Subclavius muscle
Encyclopedia
The Subclavius is a small triangular muscle, placed between the clavicle
and the first rib
.
Along with the pectoralis major and pectoralis minor muscles, the subclavius muscle makes up the anterior wall of the axilla.
.
The fleshy fibers proceed obliquely superolaterally, to be inserted into the groove on the under surface of the clavicle between the costoclavicular and conoid ligament
s.
, carrying it downward and forward. It draws the clavicle inferiorly as well as anteriorly.
The Subclavius protects the underlying brachial plexus
and subclavian vessels from a broken clavicle
- the most frequently broken long bone
.
to clavicle between Pectoralis major and coracoclavicular fascia.
Clavicle
In human anatomy, the clavicle or collar bone is a long bone of short length that serves as a strut between the scapula and the sternum. It is the only long bone in body that lies horizontally...
and the first rib
First rib
The first rib is the most curved and usually the shortest of all the ribs; it is broad and flat, its surfaces looking upward and downward, and its borders inward and outward....
.
Along with the pectoralis major and pectoralis minor muscles, the subclavius muscle makes up the anterior wall of the axilla.
Origin and insertion
It arises by a short, thick tendon from the first rib and its cartilage at their junction, in front of the costoclavicular ligamentCostoclavicular ligament
The costoclavicular ligament , is the anatomical name of a ligament that is short, flat, strong, and rhomboid in form....
.
The fleshy fibers proceed obliquely superolaterally, to be inserted into the groove on the under surface of the clavicle between the costoclavicular and conoid ligament
Conoid ligament
The Conoid Ligament, the posterior and medial fasciculus, is a dense band of fibers, conical in form, with its base directed upward.It is attached by its apex to a rough impression at the base of the coracoid process, medial to the trapezoid ligament; above, by its expanded base, to the coracoid...
s.
Action
The Subclavius depresses the shoulderShoulder
The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...
, carrying it downward and forward. It draws the clavicle inferiorly as well as anteriorly.
The Subclavius protects the underlying brachial plexus
Brachial plexus
The brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four cervical and first thoracic nerve roots...
and subclavian vessels from a broken clavicle
Clavicle
In human anatomy, the clavicle or collar bone is a long bone of short length that serves as a strut between the scapula and the sternum. It is the only long bone in body that lies horizontally...
- the most frequently broken long bone
Long bone
The long bones are those that are longer than they are wide. They are one of five types of bones: long, short, flat, irregular and sesamoid. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities and they are crucial for skeletal mobility. They grow...
.
Variations
Insertion into coracoid process instead of clavicle or into both clavicle and coracoid process. Sternoscapular fasciculus to the upper border of scapula. Sternoclavicularis from manubriumManubrium
The manubrium or manubrium sterni is the broad, upper part of the sternum. Located ventrally with a quadrangular shape, wider superiorly and narrower inferiorly, it articulates with the clavicles and the first two ribs.-Borders:The superior border is the thickest and presents at its center the...
to clavicle between Pectoralis major and coracoclavicular fascia.