Within anatomy, the arm is a upper limb of a biped mammalian, specifically the section between the shoulder and the elbow. Arm can besides refer to any correspondent structure, like one of the opposite forelimbs of a quadruped, or even any muscular hydrostat similar to a tentacle, as seen in a bit of cephalopods, such as octopuses.

A term arm likewise refers to the entire upper limb in an organism. Anatomically, a section between a elbow and wrist is properly called a forearm.

Around primates a arms come richly adapted for each climbing & for other skilled, manipulative tasks. a ball & socket shoulder joint allow movement of the arms within a wide compass plane, patch the presence of ii forearm bones which potty rotate in every more allows for extra range of motion at this level.

Anatomy of the human arm

A person arm contains bones, joints, muscles, nerves & blood vessels. Numbers of one muscles come utilized for everyday tasks. There are clinical utilizes for the arm, including venepuncture and peripheral venous cannulation in the cubital fossa.

Bony structure and joints
A humerus is the (upper) arm bone. It articulates by using a scapula above at the glenohumeral joint (shoulder) and by having a ulna and radius below as a elbow joint.

Shoulder joint
A shoulder is a ball-&-socket joint between the proximal prevent of the humerus and the clavicle and scapula.

Elbow joint
A elbow joint is a hinge joint between a distal prevent of the humerus & the proximal terminates of the radius & elbow bone.

Osteofascial compartments
the arm is divided by a fascial layer (knownn as lateral & medical intermuscular septa) separating the muscles into an front tooth & tail osteofascial compartments. A facia merges by using a periosteum (outer bone layer) of the humerus. A compartments contains muscles which are then innervated per equivalent nerve & perform a equivalent action.

A prior compartment is referred to as a "flexor compartment" when flexion is its main action. A muscles contained in this come: Biceps brachii Brachialis Coracobrachialis

It is a lot supplied per musculocutaneous nerve, which has nervous origins of C5,C6,C7 (watch brachial plexus).

the deltoid muscle is considered to have a portion of its immune system in the prior compartment. This brobdingnagian muscle is a independent adductor muscle of the upper limb & extends all over the shoulder. the brachioradialis muscle originates in a arm but inserts into the forearm. This muscle is responsible supination.

A tail compartment contains muscles which are then tons supplied per radial nerve. This compartment is also referred to as a "extensor compartment", extension existence its independent action. Muscles of this compartment come: Triceps brachii, a brobdingnagian muscle which contains iii heads, a lateral pass, medial & middle. Anconeus, a diminutive muscle which a bit of embryologists indicate can be a 4th head of the triceps brachii muscle. This muscle stabilizes a elbow joint when you took movements. When a upper & moo limbs use similar embryological origins & a moo limb contains a quadriceps femoris muscle (the moo limb same of the triceps), which has quaternion heads, this would seem to add up.

Cubital fossa
This significant region is clinically crucial for venepuncture & for blood pressure mensuration. These are an fanciful triangle by owning borders existence: Laterally, a medial border of brachioradialis muscle. Medially, a lateral border of pronator teres muscle. Superiorly, a intercondylar line, an imaginary line between them condyles of the humerus The floor is the brachialis muscle The roof is the skin and fascia of the arm and forearm

A structures which pass through the cubital fossa come vital. A a correct sequence from either either which it pass into the forearm come when follows, from medial to lateral pass: Median nerve, which starts to branch Brachial artery Tendon of the biceps brachii muscle Radial nerve Median cubital vein - this important vein is in which venepuncture occurs. It connects a basilic and cephalic veins. lymph nodes

Nervous supply
A musculocutaneous nerve, root value C5,C6,C7 is the main provider of muscles of the 'prior compartment. It originates from either a lateral cord of the brachial plexus of nerves. It pierces a coracobrachialis muscle and gives off branches to the muscle, also when to brachialis and biceps brachii. It ends when a anterior cutaneous nerve of the forearm.

A radial nerve, root value C5-T1, originates as a continuation of the tail cord of the brachial plexus. This nerve enters a lower triangular space (an imaginary space bounded by, amongst others, a shaft of a humerus & the triceps muscle) of the arm & lies deep to the triceps muscle. On this button it travels by owning a profunda brachii artery (deep artery of the arm), lying on the radial groove of the humerus. This fact is very crucial clinically, as a fracture of a bone at the shaft of the bone on this text could drive lesions or even transections in the nerve.

More nerves passing across springiness there are no supply to the arm. These include: The median nerve, nerve origin C5-T1, which is a branch of the lateral & medial cords of the brachial plexus. This nerve continues around a arm, travelling in the plane between the biceps & triceps muscles. At a cubital fossa, this nerve is deep to the pronator teres muscle and is the virtually all medial structure in the fossa. A nerve lives into a forearm. The ulnar nerve, origin C8-T1, is a continuation of the medial cord of the brachial plexus. This nerve lives in a equivalent plane when the median nerve, between the biceps & triceps muscles. At a elbow, this nerve travels tail to the medial epicondyle of the humerus. This means that condylar fractures can stimulate lesion to this nerve.

Blood supply and venous drainage
A independent artery in the arm is the brachial artery. This artery occurs as continuation of the axillary artery. A point at which a axillary becomes a brachial is distal to the moo border of musculus teres major. A brachial artery gives off an important brach, a profunda brachii (deep artery of the arm). This branching occurs upright following a moo border of teres major muscle.

A brachial artery continues to the cubital fossa in the anterior compartment of the arm. It travels inside a plane between a biceps & triceps muscles, a equivalent when the median nerve and basilic vein. These are accompanied by venae comitantes (accompanying veins). It gives branches to the muscles of the prior compartment. A artery is around between a median nerve and the tendon of the biceps muscle in the cubital fossa. It so continues into a forearm.

A profunda brachii travels through the lower triangular space with the radial nerve. From either on text forwards it has an intimate relationship by using a musculospiral nerve. It is two witnessed deep to the triceps muscle & come placed on the turbinate groove of the humerus. So fracture of the bone may not sole lead to lesion of the radial nerve, but as well haematoma of the internal structures of the arm. A artery so continues in to anastamose with the recurrent radial branch of the brachial artery, providing a diffused blood supply for the elbow joint.

A veins of a arm carry blood from either a extremities of the limb, besides when drain the arm itself. Them independent veins come a basilic and the cephalic veins. There is a copulative vein between them, a median cubital vein, which passes through the cubital fossa and is clinically important for venepuncture (withdrawing blood).

A basilic travels on a medial side of the arm & ends at the level of the Seventh rib.

A cephalic travels on a lateral side of the arm & ends when the axillary vein. It lives through a deltopectoral traingle, a space between the deltoid muscle & the pectoralis major muscles.