Lesson-10-11 (Anatomy of Pectoral Region).pdf

Anatomy of Pectoral Region Anterior Aspect of Arm Shoulder Joint Mammary Glands Pectoral Region Muscles Pectoralis Major O: Sternal → sternum + 2-6 ribs Clavicular → sternal half of clavicle I: Greater crest inner side F: Adduction, Medial rotation, Flexion N: Medial, lateral pectoral nerve Pectoral...

Anatomy of Pectoral Region Anterior Aspect of Arm Shoulder Joint Mammary Glands Pectoral Region Muscles Pectoralis Major O: Sternal → sternum + 2-6 ribs Clavicular → sternal half of clavicle I: Greater crest inner side F: Adduction, Medial rotation, Flexion N: Medial, lateral pectoral nerve Pectoralis major -Pulls the trunk upwards while climbing -Primary flexor of the arm -Anteversion: Touching to the opposite shoulder -Hugging. Differences between the pectoralis major & latissimus dorsi  Pectoralis Major: pulls anteriorly (Flexion to shoulder)  Latissimus Dorsi: pulls posteriorly (Extension to shoulder) Innervation of the Pectoralis Major Pectoralis Minor O: 3rd-5th ribs I: Coracoid process F: Pulls the scapula antero-inferiorly N: medial pectoral M. pectoralis minor -Inserts to coracoid process -Approaching to a distant object -Rotates glenoid cavity downwards Anatomical relations of Pectoralis Minor Functions of Pectoralis Minor ❑Synergistic muscles : ▪ rhomboid major ▪ rhomboid minor ▪ levator scapula Clavipectoral (Deltoidepectoral) Triangle – Infraclavicular Fossa superiorly: 1/3 of the clavicula medially: pectoralis major laterally: deltoid Clavipectoral Fascia -Lateral pectoral n -Thoracoacromial a -Cephalic v -Efferent lympathetic vessels PIERCE THE CLAVIPECTORAL FASCIA Subclavius Muscle O: 1st rib I: clavicle F: pulls the clavicle inferiorly N: nerve to subclavius Serratus Anterior serratus – serrated, toothed like a saw Serratus anterior -Hyperabduction of the arm -Boxers’ muscle - Punch -Protracts scapula (Sticks scapula towards the thoracic cage) Serratus anterior -Innervated by long thoracic nerve -Long thoracic nerve injury results in Winged scapula -Hyperabduction of arm Serratus Anterior Muscle MUSCLES OF THE ARM-ANTERIOR REGION Biceps brachii Origin: -Long head: supraglenoid tubercle -Short head: coracoid process Insertion: radial tuberosity, bicipital aponeurosis bicipital aponeurosis descensd on the medial aspect of arm fuses with the deep fascia of forearm Anatomical relations of Bicipital aponeurosis median cubital v. brachial a. & median n Long head of Biceps Brachii Coracobrachialis O: coracoid process I: medial surface of the humerus F: Flexion & adduction of arm When you stick an object in between your arm & body N: Musculocutaneus n Coracobrachialis Musculocutaneous N Anterior Aspect of Arm 1. 2. 3. 4. 5. 6. 7. 8. biceps brachii m brachialis m coracobrachialis m musculocutaneous n median n ulnar n brachial a deep veins of arm Brachialis Muscle O: anterior surface of the humerus I: ulnar tuberosity F: arm is fixed, flexes the forearm; forearm is fixed, flexes the arm main flexor muscle of the arm Clinical Note  If the musculocutaneus nerve is damaged→ flexion of the forearm is not fully lost  The brachioradialis muscle innervated by the radial nerve flexes the forearm Coracoid process –related muscles Muscles pectoralis coracobrachialis short head attached to minor of biceps the coracoid brachii process Coracoid process is a landmark for the brachial plexus anesthesia Arteries of the Upper Extremity      Subclavian Axillary Brachial - Radial -Ulnar Course of the Brachial a.  In the arm: descends laterally  At the upper half of arm: median n. lies lateral to the brachial a.  At the lower half of the arm: crosses the brachial a. anteriorly. From here median n. descends medial to the brachial a. Course of the Brachial a. Near the cubital fossa: medial to the tendon of biceps brachii m At the neck of the radius: → radial & ulnar aa. Terminal branches of Brachial a. ulnar a. radial a. Branches of Brachial a.  profunda brachii a. (deep brachial a.)  superior ulnar collateral a.  inferior ulnar collateral a. Profunda brachii a.  At the inferior border of teres major  thickest branch  descend in the radial groove  branches of brachial a. provide the collateral circulation of forearm & hand Glenohumeral Joint (Shoulder Joint) Between the head of humerus and glenoid cavity of scapula Joint surfaces covered with hyaline cartilage Spheroid type synovial joint Has a fibrous capsule Has a Glenoid labrum Glenohumeral Joint (Shoulder Joint)  Multiaxial ball and socket type of synovial joint  Hyaline cartilages covers the articular surfaces  Glenoid labrum: fibrocartilagenous structure Glenohumeral Joint (Shoulder Joint) Glenohumeral Joint (Shoulder Joint) Glenohumeral Joint (Shoulder Joint)  Fibrous articular capsule: neck of the humerus, glenoid cavity Glenohumeral Joint (Shoulder Joint)  Two apertures in the articular capsule: ❑the opening between the tubercles for the biceps brachii ❑inferior to the coracoid process. It allows the communication between the subscapular bursa & synovial cavity Glenohumeral Joint (Shoulder Joint)  The synovial membrane lines the fibrous capsule and it is reflected from it onto the glenoid labrum, neck of the humerus & head  Synovial membrane forms