth to sixth week of intra utrnine life, highlighting the early development of this bone.

Highlights

Clavicle is also known as the collar bone and is a long bone.

It lies in front of the root of the neck and forms part of the shoulder girdle.

The clavicle is a subcutaneous bone and is the only long bone in the body that lies horizontally.

It has no medullary cavity, which is a unique characteristic.

The clavicle helps keep the arm away from the trunk, allowing it to swing freely.

It transmits weight from the upper limb to the trunk and assists in arm movement.

The clavicle consists of the shaft, acromial end, and sternal end.

The shaft is divided into lateral 1/3 and medial 2/3.

The lateral 1/3 has two surfaces and two borders with specific tubercles and lines.

The medial 2/3 presents with four surfaces including the coastal impression and subclavian groove.

The acromial end is flat and has an oval facet for articulation with the scapula.

The sternal end is quadrangular and articulates with the manubrium sterni.

The clavicle's flattened acromial end is on the lateral side, and the rounded sternal end is on the medial side.

The shaft is convex forwards in the medial 2/3 and concave forwards in the lateral 1/3.

The middle 1/3 of the inferior surface is grooved, which is significant.

Clavicle is the first bone to start the process of ossification.

Ossification begins from three centers: two primary in the shaft and one secondary.

The secondary center of ossification starts during the 18th to 20th weeks of intrauterine life and fuses by the 25th year.

Transcripts

[Music]

clavicle the clavicle is also known as

the collar bone and is a long bone it

lies in front of the root of the neck

and takes part in formation of the

shoulder girdle it is a subcutaneous

bone and is the only long bone in the

body that lies

horizontally the peculiarity of this

bone is that it has no medular cavity it

is the first bone to start

oifcfg of the shoulder keeps the arm

away from the trunk which allows it to

swing freely without coming in contact

with the trunk transmits weight from the

Upper Limb to the trunk and assists in

movement of the arm above the level of

the

shoulder the clavicle consists of the

shaft a chromal end and the sternal end

the shaft is divided into the lateral

1/3 and medial 2/3 the lateral 1/3

presents with two surfaces and two

borders the superior ior surface is

subcutaneous and the inferior surface is

rough and has the conoid tubercle which

lies close to the posterior border and

gives attachment to the conoid part of

the coracoclavicular

ligament the trapezoid line which is an

oblique Ridge which runs forwards and

laterally towards the acromial end and

gives attachment to the trapezoid part

of the coracoclavicular

ligament now coming to the anterior

border it is concave and bears the

deltoid tubercle the posterior border is

convex the medial 2/3 presents with four

surfaces the anterior surface is rough

and convex the upper surface the

posterior surface is smooth and concave

and the inferior surface presents with

the coastal impression that gives

attachment to the coastal clavicular

ligament and the sub

Groove clavipectoral fascia is attached

to the margins of the subclavian Groove

the nutrient foramin is directed

laterally and is present on the lateral

part of the subclavian

Groove a chromal end this end is flat

and has an oval facet which articulates

with the clavicular facet on the

acromium process of the scapula the

margins of which gives attachment to the

capsular ligament of the

acromioclavicular

joint the sternal end is quadrangular

and it articulates with the clavicular

notch of the manubrium

sternai the upper part gives attachment

to the interclavicular ligament capsular

ligament of the sternoclavicular joint

and articular dis of the

sternoclavicular

joint determination of the side the

flattened a chromal end is on the

lateral side the rounded sternal end is

on the medial side the shaft is convex

forwards in the medial 2/3 and concave

forwards in the lateral

1/3 the middle 1/3 of the inferior

surface is grooved

oifc it is the first bone to start the

process of oifc and it oif from three

centers two primary centers which are

located in the medial and lateral

regions of the shaft start OIC by the

fifth to 6th week of intra utrine life

and fuses by the 45th day one secondary

Center that starts oifc by 18 to 20

weeks of intra utrine life and fuses by

the 25th year