APK Muscles
Terms
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- Masseter
- Origin: zygomatic arch and zygomatic bone Insertion: angle and ramus of mandible Action: prime mover of jaw closure
- Temporalis
- Origin: temporal fossa Insertion: coronoid process of mandible Action: jaw closure
- Sternocleidomastoid
- Origin: manubrium of sternum and medial portion of clavicle Insertion: mastoid process of temporal bone and superior nuchal line of occipital bone Action: flexes and laterally rotates head
- Rectus Abdominis
- Origin: pubic crest and symphysis Insertion: xiphoid process and costal cartilages of ribs 5-7 Action: flex and rotate lumbar region of vertebral column
- External Oblique
- Origin: by fleshy strips from outer surfaces of lower eight ribs Insertion: most fibers insert into linea alba via a broad aponeurosis Action: flex vertebral column and compress abdominal wall
- Internal Oblique
- Origin: lumbar fascia, iliac crest, and inguinal ligament Insertion: linea alba, pubic crest, last three or four ribs and costal margin Action: same as external oblique
- Transversus Abdominis
- Origin: inguinal ligament, lumbar fascia, cartilages of last six ribs Insertion: linea alba, pubic crest Action: compresses abdominal contents
- Diaphragm
- Origin: inferior internal surface of rib cage and sternum, costal cartilages of last six ribs, and lumbar vertebrae Insertion: central tendon Action: prime mover of inspiration
- Trapezius
- Origin: occipital bone, and spines C7, and all thoracic vertebrae Insertion: a continuous insertion along acromion and spine of scapula and lateral third of clavicle Action: stabilizes, raises, retracts, and rotates scapula
- Serratus Anterior
- Origin: by a series of muscle from ribs 1-8 (or 9) Insertion: entire anterior of surface of vertebral border of scapula Action: rotates scapula so that its inferior angle moves laterally and upward
- Pectoralis Minor
- Origin: anterior surfaces of ribs 3-5 (or 2-4) Insertion: coracoid process of scapula Action: with ribs fixed, draws scapula forward and downward
- Levator Scapulae
- Origin: transverse processes of C1 - C4 Insertion: medial border of the scapula, superior to the spine Action: elevates/adducts scapula
- Rhomboideus Major
- Origin: spinous processes of T2 - T5 Insertion: medial border of scapula Action: stabilize scapula
- Pectoralis Major
- Origin: sternal end of clavicle, sternum, cartilage of ribs 1-6 (or 7), and aponeurosis of external oblique muscle Insertion: fibers converge to insert by a short tendon into greater tubercle of humerus Action: prime mover of arm flexion
- Deltoid
- Origin: embraces insertion of the trapezius; lateral third of clavicle; acromion and spine of scapula Insertion: deltoid tuberosity of humerus Action: primer mover of arm abduction when all its fibers contract simultaneously
- Subscapularis
- Origin: subscapular fossa of scapula Insertion: lesser tubercle of humerus Action: chief medial rotator of humerus
- Suprascapularis
- Origin: supraspinous fossa of scapula Insertion: superior part of greater tubercle of humerus Action: initiates abduction
- Infraspinatus
- Origin: infraspinous fossa of scapula Insertion: greater tubercle of humerus posterior to insertion of supraspinatus Action: rotates humerus laterally
- Teres Minor
- Origin: lateral border of dorsal scapular surface Insertion: greater tubercle of humerus inferior to inraspinatus insertion Action: same as infraspinatus muscle
- Teres Major
- Origin: posterior surface of scapula at inferior angle Insertion: crest of lesser tubercle on anterior humerus Action: extends, medially rotates and adducts humerus
- Latissimus Dorsi
- Origin: indirect attachment via thoracolumbar fascia into spines of lower six thoracic vertebrae, lower 3 or 4 ribs, and iliac crest Insertion: spirals around teres major to insert in floor of intertubercular sulcus of humerus Action: prime mover of arm extension
- Coracobrachialis
- Origin: coracoid process of scapula Insertion: medial surface of humerus shaft Action: flexion and adduction of the humerus
- Biceps Brachii
- Origin: short head: coracoid process of the scapula; long head: supraglenoid tubercle and lip of glenoid cavity Insertion: by common tendon into radial tuberosity Action: flexes elbow joint and supinates forearm