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Humerus
Humerus - anterior view.png
Position of humerus (shown in red). Anterior view.
Details
Latin Humerus
Identifiers
Gray's p.209
MeSH A02.835.232.087.090.400
TA A02.4.04.001
FMA 13303
Anatomical terms of bone

The humerus (/ˈhjmərəs/, Plural: humeri) is a long bone in the arm or forelimb 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 upper extremity consists of a rounded head, a narrow neck, and two short processes (tubercles, sometimes called tuberosities). Its 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 commonly get fractured, thus often becoming the focus of surgeons.

History[edit]

The word "humerus" is derived from Latin: humerus, umerus meaning upper arm, shoulder, and is linguistically related to Gothic ams shoulder and Greek ōmos.[1]

Structure[edit]

Articulations[edit]

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.

Diagram of the human shoulder joint 
The left shoulder and acromioclavicular joints, and the proper ligaments of the scapula. 
Head of humerus 
The supinator

Nerves[edit]

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 at the distal end of the humerus near the elbow is sometimes referred to in popular culture as 'the funny bone'. Striking this nerve can cause a tingling sensation ("funny" feeling), and sometimes a significant amount of pain. It lies posterior to the medial epicondyle, and is easily damaged in elbow injuries.[2]

Horizontal section at the middle of upper arm
Horizontal section of upper arm. 
Humerus 

Function[edit]

Muscular attachment[edit]

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 A. Supraspinatus muscle
B. Latissimus dorsi muscle
C. Pectoralis major muscle
D. Deltoid muscle
E. Brachioradialis
F. Extensor carpi radialis longus muscle
G. Common extensor tendon
H. Subscapularis muscle
I. Teres major muscle
J. Coracobrachialis muscle
K. Brachialis muscle
L. Pronator teres muscle
M. 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[edit]

Primitive fossil 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 primitive mammals, the lower extremity includes a large foramen, or opening, into which nerves and blood vessels pass.[3]

Additional images[edit]

See also[edit]

References[edit]

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

  1. ^ Harper, Douglas. "Humerus". Online Etymology Dictionary. Retrieved 6 November 2014. 
  2. ^ "The Humerus". TeachMeAnatomy.net. 
  3. ^ Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 198–199. ISBN 0-03-910284-X. 

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Humerus — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.

3451 news items

sportal.co.nz

3News NZ
Thu, 11 Jun 2015 11:22:30 -0700

Sailor took on ex-Queensland front-rower Ben Ross in an arm-wrestling competition live on the Footy Show... and it went horribly wrong. Ross suffered a serious arm injury and was rushed to hospital with X-rays revealing he suffered a broken humerus bone.
 
Camden Chat
Thu, 02 Jul 2015 08:00:00 -0700

When a pitcher or player throws a baseball, the forces forces from the larger shoulder muscles act to pull the head of the humerus (ball) out of the glenoid fossa (socket). However, even though the rotator cuff muscles are relatively quite small, when ...
 
Roanoke Times
Tue, 30 Jun 2015 19:48:45 -0700

... it negligent in her treatment. Rhonda Bailey Palmer of Roanoke initially filed a $2.1 million suit last year against Virginia Orthopaedic PC, alleging that after she fractured her humerus, the injured bone was refractured during a follow-up ...

Deseret News

Deseret News
Wed, 01 Jul 2015 14:33:45 -0700

“He says he finds it quite 'humerus,' ” said his mother, Rita Spencer. Michael, a member of the Edgemont 2nd Ward, Provo Utah Edgemont Stake, was born with Amniotic Band Syndrome. Fibers from the amniotic sac in his mother's womb wrapped around his ...
 
San Jose Mercury News
Wed, 01 Jul 2015 11:44:37 -0700

After breaking her arm for the first time two years ago at a tae kwon do tournament, Su Min, a fourth-grade student at Bubb Elementary, was diagnosed with an aneurysmal bone cyst in her left humerus, a blood-filled, fibrous cyst that expands the bone ...

Newsday

Newsday
Wed, 01 Jul 2015 15:03:14 -0700

Matz's surgery used the docking technique, which Dr. James Andrews described as "just another way of fixing the ligament up in the medial epicondyle in the humerus. It's an excellent way of doing it, it depends on how you were trained, Chevy versus a ...

Ancient Origins

Ancient Origins
Wed, 01 Jul 2015 20:11:15 -0700

In 1890, while excavating the Neolithic strata of a burial mound, Georges de Lapouge discovered the humerus, tibia, and femoral shaft of an individual he estimated to be between 11 and 12 feet tall. Lapauge's conclusions were officially published in La ...
 
Richmond Times-Dispatch
Wed, 01 Jul 2015 20:11:15 -0700

Palmer's lawsuit says she was treated at the clinic after she fractured her left humerus in July 2012. The lawsuit alleges that the bone was refractured during a follow-up procedure. Palmer's attorney, Les Bowers, said that the secondary injury delayed ...
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