ACTIVITY 2
Name at least three muscles that actively contracts during the following activities and name its action and innervation:
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Turning a door knob
Latissimus dorsi
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Action: This muscle has the ability to pull the inferior angle of the scapula in various directions, resulting in shoulder joint movements (internal rotation, adduction and extension of the arm).
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Innervation: The sixth, seventh, and eighth cervical nerves innervate the latissimus dorsi via the thoracodorsal (long subscapular) nerve.
Triceps lateral head
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Action: This muscle extends the forearm the at elbow.
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Innervation: The lateral head is innervated by the radial nerve's C6 root value.
Triceps long head
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Action: The long head als helps with arm extension and adduction at the shoulder joint.
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Innervation: The axillary nerve innervates the long head of the triceps.
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Throwing a baseball overhead
Anterior deltoid
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Action: The front delts assist in moving your arm forward. They are attached to your clavicle.
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Innervation: The anterior branch of the axillary nerve wraps around the humerus deep to the deltoid muscle, innervating it as well. The teres minor and deltoid are both innervated by the posterior branch of the axillary nerve.
Pectoralis major
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Action: At the shoulder joint, the pectoralis major works as a powerful adductor and internal rotator of the humerus. The clavicular part of the muscle acts independently to flex the humerus up to 90 degrees in a horizontal plane.
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Innervation: The lateral and medial pectoral nerves of the brachial plexus innervate the pectoralis major muscle (root value C5-T1).
Upper Trapezius
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Action: to support and move the scapula Upper fibers can raise and rotate the scapula upwards, as well as lengthen the neck.
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Innervation: The sensory function of the trapezius is innervated by the ventral rami of C3, C4. Trapezius motor function is innervated by cranial nerve XI.
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Kicking a ball
Quadriceps
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Action: All of the quadriceps work together to extend (straighten) the knee.
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Innervation: Femoral nerve (L2-L4)
Iliopsoas
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Action: The iliopsoas muscle is the strongest hip flexor and aids in femoral external rotation, which is important in maintaining hip joint strength and integrity. It is necessary for proper standing or sitting lumbar posture, as well as walking and running.
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Innervation: The iliopsoas is innervated by the lumbar plexus's L2-4 nerve roots, which also send branches to the superficial lumbar muscles.
Rectus femoris
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Action: It extends the knee and assists the iliopsoas in hip flexion. As a result, it is also a hip flexor.
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Innervation: Femoral nerve (L2-L4)
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Doing sit-ups
Rectus abdominis
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Action: Flexion of the trunk (flexion of the thoracic and lumber spines), which acts by drawing the pubic symphysis and the sternum closer together. Also tense the anterior abdominal wall to help compress the contents of the abdomen.
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Innervation: Thoracoabdominal nerves enter the rectus sheath via penetrating its anterior surface and innervating the rectus abdominis muscle. They penetrate through the transversus abdominis and internal oblique muscle layers and pierce the rectus abdominis muscle sheath.
Internal and external obliques
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Action: The trunk is rotated and side bent by the external and internal oblique muscles. These muscles also help to maintain spinal stability.
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Innervation: The anterior rami of the thoracic spinal neurons T7-T12 innervate the external abdominal oblique.
Transverse abdominis
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Action: The transverse abdominis, like other core muscles, protects internal organs by holding them in place and supports the torso by maintaining abdominal wall tension, which stabilizes the spine and pelvis before any limb movement can occur.
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Innervation: Transversus abdominis is primarily supplied by the terminal branches of the lower five intercostal nerves and the subcostal nerve that emerge from the lower six thoracic spinal nerves (T7-T12).
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Walking
Soleus
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Action: To function as a skeletal muscle: Along with other calf muscles, it is a strong plantar flexor that contributes significantly to running, walking, and dancing. It is also a major postural muscle that prevents the body from falling forward during stance.
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Innervation: The anterior rami of the S1 and S2 spinal nerves innervate the soleus, which is carried into the posterior compartment of the leg by the tibial nerve. Two major branches provide blood supply.
Hamstrings
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Action: The hamstrings' primary function is to flex the knee joint and extend the hip, allowing for essential lower-limb activities such as walking, running, and climbing.
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Innervation: Nerves from the lumbar and sacral plexuses innervate the hamstring muscle complex.
Calves
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Action: Your calf muscle supports you and allows you to move your foot and lower leg when you stand. Walking or running propels (pushes) you forward. Jump, rotate your ankle, flex your foot, and "lock" your knee are also options.
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Innervation: The majority of the calf muscles are innervated by the tibial nerve (S1, S2).
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Breathing
Diaphragm
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Action: The diaphragm is a narrow skeletal muscle that separates the belly from the chest and sits at the base of the chest.
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Innervation: The phrenic nerves supply motor innervation to the diaphragm (C3-C5). After penetrating the diaphragm, these neurons innervate it from the abdominal surface.
Intercostals
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Action: Internal intercostals aid in exhalation and the return of the ribs and chest cavity to their natural position.
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Innervation: The anterior rami of spinal neurons T1-T11 innervate them.
Scalene
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Action: The posterior scalene elevates the second rib and tilts the neck to the same side. Along with the sternocleidomastoid, they serve as inspiration auxiliary muscles.
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Innervation: The third of the eight cervical spinal nerves innervate the scalene muscles (C3-C8).