Upper Limb Anatomy PDF

Anatomy 534 Upper Limb 1 56 The levator scapulae rotates the scapula with the rhomboids in the opposite direction to the trapezius. The rhomboideus major and minor stabilizes and braces the shoulder. Rotates the inferior ang...

Anatomy 534 Upper Limb 1 56 The levator scapulae rotates the scapula with the rhomboids in the opposite direction to the trapezius. The rhomboideus major and minor stabilizes and braces the shoulder. Rotates the inferior angle of the scapula. The latissimus dorsi is an adductor of the upper limb. finesse.ae iiiii i e1 ie ftp.i A eleton Muscles Arising From the Thoracic Wall The pectoralis major adducts the arm with the latissimus dorsi. Also assists with medial rotation. The pectoralis minor pulls the scapulae forward. In respiratory distress it can reverse to raise ribs when the shoulder girdle is fixed. The serratus anterior draws the scapulae forward in pushing and forward-reaching movements; rotates the inferior angle of scapula laterally turning glenoid cavity upwards when arm is raised above the head.  Anatomy 534 Upper Limb 1 57 The subclavius steadies the clavicle. The sternocleidomastoid is primarily involved with tilting motions of the head. The clavipectoral fascia is a thickening of the deep fascia extending from the periosteum of the clavicle where it encloses the subclavius m. It fills the gap between the subclavius and the pectoralis minor as the costocoracoid membrane. It then splits to enclose the pectoralis minor. It blends with the axillary fascia. 3 scapula EWE Senator by Parasagittal Section Through The Thoracic Wall nf This image shows the relationships of the pectoral muscles and the clavi- pectoral fascia. Anatomy 534 Upper Limb 1 58 Muscles of the Scapular Region A group of short, mainly stout Antevi face muscles located between the scapula and upper humerus that are essential to the stability and movement of the shoulder joint. Together, the first 4 form the rotator cuff: The subscapularis stabilizes the head of the humerus in the shallow glenoid cavity. With stiff Poirot arm by the side, its attachment facilitates medial rotation of the humerus at the shoulder. Anterior ftp.ffhnrih.qgaff.mn.im.ua Ety section Cross The supraspinatus stabilizes and prevents the head of the humerus from slipping down off the glenoid cavity. With the deltoid it can abduct the arm. The infraspinatus rotates the arm laterally as well as stabilizing the shoulder joint. The teres minor stabilizes as well as produces lateral rotation of the arm. Anatomy 534 Upper Limb 1 59 The tendons of the muscles of the rotator cuff surround the shoulder joint on all sides except inferiorly (common dislocation site). They keep the large head of the humerus applied to the shallow glenoid cavity The teres major adducts and medially rotates the arm. It can be thought of as a portion of the subscapularis that has migrated onto the dorsum of the scapula as it has a similar nerve supply (lower scapular n.) The deltoid forms the "cap" of the shoulder and provides a wide range of actions at the shoulder: anterior fibers flex the arm (swing it forward), posterior fibers extend it back behind the body, inter- mediate fibers are powerful abductors of the arm. Anatomy 534 Upper Limb 1 60 The Quadrangular and Triangular Spaces The configuration of the muscles below the shoulder allow a number of structures to pass from anterior to posterior regions of the axilla and arm. The quadrangular space: transmits the axillary n. and posterior circumflex a. The triceps hiatus medial to the shaft of the humerus: transmits the radial n. and profunda brachii a. The triangular space inferior to the quadrangular space: passes the circumflex scapular br. of the subscapular a. Axillary Artery The axillary a. is a continuation of the subclavian a. It begins at the lateral edge of R1 and becomes the brachial a. as it passes the lower border of the teres major The axillary a. is divided into 3 parts by the overlying pectoralis minor m. The number of the division is equivalent to the number of branches from that division: Anatomy 534 Upper Limb 1 61 - Branches from the first part: - superior thoracic artery supplies the pectoralis major & minor - Branches from the second part: - thoracoacromial artery is a short trunk that breaks up to supply the pectoral, acromial, clavicular and deltoid regions - lateral thoracic artery contributes substantially to the breast - Branches from the third part: - subscapular artery is the largest branch of the axillary a. and gives rise to numerous muscular branches that form an anastomosis around the scapula - the anterior and posterior circumflex humeral aa. form an anastomotic circle around the surgical neck of the humerus. The anterior is small. The posterior extends through the quadrangular space with the axillary n. to supply the shoulder joint and surrounding muscles