1. Throwing a baseball overhead
1.1Biceps brachii
Origin: Long head originates from tubercle above glenoid cavity of scapula. Short head originates from coracoid process of scapula
Insertion: Radial tuberosity of radius and bicipital aponeurosis
Action: Flexes forearm at elbow joint, supinates forearm at radioulnar joints, and flexes arms at shoulder joint.
1.2. Triceps brachii
Origin: Long head originates from infraglenoid tubercle, a projection inferior to glenoid cavity of scapula. Lateral head originates from lateral and posterior surface of humerus. Medial head originates from entire posterior surface of humerus inferior to a groove for the radial nerve.
Insertion: Olecranon of ulna
Action: Extends forearm at elbow joint and extends arm at shoulder joint
2. Kicking a ball
2.1. Rectus femoris
Origin: Anterior inferior iliac spine.
Insertion: Patella via quadriceps tendon and then tibial tuberosity via patellar ligament
Action: Extends leg at knee joint, also flexes thigh at hip joint
2.2 Vastus lateralis
Origin: Greater trochanter and linea aspera of femur
Insertion: Patella via quadriceps tendon and then tibial tuberosity via patellar ligament
Action: Extends leg at knee joint
3. Doing sit-ups
3.1. Rectus abdominis
Origin: Pubic crest and pubic symphysis
Insertion: Cartilage of the ribs 5-7 and xiphoid process
Action: Flexes vertebral column, especially lumbar portion, and compresses abdomen to aid in defecation, urination, forced exhalation, and childbirth. RMA: Flexes pelvis on the vertebral column.
3.2. Transversus abdominis
Origin: Iliac crest, inguinal ligament, lumbar fascia, and cartilages of ribs 5-10
Insertion: Xiphoid process. linea alba, and pubis
Action: Compresses abdomen
4. Breathing
4.1. Diaphragm
Origin: Xiphoid process of sternum, costal cartilages and adjacent portions of inferior six ribs, lumbar vertebrae and their intervertebral discs.
Insertion: Central tendon
Action: Contraction of diaphragm causes it to flatten and increases vertical dimension of thoracic cavity, resulting in inhalation: relaxation of diaphragm causes it to move superiorly and decreases vertical dimension of thoracic cavity, resulting in exhalation.
4.2. External intercostals
Origin: Inferior border of rib above
Insertion: Superior border of rib below
Action: Contraction elevates ribs and increases anteroposterior and lateral dimensions of thoracic cavity, resulting in inhalation; relaxation depresses ribs and decreases anteroposterior and lateral dimensions of thoracic cavity, resulting in exhalation.
and then tibi