Name at least three muscles that actively contracts during the following activities and name its action and innervation.
1. Turning a door knob
- Pronator quadratus
- Action: Pronates forearm at radioulnar joints
- Innervation: Median nerve
- Pronator teres
- Action: Pronates forearm at radioulnar joints and weakly flexes forearm at elbow joint
- Innervation: Median nerve
- Supinator
- Action: Supinates forearm at radioulnar joints
- Innervation: Deep radial nerve
- Action: Supinates forearm at radioulnar joints
2. Throwing a baseball overhead
- Teres Major
- Action: Extends arm at shoulder joint and assists in adduction and medial rotation of arm at shoulder joint
- Innervation: Lower subscapular nerve
- Subscapularis
- Action: Medially rotates arm at shoulder joint
- Innervation: Upper and lower subscapular nerve
- Deltoid
- Action: Lateral fibers abduct arm at shoulder joint; anterior fibers flex and medially rotate arm at shoulder joint; posterior fibers extend and laterally rotate arm at shoulder joint
- Innervation: Axillary Nerve
- Pectoralis major
- Action: As a whole, adducts and medially rotates arm at shoulder joint; clavicular head flexes arm, and sternocostal head extends flexed arm to side of trunk
- Innervation: Medial and lateral pectoral nerves
- Latissimus dorsi
- Action: Extends, adducts, and medially rotates arm at shoulder joint; draws arm inferiorly and posteriorly. RMA: Elevates vertebral column and torso
- Innervation: Thoracodorsal nerve
3. Kicking a ball
- Flexor hallucis brevis
- Action: Flexes great toe at metatarsophalangeal joint
- Innervation: Medial plantar nerve
- Psoas major
- Action: Psoas major and iliacus muscles acting together flex thigh at hip joint, rotate thigh laterally, and flex trunk on hip as in sitting up from supine position
- Innervation: Lumbar spinal nerves L2-L3
- Iliacus
- Action: Psoas major and iliacus muscles acting together flex thigh at hip joint, rotate thigh laterally, and flex trunk on hip as in sitting up from supine position
- Innervation: Femoral nerve
- Quadriceps femoris
- Action: Extends leg at knee joint
- Innervation: Femoral nerve
4. Doing sit-ups
- Rectus abdominis
- 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
- Innervation: Thoracic spinal nerves T7-T12
- External oblique
- Action: Acting together (bilaterally), compress abdomen and flex vertebral column; acting singly (unilaterally), laterally flex vertebral column, especially lumbar portion, and rotate vertebral column
- Innervation: Thoracic spinal nerves T7-T12 and the iliohypogastric nerve
- Internal oblique
- Action: Acting together, compress abdomen and flex vertebral column; acting singly, laterally flex vertebral column, especially lumbar portion, and rotate vertebral column
- Innervation: Thoracic spinal nerves T8-T12, the iliohypogastric nerve, and ilioinguinal nerve
- Transversus abdominis
- Action: Compresses abdomen
- Innervation: Thoracic spinal nerves T8-T12, iliohypogastric nerve, and ilioinguinal nerve
- Rectus femoris
- Action: extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint
- Innervation: Femoral nerve
5. Walking
- Rectus femoris
- Action: extend leg at knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint
- Innervation: Femoral nerve
- Soleus
- Action: Plantar flexes foot at ankle joint
- Innervation: Tibial nerve
- Gastrocnemius
- Action: Plantar flexes foot at ankle joint and flexes leg at knee point
- Innervation: Tibial nerve
- Tibialis posterior
- Action: Plantar flexes foot at ankle joint and inverts (supinates) foot at intertarsal joints
- Innervation: Tibial nerve
6. Breathing
- Diaphragm
- 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
- Innervation: Phrenic nerve, which contains axons from cervical spinal nerves (C3-C5)
- External intercostals
- 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
- Innervation: Thoracic spinal nerves T2-T12
- Internal intercostals
- Action: Contraction draws adjacent ribs together to further decrease anteroposterior and lateral dimensions of thoracic cavity during forced exhalation
- Innervation: Thoracic spinal nerves T2-T12