Deep Muscles of the Thorax Anterior Upper Arm

Deep Muscles of the Thorax, Anterior Upper Arm, and Abdomen Stacey Fain & Christina Duncan

Overview of Deep Muscles

Deep Pectoral Region & Axilla • Pectoralis Minor – – Origin: Corocoid process of scapula. Insertion: Ribs 2 to 5 Innervation: Medial pectoral nerve (C 8, T 1) Action: Protracts scapula; elevates ribs. • Serratus Anterior • External Intercostals • Internal Intercostals

Veins & Arteries of the Axilla • Main thing to be preserved from the axillary region is the axillary artery and the brachial plexus. Almost all nervous system and vascular networks for the arm originate off of these two structures.

Muscles of the Upper Arm • • • Brachialis Muscle O: Distal half of anterior surface of the humerus I: Tuberosity of the ulna and anterior surface of the coronoid process A: Powerful flexor of the forearm N: Musculocutaneous nerve and sometimes small branch of radial nerve (C 5, C 6) Coracobrachialis Muscle O: Coracoid process of the scapula I: Medial surface of humerus near its middle A: Flexes and adducts the arm N: Musculocutaneous nerve (C 6, C 7) 5

Main Blood Supply • Vasculature • Axillary Artery (Becomes Brachial Artery once past axillary region) • Profunda (deep) brachii artery • Superior ulnar collateral artery • Radial collateral artery

Innervation of the Upper (Musculocutaneous Nerve) 7

The Abdomen

Abdominal Muscles • Internal oblique • O: Lateral 2/3 of inguinal ligament; the middle lip of iliac crest; the thoracolumbar fascia • I: Inferior border of lower 3 -4 ribs; the linea alba; aponeurosis fuses with that of the external oblique to help form the rectus sheath • A: Compresses abdominal viscera; both muscles: flex the trunk forward; each muscle: bends the trunk to that side but rotates the front of the abdomen toward the same side • N: Lower five thoracic nerves and the first lumbar nerve (T 8 -L 1) • Transverse abdominis • O: Lateral third of inguinal ligament and inner lip of iliac crest; thoracolumbar fascia; inner surface of lower six ribs • I: Ends in aponeurosis; upper fibers: to line alba, help form posterior layer of rectus sheath; lower fibers: attach to pubis to form conjoined tendon • A: Tenses abdominal wall; compresses abdominal contents • N: Lower six thoracic and first lumbar nerves (T 7 -L 1)

More Abs! Rectus Abdominis – O: 5 th 6 th 7 th Costal Cartlidges, Costal xiphoid ligaments and Xiphoid process. – I: Crest of pubis and pubis tuberical, front of symphasis pubis. – A: Flexes vertebral column, tenses anterior abdominal wall. Compresses abdominal contents. – Innervations: Lower 7 thoracic nevers T 6 -T 12. 10

Vascular Supply • Superior Epigastric Artery • Inferior Epigastric Arteries • Inferior Epigastric Vein Superior Epigastric Artery Inferior Epigastric Vein Inferior Epigastric Artery 11