Humerus bone osteology Animation : Bony mandmarks, Development and Clinical anatomy 🦴🦴🦴

Summary

The video script offers an in-depth look at the anatomy of the humerus, the largest long bone in the upper limb. It details its structure from the head to the lower end, highlighting key features such as the anatomical and surgical neck, greater and lesser tubercles, intertubercular sulcus, and the shaft's borders and surfaces. The script also discusses ossification centers, clinical correlations including nerve associations and common fracture sites, and touches on shoulder joint dislocation, particularly the inferior type.

Takeaways

• 📐 The humerus is the largest and longest bone in the upper limb, with its upper end comprising the head, neck, greater and lesser tubercles, and the intertubercular sulcus.
• 🔺 The head of the humerus is smooth,球形 (spherical) in shape, and covered with articular cartilage, articulating with the glenoid cavity of the scapula to form the shoulder joint.
• 💡 The anatomical and surgical necks of the humerus are important for understanding the bone's structure and potential sites of injury or fractures.
• 🏥 The surgical neck is a common site for fractures due to its location at the junction between the upper end and the shaft of the humerus.
• 💪 The greater and lesser tubercles are prominent features of the humerus, contributing to the shoulder's shape and providing attachment points for various ligaments and muscles.
• 🏋️‍♂️ The intertubercular sulcus, also known as the bicipital groove, houses the long head of the biceps brachii and the ascending branch of the anterior circumflex humeral artery.
• 📐 The shaft of the humerus is cylindrical above and triangular below, with three borders and three surfaces that are significant for muscle attachment and bone structure.
• 🔗 The lower end of the humerus is broad and has both an articular part (capitulum) and a non-articular part, with the radial fossa being a notable feature.
• 🦴 The determination of the side of the humerus can be made by observing the position of the head, lesser tubercle, intertubercular sulcus, and medial epicondyle.
• 🧬 The humerus develops from multiple ossification centers, with the upper end fusing by age seven and the lower end by age 14, while the full fusion with the shaft occurs in early adulthood.
• 🚑 Common fractures of the humerus include the surgical neck, shaft, and supracondylar region, which can result in injury to nerves and blood vessels in the area.

Q & A

What is the humerus and where is it located?

The humerus is the largest and strongest long bone in the upper limb, located in the arm.

Describe the upper end of the humerus.

The upper end of the humerus consists of the head, neck, greater and lesser tubercles, and the intertubercular sulcus. The head is smooth, medially backwards and upwards directed, and articulates with the glenoid cavity of the scapula to form the shoulder joint.

What are the two necks of the humerus and their functions?

The anatomical neck is the constricted portion surrounding the head and gives attachment to the shoulder joint capsule, except medially. The surgical neck is the junction between the upper end and the shaft and is a common site for fractures.

What is the significance of the greater and lesser tubercles on the humerus?

The greater tubercle forms the prominence of the shoulder and has the lateral margin that gives attachment to the transverse ligament. The lesser tubercle is smaller, located in the anterior aspect of the upper end, and its lateral margin also gives attachment to the transverse ligament.

What does the intertubercular sulcus contain?

The intertubercular sulcus, also known as the bicipital groove, contains the long head of the biceps brachii and the ascending branch of the anterior circumflex humeral artery.

Describe the shaft of the humerus and its features.

The shaft of the humerus is cylindrical above and flat, triangular below, consisting of three borders (anterior, lateral, and medial) and three surfaces (anteromedial, anterolateral, and posterior). The anterior border extends from the lower end of the greater tubercle to above the radial fossa, while the medial border extends from the lesser tubercle to the medial epicondylar sulcus.

What are the two fossae located at the lower end of the humerus and their functions?

The radial fossa is a hollow depression on the posterior surface of the lower end, lodging the radial head of the radius during elbow extension. The coronoid fossa is a small depression situated just above the trochlea, lodging the anterior margin of the coronoid process of the ulna during elbow flexion.

How many centers of ossification are involved in the development of the humerus and when do they typically appear?

