Humerus - anterior view.png
Position of humerus (shown in red)
from an anterior viewpoint
Anatomical terms of bone

The humerus (/ˈhjuːmərəs/; PL humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a rounded head, a narrow neck, and two short processes (tubercles, sometimes called tuberosities). The body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes (trochlea & capitulum), and 3 fossae (radial fossa, coronoid fossa, and olecranon fossa). As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons.


The word "humerus" is derived from Latin: humerus, umerus meaning upper arm, shoulder, and is linguistically related to Gothic ams shoulder and Greek ōmos.


Upper extremity

The upper or proximal extremity of the humerus consists of the bone's large rounded head joined to the body by a constricted portion called the neck, and two eminences, the greater and lesser tubercles.


The head (caput humeri), is nearly hemispherical in form. It is directed upward, medialward, and a little backward, and articulates with the glenoid cavity of the scapula to form the glenohumeral joint (shoulder joint). The circumference of its articular surface is slightly constricted and is termed the anatomical neck, in contradistinction to a constriction below the tubercles called the surgical neck which is frequently the seat of fracture. Fracture of the anatomical neck rarely occurs. The diameter of the humeral head is generally larger in men than in women.

Head of Humerus

Anatomical neck

Anatomical vs Surgical Neck of Humerus

Surgical neck

Greater Tubercle of the Right Humerus
Attachments on the Greater Tubercle

Lesser tubercle

Lesser Tubercle of the Right Humerus
Insertion of subscapularis muscle on the lesser tubercle

Bicipital groove

The tubercles are separated from each other by a deep groove, the bicipital groove (intertubercular groove; bicipital sulcus), which lodges the long tendon of the biceps brachii muscle and transmits a branch of the anterior humeral circumflex artery to the shoulder-joint. It runs obliquely downward, and ends near the junction of the upper with the middle third of the bone. In the fresh state its upper part is covered with a thin layer of cartilage, lined by a prolongation of the synovial membrane of the shoulder-joint; its lower portion gives insertion to the tendon of the latissimus dorsi muscle. It is deep and narrow above, and becomes shallow and a little broader as it descends. Its lips are called, respectively, the crests of the greater and lesser tubercles (bicipital ridges), and form the upper parts of the anterior and medial borders of the body of the bone.

Bicipital groove


Left humerus. Anterior view.
Left humerus. Posterior view.
DetailsIdentifiersLatincorpus humeriMeSHD006811TA98A02.4.04.001TA21180FMA13303Anatomical terms of bone
[edit on Wikidata]

The body or shaft of the humerus is triangular to cylindrical in cut section and is compressed anteroposteriorly. It has 3 surfaces, namely:

Its three borders are:

Anterior View of the humerus showing borders and surfaces
Posterior view of the humerus showing the medial and lateral borders and the posterior surface of the humerus

The Deltoid tuberosity is a roughened surface on the lateral surface of the shaft of the Humerus and acts as the site of insertion of deltoideus muscle. The posterorsuperior part of the shaft has a crest, beginning just below the surgical neck of the humerus and extends till the superior tip of the deltoid tuberosity. This is where the lateral head of triceps brachii is attached.

Deltoid Tuberosity of the humerus

The radial sulcus, also known as the spiral groove is found on the posterior surface of the shaft and is a shallow oblique groove through which the radial nerve passes along with deep vessels. This is located posteroinferior to the deltoid tuberosity. The inferior boundary of the spiral groove is continuous distally with the lateral border of the shaft.

Radial groove continuing as the lateral border of shaft of the humerus

The nutrient foramen of the humerus is located in the anteromedial surface of the humerus. The nutrient arteries enter the humerus through this foramen.

Nutrient foramen of the Humerus

Distal humerus

Left humerus. Anterior view.
DetailsIdentifiersLatinExtremitas distalis humeriMeSHD006811TA98A02.4.04.001TA21180FMA13303Anatomical terms of bone
[edit on Wikidata]

The distal or lower extremity of the humerus is flattened from before backward, and curved slightly forward; it ends below in a broad, articular surface, which is divided into two parts by a slight ridge. Projecting on either side are the lateral and medial epicondyles.

Articular surface

The articular surface extends a little lower than the epicondyles, and is curved slightly forward; its medial extremity occupies a lower level than the lateral. The lateral portion of this surface consists of a smooth, rounded eminence, named the capitulum of the humerus; it articulates with the cup-shaped depression on the head of the radius, and is limited to the front and lower part of the bone.


Above the front part of the trochlea is a small depression, the coronoid fossa, which receives the coronoid process of the ulna during flexion of the forearm.

Above the back part of the trochlea is a deep triangular depression, the olecranon fossa, in which the summit of the olecranon is received in extension of the forearm.

Olecranon fossa of the Humerus

The coronoid fossa is the medial hollow part on the anterior surface of the distal humerus. The coronoid fossa is smaller than the olecranon fossa and receives the coronoid process of the ulna during maximum flexion of the elbow.

Coronoid Fossa of the Humerus

Above the front part of the capitulum is a slight depression, the radial fossa, which receives the anterior border of the head of the radius, when the forearm is flexed.

Radial Fossa of the Humerus

These fossæ are separated from one another by a thin, transparent lamina of bone, which is sometimes perforated by a supratrochlear foramen; they are lined in the fresh state by the synovial membrane of the elbow-joint, and their margins afford attachment to the anterior and posterior ligaments of this articulation.

