Muscles
Parts A: Facial expression
● Occipitofrontalis:
○ frontal belle: superficial to the frontal bone (anterior)
■ Draws scalp anteriorly, raises eyebrows and wrinkles skin of forehead
○ occipital belly: superficial to the occipital bone (posterior)
■ Draws scalp posteriorly
● Orbicularis oculi
○ Muscle surrounding the eye
■ Closes the eye, and another muscle called levator palpebrae superiorris
opens it
● Orbicularis oris
○ Musle surrounding the mouth
■ Closes and protrudes lips (kissing); compresses lips against teeth, and
shapes lips during speech
● Platysma
○ Muscle arising from the pectoral and rises over the clavicle that extends upward
in a slanting manner alongside the sides of the neck
■ Drraws outer part of upper lip inferiorly and posteriorly as in pouting;
depresses mandible
Part B: Mandible
Masseter
● The muscle of the cheek; side of the jaw nearest the ear
○ Elevates mandible when closing mouth
Temporalis
● Thin, fan-shaped muscle in the side of skull and in front of the ear
○ Elevates and retracts mandible
Part C: Head
Sternocleidomastoid
●
○ Flex cervical portion of vertebral column, extend head at atlanto-occcipital joints.
Acting singly, laterally flex neck and head to same side and rotate head to side
opposite contracting muscle. Laterally rotate and flex head to opposite side of
contracting muscle. Posterior fibers of muscle can assist in extension of head.
, Elevate sternum during forced inhalation
■ The function of this muscle is to rotate the head to the opposite side or
obliquely rotate the head. It also flexes the neck. When both sides of the
muscle act together, it flexes the neck and extends the head. When one side
acts alone, it causes the head to rotate to the opposite side and flexes
laterally to the same side (ipsilaterally).
Part D:
Ext. oblique:
● The external oblique is situated on the lateral and anterior parts of the abdomen.
○ Acting bilaterally: Compress abdomen and flex vertebral column.
○ Acting singly: laterally flex vertebral column (lumbar portion) and rotate vertebral
column
Intern. Oblique
● Intermediate flat muscle; lies below the external oblique and above the tranverse
abdominal muscle
○ Together: compress abdomen and flex vertebral columns
○ Singly: laterally flex vertebral column, and rotate vertebral column
Rectus abdominis
● The long muscle that extends the entire length of the anterior abdominal wall
○ Flexes vertebral column, and compresses abdomen to aid in defecation,
urination, forced inhalation, and childbirth
Transverse abdominis
● Deepest of the abdominal muscles; wraps around the abdomen between the lower ribs
and top of pelvis
○ Singly: compresses abdomen
●
Part E:
Diaphragm
● Function: contracts -> increase vertical dimension of thoracic activity = inhalation
○ Relaxation: move superiorly and decreases vertical dimension -> exhalation
Parts A: Facial expression
● Occipitofrontalis:
○ frontal belle: superficial to the frontal bone (anterior)
■ Draws scalp anteriorly, raises eyebrows and wrinkles skin of forehead
○ occipital belly: superficial to the occipital bone (posterior)
■ Draws scalp posteriorly
● Orbicularis oculi
○ Muscle surrounding the eye
■ Closes the eye, and another muscle called levator palpebrae superiorris
opens it
● Orbicularis oris
○ Musle surrounding the mouth
■ Closes and protrudes lips (kissing); compresses lips against teeth, and
shapes lips during speech
● Platysma
○ Muscle arising from the pectoral and rises over the clavicle that extends upward
in a slanting manner alongside the sides of the neck
■ Drraws outer part of upper lip inferiorly and posteriorly as in pouting;
depresses mandible
Part B: Mandible
Masseter
● The muscle of the cheek; side of the jaw nearest the ear
○ Elevates mandible when closing mouth
Temporalis
● Thin, fan-shaped muscle in the side of skull and in front of the ear
○ Elevates and retracts mandible
Part C: Head
Sternocleidomastoid
●
○ Flex cervical portion of vertebral column, extend head at atlanto-occcipital joints.
Acting singly, laterally flex neck and head to same side and rotate head to side
opposite contracting muscle. Laterally rotate and flex head to opposite side of
contracting muscle. Posterior fibers of muscle can assist in extension of head.
, Elevate sternum during forced inhalation
■ The function of this muscle is to rotate the head to the opposite side or
obliquely rotate the head. It also flexes the neck. When both sides of the
muscle act together, it flexes the neck and extends the head. When one side
acts alone, it causes the head to rotate to the opposite side and flexes
laterally to the same side (ipsilaterally).
Part D:
Ext. oblique:
● The external oblique is situated on the lateral and anterior parts of the abdomen.
○ Acting bilaterally: Compress abdomen and flex vertebral column.
○ Acting singly: laterally flex vertebral column (lumbar portion) and rotate vertebral
column
Intern. Oblique
● Intermediate flat muscle; lies below the external oblique and above the tranverse
abdominal muscle
○ Together: compress abdomen and flex vertebral columns
○ Singly: laterally flex vertebral column, and rotate vertebral column
Rectus abdominis
● The long muscle that extends the entire length of the anterior abdominal wall
○ Flexes vertebral column, and compresses abdomen to aid in defecation,
urination, forced inhalation, and childbirth
Transverse abdominis
● Deepest of the abdominal muscles; wraps around the abdomen between the lower ribs
and top of pelvis
○ Singly: compresses abdomen
●
Part E:
Diaphragm
● Function: contracts -> increase vertical dimension of thoracic activity = inhalation
○ Relaxation: move superiorly and decreases vertical dimension -> exhalation