There is one primary center for the shaft, three secondary centers for the upper end, and four secondary centers for the lower end of the humerus. The upper end centers appear in the first year for the head, third year for the greater tubercle, and fifth year for the lesser tubercle. The lower end centers appear in the second year for the capitulum and lateral lip of the trochlea, in the 10th year for the medial part of the trochlea, and in the 16th year for the lateral epicondyle.

What are the clinical implications of humerus fractures and common sites?

Common sites for humerus fractures include the surgical neck, shaft, and the supracondylar region. These fractures can injure nerves such as the auxiliary nerve around the surgical neck, radial nerve in the radial groove, and the ulnar nerve behind the medial epicondyle. Supracondylar fractures often occur in young individuals due to falls on outstretched hands.

What is the most common dislocation involving the humerus and why does it occur?

The most common dislocation involving the humerus is the inferior dislocation of the shoulder joint. This occurs more frequently due to the loose nature of the capsule and the large size of the head compared to the glenoid cavity.

Outlines

00:00

🦴 Anatomy of the Humerus

This paragraph delves into the detailed anatomy of the humerus, the largest and strongest long bone in the upper limb. It describes the upper end of the humerus, which includes the head, neck, greater and lesser tubal, and the intertubercular sulcus. The head's articulation with the glenoid cavity of the scapula forms the shoulder joint. The paragraph also explains the anatomical and surgical necks, the greater and lesser tubercles, and the intertubercular sulcus, which contains the long head of the biceps brachii and the ascending branch of the anterior circumflex humeral artery. The shaft of the humerus is cylindrical above and triangular below, with three borders and surfaces. The lower end of the humerus is broad, with an articular and non-articular part, and the paragraph concludes with the clinical correlation of nerves related to the humerus and common sites for fractures.

05:06

💪 Development and Fractures of the Humerus

The second paragraph focuses on the development of the humerus, detailing the primary and secondary ossification centers for the upper and lower ends. It outlines the timeline for the appearance of these centers, from the first year of life to the 14th year. The paragraph also discusses the fusion of these centers with the shaft, which occurs by the 20th year for the upper end and between 16 to 17 years for the lower end, with the medial epicondyle fusing by 18 years. Additionally, it touches on the clinical aspects of the humerus, including the nerves related to it, such as the auxiliary nerve around the surgical neck, the radial nerve in the radial groove, and the ulnar nerve behind the medial epicondyle. The paragraph concludes with a discussion on common sites for fractures of the humerus and the potential injuries to the median nerve and brachial artery that can result from such fractures.

Keywords

💡Humerus

The humerus is the largest and longest bone in the upper limb, playing a crucial role in the video's discussion of human anatomy. It is characterized by its upper and lower ends, each with distinct features that facilitate various articulations and muscle attachments. The humerus's structure is integral to the functioning of the shoulder and elbow joints, as detailed in the script.

💡Anatomical Neck

The anatomical neck of the humerus refers to the constricted portion surrounding the head of the bone. It is significant in the video as it provides attachment for the shoulder joint capsule, except medially. This part is critical for shoulder joint stability and is involved in various shoulder pathologies and injuries.

💡Surgical Neck

The surgical neck is the junction between the upper end and the shaft of the humerus. It is a common site for fractures, as mentioned in the script, highlighting its vulnerability in trauma and the importance of proper healing and care to maintain upper limb function.

💡Greater Tubercle

The greater tubercle is a prominent feature on the posterior lateral aspect of the humerus's upper end. It forms the shoulder's prominence and is a critical attachment site for several muscles and ligaments, including the transverse ligament, as discussed in the video. Its structure is essential for shoulder mobility and strength.

💡Lesser Tubercle

The lesser tubercle is smaller than the greater tubercle and located on the anterior aspect of the humerus's upper end. It is just above the surgical neck and provides attachment for the transverse ligament, as mentioned in the script. This tubercle's position is vital for the stability of the shoulder joint and the passage of nerves and blood vessels.

💡Intertubercular Sulcus

The intertubercular sulcus, also known as the bicipital groove, is a depression between the greater and lesser tubercles of the humerus. As described in the video, it contains the long head of the biceps brachii and the ascending branch of the anterior circumflex humeral artery. This sulcus is crucial for the passage of important structures and the function of the biceps muscle.

