Muscles that have both their origins and insertions on parts of the axial skeleton.
Function of Axial Muscles
Support and move the head and spinal column, function in nonverbal communication by affecting facial features, move the lower jaw during chewing, assist in food processing, and help in swallowing, aid in breathing, and support and protect the abdominal and pelvic organs.
Consists of the occipitofrontalis muscle and a broad epicranial aponeurosis or galea aponeurotica.
Facial muscle which is part of the epiranius and has two bellies separated by the galea aponeurotica.
Frontal Belly of Occipitofrontalis
Overlays the frontal bone. Origin=frontal bone and skin of eyebrows. Insertion= epicranial aponeurosis. Action= moves the scalp, wrinkles forehead, and elevates the eyebrows.
Occipital Belly of Occipitofrontalis
Covers the posterior of the head. Origin= superior nuchal line. Insertion= epicranial aponeurosis. Action= moves the scalp slightly posteriorly.
Consists of muscle fibers that encircle the opening of the mouth. Origin= mandible and maxillae as well as fascia and fibers from other muscles. Insertion= skin and lips surrounding the mouth. Action= closes lips, puckers up the lips.
Consists of muscle fibers on the anteriolateral portions of the neck. Origin= fascia of deltoid and pectoralis major muscles and acromion of scapula. Insertion= skin of cheek and mandible. Action= pulls lower lip inferiorly, tenses skin of neck, and contributes to depression of the mandible.
Muscle located between the maxillae and the mandible and composes much of he fleshy wall of the cheeks. Origin= alveolar processes of mandible and maxillae. Insertion= orbicularis oris. Action= compresses cheek, hold food between teeth during chewing, aids in sucking and blowing.
Clinical: Facial Nerve Paralysis
Clinical: Unilateral paralysis of the muscles of facial expression.
Clinical: Idiopathic Facial Nerve Paralysis or Bell Palsy
Clinical: Facial nerve paralysis when the cause is unknown. Caused by interruption of the CN 7nerve, on the same side of the paralysis, through herpes, cold temperatures, sleeping on one one side while facing an open window, and compression by the blood vessels.
Clinical: Treatment for Bell Palsy
Clinical: Prednisone(type of steroid), acyclovir(zovirax) for herpes, and eyedrops or an eye patch for dry eyes.
Clinical: Improper alignment of eyes.
Clinical: Lazy Eye
Clinical: Condition in strabismus where the ignored eye becomes weaker and weaker over time.
Clinical: Strabismic Amblyopia
Clinical: Loss of visual acuity due to an uncorrected lazy eye.
Clinical: Causes of Strabismus
Clinical: Birth injuries, diseases localized to the eye or its bony orbit, improper attachment of the extrinsic eye muscles, and heredity.
Clinical: External Strabismus
Clinical: Type of strabismus that occurs when the oculomotor nerve is injured, so that the affected eye moves laterally while at rest but cannot move medially and inferiorly.
Clinical: Internal Strabismus
Clinical: Typed of strabismus that occurs when the abducens nerve is injured. The affected eye moves medially but cannot move laterally.
A broad, fan-shaped muscle that extends from the temporal region of the skull, passes deep to the zygomatic arch, and attaches to the coronoid process of the mandible. Origin= superior and inferior portions of temporal bone. Insertion= coronoid process of mandible. Action= elevates and retracts mandible.
Superficial to the temporalis and posterior portions of the buccinator. Origin= zygomatic arch. Insertion= lateral surface of coronoid process; lateral surface and angle of mandible. Action= elevates and protracts mandible; prime mover of jaw closure.
Medial and Lateral Pterygoid
Muscles that are located near the TMJ. They help maximize the efficiency of the teeth while chewing or grinding foods of various consistencies. Origin= pterygoid processes of the sphenoid bone. Insertion= mandible. Action= elevate and protract the mandible and move it from side to side during chewing.
