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Muscular System
Term | Definition |
---|---|
Flexion | The angle between the bones is reduced |
Extension | The angle between the bones is increased |
Abduction | The whole limb moves away from the midline of the body |
Adduction | The whole limb moves towards the midline of the body |
Protraction | The whole limb moves cranially |
Retraction | The whole limb moves caudally |
Supination | The under surface of the paw is turned downwards |
Pronation | The under surface of the paw is turned upwards |
Digastricus | Opens the jaw (aided by gravity) Located on the caudoventral surface of the mandible |
Masseter | Closes the jaw, lies lateral to mandible |
Temporalis | Closes the jaw and is the largest and strongest muscle of the head. Covers most of the dorsal and lateral surface |
Medial/Lateral Pterygoids | Deep muscles that lie medial to the mandible. They aid the temporalis and masster muscles closing the jaw. But are responsible for the side to side movement |
Rectus (dorsal, ventral, medial, lateral) | Are all inserted on the sclera of the eyeball near the equator. They rotate the eyeball |
Oblique (dorsal, ventral) | They rotate the eyeball |
Retactor bulbi | Forms a muscular cone around the optic nerve. Action is to pull the eyeball deeper |
Intrinsic | Enables the tongue to move |
Extrinsic | Attach the head to the neck and move the head as a whole |
Epaxial Muscle | Dorsal to the transverse processes of the vertabrae. Function are to support the spine, extend the vertebral column and allow lateral flexion |
Hypaxial Muscles | Ventral to the transverse processes of the vertebrae. Function is to flex the neck and tail & contribute to flexion of the vertebral |
External Intercostal | Assist in inspiration |
Internal Intercostal | Assist in expiration |
External Abdominal Oblique | Most superficial of the lateral abdominal muscles |
Internal Abdominal Oblique | Intermediate muscle of the lateral abdominal wall |
Transversus Abdominis | Deepest of the lateral abdominal muscles |
Rectus Abdominis | Broad band of muscle on each side of the linea alba that forms the floor of the abdomen |
Trapezius | Triangular sheet of muscle that originates from the doral midline (C2-C7) and inserts on the spine of the scapula. Draws the leg forward and protracts limb. |
Pectoral | Runs from ribs & sternum and inserts on the humerus. Adducts the forelimb |
Latissimus Dorsi | Fan shaped muscle which has a very broad origin on the thoracic spine and inserts on the humerus. Extends the elbow joint |
Brachiocephalicus | From the base of the skull to insertion on cranial aspect of humerus. flexes neck and bends neck laterally when foot is on the floor. When lifted it protracts the limb |
Supraspinatus | Fills supraspinous fossa of the scapula. Extends the shoulder and stabilises the shoulder joint. |
Infraspinatus | Fills Infraspinatus fossa of the scapula. Helps to stabilise the shoulder joint and flex the shoulder joint. |
Triceps Brachii | Has four heads with separate origins all insert on the olecranon of the ulna. Extend the elbow |
Biceps Brachii | Originates from the supralenoid tubercle of the scapula and inserts on the radius and ulna. Flexes the elbow joint |
Brachialis | Originates from the humerus and inserts on the radius and ulna. Flexes elbow joint |
Carpal extensors x 2 | they run in front of the lower limb and foot. |
Digital Extensors x 2 | they run in front of the lower limb and foot. |
Carpal Flexors x 2 | Run behind the carpus and foot |
Digital Flexors x 2 | Superficial digital flexor inserts on the 2nd phalanx and the deep digital flexor inserts on the 3rd phalanx |
Gluteal (Superficial, middle & deep) | Extensors of the hip joint |
Hamstring | Providing the main propulsive force of the animal. |
Biceps Femoris | Extends the hip, flexes the stifle and extends the hock |
Semitendinosus | Extends the hip, flexes the stifle and extends the hock |
Semimembranosus | Extend the hip and flexes the stifle |
Quadriceps Femoris | The tendon of this muscle contains the patella. Extends the stifle joint |
Pectineus | Run from pubis to the distal femur. Adducts the limb |
Sartorius | Cranial border of the tibia with the gracilis muscle. Adduct the limb |
Gracilis | Form caudal half of the medial surface of the thigh. Adducts the limb |
Gastrocnemuis | The tendons of this muscle contain fabellae. Extend the hock and flexes the stifle |
Achillies Tendon | Large strong tendon that runs down the back of the leg to the point of the hock |
Anterior Tibialis | Proximal end of the tibia to the tarsus. Flexes the hock and rotates the paw medially |
Digital Extensors x 3 | Runs in front of the hock and foot |
Digital Flexors x 2 | Runs behind the foot. |