💡Shaft of Humerus

The shaft of the humerus is the long, cylindrical part that connects the upper and lower ends of the bone. It has three borders and three surfaces, as mentioned in the script, which are important for muscle attachment and bone stability. The shaft's structure is essential for the support and movement of the upper limb.

💡Radial Groove

The radial groove is a feature on the posterior surface of the humerus's shaft, located below an oblique ridge. It runs down and laterally, as described in the script, and contains the radial nerve and profunda brachii vessels. This groove is significant for the transmission of nerve signals and blood supply to the arm and forearm.

💡Epicondyles

The epicondyles are prominent projections on either side of the humerus's lower end. The medial epicondyle is more prominent than the lateral, as mentioned in the script, and both play a crucial role in muscle attachment and elbow joint stability. They are sites where several important muscles, including those that flex and extend the wrist and fingers, attach to the bone.

💡Capitulum

The capitulum is the rounded, convex articular part of the humerus's lower end. It is lateral to the trochlea and medial to the lateral epicondyle, as described in the script. The capitulum's shape and position are essential for the smooth movement of the forearm during elbow flexion and extension.

💡Ossification Centers

Ossification centers are the primary and secondary centers of bone growth and development. The video script mentions several ossification centers for the humerus, including the head, greater and lesser tubercles, shaft, capitulum, and lateral epicondyle. Understanding these centers is crucial for studying skeletal maturity and diagnosing bone-related conditions.

💡Fracture

A fracture is a break or crack in a bone, and the video script discusses common fracture sites in the humerus, such as the surgical neck and the shaft. Fractures can result from various traumas, including falls on an outstretched hand, and can have significant implications for the function and mobility of the upper limb.

Highlights

The humerus is the largest and strongest long bone in the upper limb.

The upper end of the humerus consists of the head, neck, greater and lesser tubercles, and the intertubercular sulcus.

The head of the humerus articulates with the glenoid cavity of the scapula to form the shoulder joint.

There are two types of necks in the humerus: the anatomical neck and the surgical neck.

The greater tubercle forms the prominence of the shoulder.

The lesser tubercle is located in the anterior aspect of the upper end, just above the surgical neck.

The intertubercular sulcus, also known as the bicipital groove, contains the long head of the biceps brachii and the ascending branch of the anterior circumflex humeral artery.

The shaft of the humerus is cylindrical above and triangular below, with three borders and three surfaces.

The posterior surface of the humerus has an oblique ridge and a radial groove containing the radial nerve and profunda brachii vessels.

The lower end of the humerus is broad and consists of an articular and non-articular part.

The capitulum of the humerus is rounded and convex, articulating with the trochlea of the ulna.

The radial fossa lodges the head of the radius during elbow flexion.

The determination of the side of the humerus can be made by the position of the head, lesser tubercle, intertubercular sulcus, and medial epicondyle.

Ossification of the humerus begins with one primary center for the shaft and additional secondary centers for the upper and lower ends.

Clinically, the humerus is susceptible to fractures, particularly at the surgical neck, shaft, and supracondylar region.

The most common dislocation of the shoulder joint is the inferior dislocation.

Transcripts

[Music]

