The fascial compartments of arm refers to the specific anatomical term of the compartments within the upper segment of the

upper limb The upper limbs or upper extremities are the forelimbs of an upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digits, including all the musculatures and ligaments involved with the shou ...

(the arm) of the body. The upper limb is divided into two segments, the arm and the

forearm The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...

. Each of these segments is further divided into two compartments which are formed by

deep fascia Deep fascia (or investing fascia) is a fascia, a layer of dense connective tissue that can surround individual muscles and groups of muscles to separate into fascial compartments. This fibrous connective tissue interpenetrates and surrounds the ...

– tough

connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...

septa (walls). Each compartment encloses specific muscles and nerves. The compartments of the arm are the anterior compartment of the arm and the posterior compartment of the arm, divided by the lateral and the medial intermuscular septa. The compartments of the forearm are the anterior compartment of the forearm and posterior compartment of the forearm.

Intermuscular septa

The lateral intermuscular septum extends from the lower part of the crest of the greater tubercle of the

humerus The humerus (; ) 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 r ...

, along the

lateral supracondylar ridge The lateral supracondylar ridge is a prominent, rough margin on the lower part of the lateral border of the humerus. It presents an anterior lip for the origin of forearm extensors, including the brachioradialis muscle above, and the extensor car ...

, to the lateral epicondyle; it is blended with the tendon of the

deltoid muscle The deltoid muscle is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle appears to be made up o ...

, gives attachment to the

triceps brachii The triceps, or triceps brachii (Latin for "three-headed muscle of the arm"), is a large muscle on the back of the upper limb of many vertebrates. It consists of 3 parts: the medial, lateral, and long head. It is the muscle principally respon ...

behind, and to the

brachialis The brachialis (brachialis anticus), also known as the Teichmann muscle, is a muscle in the upper arm that flexes the elbow. It lies deeper than the biceps brachii, and makes up part of the floor of the region known as the cubital fossa (elbow ...

brachioradialis The brachioradialis is a muscle of the forearm that flexes the forearm at the elbow. It is also capable of both pronation and supination, depending on the position of the forearm. It is attached to the distal styloid process of the radius by way ...

, and

extensor carpi radialis longus A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each ...

muscles in front. It is perforated by the

radial nerve The radial nerve is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial comp ...

and profunda branch of the

brachial artery The brachial artery is the major blood vessel of the (upper) arm. It is the continuation of the axillary artery beyond the lower margin of teres major muscle. It continues down the ventral surface of the arm until it reaches the cubital foss ...

. The medial intermuscular septum, is thicker than the lateral intermuscular septum. It extends from the lower part of the crest of the lesser tubercle of the humerus below the teres major, and passes along the

medial supracondylar ridge The inferior third of the medial border of the humerus is raised into a slight ridge, the medial supracondylar ridge (or medial supracondylar line), which becomes very prominent below; it presents an anterior lip for the origins of the Brachiali ...

to the medial epicondyle; it is blended with the tendon of the coracobrachialis, and gives attachment to the

behind and the

in front. It is perforated by the

ulnar nerve In human anatomy, the ulnar nerve is a nerve that runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is ...

, the superior ulnar collateral artery, and the posterior branch of the inferior ulnar collateral artery.

Anterior compartment

The anterior compartment of the arm is also known as the ''flexor compartment'' of the arm as its main action is that of flexion. The anterior compartment is one of the two anatomic compartments of the upper arm, the other being the posterior compartment. The compartment contains three muscles; the

biceps brachii The biceps or biceps brachii ( la, musculus biceps brachii, "two-headed muscle of the arm") is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join ...

, the

and the coracobrachialis. These muscles are all innervated by the musculocutaneous nerve which arises from the fifth and sixth and seventh cervical spinal nerves. The blood supply is from the

Posterior compartment

The posterior compartment of the arm is also known as the "extensor compartment", as its main action is

extension Extension, extend or extended may refer to: Mathematics Logic or set theory * Axiom of extensionality * Extensible cardinal * Extension (model theory) * Extension (predicate logic), the set of tuples of values that satisfy the predicate * Ext ...

. The muscles of this compartment are the

and anconeus muscle and these are innervated by the

. Their blood supply is from the profunda brachii. The ''triceps brachii'' is a large muscle containing three heads a lateral, medial, and middle. The ''anconeus'' is a small muscle that stabilizes the elbow joint during movement. Some embryologists consider it as the fourth head of the triceps brachia as the upper and lower limbs have similar embryological origins, and the lower limb contains the quadriceps femoris muscle which has four heads, and is the lower limb equivalent of the triceps.

References

External links

* *
elbow/muscles/muscles2
at the Dartmouth Medical School's Department of Anatomy
Dissection at tufts.edu
* https://web.archive.org/web/20080103065905/http://anatomy.med.umich.edu/musculoskeletal_system/axilla_ans.html {{Authority control Muscles of the upper limb

Intermuscular septa

Anterior compartment

Posterior compartment

See also

References

External links