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Muscle Origin/Insert
Muscle original, insertion and action
Question | Answer |
---|---|
Epicranius - frontal and occipital bellies (Occipital Frontalis) | O: Frontal/Occipital Belly I: Galea Aponeurosis A: Raises Eyebrow |
Orbicularis Oculi | O: Bones & Ligaments around orbit I: Tissue of eyelid A: Closes eyes |
Orbicularis Oris | O: Upper and lower lips I: Angles of mouth (moduli) A: Closes mouth, Kissing and Whistling muscle |
Buccinator (Facial Expression & Mastication) | O: Maxilla and Mandible I: Orbicularis Oris A: Compresses cheeks (whistling), Chewing |
Masseter | O: Maxilla I: Mandible A: Closes jaw and elevates mandible |
Temporalis | O: Temporal fossa I: Superior Temporal Line A: Closes jaw, elevates & retracts mandible |
Medial Pterygoid | O: Medial Pterygoid plate I: Mandible A: Elevates mandible, grinding movements |
Lateral Pterygoid | O: Later Pterygoid plate I: Mandible A: moves jaw anteriorly (protects jaw) |
Platysma (hypodermis layer of nect) | O: Fascia of chest (over pectoral muscles) I: Lower margin mandible A: Depresses mandible, pulls down and back lower lip (downward sag of mouth) |
Sternocleidomastoid | O: Sternum & clavicle I: Mastoid A: Flexion of neck forward, generally against resistance; rotate head toward shoulder on opposite side |
Digastric | O: Lower margin of mandible (anterior belly) and mastoid process (posterior belly) I: By a connective tissue loop to hyoid bone A: Opens mouth and depresses mandible |
Mylohyoid | O: Medial surface of mandible I: Medial raphe A: Elevates hyoid bone and base of tongue during swallowing |
Sternohyoid | O: Sternum I: Hyoid bone A: Acting with sternothyroid and omohyoid (all inferior to hyoid bone), depresses Larynx and hyoid bone if mandible is fixed, may also flex skull |
Sternothyroid | O: Sternum I: Thyroid cartilage A: Acting with sternothyroid and omohyoid (all inferior to hyoid bone), depresses Larynx and hyoid bone if mandible is fixed, may also flex skull |
Thyrohyoid | O: Thyroid Cartilage I: Hyoid bone A: Depress hyoid bone;elevates larynx if hyoid is fixed |
Pectoralis Major | O: Clavicle, sternum, ribs I: Head of humerus A: Adducts |
Serratus Anterior | O: Lateral aspect of ribs I: Scapula A: Moves scapula forward |
Deltoid | O: Clavicle, scapula I: Deltoid Tuberosity (humerus) A: Abduction |
External Intercostals | O: Inferior border of rib above I: Superior border of rib below A: Pulls ribs towards each other to elevate rib cage, aid in inspiration |
Internal Intercostals | O: Superior border of rib below I: Inferior border of rib above A: Draws ribs together to depress rib cage, aid in forced expiration, antagonistic to external intercostals |
Diaphragm | O: Ribs, sternum, lumbar I: Central tendon A: Prime mover of inspiration |
Rectus Abdominis | O: Pubic crest and symphysis I: Xiphoid process and costal cartilages of ribs 5 - 7 A: Flexes and rotates vertebral column; increases abdominal pressure; fixes and depresses ribs; stabilizes pelvis during walking; used in sit ups and curls |
External Oblique | O: Anterior surface of last eight ribs I: Linea Alba, pubic crest and tubercles, and iliac crest A: Same as rectus abdominis; aids in nuscles of back in trunk rotation and lateral flexion; used in oblique curls |
Internal Oblique | O: Lumbar fascia, iliac crest and inquinal ligament I: Linea alba, pubic crest and costal cartilages of last 3 ribs A: same as external obliques |
Transverse Abdominis | O: Inguinal ligament, iliac crest, cartilages of last 5 or 6 ribs and lumbar fascia I: Linea alba and pubic crest |
Trapezius | O: Spines of cervical and thoracic vertebrae I: Scapula A: Adducts scapula |
Latissimus dorsi (posterior fold of axilla) | O: Thoracic vertebrae, last 4 ribs I: Intertubercular sulcus (groove) of humerus A: Prime mover of arm extension (ABDUCTION) |
Infraspinatus | O: Infraspinatus fossa of scapula I: Greater tubercle of humerus A: Stabilizes shoulder joint |
Supraspinatus | O: Supraspinatus fossa of scapula I: Greater tubercle of humerus A: Helps stabilize shoulder joint |
Semispinalis: Capitis, Cervicis, Thoracis | O: Transverse processes of C7-T12 I: Capitis-Occipital Bone, Cervicis-Cervical Vertebrae, Thoracic-T1-T4 A: Extend head and vertebral column |
Triceps Brachii | O: Long head, lateral head, medial head on head of humerus and scapula I: Olecranon process of ulna A: Powerful forearm extensor |
Biceps Brachii | O: Scapula I: Radial tuberosity A: Powerful forearm flexion |
Brachioradialis | A: Flexion |
Brachialis | O: Lower, distal portion of humerus I: Ulna A: Forearm flexion |