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Arm
The human arm
Cross-section through the middle of upper arm.
Latin	bracchium GraySubject =
MeSH	Arm

In human anatomy, the arm is the part of the upper limb between the shoulder and the elbow joints. In other animals, the term arm can also be used for analogous structures, such as one of the paired forelimbs of a four-legged animal or the arms of cephalopods. In anatomical usage, the term arm refers specifically to the segment between the shoulder and the elbow,^[1][2] while the segment between the elbow and wrist is the forearm. However, in common, literary, and historical usage, arm refers to the entire upper limb from shoulder to wrist. This article uses the former definition; see upper limb for the wider definition.

In primates the arm is adapted for precise positioning of the hand and thus assist in the hand's manipulative tasks. The ball and socket shoulder joint allows for movement of the arms in a wide circular plane, while the structure of the two forearm bones which can rotate around each other allows for additional range of motion at that level.

Skeleton[link]

Bone structure of a human arm.

The humerus is the bone of the arm. It joins with the scapula above in the shoulder at the glenohumeral joint and with the ulna and radius below at the elbow. The elbow joint is the hinge joint between the distal end of the humerus and the proximal ends of the radius and ulna. The humerus cannot be broken easily. Its strength allows it to handle loading up to 300 pounds (140 kg).

Muscles[link]

The arm is divided by a fascial layer (known as lateral and medial intermuscular septa) separating the muscles into two osteofascial compartments: the anterior and the posterior compartments of the arm. The fascia merges with the periosteum (outer bone layer) of the humerus. The compartments contain muscles which are innervated by the same nerve and perform the same action.

Two other muscles are considered to be partially in the arm:

• The large deltoid muscle is considered to have part of its body in the anterior compartment. This muscle is the main abductor muscle of the upper limb and extends over the shoulder.
• The brachioradialis muscle originates in the arm but inserts into the forearm. This muscle is responsible for rotating the hand so its palm faces forward (supination).

Nerve and blood supply[link]

The cubital fossa (colloquially known as the elbow pit) is clinically important for venepuncture and for blood pressure measurement.

Innervation[link]

Cutaneous innervation of the right upper extremity.

The musculocutaneous nerve, from C5, C6, C7, is the main supplier of muscles of the anterior compartment. It originates from the lateral cord of the brachial plexus of nerves. It pierces the coracobrachialis muscle and gives off branches to the muscle, as well as to brachialis and biceps brachii. It terminates as the anterior cutaneous nerve of the forearm.

The radial nerve, which is from the fifth cervical spinal nerve to the first thoracic spinal nerve, originates as the continuation of the posterior cord of the brachial plexus. This nerve enters the lower triangular space (an imaginary space bounded by, amongst others, the shaft of the humerus and the triceps brachii) of the arm and lies deep to the triceps brachii. Here it travels with a deep artery of the arm (the profunda brachii), which sits in the radial groove of the humerus. This fact is very important clinically as a fracture of the bone at the shaft of the bone here can cause lesions or even transections in the nerve.

Other nerves passing through give no supply to the arm. These include:

• The median nerve, nerve origin C5-T1, which is a branch of the lateral and medial cords of the brachial plexus. This nerve continues in the arm, travelling in a plane between the biceps and triceps muscles. At the cubital fossa, this nerve is deep to the pronator teres muscle and is the most medial structure in the fossa. The nerve passes into the forearm.
• The ulnar nerve, origin C8-T1, is a continuation of the medial cord of the brachial plexus. This nerve passes in the same plane as the median nerve, between the biceps and triceps muscles. At the elbow, this nerve travels posterior to the medial epicondyle of the humerus. This means that condylar fractures can cause lesion to this nerve.

Arteries[link]

Main arteries of the arm.

The main artery in the arm is the brachial artery. This artery is a continuation of the axillary artery. The point at which the axillary becomes the brachial is distal to the lower border of teres major. The brachial artery gives off an important branch, the profunda brachii (deep artery of the arm). This branching occurs just below the lower border of teres major.

The brachial artery continues to the cubital fossa in the anterior compartment of the arm. It travels in a plane between the biceps and triceps muscles, the same as the median nerve and basilic vein. It is accompanied by venae comitantes (accompanying veins). It gives branches to the muscles of the anterior compartment. The artery is in between the median nerve and the tendon of the biceps muscle in the cubital fossa. It then continues into the forearm.

The profunda brachii travels through the lower triangular space with the radial nerve. From here onwards it has an intimate relationship with the radial nerve. They are both found deep to the triceps muscle and are located on the spiral groove of the humerus. Therefore fracture of the bone may not only lead to lesion of the radial nerve, but also haematoma of the internal structures of the arm. The artery then continues on to anastamose with the recurrent radial branch of the brachial artery, providing a diffuse blood supply for the elbow joint.

Veins[link]

The veins of the arm carry blood from the extremities of the limb, as well as drain the arm itself. The two main veins are the basilic and the cephalic veins. There is a connecting vein between the two, the median cubital vein, which passes through the cubital fossa and is clinically important for venepuncture (withdrawing blood).

The basilic vein travels on the medial side of the arm and terminates at the level of the seventh rib.

The cephalic vein travels on the lateral side of the arm and terminates as the axillary vein. It passes through the deltopectoral triangle, a space between the deltoid and the pectoralis major muscles.

