Anatomy Muscle Study Guide
Origin: Site of muscle attachment to a fixed bone
Insertion: Site of muscle attachment to a more freely movable bone
Muscles of the Chest
Pectoralis muscles
Originates: Sternum
Inserts: Humerus
1. Pectoralis Descendens
2. Pectoralis Transversus
3. Pectoralis Profundus
4. Xiphihumeralis
Muscles of the Shoulder and Back
1.
2.
3.
4.
5.
Trapezius:
a. Action: to adduct the scapula.
Latissiums dorsi
a. Originates: spinous processes of the thoracic vertebrae
b. Inserts: proximal end of the humerus
c. Action: draw the limb caudally during flexion of the shoulder joint.
Deltoid
a. Action: Flex, extend, rotate, and abduct the humerus.
Supraspinatus and Infraspinatus
a. Origin: scapula
b. Inserts: Humerus
c. Action: Extends the humerus, Infraspinatus: rotates humerus laterally
Serratus ventralis
a. Origin: ventral aspect of ribs
b. Inserts: medial dorsal border of scapula
c. Action: pull the scapula forward and down
Muscles of the Front Leg
1. Epitrochlearis
2. Triceps brachii (3 muscles)
a. Long head
i. Origin: scapula
ii. Inserts: olcranon process
iii. Action: Extend the elbow joint
b. Lateral head
i. Origin: proximal humerus
ii. Inserts Olecranon process
c. Medial Head
i. Origin: Proximal humerus
ii. Inserts: Olecranon process
3. Brachialis
a. Origin: humerus
b. Inserts: proximal end of tibia
c. Action: Aid in flexion of the elbow joint
4. Biceps brachii
a. Origin: scapula
b. Inserts: Radius
c. Action: Aid in flexing the elbow joint.
5.
Coracobrachialis
a. Origin: Coracoid process of scapula
b. Inserts: Proximal end of humerus
c. Action: Adduct the front leg
6.
7.
8.
9.
10.
Extensor digitorum communis
Extensor carpi radialis, brevis and longus
Brachioradialis
Extensor digitorum lateralis
Ulnaris lateralis
a. This group of muscles is known as the extensors
11. Flexor carpi ulnaris
12. Flexor digitorum superficialis
13. Flexo carpi radialis
Abdominal Wall Muscles
1. Lumbodorsal fascia
2. External Abdominal Oblique
a. Origin: Posterior ribs
b. Inserts: fascia on ventral midline
3. Internal Abdominal Oblique
a. Origin: Lumbodorsal fasia
b. Inserts: On top of transverses abdominus
4. Transversus abdominus
a. Origin: vertebral column, lumbodorsal fascia, and sacrum
b. Inserts: Linea alba
5. Linea alba
Muscles of the Hind Legs
1. Sartorius
a. Action:
2. Gracilis
a. Origin:
b. Inserts:
c. Action:
Adduct and rotate the thigh
Os coxae
Tibia and fascia of knee
Adduct the thigh
3. Iliotibial Band
4. Tensor fasciae latae
5. Biceps femoris
a. Origin: ischium
b. Inserts: tibia and fascia of lower hind leg
c. Action: Abduct the thigh and flex the lower leg
6. Caudofemoralis
a. Origin: coccygeal vertebrae
b. Inserts: patella
c. Action: adduct the thigh
7. Superficial gluteal
a. Action: abduct the thigh
8. Middle gluteal
a. Action: abduct the thigh
9. Semitendinousus
a. Origin: Ischial tuberosity
b. Inserts: tibia
c. Action: Flex the leg
10. Semimembranosus
a. Origin: Ischium
b. Inserts: Femur
c. Action: adduct the thigh
11. Adductor Femoris and longus
a. Origin: ischium and pubis
b. Insert: length of femur
c. Action: adduct thigh
12. Pectineus
a. Action: extend the thigh
13. Iliopsoas
a. Action: rotate and flex thigh
14. Quadriceps femoris group
a. Vastus lateralis
b. Rectus femoris
c. Vastus medialis
d. Vastus intermedius
i. 3 vastus muscles origin: upper femur (encompass the patella), insert: patellar
ligament on tibial tuberosity, action: extend the stifle joint.
15. Gastrocnemius (calf muscle)
a. Origin: distal femur
b. Inserts: tendon of Achilles on calcaneal tuberosity
c. Action: extend the hock joint and flex the digits of the foot
16. Soleus
a. Origin: Fibula
b. Inserts: tendon of Achilles on the calcaneal tuberosity
17. Peroneus brevis
18. Extensor digitorum lateralis
19. Peroneus longus
20. Extensor digitorum longus
21. Tibialis cranialis
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