Anterior Upper Arm/Thorax & Abdomen Study Guide
1. Deltoid Muscle
O: Lateral 3rd of clavicle; the acromion, spine of scapula
I: Deltoid tubercle on lateral surface of humerus
N: Axillary Nerve from post. Cord of brachial plexus
A: Abduction of humerus; anterior fibers assist in flexion.
2. Pectoralis Major
O: Clavicle (clavicular head), sternum, and costal cartilages of second to sixth ribs and
sometimes first to seventh ribs (sternocostal head).
I: Greater tubercle and lateral lip of the intertubercular sulcus of humerus.
N: Medial and lateral pectoral nerves.
A: As a whole, adducts and medially rotates arm at shoulder joint; clavicular head flexes
arm, and sternocostal head extends the flexed arm to side of trunk.
3. Pectoralis Minor
O: Coracoid process of scapula
I: Ribs 2 to 5
N: Medial Pectoral nerve
A: protracts scapula and elevates ribs
4. Biceps Brachii Long Head
O: Supraglenoid Tubercle of Scapula (LH)
I: Tuberosity of the radius and the bicipital aponeurosis.
N: Musculocutaneous nerve (C5 and C6). (lies under the biceps)
A: Flexes and supinates the forearm; long head can also assist in flexing the humerus
5. Biceps Brachii Short Head Coracoid process of scapula (SH)
I: Tuberosity of the radius and the bicipital aponeurosis.
N: Musculocutaneous nerve (C5 and C6). (lies under the biceps)
A: Flexes and supinates the forearm; long head can also assist in flexing the humerus
6. Brachialis
O: Distal, anterior surface of humerus.
I: Ulnar tuberosity and coronoid process of ulna.
N: Musculocutaneous and radial nerves.
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A: Flexes forearm at elbow joint.
7. Coracobrachialis
O: Coracoid process of scapula.
I: Middle of medial surface of shaft of humerus.
N: Musculocutaneous nerve.
A: Flexes and adducts arm at shoulder joint.
8. External Oblique
O: Outer surface of T5-T12
I: Outer lip of iliac crest, aponeurosis of external oblique (ends in linea alba)
N: Lower 7 thoracic nerves (T6-T12)
A: Compresses abdominal viscera. Flexion of trunk forward. Ipsilateral bend with
contralateral forward bend
9. 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
N: Lower five thoracic nerves and the first lumbar nerve (T8-L1)
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
10. 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
N: Lower six thoracic and first lumbar nerves (T7-L1)
A: Tenses abdominal wall; compresses abdominal contents
11. Rectus Abdominis
O: 5th 6th 7th Costal Cartlidges, Costal xiphoid ligaments and Xiphoid process.
I: Crest of pubis and pubis tuberical, front of symphasis pubis.
N: Lower 7 thoracic nevers T6-T12.
A: Flexes vertebral column, tenses anterior abdominal wall. Compresses abdominal
contents.
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12. External Intercostals
O: Inferior Border of Rib Above
I: Superior Border of Rib Below
A: Elevates Ribs for inspiration.
Vascular Structures & More
13. Cephalic Vein
14. Basilic Vein
15. Axillary Nerve
16. Medial Cubital Vein
17. Rectus Sheath
18. Musculocutaneous Nerve
19. Brachial Plexus (Lateral cord)
20. Brachial Plexus (Medial Cord)
21. Brachial Plexus (Posterior Cord)
22. Brachial Artery
23. Median Pectoral Nerve
24. Thorocromial Artery
25. Bicipital Apenourosis
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