Facial Muscles and Neck Muscles Quiz

Muscles of the Face

• Buccinator: flat muscle of the cheek, origins from alveolar processes of maxilla and mandible, inserts into orbicularis oris, presses cheeks against teeth and lips as in whistling, innervated by facial nerve.
• Orbicularis oris: closes the lips, shapes lips during speech and whistling, innervated by facial nerve.

Muscles of the Neck

• Sternocleidomastoid: assists in turning the head from side to side, accessory muscle in respiration, innervated by accessory nerve.
• Trapezius: pulls the head backwards, squares the shoulders, controls the movement of the scapula when the shoulder joint is in use, innervated by accessory nerve and cervical spinal nerves C3-C5.

Muscles of the Trunk

• Muscles of the back: stabilize the association between the appendicular and axial skeletons, allow movement of the shoulders and upper arms, divided into trapezius, latissimus dorsi, teres major, quadratus lumborum, and sacrospinalis.
• Latissimus dorsi: originates from posterior part of the iliac crest and spinous processes of the lumbar and lower thoracic vertebrae, inserts into bicipital groove of the humerus, abducts, medially rotates, and extends the arm, innervated by thoracodorsal nerve.
• Teres major: originates from inferior angle of the scapula, inserts into humerus below the shoulder joint, extends, abducts, and medially rotates the arm, innervated by lower subscapular nerve.
• Quadratus lumborum: originates from iliac crest, inserts into inferior border of the 12th rib, together with two muscles fix the lower rib during respiration, causes extension of the vertebral column (bending backwards), innervated by thoracic spinal nerve T12 and lumbar spinal nerves L1-L4.
• Sacrospinalis (erector spinae): lies between the spinous and transverse process of the vertebrae, originates from sacrum, inserts into occipital bone, extends the vertebral column (bending backwards), innervated by spinal nerves.
• Muscles of the abdominal wall: form the strong muscular anterior wall of the abdominal cavity, compress the abdominal organs, flex the vertebral column in the lumbar region.

Muscles of the Thorax

• Serratus anterior: originates from 1st to 8/9th rib, inserts into anterior surface of the medial border of the scapula, abducts scapula and rotates it upwards, innervated by long thoracic nerve.
• Internal intercostal muscles: originate from superior border of the ribs below, insert into inferior border of the rib above, depress the rib cage, aid in forced expiration, innervated by thoracic spinal nerves (T2-T12).
• External intercostal muscles: originate from inferior border of the rib above, insert into superior border of the rib below, contract elevate rib cage, aid in inhalation, and relax depress the rib resulting in exhalation, innervated by thoracic spinal nerves (T2-T12).
• Diaphragm: dome-shaped muscular structure, separates the thoracic and abdominal cavities, formed partly by muscle and partly by flattened tendon called central tendon, originates from xiphoid process of the sternum and costal cartilage, inserts into central tendon, helps in inhalation and exhalation, innervated by phrenic nerve.

Muscles of the Shoulder and Upper Limb

• Deltoid: originates from clavicle, acromion process, and spine of scapula, inserts into deltoid tuberosity of the humerus, forms the fleshy and rounded contour of the shoulder, movement of the arm, flexion, abduction, and lateral rotation of the shoulder joint, innervated by axillary nerve.
• Pectoralis major: forms anterior part of the axilla, originates from middle third of the clavicle and sternum, inserts into lip of the intertubercular groove of the humerus, draws the arm forwards and towards the body, innervated by medial and lateral pectoral nerves.
• Biceps brachii: lies on the anterior aspect of the upper arm, originates from short head from the coracoid process of the scapula and long head from the rim of the glenoid cavity of the scapula, inserts into radial tuberosity of the radius, stabilizes and flexes the shoulder joint, assists in flexion and supination at the elbow joint, innervated by musculocutaneous nerve.
• Triceps: lies on the posterior aspect of the humerus, originates from one head from the scapula and two heads from the posterior surface of the humerus, inserts into common tendon to the olecranon process of the ulna, stabilizes the shoulder joint, assists in abduction of the arm and extends the elbow joint, innervated by radial nerve.

Muscles of the Pelvic Floor

• Levator ani: supports the organs of the pelvis and maintains continence, resists raised intra-pelvic pressure during micturition and defecation, innervated by sacral spinal nerves (S2-S4).
• Coccygeus: supports the pelvic viscera, supports the coccyx and pulls it forward, innervated by sacral spinal nerves (S4-S5).

Muscles of the Hip and Lower Limb

• Quadriceps femoris: group of four muscles lying on the front and sides of the thigh, consists of rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius (lies deep), innervated by femoral nerve.
• Gluteal muscles: consist of gluteus maximus, medius, and minimus, form the fleshy part of the buttock, originate from ilium and sacrum, insert into femur, extend, abduct, and medially rotate at the hip joint, innervated by inferior and superior gluteal nerve.
• Hamstrings: lie on the posterior aspect of the thigh, consist of biceps femoris, semimembranosus, and semitendinosus muscles, originate from ischium, insert into upper end of the tibia, flex the knee joint, innervated by tibial nerve.
• Soleus: lies on the posterior aspect of the leg, originates from heads and upper parts of the fibula and the tibia, inserts into calcanean (Achilles) tendon, plantar flexion at the ankle, helps to stabilize the joint when standing, innervated by tibial nerve.

Intramuscular Injection (IM)

• Penetrates the skin and subcutaneous tissue, used when prompt action is desired, has a faster speed of delivery than oral medications but slower than intravenous, common sites of injection include gluteus medius (ventrogluteal), vastus lateralis muscle, rectus femoris, and deltoid muscle.

Diseases of Muscle

• Myasthenia gravis: autoimmune disease, the immune system inappropriately produces antibodies that bind and block the acetylcholine receptors of the neuromuscular junction, causes progressive and extensive muscle weakness, affects extrinsic and eyelid muscles first, causing ptosis (drooping of the eyelid) or diplopia (double vision), affects chewing, swallowing, and speech.
• Muscular Dystrophy: a group of inherited muscle-destroying diseases that cause progressive degeneration of skeletal muscle fibers.