8.4: MODELS- Head and Neck and Torso

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Name	Action	Origin	Insertion
Muscles of facial expression
Frontalis (epicranius)	Raises eyebrows , wrinkles forehead	Frontal Bone	Skin of the brow
Occipitalis (epicranius)	Pull scalp posteriorly	Occipital bone	Aponeurosis connecting to frontalis
Orbicularis oris	Closes mouth	Maxillae and Mandible	Lips
Zygomaticus (major/minor)	smile 	Zygomatic Bone	mouth
Orbicularis oculi	Closes eye	Margin of Orbit	Eyelid
Masseter	Elevates mandible	Zygomatic Arch	Mandible
Temporalis	Elevates mandible	Temporal Bone	Mandible
Buccinator	Presses cheek inward	Maxillae and Mandible	orbicularis oris
Muscles of the head, vertebral column and abdominal wall
Splenius capitis	extend + laterally flex head	upper spine	Temporal & occipital
Sternocleidomastoid	Flexes + rotates neck (also elevates ribs)	Sternum & Clavicle	Mastoid Process
Scalenes	Flexes neck (also elevates ribs)	Cervical Vertebrae	1st Two Ribs
Rectus abdominus	Flexes vertebral column , compresses abdomen	Pubis	Lower Ribs and Xiphoid
External oblique	Flexes + rotates vertebral column, compresses abdomen	Lower Ribs	Linea alba and Ilium
Internal oblique	Flexes + rotates vertebral column, compresses abdomen	Lumbar Vertebrae & Ilium	Lower Ribs, Linea alba, Sternum
Transverse abdominus	Compresses abdomen	Lower Ribs, Ilium, Lumbar Vertebrae	Linea Alba & Pubis
Erector spinae group	Extends vertebral column	Ilium, Sacrum, Ribs, Vertebrae	Ribs, Vertebrae, Base of Skull
Levator scapulae	Extends neck (also elevates scapula)	Cervical Vertebrae	Scapula
Name		Action	Origin	Insertion
Thoracic & shoulder muscles
Pectoralis major		Flexes, adducts + medially rotates arm at shoulder	Sternum & Clavicle	Humerus
Pectoralis minor		Elevates ribs (also moves scapula anterior and inferior)	Ribs	Scapula
External intercostals		Elevates ribs	Inferior Rib	Superior rib
Internal intercostals		Depresses ribs	Superior rib	Inferior Rib
Diaphragm		Increases thoracic volume	Xiphoid Process, Ribs, Lumbar Vertebrae	Central Tendinous Sheet
Arm movers
Serratus anterior		Moves and fixes scapula anteriorly	Ribs	Scapula
Trapezius		Elevates, retracts, depresses+ rotates scapula upward (also extends neck)	Occipital Bone & Thoracic Vertebrae	Scapula
Rhomboids (major & minor)		Elevates + adducts scapula	Cervical & Thoracic Vertebrae	Scapula
Latissimus dorsi		Extends, adducts + medially rotates arm at shoulder	Thoracic, Lumbar Vertebrae, Ribs	Humerus
Deltoid		Abducts arm at shoulder (also anterior fibers flex + posterior fibers extend arm at shoulder)	Clavicle & Scapula	Humerus
Teres major		Medially rotate arm	Scapula	Humerus
Rotator cuff (SITS)
Infraspinatus		Laterally rotates shoulder	Scapula	Humerus
Supraspinatus		Abducts shoulder	Scapula	Humerus
Subscapularis		Medially rotates shoulder	Scapula	Humerus
Teres minor		Laterally rotates shoulder	Scapula	Humerus