Pectoral fascia
Encyclopedia
The pectoral fascia is a thin lamina, covering the surface of the Pectoralis major, and sending numerous prolongations between its fasciculi
: it is attached, in the middle line, to the front of the sternum; above, to the clavicle
; laterally and below it is continuous with the fascia of the shoulder
, axilla, and thorax
.
It is very thin over the upper part of the Pectoralis major, but thicker in the interval between it and the Latissimus dorsi, where it closes in the axillary space
and forms the axillary fascia; it divides at the lateral margin of the Latissimus dorsi into two layers, one of which passes in front of, and the other behind it; these proceed as far as the spinous processes of the thoracic vertebræ, to which they are attached.
As the fascia leaves the lower edge of the Pectoralis major to cross the floor of the axilla it sends a layer upward under cover of the muscle; this lamina splits to envelop the Pectoralis minor, at the upper edge of which it is continuous with the coracoclavicular fascia.
The hollow of the armpit, seen when the arm is abducted, is produced mainly by the traction of this fascia on the axillary floor, and hence the lamina is sometimes named the suspensory ligament of the axilla.
At the lower part of the thoracic region the deep fascia is well-developed, and is continuous with the fibrous sheaths of the Recti abdominis.
Muscle fascicle
In anatomy, a fascicle is a bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue.Specialized muscle fibers in the heart that transmit electrical impulses from the Atrioventricular Node to the Purkinje Fibers are fascicles, also referred to as bundle branches...
: it is attached, in the middle line, to the front of the sternum; above, to the 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...
; laterally and below it is continuous with the fascia of the shoulder
Shoulder
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...
, axilla, and thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
.
It is very thin over the upper part of the Pectoralis major, but thicker in the interval between it and the Latissimus dorsi, where it closes in the axillary space
Axillary space
The axillary space is an anatomic space, bounded by teres major muscle, teres minor muscle and humerus. Furthermore, it is split into two parts, the lateral and medial, by the long head of triceps brachii muscle.-Medial axillary space:...
and forms the axillary fascia; it divides at the lateral margin of the Latissimus dorsi into two layers, one of which passes in front of, and the other behind it; these proceed as far as the spinous processes of the thoracic vertebræ, to which they are attached.
As the fascia leaves the lower edge of the Pectoralis major to cross the floor of the axilla it sends a layer upward under cover of the muscle; this lamina splits to envelop the Pectoralis minor, at the upper edge of which it is continuous with the coracoclavicular fascia.
The hollow of the armpit, seen when the arm is abducted, is produced mainly by the traction of this fascia on the axillary floor, and hence the lamina is sometimes named the suspensory ligament of the axilla.
At the lower part of the thoracic region the deep fascia is well-developed, and is continuous with the fibrous sheaths of the Recti abdominis.