Muscles of the Shoulder and Pectoral Regions (PDF)

 Faculty of Physical Therapy ❑Course Title: Anatomy I ❑Course Code: FM 101 ❑Department: Anatomy and embryology ❑Lecture Title: Muscles of the shoulder and pectoral regions ❑Lecturer Name : Pr.Dr. Morsy Abdelfattah Morsy ❑ Objectives: By the end of this lectu...

 Faculty of Physical Therapy ❑Course Title: Anatomy I ❑Course Code: FM 101 ❑Department: Anatomy and embryology ❑Lecture Title: Muscles of the shoulder and pectoral regions ❑Lecturer Name : Pr.Dr. Morsy Abdelfattah Morsy ❑ Objectives: By the end of this lecture the students will be able to: ❖Identify the shoulder region. ❖Describe the muscles of shoulder region ❖Identify the pectoral region ❖Identify the breast ❖Describe the muscles of pectoral region SHOULDER REGION ❑ Muscles of the shoulder region are: Deltoid muscle. Trapezius. Levator scapulae. Rhomboid minor. Rhomboid major. Subscapularis muscle. Supraspinatus muscle. Infraspinatus muscle. Teres major. Teres minor. ❑Deltoid muscle: Origin: ▪ Anterior border of lateral 1/3 of clavicle. ▪ Lateral border of acromion process and inferior lip of crest of spine. Insertion: deltoid tuberosity. Nerve supply: axillary nerve. Action: ✓ Anterior fibers flexion and medial rotation of the arm. ✓ Middle fibers abducts the arm from 15⁰ to 90⁰. ✓ Posterior fibers extended and lateral rotation of the arm. ❑Origin of deltoid muscle. ❑Insertion of deltoid muscle: Deltoid tuberosity. ❑Trapezius muscle: 1-Origin: External occipital protuberance and medial 1/3 of the superior nuchal line. Ligamentum nuchae. 7th cervical spine and all 12 thoracic spines. 2-Insertion: Upper fibers into the posterior border of the lateral 1/3 of the clavicle. Middle fibers into the medial border of the acromion and upper lip of the crest of the spine of the scapula. Lower fibers into medial part of the crest of the spine of the scapula. 3-Nerve supply: Spinal roots of accessory nerve. 4-Action: Upper fibers rotate the scapula upwards and elevate the shoulder. Middle fibers retract the scapula. Lower fibers depress the scapula and shoulder. Middle and lower fibers help serratus anterior to rotate the scapula forwards around the chest to raise the arm above the head. Origin of the trapezius muscle: Insertion of the trapezius muscle: ❑Levator scapula muscle: 1-Origin: ✓ Transverse process of upper 4 cervical vertebrae. 2-Insertion: ✓ Into the back of the medial border of the scapula from the superior angle to the root of the spine. 3-Nerve supply: ✓ Dorsal scapular nerve(Nerve to rhomboids) C5. 4-Action: ✓ Raises the medial border of the scapula. ❑Rhomboideus minor muscle: 1-Origin: ✓ Ligamentum nuchae (Lower part). ✓ Spines of 7th cervical and 1st thoracic vertebrae. 2-Insertion: ✓ Into the back of the medial border of the scapula opposite the root of the spine of the scapula. 3-Nerve supply: ✓ Dorsal scapular nerve(N. to Rhomboideus) C5. 4-Action: ✓ Raises the medial border of the scapula upwards and medially. ❑ Rhomboideus major muscle: 1-Origin: ✓ 2nd,3rd,4th,5th thoracic spines. 2-Insertion: ✓ Into the back of the medial border of the scapula from the root of the spine to the inferior angle. 3-Nerve supply: ✓ Dorsal scapular nerve(N. to Rhomboideus) C5. 4-Action: ✓ The two rhomboideus muscles rotate the scapula upwards and medially. Levator scapula muscle. Rhomboideus minor muscle. Rhomboideus major muscle. Levator scapula(I). Rhomboideus Minor(I). Rhomboideus major(I). ❑ Subscapularis muscle: Origin: ▪ Medial 2/3 of subscapular fossa. Insertion: ▪ Lesser tubercle. Nerve supply: ▪ Upper and lower subscapular nerves. Action: ✓Adduction and medial rotation of the arm. ✓One of the rotator cuff muscles.  Subscapularis (O). I Subscapularis (I). O ❑ Supraspinatus muscle. (Suprascapular nerve). ❑ Infraspinatus muscle. (Suprascapular nerve). ❑ Teres minor muscle. (posterior division of axillary nerve). ❑ Teres major (lower Subscapular nerve). ❑ Supraspinatus Muscle: Origin :Medial two-thirds of the supra-spinous fossa of the scapula. Insertion: Tip of the greater tubercle of the humerus. Nerve supply: Suprascapular nerve [C5,C6]. Action: Rotator cuff muscle; initiation of abduction of arm from 0- 15°. ❑ Infraspinatus muscle: Origin: Medial two-thirds of the infra-spinous fossa of the scapula. Insertion: Middle facet on posterior surface of the greater tubercle of the humerus Nerve supply: Suprascapular nerve [C5,C6] Action: Rotator cuff muscle; lateral rotation of arm. Supraspinatus Supraspinatus origin insertion Infraspinatus Infraspinatus insertion origin ❑ Teres minor muscle: Origin: Upper two-thirds of posterior surface of the lateral border of the scapula. Insertion: Inferior facet on the posterior surface of the greater