Pectoral Region Anatomy 2024 PDF

Hanan Mohammed Tarabeh Lecturer of Anatomy & Human Embryology Faculty of Medicine, Helwan University Objectives Definition. Boundaries. Layers of pectoral region Muscles of pectoral region. Fasciae of pectoral region.  Vertical Lines of the body 1)-Midline:- line passing through median sa...

Hanan Mohammed Tarabeh Lecturer of Anatomy & Human Embryology Faculty of Medicine, Helwan University Objectives Definition. Boundaries. Layers of pectoral region Muscles of pectoral region. Fasciae of pectoral region.  Vertical Lines of the body 1)-Midline:- line passing through median sagittal plane of the body. 2)-Para-sternal line:- line passing through lateral margin of the sternum. 3)-Mid-clavicular line:- line passing through the middle of the clavicle. 4)-Anterior axillary line:- line passing through anterior axillary fold. 5)-Mid-axillary line:- line passing in the middle of the axilla. 6)-Posterior axillary line:- line passing through posterior axillary fold. Vertical Lines of the body  Definition The pectoral region includes the structures present on the front of the upper part of chest (anterior thoracic wall). Boundaries 1) Above : clavicle. 2) Below : 6th rib. 3) Medially : Midline. 4) Laterally : Mid-axillary line. Layers of the pectoral region S. 1 P. Mn. 2 P. Mj. 3 1. Skin. 2. Fascia:- 1) Superficial fascia. 2) Deep fascia (pectoral fascia). 3) Clavipectoral fascia. 3. Muscles: (pectoral muscles) 1) Superficial layer:-Pectoralis major. 2) Deep layer:- 1. Above:- Subclavius. 2. Below:- Pectoralis minor.  Muscles of the pectoral region Each pectoral region contains: 1.the pectoralis major. 2.pectoralis minor. 3.subclavius muscles. All originate from the anterior thoracic wall and insert into bones of the upper limb.  (1)-Pectoralis major Origin: 1- clavicular head anterior surface of medial half of clavicle 2- sternocostal head from anterior surface of sternum; first seven costal cartilages; aponeurosis of external oblique. Insertion : Lateral lip of Intertubercular sulcus (bicipital groove) of humerus Nerve supply (N.S): Medial and Lateral Pectoral nerves  ACTION 1-Adduction Of the arm 2-Flexion of arm 3-Medial rotation of arm. 4-Accessory muscle of inspiration [by drawing the ribs outwards towards humerus].  (2)-Pectoralis minor Origin : Anterior surfaces and superior borders of ribs III to V; and from deep fascia overlying the related intercostal spaces. Insertion : Coracoid process of scapula (medial border and upper surface) N.S: Medial pectoral nerve  ACTION 1Protraction of scapula:- pulls scapula downwards & forwards. 2Depresses shoulder. [as it pulls coracoid process downward] 3Accessory muscle of inspiration [with scapula fixed, pulls ribs upwards] (3)-Subclavius Origin : First rib at junction between rib and costal cartilage (costochondral joint). Insertion : Groove on inferior surface of middle one third of Clavicle (subclavius groove). N.S : Nerve to subclavius  ACTION Steadies the clavicle during movements of shoulder girdle. Protects the great vessels & nerves from the bone (Acts as a cushion). Fasciae of pectoral region. 1) SUPERFICIAL FASCIA It encloses:- 1. mammary glands (breast). 2. Platysma. 3. Cutaneous nerves. CLAVIPECTORAL FASCIA 1) DEFINITION:A strong fibrous sheet lies deep to clavicular head of pectoralis major. 2) SITE: Extends from pectoralis minor (below) to clavicle (above) where it splits to enclose subclavius 3) ATTACHMENT Its upper border, along lower border of subclavius, thickened to form costo-coracoid ligament that extends from anterior end of 1st rib medially to coracoid process laterally. Superiorly (bone):- *It splits to enclose the subclavius muscle. *It is attached to clavicle. Inferiorly (soft tissue):- *It splits to enclose the pectoralis minor. *It continues downward as the suspensory ligament of the axilla & joins the floor of axilla. CLAVIPECTORAL FASCIA 4)STRUCTURES PIERCING CLAVI-PECTORAL FASCIA (CALL) =VEIN:- Cephalic vein terminates in axillary vein. =ARTERY:- Acromiothoracic artery branch from axillary artery. =NERVE:- Lateral pectoral nerve From lateral cord of brachial plexus. =LYMPHATIC VESSELS:- into infra-clavicular lymph nodes (L.N). STRUCTURES PIERCING CLAVI-PECTORAL FASCIA  MCQ What is the innervation of pectoralis major? Medial and lateral pectoral nerves Intercostal nerves Long thoracic nerve Thoracodorsal nerve The pectoralis major is comprised of two heads: clavicular and sternocostal. Which of the following movements is specifically carried out by the clavicular head? Scapular rotation Shoulder abduction Shoulder flexion Lateral rotation of upper limb Where on the scapula does pectoralis minor attach? Acromion Glenoid fossa Subscapular fossa Coracoid process