Bio lab muscles
Muscle | Origin | Insertion | Action |
|---|---|---|---|
Rectus abdominis | Pubic crest & pubic symphysis | Xiphoid process and costal cartilages of ribs 5-7 | Flex & rotate lumbar region of vertebral column |
Deltoid | Lateral third of clavicle, acromion and spine of scapula | Deltoid tuberosity of the humerus | Abduction of the arm |
Biceps brachii | Short head: coracoid process; long head: supraglenoid tubercle and lip of glenoid cavity | Tendon into radial tuberosity | Flexes and supinates forearm |
Rectus femoris | Anterior inferior iliac spine and superior margin of acetabulum | Patella and tibial tuberosity via patellar ligament | Extends leg and flexes thigh at hip |
Gluteus maximus | Dorsal ilium, sacrum and coccyx | Gluteal tuberosity of femur; iliotibial tract | Major extensor of thigh, laterally rotates and abducts thigh |
Tibialis anterior | Lateral condyle and upper 2/3 of tibial shaft; interosseous membrane | By tendon into inferior surface of medial cuneiform and first metatarsal bone | Prime mover of dorsiflexion |
Gastrocnemius | By two heads from medial and lateral condyles of femur | Posterior calcaneus via calcaneal tendon | Plantar flexes foot |
Sartorius | Anterior superior iliac spine | Winds around medial aspect of knee and inserts into medial aspect of proximal tibia | Flexes, abducts, and laterally rotates thigh |
Trapezius | Occipital bone, ligamentum nuchae, and spinous processes of C7 & all thoracic vertebrae | A continuous insertion along acromion and spine of scapula & lateral third of clavicle | Stabilizes, elevates, retracts and rotates scapula Neck extensors |
Sternocleidmastoid: neck flexors
Trunk flexors:
Obliques: Diagonal flexion of the trunk
Rectus Abdominis: Flexion of trunk; take a bow
Transverse Abdominis: Lateral rotation of trunk
Trunk Extensors:
Erector Spinae: Extension of the trunk; stand up after bowing
Latissimus Dorsi: Adduction and rotation of the arm
Trunk Lateral Flexion & Rotation
Obliques: Flex and rotate the trunk; hula-hoop rotation
Respiration:
Diaphragm: Drop the thoracic cavity toward the abdominal cavity; to expand the respiratory cavity to induce inhalation
Antagonistic Muscle is a muscle that opposes the action of another. For example, when the triceps oppose the contraction of the flexing biceps by relaxing, the triceps would be regarded as the antagonistic muscle to the biceps whereas the biceps would be the agonist muscle (or prime mover).
Synergist: Muscle whose contraction helps a prime mover (aka agonist) in an action
Prime mover: (Also, agonist) Principal muscle involved in an action
Origin: End of a skeletal muscle that is attached to another structure (usually a bone) in a fixed position
Insertion: End of a skeletal muscle that is attached to the structure (usually a bone) that is moved when the muscle contracts
Muscles that Stabilize the Rotator Cuff
Subscapularis
Supraspinatus
Infraspinatus
Teres Minor