Humerus Diagram, Location, and Common Student Questions
A humerus is also defined as a long bone that is present in the upper limb or forelimb of the land vertebrae. It joins the shoulder joint where it gets prominence with a lateral depression of the shoulder blade and the elbows joint below where it is connected with the projections in the ulna and radius. The humor bone is the foundation of several muscle inserts like the pectoralis major, deltoid, and others. Since the humerus connects the shoulder with rotational joints it is held pivotal for arm movement and function. Typically, it is the longest bone present in the human body.
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Meaning of a Fractured Humerus
The fractured humerus signifies the breakage of the humerus bone in the upper arm. A broken arm injury is a very common phenomenon that results from the consequential falling of an outstretched hand, slippage, car accidents, or maybe any other type of mishaps. This reduces the ability to move an arm and the person may result in holding their elbows. The common symptoms involve swelling, bruising, and paining. The proper way of diagnosing the problem is usually done with the help of an X-ray. The treatment methodologies involve splint, sling, brace or surgery.
Solved Questions and Answers
1. What is Fractured Proximal Humerus?
Ans. A fractured proximal humerus indicates a significant injury to the humerus bone in the shoulder joint that needs instant treatment to restore the previous healthy functioning of the bone. A fracture of the humerus bone results from the possible consequence of traumatic conditions like forceful collision or falling. Now it completely depends on the type of fracture and specific location of the proximal humerus, a surgical intervention can also be the need of the hour. On the treatment front, whether a surgical or non-surgical method is required or not but a physical therapy treatment is essential. This helps to effectively and safely restore the shoulder function and enables the individual to get back to his normal activities.
2. How Does an Individual Feel When He Undergoes a Proximal Humerus Injury?
Ans. An individual who undergoes a proximal humerus fracture might experience the following conditions after immediately getting an injury.
Pains
Bruising
Swelling
There is a complete restriction on the movement of the injured shoulders
A grinding sensation with arm’s movement.
Noticeable deformity in the arm.
Numbness and tingling in the arm.
Occasional bleeding for an open fracture.
Loss of arm’s mobility in case of additional nerve injury.
3. What are the Most Common Arm Fractures Observed in Children?
Ans. The most typical type of fracture that happens in the arms of the children is the fracture in the supracondylar humerus. This fracture is a rare observance in adults. A supracondylar fracture is a breakage of the distal humor bone situated just above the elbows. This type of fracture is transverse or oblique in nature and above the medial and lateral epicondyles and condyles. Most of the non-displaced fractures in the children can be treated with casting. In case, these fractures are displaced or angulated it can be treated with surgery. Complications in this type of fracture arise only when it gets associated with nerve injuries or blood vessels.
4. Are Humerus and Ulna Connected?
Ans. Yes, the humerus and ulna are connected by the humeroulnar joint that is a part of the elbow joint. It comprises mainly two bones the humerus and ulna, and it is the junction between the trochlea of humerus and the trochlea of ulna. It is a simple hinge joint that enables the movement of the extension, flexion, and circumduction.
5. What is Humerus of a Frog?
Ans. Just like a human, the frog's front legs are known as the humerus of the frog. It also comprises the other two bones called the radius and ulna. Though, the radius and ulna of the frog are merged within the bones.
Did You Know
The proximal humerus consists of the head, anatomical neck, surgical neck, lesser and greater tubercle, and intertubercular sulcus. On a humerus, the greater tubercle is located laterally and has both anterior and posterior surfaces. While the lesser tubercle is smaller and located more medially inside the bone. This is known as tubercle humerus.
FAQs on Humerus: Definition, Anatomy & Functions
1. What is the humerus and where is it located in the human body?
The humerus is the single long bone of the upper arm. It is located between the shoulder and the elbow. Proximally (at the top), it connects with the scapula (shoulder blade) to form the shoulder joint, and distally (at the bottom), it connects with the radius and ulna of the forearm to form the elbow joint.
2. What are the three main anatomical parts of the humerus?
The humerus is structurally divided into three main parts:
Proximal End: This includes the head, which articulates with the scapula, and the greater and lesser tubercles, which serve as attachment points for rotator cuff muscles.
Shaft (or Body): This is the long, cylindrical middle section of the bone that provides structural support and serves as an attachment point for muscles like the deltoid and brachialis.
Distal End: This part flattens out and includes features like the capitulum and trochlea, which articulate with the forearm bones to form the elbow joint.
3. What are the primary functions of the humerus bone?
The humerus serves several critical functions in the upper limb. Its primary roles are to provide structural support for the arm, act as a lever for muscles to facilitate a wide range of arm movements (like lifting, throwing, and pushing), and to form the crucial shoulder and elbow joints, enabling arm rotation, flexion, and extension.
4. Which bones does the humerus articulate with to form the shoulder and elbow joints?
The humerus articulates with different bones at its two ends:
At the shoulder joint (glenohumeral joint), the rounded head of the humerus articulates with the glenoid cavity of the scapula.
At the elbow joint, the distal end of the humerus articulates with two forearm bones: the trochlea connects with the ulna, and the capitulum connects with the radius.
5. What is the significance of the 'surgical neck' of the humerus?
The surgical neck is a constricted area located just below the tubercles at the proximal end of the humerus. Unlike the 'anatomical neck' which is located higher up, the surgical neck is a common site for fractures. Its importance lies in its close proximity to the axillary nerve and major blood vessels. A fracture at this location can potentially damage these vital structures, making it a clinically significant area for diagnosis and treatment.
6. How do the various bumps and grooves on the humerus shaft relate to muscle function?
The surface of the humerus is not smooth; it has specific markings that are essential for muscle attachment. For example, the deltoid tuberosity on the lateral side of the shaft is a roughened area where the powerful deltoid muscle inserts, enabling arm abduction. Similarly, the intertubercular sulcus (or bicipital groove) at the proximal end guides the tendon of the biceps brachii muscle, ensuring smooth and efficient movement during elbow flexion.
7. Compare the functions of the capitulum and the trochlea at the distal end of the humerus.
Both the capitulum and trochlea are articular surfaces at the distal humerus, but they have distinct functions and articulate with different bones. The capitulum is a rounded, ball-like structure on the lateral side that articulates with the head of the radius, allowing for pivoting movements like supination and pronation of the forearm. In contrast, the trochlea is a grooved, pulley-like structure on the medial side that articulates with the ulna, primarily allowing for the hinge-like movements of flexion and extension at the elbow.
8. Why is the humerus a good example of a typical long bone?
The humerus exemplifies the structure of a typical long bone as it possesses all the characteristic features. It has a long, cylindrical shaft, known as the diaphysis, which is made of compact bone and contains a medullary cavity for bone marrow. It also has two expanded ends, known as the epiphyses (proximal and distal), which are primarily composed of spongy bone and are covered with articular cartilage to form joints. This classic structure is designed for leverage and weight-bearing, which is the primary role of the humerus in the arm.