tubercle of the humerus. Nerve supply: Axillary nerve [C5,6]. Action: Rotator cuff muscle; lateral rotation of arm at the shoulder joint. ❑ Teres major muscle: Origin: Elongated oval area on the posterior surface of the inferior angle of the scapula Insertion: Medial lip of the intertubercular sulcus (Bicipital groove) on the anterior surface of the humerus. Nerve supply: Lower subscapular nerve [C5 ,C6, C7]. Action: Medial rotation and extension of the arm at the shoulder joint  Teres major insertion. Teres minor origin Insertion of teres minor Teres major origin. Pectoral region ❑ The pectoral region: It is external to the anterior thoracic wall and anchors the upper limb to the trunk. It consists of a superficial compartment containing skin, superficial fascia, and breasts; and a deep compartment containing muscles and associated structures. The breasts consist of mammary glands and associated skin and connective tissues. The mammary glands are modified sweat glands in the superficial fascia anterior to the pectoral muscles and the anterior thoracic wall.  The mammary glands consist of a series of ducts and associated secretory lobules. These converge to from 15 to 20 lactiferous ducts, which open independently onto the nipple. The nipple is surrounded by a circular pigmented area of skin termed the areola. The breast lies on deep fascia related to the pectoralis major muscle and other surrounding muscles. The base, or attached surface, of each breast extends vertically from ribs II to VI, and transversely from Base extended the sternum to as far laterally as from the ribs the midaxillary line. 2nd-6th ❑ Pectoralis major muscle: ❖ Origin: Clavicular head from anterior surface of medial 2/3 of the clavicle. Sternocostal head from upper 6 costal cartilage and anterior surface of the manubrium sterni and body of the sternum. Aponeurosis of external oblique muscle. ❖ Insertion: Lateral lip of bicepital groove. ❖ Nerve supply: Lateral and medial Pectoral nerves. ❖ Action: Flexion ,Adduction and Medial rotation of the arm.  Clavicular head Sternocostal Pectoralis head major muscle Pectoralis major muscles  Bony origin of the pectoralis major muscle Clavicular head Sternocostal head Insertion of pectoralis major muscle into the lateral lip of bicipital groove ❑ Clavipectoral fascia: The clavipectoral fascia is a strong sheet of connective tissue lying immediately deep to the pectoralis major muscle. Superiorly, it attaches to the clavicle. Inferiorly, it splits to enclose the subclavius and pectoralis minor muscles and then continues downward as the suspensory ligament of the axilla and joins the fascial floor of the armpit. ❑ Serratus anterior muscle: ❖ Origin: Upper 8 ribs. ❖ Insertion: Inner surface of the medial border and inferior angle of the scapula. ❖ Nerve supply: long thoracic nerve (C,5,6,7). ❖ Action: Protraction of the scapula and rotation of the scapula upwards.  Serratus anterior muscle 1st digit 2nd&3rd digits Lower five digits Insertion Origin Winging of the scapula due to paralysis of the long thoracic nerve. ❑ Pectoral minor muscle: ❖ Origin: ✓ 3,4,5 ribs. 1st rib ❖ Insertion: ✓ Coracoid process (upper surface and medial border. 3rd rib ❖ Nerve supply: ✓ Medial pectoral nerve. 4th ❖ Action: ✓ Protraction and depression of 5th the scapula. ❑ Subclavius muscle: ❖ Origin: Upper surface of 1st rib. ❖ Insertion: Subclavian groove. ❖ Nerve supply: Nerve to subclavius ❖ Action: Pulls clavicle medially to stabilize sternoclavicular joint  Pectoralis minor muscle Insertion 3 4 5 Origin Subclavius muscle Origin Insertion  MCQ 1-Which of the following muscles is inserted into acromion process? a. Deltoid. b. Trapezius c. Supraspinatus d. Teres major 2-The deltoid muscle takes its nerve supply from which of the following nerves? a. Suprascapular b. Subscapular c. Axillary d. Dorsal scapular 3-Which one of the following muscles is inserted into the top of the greater tubercle of the humorous? a. Deltoid b. Trapezius. c. Supraspinatus. d. Infraspinatus. 4-Which one of the following muscles can abduct the arm from 0 to 15˚? a. Supraspinatus. b. levator scapulae. c. Deltoid d. Infraspinatus 5-Which one of the following muscles is medial rotator and extensor of the shoulder joint? a. Teres minor b. Teres major c. Rhomboids major d. Rhomboids minor  References 1-Gray H, Anatomy of the Human Body. 20th ed. New York: Bartleby 2000. 2-Gray, s anatomy for students by Richard Drake and A. Wayne Vogel, 2019. 3-Snell R. " Clinical Anatomy by Regions ' 8th ed. Lippincott Williams and Wilkins, Philadelphia, 2008. 4-Agur A. & Dalley A. " Atlas of Anatomy" Lippincott Williams and Wilkins, Philadelphia, 2005 Thanks, with the best wishes. Pr.Dr/Morsy Abdelfattah.