ORIGINS, INSERTIONS AND PRIME MOVER ACTIONS OF MUSCLES IN FIGURE 6.8

Muscle Origin Insertion Actions Adductor Longus Anterior surface of pubis Adducts thigh Adductor Magnus Ischial and pubic rami and ischial tuberosity Medial half of linea aspera Adducts thigh on the femur Biceps Brachii Long head – upper margin of glenoid fossa; Radial (bicipital) tuberosity Flexes and supinates forearm short head – coracoid process of scapula of radius Biceps Femoris Long head – ischial tuberosity; short head – Lateral aspect of head of Flexes knee; long head extends thigh linea aspera of femur fibula and lateral condyle of tibia Brachialis Anterior surface of lower ½ of humerus Anterior surface of Flexes forearm coranoid process of ulna Brachioradialis Upper 2/3rd of lateral supracondylar ridge of Base of styloids process of Flexes forearm humerus humerus Deltoid - Anterior Anterior border of outer 1/3rd of clavicle } Flexes and horizontally flexes humerus } - Medial Acromion process and lateral end of clavicle }Deltoid tuberosity of Abducts and horizontally flexes humerus }humerus (lateral aspect of - Posterior Lower margin of spine of scapula }humerus near midpoint) Extends and horizontally extends } humerus Extensor Digitorum Lateral epicondyle of humerus Distal phalanges of fingers Extends fingers at metacarpophalangeal 2-5 and interphalangeal joints Extensor Digitorum Lateral condyle of tibia and upper ¾ of Second and third phalanges Dorsiflexes and everts foot and extends Longus anterior surface of fibula of four lesser toes toes Extensor Carpi Lateral epicondyle and supracondylar ridge Base of 2nd metacarpal Extends and abducts wrist Radialis Longus of humerus Extensor Carpi Lateral epicondyle of humerus and posterior Base of 5th metacarpal Extends and adducts wrist Ulnaris border of ulna External Obliques Outer surfaces of lower eight ribs Anterior half of crest of Flexes and laterally flexes trunk, rotates ilium and from ribs to trunk to opposite side public crest Flexor Carpi Radialis Medial epicondyle of humerus Base of 2nd metacarpal Flexes and abducts wrist Flexor Carpi Ulnaris Medial epicondyle of humerus, posterior Pisiform bone and base of Flexes and adducts wrist surface and olecranon process of ulna 5th metcarpal Gastrocnemius By two heads from medial and lateral Calcaneus through Achilles Plantar flexes foot; can help flex knee condyles of femur tendon Gluteus Maximus Posterior gluteal line of ilium, lower part of Posterior surface of femur Extends and externally rotates thigh sacrum, coccyx at gluteal tuberosity, iliotibial tract Gluteus Medius Lateral surface of ilium between anterior and Lateral aspect of greater Abducts and internally rotates thigh posterior gluteal lines trochanter of femur Gracilis Inferior ramus and body of pubis Medial surface of tibia just Adducts thigh; helps extend and below medial condyle internally rotate knee Iliopsoas Iliacus – iliac fossa; Psoas Major – transverse Lesser trochanter of femur Flexes thigh processes, bodies and discs of 12th thoracic vertebra and all lumbar vertebrae Infraspinatus Medial 2/3rd of infraspinous fossa of scapula Greater tubercle of humerus Outwardly rotates and horizontally extends humerus Intercostals External – inferior border of rib above; External – superior border Respiration Internal – superior border of rib below of rib below; Internal – inferior border of rib above Internal Obliques Linea alba, pubic crest and lower three ribs Crest of ilium and inguinal Flexes and laterally flexes trunk, rotates ligament trunk to same side Latissimus Dorsi Spinous processes of lower six thoracic and Inferior portion of Extends and adducts humerus all lumbar vertebrae, posterior surface of intertubercular groove of sacrum, iliac crest, lower three ribs humerus Palmaris Longus Medial epicondyle of humerus Palmar aponeurosis Weak flexor of wrist Pectineus Pectineal line of pubis on superior ramus Pectineal line of femur Flexes and adducts thigh between lesser trochanter and linea aspera Pectoralis Major Medial 2/3rd of anterior border of clavicle, Greater tubercle of humerus Flexes, internally rotates, adducts and anterior surface of sternum, cartilage of ribs (lateral surface of humerus) horizontally flexes humerus 1-6 Pectoralis Minor Anterior surfaces of ribs 3 to 5 Tip of coracoid process of Depresses, protracts and downwardly scapula rotates scapula Peroneus Longus Lateral condyle of tibia, head and upper 2/3rd Lateral margin of plantar Everts foot of fibula surface of medial cuneiform and base of first metatarsal Pronator Teres Medial epicondyle of humerus, coronoid Lateral surface of radius Pronates forearm process of ulna near middle Rectus Abdominis Cartilages of ribs 5 to 7 Pubic crest and pubic Flexes trunk symphysis Rectus Femoris Anterior inferior iliac spine and superior Base of patella and, by Flexes thigh and extends knee margin of acetabulum patellar ligament, tibial tuberosity Rhomboideus Major Spinous processes of 7th cervical vertebra and Medial border of scapula Elevates, retracts and downwardly rotates all thoracic vertebrae scapula Sartorius Anterior superior iliac spine Anterior and medial surface Helps flex and laterally rotate thigh and of tibia just below medial flex knee condyle Semimembranosus Upper and lateral aspects of ischial tuberosity Medial condyle of tibia Extends thigh; flexes and internally rotates knee Semitendinosus Lower and medial aspects of ischial Upper part of medial Extends thigh; flexes and internally tuberosity surface of shaft of tibia rotates knee Serratus Anterior Outer surfaces of upper nine ribs at side of Anterior surface of medial Protracts and upwardly rotates scapula chest border of scapula Soleus Posterior surface of head of fibula and upper Calcaneus through Achilles Plantar flexes foot 2/3rd of shaft, medial border of middle 1/3 of tendon tibia Sternocleidomastoid Manubrium of sternum; medial 1/3rd of Mastoid process of Flexes, laterally flexes, and rotates to the clavicle temporal bone opposite side the head and cervical spine Tensor Fasciae Latae Anterior aspect of iliac crest and anterior Iliotibial tract Helps flex, abduct and internally rotate superior iliac spine thigh Teres Major Posterior surface of inferior angle of scapula Crest of lesser tubercle on Extends, adducts and internally rotates anterior surface of humerus humerus Tibialis Anterior Lateral condyle and upper 2/3rd of lateral Inferior surface of medial Dorsiflexes and inverts foot surface of tibia cuneiform and first metatarsal Transversus Inguinal ligament, iliac crest, lumbodorsal Linea alba and pubic crest Compresses abdominal contents Abdominis fascia, cartilages of lower six ribs Trapezius Occipital bone, ligamentum nuchae, spinous Acromion process, spine of Retracts and upwardly rotates scapula; processes of 7th cervical vertebra and all scapula and posterior upper fibres elevate scapula; middle thoracic vertebrae border of lateral 1/3rd of fibres retract scapula; lower fibres clavicle depress scapula Triceps Brachii Long head – infraglenoid tuberosity of Olecranon process of ulna Extends forearm scapula; lateral head – posterior surface of upper half of humerus; medial head – posterior surface of lower 2/3rd of humerus Vastus Lateralis Greater trochanter, upper part of Base of patella and, by Extends knee intertrochanteric line, and linea aspera of patellar ligament, tibial femur tuberosity Vastus Medialis Linea aspera and lower half of Base of patella and, by Extends knee intertrochanteric line of femur patellar ligament, tibial tuberosity