Pectoral Region Anatomy PDF

Pectoral region The region of the chest demarcated by the outline of the pectoralis major muscle; includes mammillary, and inframammary regions. It is formed from superficial to deep as follow: 1. Skin 2. Superficial fascia , containing the well developed mammary gland in female...

Pectoral region The region of the chest demarcated by the outline of the pectoralis major muscle; includes mammillary, and inframammary regions. It is formed from superficial to deep as follow: 1. Skin 2. Superficial fascia , containing the well developed mammary gland in female 3. Deep fascia ; Pectoral fascia 4. Pectoralis major muscle 5. Subclavius muscle , clavipectoral fascia and muscle. Muscle Origin Insertion Innervation Action Pectoralis major Clavicular head – anterior Lateral lip of inter- Medial and lateral Whole muscle: surface of medial half of tubercular groove of pectoral nerves. adduction, and medial clavicle; humerus by bilaminar rotation of arm. Sternocostal head : tendon. (The anterior lamina is Clavicular head: -anterior surface of sternum; formed by the clavicular head;the flex arm posterior is formed by sternocostal -upper six costal cartilages head) Pectoralis minor Outer surfaces of 3-5 ribs near Coracoid process of Medial and lateral -Pulls scapula downward to their costal cartilage. scapula (medial border pectoral. -Protracts scapula and upper surface) - Helps deep inspiration (Insertion pull on the ribs). Subclavius Upper surface of first costo- Groove on inferior surface Nerve to -Prevents excessive chondral of middle one-third of subclavius (C5, movements of clavicle junction clavicle C6) Serratus anterior 8 digitations from outer Anterior surface of medial Long thoracic -Powerful protraction of the surfaces of upper 8 ribs border of scapula. nerve (C5, C6, scapula; midway between the angle *1st digitations run C7). -Rotation of the scapula and their costal cartilage. horizontal to end at upper (Nerve of Bell). upward to put the arm on the - Each digitation arises from angle. head. the corresponding *2nd&3rd digitations fan -Keeps medial border of -The first one arises out to insert in whole scapula closed to thoracic also from 2nd rib. length of medial border. wall *Lower 5 digitations (paralysis leads to winging converge to insert at of scapula) inferior angle. -Helps deep inspiration Serratus anterior muscle  CLAVIPECTORAL FASCIA * It is a thickened part of deep fascia which occupies the interval between the pectoralis minor and clavicle, and encloses the subdavius muscle. It is covered by the clavicular head of pectoralis major. * This fascia is pierced by the following 4 structures: I.Cephalic vein. 2. Thoraco-acromial artery. 3. Lateral pectoral nerve. 4. Lymphatics.from infraclavicular lymph nodes to the apical lymph nodes. Below: it splits to enclose pectoralis minor. (NB. From the lower border of this muscle the fascia that covers it is continues downwards as suspensory ligament of the axilla to join the axillary fascia (n the floor of the axilla. The fascia from the clavicle to the floor of axilla is called axillary septum)  Shoulder region Muscle Origin Insertion Innervation Action Deltoid Anterior fibers: Deltoid tuberosity at Axillary nerve (C5, 6) Anterior fibers: Forms rounded anterior border of lateral middle of lateral surface Flexion & medial rotation contour of shoulder 1/3 of clavicle of humerus Middle fibers: Middle fibers: Abduction of arm from lateral border of acromial 15-90 process Posterior fibers: Posterior fibers: Extension & lateral rota lower lip of the crest of Tion spine of scapula Supraspinatus Medial 2/3 of the supraspinous Highest impression on the Suprascapular nerve (C5, -Stability of shoulder joint; fossa of the scapula greater tuberosity of the C6) -Initiation of abduction of humerus arm to 15o at shoulder joint Infraspinatus Medial 2/3 of the infra-spinous Middle impression on Suprascapular nerve (C5, -Stability of shoulder joint fossa of the scapula posterior surface of the C6) - Lateral rotation of arm. greater tuberosity of the humerus Teres minor Upper 2/3 of posterior surface Inferior impression on the Axillary nerve (C5, 6) -Stability of shoulder joint of the the lateral border of the posterior surface of the -Adduction and lateral scapula greater tuberosity of the rotation of arm humerus. Teres major Lower 1/3 of posterior surface Medial lip of the biciptal Lower subscapular nerve -Stability of shoulder joint of the lateral border of scapula. groove. (C5 ,C6) -Medial rotation ,adduction and extension of the arm-. Subscapularis Medial 2/3 of subscapular fossa Lesser tuberosity of Upper and lower -Stability of shoulder joint. humerus subscapular nerves (C5, -Adduction;& medial C6) rotation of the arm. Deltoid muscle Teres major  Muscles of the back 1. Superficial layer : trapezius and latissimus dorsi 2. Deep layer: levator scapulae , rhomboids minor and rhomboids major Muscle Origin Insertion Nerve supply Action Trapezius Skull: Upper fibers: Motor: Upper fibers elevates tip of External occipital Back of lateral one-third of Spinal root of shoulder protuberance & medial 1/3 of clavicle. accessory nerve (XI). Middle fibers superior nuchal line. Middle fibers: Sensory Retraction of scapula. Medial border of acromion (Proprioception): Lower fibers depress Neck: process & upper lip of crest C3 and C4 scapula & with the upper Ligamentum nuchae & spine of spine of scapula fibers assist in rotating the of C 7. Lower fibers: scapula upward during Thorax : Tubercle of crest of spine abduction from90 -180 All thoracic spines and of scapula supraspinous ligament. Latissimus dorsi *Posterior 1/ 3 of outer lip Floor of bicipital groove. Thoracodorsal nerve -Adduction, medial of iliac crest NB. It tendon has triple (C6, C7, 8) rotation, and extension of *Thoracolumbar fascia relation with teres major; the arm *Spine of lower six behind then below then in -Deep expiration. thoracic vertebrae front. -Helps climbing with * Lower 3-4 ribs and pectoralis major by acting *Back of inferior angle of from insertion scapula. Levator scapulae Transverse processes of C 1 Dorsal surface of medial C3 to C4 and dorsal -Elevates scapula with to C 4 border of scapula between scapular nerve (C5) upper fibers of trapezius. spine and superior angle -Rotates scapula downward Rhomboid minor Lower portion of ligamentum Dorsal surface of medial Dorsal scapular nerve Retracts with middle nuchae, spinous processes of border of scapula at the (C5) fibers of trapezius. C7 and T1 root of spine of scapula Rotates scapula downward Rhomboid major Spinous processes of T 2 to T Dorsal surface of medial Dorsal scapular nerve -like minor 5. border of scapula between (C5) spine and inferior angle  Quadrangular and Triangular Spaces They are inter-muscular spaces lying just below the shoulder joint. A. Quadrangular space (laterally) : - Boundaries: Above: by the teres minor (seen from behind), the subscapularis (seen from in front) and the capsule of the shoulder joint. Below: by teres major. Medially: by long head of triceps. Laterally: by surgical neck of humerus. - Contents: Posterior circumflex humeral vessels. Axillary (circumflex) nerve. B. Upper triangular space (medially) : - Boundaries: Above: by teres minor (seen from behind) and subscapularis (seen from in front). Below: by teres major. Laterally: by long head of triceps. - Contents: it transmits only the circumflex scapular artery. C. Lower triangular space (triangular interval) : - Boundaries: Above by: teres major. Medially by: long head of triceps. Laterally by: lateral head of triceps and the shaft of humerus. - Contents: radial nerve and profunda brachii vessels.