ANAT - M3: S3: Axial Muscles

Frontalis

the muscle that covers the frontal bone and lifts the eyebrows, causing the forehead to wrinkle.

Orbicularis Oculi

a muscle surrounding the eye that forcefully closes the eye when contracted. It originates on the frontal and maxillary bones. 

Orbicularis Oris

surrounds the mouth and enables the puckering of lips. It originates on the maxillary bones or mandible and sometimes referred as a kissing muscle.

Zygomaticus

extends from the zygomatic arch to the corners of the mouth. It draws the angle of the mouth superiorly and posteriorly, causing one to smile. 

What is mastication and what muscles are involved.

The process of chewing. These muscles include the masseter and temporalis

Temporalis

a fan-shaped muscle that extends from the temporal fossa of the parietal bone to the coronoid process of the mandible. elevates and pulls the mandible posteriorly (retract). 

Masseter

powerful muscle that extends from the zygomatic arch to the angle of the mandible (lower jaw). Its action is to elevate and protract (move forward) the jaw.

Anterior sternocleidomastoid

flexes the neck with bilateral contraction (when matching muscles on both sides of the body contract or tighten at the same time), and rotates the head to the opposite site with unilateral contraction.

inferior attachment: sternum & clavicle 

superior attachment: mastoid process of temporal bone

two main posterior muscles that move the head:

the semispinalis capitis and the splenius capitis. 

semispinalis capitis

extends the neck with bilateral contraction, and turns the face slightly to the opposite side with unilateral contraction.(attaches to occipital bone and lies on each side of the spine.)

splenius capitis

extends the neck with bilateral contraction, and causes flexion and lateral rotation of the neck with unilateral contraction.(attaches to occipital bone, spleneus means bandage bc it looks like one)

Thorax and contains what

The region of the body between the neck and abdomen - contains intercostal muscles (groups of muscles situated in the gaps between your ribs).

External intercostal muscles

the most superficial, and their fibres run anteriorly and inferiorly between the ribs. They aid in inspiration. (inhaling)

Internal intercostal muscles

lie deep to the externals, and their fibres run posteriorly and inferiorly. They aid in expiration 

Erector spinae muscles

are a group of muscles that help to keep the spine erect. They run down both sides of the spinal column. 

The____________ muscles facilitate movement of the trunk, and aid in breathing.  

abdominal wall

External Oblique

most superficial of the anterolateral abdominal wall musculature. Its fibres run anteriorly and inferiorly.  

-bilateral: flexes the vertebral column and compresses the abdominal wall. Used in forced expiration. 

-Unilateral: lateral flexion and rotation of the vertebral column. 

Internal Oblique

lies deep to the external oblique, and its fibres run anteriorly and superiorly. 

-Bilateral: flexes the vertebral column and compresses the abdominal wall 

-Unilateral: lateral flexion and rotation of the vertebral column. 

Transversus Abdominis

The transversus abdominis runs horizontally, deep to the internal oblique. 

-Bilateral: flexes the vertebral column and compresses the abdominal wall. Used in forced expiration. 

-Unilateral: lateral flexion of the vertebral column. 

Rectus Abdominis

The rectus abdominis lies on either side of the linea alba (line of connective tissue down the middle of the abdomen for muscle attachment.)  and is separated by tendinous intersections. 

-Flexion of the trunk  

-Forced expiration