The pectoral fascia is a thin lamina, covering the surface of the

pectoralis major The pectoralis major () is a thick, fan-shaped or triangular convergent muscle, situated at the chest of the human body. It makes up the bulk of the chest muscles and lies under the breast. Beneath the pectoralis major is the pectoralis minor, a ...

, and sending numerous prolongations between its

fasciculi Fascicle or ''fasciculus'' may refer to: Anatomy and histology * Muscle fascicle, a bundle of skeletal muscle fibers * Nerve fascicle, a bundle of axons (nerve fibers) ** Superior longitudinal fasciculus *** Arcuate fasciculus ** Gracile fas ...

: it is attached, in the middle line, to the front of the

sternum The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sh ...

; above, to the

clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the rig ...

; laterally and below it is continuous with the fascia of the

shoulder The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...

axilla The axilla (also, armpit, underarm or oxter) is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm and the thoracic cage, bounded superior ...

, and

thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...

. It is very thin over the upper part of the pectoralis major, but thicker in the interval between it and the

latissimus dorsi The latissimus dorsi () is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline. The word latissimus dorsi (plural: ''latissimi dorsorum'') comes from L ...

, where it closes in the

axillary space The axillary spaces are anatomic spaces. through which axillary contents leave the axilla. They consist of the quadrangular space, triangular space, and triangular interval. It is bounded by teres major, teres minor, medial border of the humerus, ...

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 vertebrae, 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 Pectoralis minor muscle () is a thin, triangular muscle, situated at the upper part of the chest, beneath the pectoralis major in the human body. Structure Attachments Pectoralis minor muscle arises from the upper margins and outer surfaces ...

, 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

rectus abdominis The rectus abdominis muscle, ( la, straight abdominal) also known as the "abdominal muscle" or simply the "abs", is a paired straight muscle. It is a paired muscle, separated by a midline band of connective tissue called the linea alba. It exte ...

References

External links

* - "Pectoral Region: Reflect Pectoralis Major Muscle" {{Authority control Fascia