1. Turning a door knob
- Pronator quadratus muscles
- Action - Proximal radioulnar joint: Forearm pronation
- Innervation - Median nerve (anterior interosseous nerve, C7, C8)
- Action - Proximal radioulnar joint: Forearm pronation
- Pronator teres
- Action - Pronation of forearm at the proximal radioulnar joint, flexion of the forearm at the elbow joint
- Innervation - Median nerve (C6, C7)
- Supinator
- Action - Proximal radioulnar joint: Forearm supination
- Innervation - Posterior interosseous nerve (C7, C8)
2. Throwing a baseball overhead
- 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 (C5, C6)
- 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.
- Subscapularis
- Action - Shoulder joint: Arm internal rotation, Stabilizes humeral head in glenoid cavity
- Innervation -Upper and lower subscapular nerves (C5 - C6)
- Action - Shoulder joint: Arm internal rotation, Stabilizes humeral head in glenoid cavity
- Teres Major
- Action - Extends arm at shoulder joint and assists in adduction and medial rotation of arm at shoulder joint.
- Innervation - Lower subscapular nerve (C5-C7)
3. Kicking a ball
- Semitendinosus
- Action - Flexes leg at knee joint and extends thigh at hip joint.
- Innervation - Tibial branch of sciatic nerve (L5 - S2)
- Action - Flexes leg at knee joint and extends thigh at hip joint.
- Iliopsoas
- 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)
- 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.
- Quadriceps femoris
- Action - knee joint; rectus femoris muscle acting alone also flexes thigh at hip joint.
- Innervation - Femoral nerve (L2-L4)
4. Doing sit-ups
- Internal Oblique
- Action - Bilateral contraction - Trunk flexion, compresses abdominal viscera, expiration; Unilateral contraction - Trunk lateral flexion (ipsilateral), trunk rotation (ipsilateral)
- Innervation: Intercostal nerves (T7-T11), subcostal nerve (T12), iliohypogastric nerve (L1), ilioinguinal nerve (L1)
- Action - Bilateral contraction - Trunk flexion, compresses abdominal viscera, expiration; Unilateral contraction - Trunk lateral flexion (ipsilateral), trunk rotation (ipsilateral)
- External Oblique
- Action: Bilateral contraction - Trunk flexion, compresses abdominal viscera, expiration; Unilateral contraction - Trunk lateral flexion (ipsilateral), trunk rotation (contralateral)
- Innervation - Motor: Intercostal nerves (T7- T11), Subcostal nerve (T12)
Sensory: Iliohypogastric nerve (L1)
- Action: Bilateral contraction - Trunk flexion, compresses abdominal viscera, expiration; Unilateral contraction - Trunk lateral flexion (ipsilateral), trunk rotation (contralateral)
- Transversus abdominis
- Action - Bilateral contraction - Compresses abdominal viscera, expiration
Unilateral contraction - Trunk rotation (ipsilateral) - Innervation - Intercostal nerves (T7-T11), subcostal nerve (T12), iliohypogastric nerve (L1), ilioinguinal nerve (L1)
- Action - Bilateral contraction - Compresses abdominal viscera, expiration
- Rectus abdominis
- Action - Flexes trunk, aids forced expiration and raise intra-abdominal pressure
- Innervation - Intercostal nerves (T7-T11), subcostal nerve (T12)
5. Walking
- Fibularis longus
- Action - Plantar flexes foot at ankle joint and everts (pronates) foot at intertarsal joints.
- Innervation: Superficial fibular nerve (L5, S1)
- Action - Plantar flexes foot at ankle joint and everts (pronates) foot at intertarsal joints.
- Tibialis anterior
- Action - Dorsiflexes foot at ankle joint and inverts (supinates) foot at intertarsal joints
- Innervation: Deep fibular nerve (L4, L5)
- Action - Dorsiflexes foot at ankle joint and inverts (supinates) foot at intertarsal joints
- Soleus
- Action - Plantar flexes foot at ankle joint.
- Innervation - Tibial nerve (S1, S2)
6. Breathing
- External intercostal muscles
- 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
- 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.
- Internal intercostal muscles -
- 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.
- Action : Contraction draws adjacent ribs together to further decrease anteroposterior and lateral dimensions of thoracic cavity during forced exhalation.
- 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 nerves (C3-C5) (sensory innervation of peripheries via 6th-11th intercostal nerves)
References
Tortora GJ & Derrickson B. (2014). Chapter 11 Muscular System. Principles of Anatomy and Physiology. John Wiley & Sons, Inc. 14 edition. Pp 327-446.