Pectoralis major muscle

Pectoralis major muscle
Pectoralis major
origin
Clavicle , sternum , cartilage of the second to sixth ribs
approach
Humerus ( crista tuberculi majoris humeri )
function
Adduction , advancement, and inward rotation of the arm
Innervation
Nervi pectorales lateralis et medialis
Spinal segments
C5-Th1

Activation and protection of the pectoralis major muscle by an apparatus gymnast with the aid of talc .

The pectoralis major muscle ( Latin for "larger pectoral muscle"), German front pectoral muscle or large pectoral muscle , is a skeletal muscle and covers the entire front rib area.

The fibers of the pectoralis major muscle intersect on the arm: the fibers that come from far below start higher up on the upper arm than the fibers that come from the collarbone . This creates an arch that forms the anterior border of the armpit . The pectoralis major muscle covers the small chest muscle ( pectoralis minor muscle ). The chest fascia lies on the outside , separating it from the superficial layer of the chest wall.

The pectoralis major consists of three parts:

• Pars clavicularis (clavicle part)
• Pars sternocostalis (sternum-rib part)
• Pars abdominalis (abdominal part)

function

The pectoralis major muscle pulls the arm towards the body ( adduction ), turns it inward ( internal rotation ) and pulls it forward ( anteversion ). It also belongs to the auxiliary breathing muscles . However, depending on the position of the upper arm, the pectoralis changes its function. He returns the arm from an anteversion position (retroversion)

Innervation

The pectoralis major muscle is innervated by the lateral pectoral nerve and the medial pectoral nerve.

Varieties

Primarily there may be adhesions with the latissimus dorsi or the deltoideus muscle , then a clear optical separation of these muscles is hardly possible. These adhesions are not uncommon; they occur in about 7% of all people.

The pectoralis major muscle can also be completely absent on one side. This defect is known as Poland syndrome .

literature

• Walther Graumann, Dieter Sasse: Compact: Textbook Anatomy . tape 2 : musculoskeletal system . Schattauer Verlag, Stuttgart 2004, ISBN 978-3-7945-1944-6 , pp. 271-272 .
• H. Ferner, J. Staubesand: Sobotta. Atlas of Human Anatomy. 18th edition. Urban & Schwarzenberg, 1982, ISBN 3-541-02828-9

Web links

Commons : pectoralis major muscle  - collection of images, videos and audio files

Individual evidence

1. ↑ Waschke, Böckers, Paulsen: Anatomie Das Lehrbuch (Sobotta) . 1st edition. Urban & Fischer Verlag, Munich 2015, ISBN 978-3-437-44080-9 , pp. 155 .