Arm

Source: Wikipedia, the free encyclopedia.
This article is about the upper part of the limb in humans and other animals. For the British semiconductor and software design company, see Arm Holdings. For other uses, see Arm (disambiguation).
Arm
The left arm of a human male
Details
ArteryAxillary artery
VeinAxillary vein
NerveBrachial plexus
Identifiers
Latinbrachium
Anatomical terminology

In

radiocarpal joint (wrist joint) is known as the forearm or "lower" arm, and the extremity beyond the wrist is the hand
.

By anatomical definitions, the

root word for naming many anatomical structures, may refer to either the upper limb as a whole or to the upper arm on its own.[3][4][5]

Structure

Bones

upper limbs, together with shoulder girdles
, that compose the human arm.

The

shoulder joint and with the other long bones of the arm, the ulna and radius at the elbow joint.[6] The elbow is a complex hinge joint between the end of the humerus and the ends of the radius and ulna.[7]

Muscles

The arm is divided by a

posterior compartments of the arm. The fascia merges with the periosteum (outer bone layer) of the humerus.[8]

The anterior compartment contains three muscles:

brachialis and coracobrachialis muscles. They are all innervated by the musculocutaneous nerve. The posterior compartment contains only the triceps brachii muscle, supplied by the radial nerve.[9][10][11]

Nerve supply

Further information: Cutaneous innervation of the upper limbs
Cutaneous innervation of the right upper extremity.

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 the deep artery of the arm, which sits in the radial groove of the humerus. This fact is very important clinically as a fracture of 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:

Blood supply

Main arteries of the arm.

The main artery in the arm is the

teres major
.

The brachial artery continues to the

biceps muscle in the cubital fossa. It then continues into the forearm
.

The deep artery of the arm travels through the

elbow joint
.

Veins

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

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.

Society and culture

In Hindu, Buddhist and Egyptian iconography the symbol of the arm is used to illustrate the power of the sovereign. In Hindu tradition gods are depicted with several arms which carry specific symbols of their powers. It is believed that several arms depict omnipotence of gods. In popular culture Thakur did not have arms in the movie Sholay.

In West Africa, the Bambara use forearm to symbolize the spirit, which is a link between God and man.

Three North Koreans surrender to USS Manchester by raising their arms

Symbolic gestures of raising both hands signal surrender, appeals for mercy, and justice.[12]

hieroglyphs

Clinical significance

The

venepuncture and for blood pressure measurement.[13]

When the arm is fractured this may refer to a fracture of the humerus bone.

Veins on the arm may be taken when a

coronary artery bypass graft
is needed.

Other animals

In other animals, the term arm can also be used for homologous or analogous structures (such as one of the paired

arms of cephalopods, respectively). In anatomical usage, the term arm may[3] sometimes refer specifically to the segment between the shoulder and the elbow,[14][15] 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.[8]

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.[16]

Additional images

  • Gross anatomy of the upper arm and elbow.
    Gross anatomy of the upper arm and elbow.

See also

This article uses anatomical terminology.
Wikimedia Commons has media related to Arm.
Look up arm in Wiktionary, the free dictionary.

References

  1. ^ Gray, Henry (1918). "The Humerus (Arm Bone)".
  2. PMID 29939618
    .
  3. ^ a b "brachium – free dictionary". Retrieved December 2, 2013.
  4. ^ "Dictionary.com". Retrieved December 2, 2013.
  5. ^ Encyclopaedia britannica 2013.
  6. ISBN 978-0443103735
    . Retrieved January 19, 2018.
  7. OCLC 1111734654.{{cite book}}: CS1 maint: location missing publisher (link
    )
  8. ^
    OCLC 881508489.{{cite book}}: CS1 maint: location missing publisher (link
    )
  9. OCLC 813301028.{{cite book}}: CS1 maint: location missing publisher (link
    )
  10. OCLC 920806541.{{cite book}}: CS1 maint: location missing publisher (link
    )
  11. ^ "Elbow and Forearm". Kenhub. Retrieved 2019-09-14.
  12. ISBN 1-85986-059-1
    .
  13. ^ "How To Draw Blood Like A Pro: Step-By-Step Guide". nurse.org. Retrieved 2019-09-14.
  14. ^ "Arm". The Lecturio Medical Concept Library. 3 November 2020. Retrieved 2021-06-22.
  15. ^ Arm at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
  16. PMID 20495602
    .
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