Humerus

You have a long bone in your arm.

It goes from your shoulder to your elbow.

This bone connects to your shoulder. It also connects to two bones in your lower arm.

The top part of the bone is round. It has a narrow part called a neck. This neck can sometimes break.

The middle part is a long shaft. It is shaped like a tube. This part is very strong.

The bottom part is near your elbow. It helps your arm bend and move. This bone helps you play!

The humerus is a long bone in your arm.

It runs from your shoulder to your elbow. This bone connects your shoulder to your lower arm.

The lower arm has two bones called the radius and ulna.

The top of the bone has a round head. This head joins with your shoulder bone.

Below the head is a narrow part called the neck. There is an anatomical neck near the head. There is also a surgical neck further down. The surgical neck is a common place for breaks.

The middle part is called the shaft. It is shaped like a tube. This part has bumps where muscles attach. One bump is the deltoid tuberosity.

This is where your deltoid muscle connects.

The bottom part is near your elbow. It has two bumps called epicondyles. This part has small hollows called fossae. One is the olecranon fossa.

These hollows help your arm bend and move.

The humerus is a long bone in the arm.

It runs from the shoulder down to the elbow. This bone connects the scapula, which is the shoulder bone, to the lower arm. The lower arm contains two bones called the radius and the ulna.

The humerus is important because it helps the arm move. It provides a strong structure for many muscles to attach to. Understanding this bone helps us see how our arms work.

The bone has three main sections. The top part is called the proximal extremity. It has a rounded head that fits into the glenoid cavity of the scapula.

This connection creates the glenohumeral joint, also known as the shoulder joint. Below the head is the anatomical neck. Further down, there is a narrow area called the surgical neck. This area is a common place for a fracture to happen.

The middle part of the bone is the shaft. It is shaped like a cylinder or a tube.

The shaft has different surfaces and borders. One part is the deltoid tuberosity, which is a rough bump. This is where the deltoid muscle attaches to the bone.

There is also a spiral groove on the back side. This groove carries the radial nerve and some blood vessels.

A small hole called the nutrient foramen lets blood vessels enter the bone.

The bottom part is the distal extremity. It is near the elbow and is somewhat flattened. This section has two bumps called the medial and lateral epicondyles. It also has parts called the trochlea and the capitulum. The capitulum is a smooth, rounded part that connects to the radius.

There are also three hollow areas called fossae. These include the radial fossa, the coronoid fossa, and the olecranon fossa.

These hollows allow the bones of the arm to move during flexion.

Many muscles use the humerus as an anchor point. The greater tubercle is a large bump on the top.

It is a place where muscles like the supraspinatus attach. The lesser tubercle is a smaller bump nearby.

The bicipital groove is a deep path between these two bumps. This groove holds the long tendon of the biceps brachii muscle.

By acting as a base, the humerus lets us lift and move our arms.

The humerus is a long bone located in the upper arm.

It spans the distance from the shoulder to the elbow. This bone serves as a vital bridge in the arm's structure. It connects the scapula, which is the shoulder blade, to the two lower arm bones. These lower bones are the radius and the ulna.

The humerus is essential for movement and stability. It provides many attachment points for the muscles that move the arm. Understanding its complex shape helps us see how the human arm functions.

The bone is divided into three distinct sections. The first is the proximal extremity, or the upper end.

The second section is the shaft, which forms the long middle part of the bone. The third section is the distal extremity, located at the bottom near the elbow.

Each section has specific shapes and features. These features allow the bone to interact with muscles, nerves, and other bones. The way these parts fit together determines how we can swing or lift our arms.

At the top, the proximal extremity begins with a large, rounded head. This head is nearly hemispherical in shape. It directs upward and inward to meet the glenoid cavity of the scapula. This connection creates the glenohumeral joint, or the shoulder joint.

Below the head is the anatomical neck. This is a narrow groove that separates the head from the tubercles. The anatomical neck provides an attachment site for the articular capsule. It also contains many small holes called vascular foramens for blood vessels. Fractures at the anatomical neck are quite rare.

Just below the tubercles lies the surgical neck. This area is a narrow constriction of the bone. It is called the surgical neck because it is a frequent site for fractures.

This part of the bone is very important for surgeons to study. The surgical neck makes contact with the axillary nerve. It also sits near the posterior humeral circumflex artery. Because of its location and shape, it is more vulnerable to injury than the anatomical neck.

The upper end also features two bony projections called tubercles. The greater tubercle is a large projection located on the outer side.

It serves as an attachment point for three muscles: the supraspinatus, infraspinatus, and teres minor. The lesser tubercle is a smaller projection located toward the front.

It provides an insertion point for the subscapularis muscle. Between these two tubercles is the bicipital groove.

This deep groove holds the long tendon of the biceps brachii muscle. It also carries a branch of the anterior humeral circumflex artery.

The shaft of the humerus is the long, middle portion. It is shaped like a cylinder or a triangle. The shaft has three main surfaces: the anterolateral, the anteromedial, and the posterior surface.

On the lateral side, a rough bump called the deltoid tuberosity exists. This is where the deltoid muscle attaches.

On the back of the shaft is the radial sulcus, or spiral groove.

This groove allows the radial nerve and deep vessels to pass through. Additionally, a small hole called the nutrient foramen allows nutrient arteries to enter the bone.

The distal extremity is the lower end of the bone near the elbow. This section is somewhat flattened and curves slightly forward. It features two bony bumps called the medial and lateral epicondyles. The articular surface here is split into two parts. One part is the capitulum, which is a smooth, rounded knob.

The other part is the trochlea.

The bone also contains three hollow spaces called fossae. These include the radial fossa, the coronoid fossa, and the olecranon fossa.

These depressions allow the bones of the forearm to fit into the humerus during movement.