Throwing a baseball overhead
1. Subscapularis
- Actions: It rotates arm at shoulder joint medially.
- Innervations: It is innervated by upper and a lower subscapular nerve, which both originating from the brachial plexus.
2. Latissimus dorsi
- Actions: It extends, adducts, and rotates arm medially at shoulder joint. It also draws arm inferiorly and posteriorly.
- Innervation: It is innervated by the thoracodorsal nerve.
Kicking a ball
1. Rectus femoris (from the quadriceps group)
- Actions: It helps with leg extension. When it acts alone, it can also flex thighs at hip joint.
- Innervation: It is innervated by the femoral nerve.
2. Extensor digitorum longus
- Actions: It is responsible for foot dorsiflexion at ankle joint and extension of distal and middle phalanges of each toe at interphalangeal joints and proximal phalanx of each toe at metatarsophalangeal joint.
- Innervation: It is innervated by the deep fibular (peroneal) nerve, a branch of the common fibular nerve.
Doing sit-ups
1. Rectus abdominis
- Actions: It flexes the vertebral column, especially the lumbar region. It also compresses the abdomen for defecation, urination, forced exhalation, and childbirth.
- Innervation: It is innervated by the thoracic spinal nerves T7 - T12.
2. External oblique
- Actions: It compress abdomen and flex vertebral column when acting bilaterally. When it acts unilaterally, it laterally flex vertebral column, especially lumbar portion, and rotate vertebral column.
- Innervation: It is being innervated by the thoracic spinal nerves T7–T12 and the iliohypogastric nerve.
Breathing
1. Diaphragm
- Actions: During inhalation, the diaphragm contracts and flattens, which increases the vertical dimension of the thoracic cavity. On the other hand, in exhalation, diaphragm causes it to move superiorly and decreases the vertical dimension of thoracic cavity, which signifies the relaxation of diaphragm.
- Innervation: It is innervated by the phrenic nerve (C3-C5), which contains the axons from cervical spinal nerves.
2. Internal intercostals
- Actions: Its contraction draws adjacent ribs together for the anteroposterior and lateral dimensions of the thoracic cavity to decrease during forced exhalation.
- Innervation: It is innervated by thoracic spinal nerves T2 - T12
REFERENCES:
- Tortora, G. J., & Derrickson, B. (2017). The Muscular System . In Principles of anatomy and physiology (15th ed., pp. 357–413). essay, Wiley Custom Learning Solutions.