the tubular sheath for the tendon of long head of biceps brachii Glenohumeral Joint (Shoulder Joint)  Intrinsic ligaments of the capsule of the joint:  The glenohumeral ligs anterior part of the capsule is thickened to form. The superior, middle & inferior glenohumeral ligs extend from the supraglenoid tubercle to the lesser tubercle & anatomical neck Glenohumeral Joint (Shoulder Joint)  Intrinsic ligaments of the capsule of the joint:  Transverse humeral lig forms the bridge over the superior part of intertubercular groove Glenohumeral Joint (Shoulder Joint)  Intrinsic ligaments of the capsule of the joint:  Coracohumeral ligament: → anatomical neck support the joint superiorly Glenohumeral Joint (Shoulder Joint)  Intrinsic ligaments of the capsule of the joint:  Coracoacromial arch formed by the coracoid process, acromion & coracoacromial lig prevents the displacement of the humeral head superiorly from the glenoid cavity Glenohumeral Joint (Shoulder Joint) Between Acromion and coracoid proc. : Coracoacromial lig. (Prevents superior dislocation of humerus) Glenohumeral Joint (Shoulder Joint) Long head of biceps, courses inside the shoulder joint Bursae of the joint  There are several bursae containing capillary films in the shoulder joint.  Bursae are located where tendons rub againts bone, ligaments, or other tendons and where skins moves over the bony prominence. Bursae of the joint Bursae of the joint  subscapular bursa:  subacromial bursa: between the deltoid m. & supraspinatus tendon. This bursa facilitates movement of the deltoid over the capsul & supraspinatus tendon Dislocations of the Shoulder Joint  Almost 95% of shoulder (glenohumeral joint) dislocations occur in an anterior direction.  Abduction, extension, and lateral (external) rotation of the arm at the shoulder (e.g., the throwing motion) place stress on the capsule and anterior elements of the rotator cuff (subscapularis tendon).  The types of anterior dislocations include the following: Subcoracoid (most common) Subglenoid Subclavicular (rare)  The axillary (most often) and musculocutaneous nerves may be injured during such dislocations. Dislocations of the Shoulder Joint Dislocations of the Shoulder Joint Blood supply & Innervation of the Shoulder Joint  anterior & posterior circumflex humeral arteries from the axillary and suprascapular arteries from the subclavian artery  suprascapular, axillary and lateral pectoral nerves The muscles affecting the shoulder joint  FLEXION 1. pectoralis major (clavicular) 2. coracobrachialis 3. biceps brachii (short head) 4. deltoid (clavicular) The muscles affecting the shoulder joint EXTENSION 1. latissimus dorsi 2. teres major 3. deltoid (spinal) The muscles affecting the shoulder joint ABDUCTION 1. supraspinatus 2. deltoid (acromial) 3. serratus anterior 4. upper part of trapezius The muscles affecting the shoulder joint ADDUCTION 1. pectoralis major 2. latissimus dorsi 3. teres major 4. coracobrachialis 5. subscapularis The muscles affecting the shoulder joint LATERAL ROTATION 1. infraspinatus 2. teres minor 3. deltoid (spinal) The muscles affecting the shoulder joint MEDIAL ROTATION 1. subscapular 2. teres major 3. latissimus dorsi 4. pectoralis major 5. deltoid (clavicular) Glenohumeral Joint (Shoulder Joint) The joint capsule is supported by: Supraspinatus on the superior side Infraspinatus and teres minor on the posterior side Subscapularis on the anterior side These muscles are the rotator cuff muscles Mammary Glands  2nd to 6th ribs  in the superficial fascia derived from the ectoderm  the amount of fat contribute the size of gland  the gland extend toward the axilla as a tail Mammary Glands  The circular area of skin around the nipple is areola  is pink in women  During the first pregnancy the colour changes permanently to the brown Mammary Glands  Nipples are conical process  level of the 4th intercostal space  The tip of the nipple contains opening of the lactiferous ducts Mammary Glands  Each gland consist of 15-20 lobules seperated by fibrous septum  each lobules contains lactiferous duct, which open onto the nipple  before opening they are expanded to form the lactiferous sinus Mammary Glands  between the deep surface of breast & deep fascia there is a space called as retromammary space, containing small amount of fat.  permits the movement Mammary Glands  The mammary gland is firmly attached to the skin of the breast by the suspensory ligs (Cooper’s ligs). Blood Supply of Mammary Gland ❑internal thoracic a. (internal mammary) ❑axillary a. mainly from its lateral thoracic & thoracoacromial branches ❑intercostal arteries Sensory Innervation of the Breast Lympathetic drainage  Most of lympathetics drains into the axillary lymph node (75%) mainly the axillary LN. (pectoral nodes)  They are located along the inf border of pectoralis minor Lympathetic drainage Lympathetic drainage  From the deep surfaces of breast →apical nodes  From medial part→ parasternal nodes  From the skin may pass to the abdominal wall & the opposite breast 1. 2. 3. 4. 5. CENTRAL LATERAL PECTORAL APICAL SUBSCAPULAR - lateral LN - pectoral LN - subscapular LN - central LN - apical LN Truncus subclavius Ductus thoracicus ductus lymphaticus dexter