Additional images[link]

See also[link]

• Anatomical terms of location
• Anthropometry of the upper arm
• Humerus fracture

References[link]

Wikimedia Commons has media related to: Arm

Look up arm in Wiktionary, the free dictionary.

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Christina Perri
Christina Perri in an interview
Background information
Birth name	Christina Judith Perri
Born	(1986-08-19) August 19, 1986 (age 25)
Origin	Philadelphia, Pennsylvania, U.S.
Genres	Pop rock, piano rock, alternative rock, soul
Occupations	Singer-songwriter, guitarist, pianist
Instruments	Vocals, piano, guitar
Years active	2010–present
Labels	Atlantic
Website	www.christinaperri.com

Christina Judith Perri (born August 19, 1986)^[1][2] is an American singer-songwriter and musician from Philadelphia. Her song "Jar of Hearts" charted in the United States after it was featured on the Fox television show So You Think You Can Dance in 2010. Rolling Stone named her the "Band of the Week" on October 26, 2010.^[3] On May 10, 2011, Perri's "Jar of Hearts" was featured on Glee (Season 2, Episode 20 "Prom Queen").^[4] Also, on June 27, 2011, Perri's "Jar of Hearts" was featured on Switched at Birth (Season 1, Episode 4 "Dance Amongst Daggers"). One of her songs, "A Thousand Years", has been in the Twilight saga movie Breaking Dawn.

Early life[link]

Perri grew up in Bensalem, Pennsylvania (a suburb of Philadelphia) with her older brother, Nick Perri, who formerly played guitar with Shinedown, Silvertide, Perry Farrell and Matt Sorum.^[5] Her father is from Italy.^[6] She attended Archbishop Ryan High School as a member of the class of 2004.^[7] She taught herself how to play guitar as a 16-year-old by watching a videotape of Shannon Hoon from the group Blind Melon performing on VH1.^[3]

Career[link]

Early career[link]

Perri moved to Los Angeles on her 21st birthday. Later that year she got married and began to produce music videos. She divorced 18 months later and moved back to Philadelphia by the end of 2009; during this time she wrote "Jar of Hearts". She moved back to Los Angeles, waitressing at the Melrose Cafe during the day and recording at night.^[3][8]

[edit] 2010–present: Lovestrong.

Perri's song "Jar of Hearts" was featured on So You Think You Can Dance during the June 30, 2010 show.^[9] It was featured in performance by Billy Bell and Kathryn McCormick.^[10] Perri's friend Keltie Colleen passed the song to show choreographer Stacey Tookey; Perri and Colleen watched the performance in the audience.^[9] Following its exposure on the show, "Jar of Hearts" sold 48,000 digital copies, debuting on the Billboard Hot 100 at #63 and reaching #28 on Billboard's Hot Digital Songs.^[10] Within a month, it sold more than 100,000 copies.^[8] Then, her music video for "Jar of Hearts" landed on the VH1 top 20 music video countdown.

Shortly after, Perri made her debut on national day time and prime time television, performing the song live on the July 10, 2010 episode of The Early Show on CBS as well as the July 15, 2010 episode of So You Think You Can Dance^[8] Perri signed a deal with Atlantic Records on July 21, 2010.^[11] Roadrunner Records continue to promote "Jar of Hearts" on the radio.^[12] Perri appeared on the Tonight Show with Jay Leno on July 29, 2010 and Conan on December 7, 2010 where she played "Jar of Hearts." In addition, "Jar of Hearts" was on the show Pretty Little Liars. "Arms" was also in the ABC Family movie Teen Spirit. Perri recorded an EP named The Ocean Way Sessions that was released on November 9, 2010.^[13]

Perri singing "Distance" (left) and "Jar of Hearts" (right) at the lovestrong. tour in San Juan, Puerto Rico.

Perri's debut album is titled lovestrong. and was released on May 10, 2011. It follows the release of "Arms", its lead single, released on March 15. She appeared on Late Show with David Letterman, playing her song "Arms." "Arms" was used in the August 26, 2011 episode of The Bold and the Beautiful and has also been used in TV spots for the Fall 2011 season of Investigation Discovery's show "Disappeared."

Perri's single, "A Thousand Years," appeared on The Twilight Saga: Breaking Dawn's movie soundtrack.

On November 1, 2011 Perri appeared on ABC's Dancing With The Stars Results show to perform her song "Arms". On 13 November 2011, she also performed "Jar of Hearts" on the BBC's Strictly Come Dancing results show. On February 19, she performed "Jar of Hearts" in the pre-fight buildup to Vitali Klitschko vs. Derek Chisora World Heavyweight Championship boxing contest in Munich.

On 29th January 2012, Perri performed Jar of Hearts live on UK ITV's Dancing on Ice show, with Jayne Torvill and Christopher Dean in a specially choreographed routine.

She will be joining Jason Mraz in his tour across continental North America in 2012. Perri also announced that she will be releasing her second studio album in Spring 2013.

On 22nd April 2012, Perri performed live on Australia's Dancing with the Stars.

Discography[link]

EP[link]

• The Ocean Way Sessions (2010)

Albums[link]

• Lovestrong (2011)

References[link]