humorus the humorus is the largest and

strongest long bone in the Upper Limb

the upper end consists of the head neck

greater tual lesser tubal and the

intertubercular

sulcus the head forms less than half of

a sphere and is smooth it is directed

medially backwards and

upwards it is covered by Hine articular

cartilage and articulates with the

glenoid cavity of the scapula to form

the shoulder

joint neck there are two necks

anatomical and

surgical the anatomical neck is the

constricted portion surrounding the head

it gives attachment to the capsule of

the shoulder joint except INF fom medial

surgical neck it is the junction between

the upper end and the shaft and is a

common site for

fractures the greater tubercle lies in

the posterior lateral aspect of the

upper end and forms the prominence of

the shoulder the medial margin gives

attachment to the transverse

ligament lesser tubercle is smaller than

the greater tubercle and lies in the

anterior aspect of the upper end just

above the surgical neck the lateral

margin gives attachment to the

transverse

ligament intertubercular sulcus it is

also known as the bicipital groove it is

a depression which lies between the two

tubes it consists of the medial lip

lateral lip and the

floor intertubercular sulcus contains

the long head of biceps brachi and the

ascending branch of the anterior

circumflex humoral artery the shaft is

like a cylinder above but flat and

triangular below it consists of three

borders anterior lateral and medial and

three surfaces anteromedial

anterolateral and

posterior the anterior border extends

from the lower end of the greater

tubercle till right above the radial

fosa the upper part forms the lateral

lip of the intertubercular

sulcus the lateral

border it extends from the greater

tubercle till the lateral

epicondylalgia medial border it extends

from the Lesser tubercle till the medial

epicondylar

sulcus it becomes prominent to form the

medial Supra condill line which gives

attachment to the medial intermuscular

septum the anterior lateral surface it

lies between the anterior and lateral

borders it presents a rough tubercle at

the middle called the deltoid

tuberosity anterior medial surface it

lies between the anterior and medial

borders a nutrient foramin is present

near the medial border and is directed

downwards hence the upper end is the

growing

end the posterior surface it lies

between the medial and lateral borders

an oblique Ridge is present in the upper

part the radial Groove the radial Groove

lies below the oblique Ridge runs down

and laterally till it reaches the

lateral border it contains the radial

nerve and the profunda brachi

vessels the lower end is Broad from side

to side and consists of an articular and

non-articular part articular part

capitulum it is rounded and convex and

lies latal to the proca and medial to

the lateral

epicondyle it is shaped like a pulley

and lies medial to the capitulum it

articulates with the trar notch of the

alna nonarticular part medial

epicondilite prominent than the lateral

epicondylus on its posterior surface for

the alar

nerve lateral

epicondilite of the lower

end the electron fosa it is a hollow

depression situated on the posterior

surface of the lower end its floor is

very thin hence may get perforated it

lodges the electron process of the alna

during extension of the

elbow coronoid fosa it is a small

depression situated just above the troca

it lodges the anterior margin of the

coronoid process of the alna during

elbow

flexion radial fosa it is a very small

depression lying lateral to the coronoid

fosa and above the capitulum it lodges

the head of the radius during elbow

flexion determination of the side the

head lies on the medial side of the

upper end and faces medially backwards

and upwards the Lesser tubercle projects

from the anterior part of the upper end

the intertubercular sulcus lies on the

lateral side of the lesser

tubercle the electron process lies on

the posterior side and the more

prominent medial

epicondyle

epicondilite the side they belong

to

oifc the humoris is aifi by one Primary

Center for the shaft three secondary

centers for the upper end and four

secondary centers for the lower end

upper end of

humoris the oifc for the head appears in

the first year for the greater tubercle

in the third year and lesser tubercle in

the fifth year the oifc center for the

shaft appears in the eighth week of

intra utrine

life lower end of the

humoris the center for capitulum and

lateral fange of the tra appears in the

second year medial part of the tra in

the 10th year lateral

epicondilite di in the sixth

year all the oifc centers in the upper

end fuse together by the seventh

Year all the oifc centers in the lower

end fuse together by 14 years of

life fusion with the

shaft the upper end joins with the shaft

by the 20th

year lower end joins with the shaft by

16 to 17 years and the medial

epicondilite by 18

years clinical

correlation nerves related to the

humoris are auxiliary nerve around the

surgical neck radial nerve in the radial

or spiral Groove and the olar nerve

behind the medial

epicondilite

common sites for the fracture of humorus

are surgical neck shaft and the suond

region

suond fracture of the humorus it is

caused by fall on an outstretched hand

and commonly occurs at a young age

clinically it presents as a backward

displacement of the lower fragment with

unduly prominent elbow this fracture May

injure the median nerve and the brachial

artery this location of the shoulder

joint is more common due to the capsule

being loose and the size of the head

being very large compared to the size of

the glenoid cavity the most common

dislocation of the shoulder joint is the

inferior dislocation