Muscles Flashcards
What is an isotonic contraction?
A muscle contraction where the muscle shortens, and movement occurs (e.g., normal exercise)
What is an isometric contraction?
A muscle contraction where tension increases, but no movement occurs (e.g., pushing against an immovable object)
What are the three types of muscle?
- Skeletal muscle: Maintains posture and locomotion.
- Cardiac muscle: Found only in the heart.
- Smooth muscle: Found in organs and blood vessels.
What are the two key points of muscle attachment?
- Origin: Fixed attachment, does not move.
- Insertion: Movable attachment, where movement occurs
How are muscles attached to bones?
Via tendons
What are the four main shapes of muscles and examples?
- Triangular → Found in shoulder and neck.
- Spindle-shaped → Found in arms and legs.
- Flat → Found in the diaphragm and forehead.
- Circular → Found in mouth and anus.
What are the six key muscles of the forelimb?
- Trapezius
- Rhomboideus
- Latissimus dorsi
- Brachiocephalicus
- Pectoral muscles
- Serratus ventralis
What is the origin and insertion of the trapezius muscle?
- Origin: Dorsal midline (connective tissue along the top of the horse).
- Insertion: Scapular spine.
What is the function of the trapezius muscle?
Elevates the shoulder or moves it cranially/caudally
What is the origin and insertion of the latissimus dorsi?
- Origin: Supraspinous ligament and thoracolumbar fascia.
- Insertion: Teres tuberosity of the humerus.
What is the function of the latissimus dorsi?
Retracts the limb or pulls the trunk toward the limb
What happens if the latissimus dorsi is damaged?
The animal turns stiffly when asked to turn
What is the origin and insertion of the brachiocephalicus muscle?
- Origin: Temporal bone, wing of atlas, and transverse processes of C2-C4.
- Insertion: Deltoid tuberosity of the humerus.
What is the function of the brachiocephalicus muscle?
Moves the limb forward when the head and neck are fixed
What is the origin and insertion of the pectoral muscles?
- Origin: Sternum.
- Insertion: Deltoid tuberosity, proximal forearm fascia, and greater & lesser tubercles of the humerus.
What is the function of the pectoral muscles?
Adduction of the limb
What are the three types of hip joint muscles?
- Extensors → Hamstring muscles (biceps femoris, semitendinosus, semimembranosus).
- Flexors → Psoas, iliacus, sartorius, tensor fasciae latae.
- Abductors → Superficial and deep gluteus.
What are the three hamstring muscles?
- Biceps femoris.
- Semitendinosus.
- Semimembranosus.
What is the origin and insertion of the biceps femoris?
- Origin: Vertebral head (last 3 sacral vertebrae, sacrosciatic ligament) & pelvic head (ischial tuber).
- Insertion: Patella and cranial border of tibia.
What is the function of the biceps femoris?
Hip extension and knee flexion.
What are the primary hip flexor muscles?
Psoas and iliacus (form the iliopsoas muscle)
What is the origin and insertion of the psoas muscle?
- Origin: Ventral surface of lumbar transverse processes.
- Insertion: Lesser trochanter of the femur.
What are the two elbow flexors?
- Biceps brachii.
- Brachialis.
What is the function of the biceps brachii?
Elbow flexion and forearm supination