A toxigenic disease that often follows a dirty puncture wound. The resulting involuntary contraction(tetany) usually affects the muscles that move the mandible first, which is why the disease is commonly known as lock jaw.
Clinical: Form of spastic paralysis caused by clostridium tetani under anaerobic conditions. Blocks release of glycine which overstimulates muscles. C. tetani is a common soil organism that can transfer the disease.
Clinical: Potentially fatal muscular paralysis caused by clostridium botulinum under anaerobic conditions. Prevents acetylcholine to be released causing muscle relaxation and paralysis. C. botulinum is a common soil organism that can transfer the disease.
Clinical: Approved injection of botulinum that takes away wrinkles for 120 days.
Form the lateral borders of the suprasternal fossa of the skin. Origin= manubrium and sternal ends of clavicles. Insertion= mastoid processes of temporal bones. Action= when both contract, the head is pulled forward and down, when one contracts it turns the head sideways in a direction opposite the side on which the contracting muscle is located.
Clinical:Congenital Muscular Torticollis
Clinical: Often known as wryneck, it is a condition where a newborn presents with a shortened and tightened sternocleidomastoid muscle.
Clinical: Causes of CMT
Clinical: Trauma resulting from either a difficult birth or prenatal position of the fetus. Also can be caused by car seats.
Clinical: Flattening of the head which accompanies CMT.
Clinical: Treatment for CMT
Clinical: Daily stretching, changing sleeping positions, using affected side, and surgery in severe cases. Botox has also been used to treat this disorder.
Origin= ligamentum nuchae. Insertion= occipital bone and mastoid process of temporal bone. Action= when both contract it pulls the head back and extends and hyperextends the cervical vertebrae, however, when one contracs it turns the head sideways in a direction towards the same side on which the contracting muscle is located.
Origin= seventh cervical vertebrae and first six thoracic vertebrae. Insertion= between the superior and inferior nuchal lines of the occipital bone. Action= same as splenius capitus.
It is actually part of the vertebral column, so the splenius capitis and semispinalis capitis extend the cervical portion of the vertebral column.
Muscles used to maintain posture and to help us stand erect. Found along the entire vertebral column. When the left and right erector spinae muscles contract together, they extend the vertebral column. If the erector spinae muscles on only one side contract, the vertebral column flexes laterally toward the same side.
Muscles that connect ans stabilize the vertebrae and are deep to the erector spinae. These muscles, like the erector spinae muscles, can cause either lateral flexion or extend the spine.
Used for restful breathing and extend inferomedially from the superior rib to the adjacent inferior rib. Origin= inferior border of superior rib. Insertion= superior border of inferior rib. Action= elevates the ribs by causing them to move up and out during inhalation to increase the dimension of the thoracic cavity.
Used during forceful exhalation(remember: internals are "intense breathing") and are located at right angles to themore superficial external intercostals. Origin= superior border of inferior rib. Insertion= inferior border of superior rib. Action= Depresses the ribs during forced exhalation.
Internally placed, dome-shaped skeletal muscle tht forms a partition between the thoracic and abdominal cavities. It is the most important muscle associated with breathing. Origin= inferior internal surface of lower ribs, xiphoid process, costal cartilages of inferior ribs, and lumbar vertebrae. Insertion= Central Tendon. Action= contraction during inhalation causes flattening of the diaphragm, thereby expanding the thoracic cavity and compressing the abdominopelvic cavity.
A strong aponeurosis that is the insertion for all peripheral muscle fibers of the diaphragm.
Clinical: Paralysis of the Diaphragm
Clinical: Injury to critical parts of the brain, spinal cord, or phrenic nerves can result in this deadly condition in which the primary muscle of respiration becomes inutil. The most common cause is injury at or superior to the fourth cervical vertebra.
Clinical: Virus that commonly caused paralysis of the diaphragm. Treatment included the "Iron Lung".
Clinical: Treatment for Diaphragm Paralysis
Clinical: A modern ventilator or the old iron lung can aid in breathing for those with diaphragm paralysis.