The Capitulum is a rounded eminence forming the lateral part of the distal humerus. The head of the radius articulates with the capitulum.

Capitulum on the lateral side and trochlea on the medial side of the Humerus

The trochlea is spool-shaped medial portion of the distal humerus and articulates with the ulna.

Trochlea of the Humerus


The epicondyles are continuous above with the supracondylar ridges.

Medial and Lateral epicondyles of the Humerus
Medial and lateral supracondylar ridges of the Humerus

The Medial supracondylar crest forms the sharp medial border of the distal humerus continuing superiorly from the medial epicondyle. The Lateral Supracondylar crest forms the sharp lateral border of the distal humerus continuing superiorly from the lateral epicondyle.


The medial portion of the articular surface is named the trochlea, and presents a deep depression between two well-marked borders; it is convex from before backward, concave from side to side, and occupies the anterior, lower, and posterior parts of the extremity.

The grooved portion of the articular surface fits accurately within the semilunar notch of the ulna; it is broader and deeper on the posterior than on the anterior aspect of the bone, and is inclined obliquely downward and forward toward the medial side.


At the shoulder, the head of the humerus articulates with the glenoid fossa of the scapula. More distally, at the elbow, the capitulum of the humerus articulates with the head of the radius, and the trochlea of the humerus articulates with the trochlear notch of the ulna.


The axillary nerve is located at the proximal end, against the shoulder girdle. Dislocation of the humerus's glenohumeral joint has the potential to injure the axillary nerve or the axillary artery. Signs and symptoms of this dislocation include a loss of the normal shoulder contour and a palpable depression under the acromion.

The radial nerve follows the humerus closely. At the midshaft of the humerus, the radial nerve travels from the posterior to the anterior aspect of the bone in the spiral groove. A fracture of the humerus in this region can result in radial nerve injury.

The ulnar nerve lies at the distal end of the humerus near the elbow. When struck, it can cause a distinct tingling sensation, and sometimes a significant amount of pain. It is sometimes popularly referred to as 'the funny bone', possibly due to this sensation (a "funny" feeling), as well as the fact that the bone's name is a homophone of 'humorous'. It lies posterior to the medial epicondyle, and is easily damaged in elbow injuries.[citation needed]

Horizontal section at the middle of upper arm.

  • Horizontal section of upper arm.

    Horizontal section of upper arm.

  • Humerus


  • Function

    Muscular attachment

    The deltoid originates on the lateral third of the clavicle, acromion and the crest of the spine of the scapula. It is inserted on the deltoid tuberosity of the humerus and has several actions including abduction, extension, and circumduction of the shoulder. The supraspinatus also originates on the spine of the scapula. It inserts on the greater tubercle of the humerus, and assists in abduction of the shoulder.

    The pectoralis major, teres major, and latissimus dorsi insert at the intertubercular groove of the humerus. They work to adduct and medially, or internally, rotate the humerus.

    The infraspinatus and teres minor insert on the greater tubercle, and work to laterally, or externally, rotate the humerus. In contrast, the subscapularis muscle inserts onto the lesser tubercle and works to medially, or internally, rotate the humerus.

    The biceps brachii, brachialis, and brachioradialis (which attaches distally) act to flex the elbow. (The biceps do not attach to the humerus.) The triceps brachii and anconeus extend the elbow, and attach to the posterior side of the humerus.

    The four muscles of supraspinatus, infraspinatus, teres minor and subscapularis form a musculo-ligamentous girdle called the rotator cuff. This cuff stabilizes the very mobile but inherently unstable glenohumeral joint. The other muscles are used as counterbalances for the actions of lifting/pulling and pressing/pushing.

    Left humerus. Anterior view.
    Humerus ant (mirroed).png Left humerus - anterior view.png Left humerus - close-up - animation - stop at anterior view.gif HumerusFront.png Human left humerus - anterior view - muscles.svg
    1. Supraspinatus muscle
    2. Latissimus dorsi muscle
    3. Pectoralis major muscle
    4. Deltoid muscle
    5. Brachioradialis
    6. Extensor carpi radialis longus muscle
    7. Common extensor tendon
    8. Subscapularis muscle
    9. Teres major muscle
    10. Coracobrachialis muscle
    11. Brachialis muscle
    12. Pronator teres muscle
    13. Common flexor tendon
    Left humerus. Posterior view.
    Humerus post (mirroed).png Left humerus - posterior view.png Left humerus - close-up - animation - stop at posterior view.gif HumerusBack.png Gray208.png

    Other animals

    Primitive fossils of amphibians had little, if any, shaft connecting the upper and lower extremities, making their limbs very short. In most living tetrapods, however, the humerus has a similar form to that of humans. In many reptiles and some mammals (where it is the primitive state), the lower extremity includes a large opening called the entepicondylar foramen to allow the passage of nerves and blood vessels.

    Additional images


    medial epicondyle of the humerus Edit this at Wikidata
    lateral epicondyle of the humerus Edit this at Wikidata
    surgical neck of the humerus Edit this at Wikidata
    anatomical neck of humerus Edit this at Wikidata
    greater tubercle Edit this at Wikidata
    lesser tubercle Edit this at Wikidata
    head of humerus Edit this at Wikidata
    intertubercular sulcus of the humerus Edit this at Wikidata
    condyle of humerus Edit this at Wikidata
    body of humerus Edit this at Wikidata

    This page was last updated at 2023-05-14 03:04 UTC. Update now. View original page.

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