Three pairs of muscles (external oblique, internal oblique, and transverse abdominis) form this aponeurosis which surrounds and enfolds the rectus abdominis.
Cutaneous depression formed just lateral to the rectus abdominis.
Partitions the rectus abdominis horizontally into four segments. Responsible for the "six pack".
Partitions the rectus abdominis into left and right halves.
Not only forms an aponeurosis that contributes the rectus sheath, this aponeurosis also extends inferiorly to form a strong inguinal ligament. Origin= external inferior borders of lower ribs. Insertion= linea alba by a broad aponeurosis; some to the iliac crest. Action= when both contract they compress the abdomen and flex the vertebral column, when only one contracs, it causes lateral flexion of the vertebral column.
Ligament that extends from the anterior superior iliac spine to the pubic tubercle.
Clinical: The condition in which a portion of the viscera protrudes through a weakened point of the muscular wall of the abdominopelvic cavity.
Clinical: Strangulated Intestinal Hernia
Clinical: Occurs when the herniated portion of the intestine swells and cuts off blood flow which kills that portion of the intestine.
Clinical: Inguinal Hernia
Clinical: Hernia in which the intestine protrudes through the inguinal canal. More common in males and is caused by increased pressure to the abdominal cavity(i.e. lifting weights).
Clinical: Superficial Inguinal Ring
Clinical: Opening of the inguinal canal and often a site of rupture with an inguinal hernia.
Clinical: Direct Inguinal Hernia
Clinical: Inguinal hernia in which the intestine protrudes only through the superficial inguinal ring. Common in middle-aged males with poorly developed abdominal muscles and protruding abdomens.
Clinical: Indirect Inguinal Hernia
Clinical: Inguinal hernia where the intestine travels down the inguinal canal and may extend all the way into the scrotum. The congenital anomaly called Patent Process Vaginalis may predispose someone to this hernia.
Clinical: Patent Process Vaginalis
Clinical: Congenital anomaly, that predisposes younger males or male children to indirect inguinal hernias, in which the embryonic path taken by the testis into the scrotum fails to regress.
Clinical: Femoral Hernia
Clinical: Hernia common in females. Occurs in the upper thigh, just inferior to the inguinal ligament, originating in a region called the femoral triangle.
Immediately deep to the external oblique, it also forms an aponeurosis that contributes to the rectus sheath. Origin= lumbar fascia, inguinal ligament, and iliac crest. Insertion= linea alba, pubic crest, costal cartilages and surfaces of the lower ribs. Action= same as external oblique.
Deepest muscle of the rectus sheath, whose fibers project transversely across the abdomen. Origin= iliac crest, lumbar fascia, inguinal ligament and cartialges of lower ribs. Insertion= linea alba and pubic crest. Action= primarily compresses the abdomen.
A long, strap-like muscle that extends vertically the entire length of the anteriomedial wall between the sternum and the pubic symphysis. Origin= superior surface of pubis near symphysis. Insertion= xiphoid process of sternum and inferior surfaces of middle ribs. Action= flexes vertebral column and compresses the abdominal wall.
The floor of the pelvic cavity which is formed by three layers of muscles and associated fasciae. Extends from the ischium and pubis of the ossa coxae across the pelvic outlet to the sacrum and coccyx.
The diamond-shaped region between the lower appendages. Its limits are the pubic symphysis anteriorly, the coccyx posteriorly, and both ischial tuberosities laterally.
Anterior portion of the perineum which contains the external genitalia and urethra.
Posterior portion of the perineum which contains the anus.
Supports the pelvic viscera and fuctions as a sphincter at the anorectal junction, urethra, and vagina.
One of the muscles of the levator ani group. Kegal exercises target this muscle to specifically strengthen it to help control urinary incontinenece and to compress the vagina to aid in sexual enjoyment during coitus.
Clinical: A surgical incision made in the perineal skin and soft tissues between the vagina and the anus during childbirth to prevent tearing of the mother's tissues and to minimize fetal injury.