Muscles of the head, neck and trunk 11 lab

The four muscles of mastication are involved in chewing food.

1. Temporalis 2. Masseter 3. Lateral pterygoid 4. Medial pterygoid

Muscle: Nasalis

Action: Compresses and dilates nostrils.

Muscle: Depressor labii inferioris

Action: Depresses lower lip.

Muscle: Zygomaticus major

Action: Elevates lateral corner of mouth for smiling.

Muscle: Lavator labii superioris

Action: Elevates upper lip.

Muscle: Zygomaticus minor

Action: Elevates upper lip.

Muscle: Platysma

Action: Tenses skin of the neck; depresses the mandible.

Muscle: Orbicularis oris

Action: closes and protrudes lips while speaking, kissing, and whistling.

Muscle: Orbicularis Oculi

Action: closes eyelid during squinting and blinking.

Muscle: Buccinator

Action: compresses cheeks while whistling or blowing

Muscle: Depressor anguli oris

Action: depresses angle of mouth.

Muscle: Mentalis (cut)

Action: protrudes lip; wrinkles skin on chin.

Muscle: Procerus

Action; Depresses eyebrow; wrinkles skin over bridge of nose.

Three layers of oblique muscles cover the

Anterolateral aspect of the abdominal wall.

The _____ muscles perform voluntary eye movements.

Extraocular

The Rectus abdominis is the primary respiratory muscle.

False

When a muscle contracts to cause an action at a joint, the origin is the moving attachment of the muscle, and the insertion is the stationary attachment.

False

The intercostal spaces (between the ribs) contain three layers of

Intercoastal muscles, which play an important role in respiration ( breathing)

Most of which group of muscles originate on bone and insert on the skin?

Muscles of facial expression.

External oblique

Origin: External surfaces of inferior eight ribs Insertion: Linea alba, pubic tubercle, iliac crest.

Internal oblique

Origin: Thoracolumbar (lumbodorsal) fascia, iliac crest Insertion: Linea alba, inferior three or four ribs, pubic crest

rectus abdominis

Origin: pubic symphysis and pubic crest Insertion: xiphoid process of the sternum and costal cartilages of ribs 5 through 7

Transversus abdominis

Origin: thoracolumbar (lumbodorsal) fascia, costal cartilages of inferior six ribs, iliac crest. Insertion: Linea alba, pubis

Muscles of the pelvic floor are located in a region known as the

Perineum

The diaphragm is the

Primary respiratory muscle

The suprahyoid muscles connect the hyoid bone to the

Skull.

The most prominent muscle in the neck is the

Sternocleidomastoid which is a relatively long and superficial strap like muscle on each side of the neck. It is an important anatomical landmark because it separates the neck on each side into two triangular-shaped regions known as the Anterior and posterior triangles.

Muscles of the anterior triangle include two groups of muscles.

Suprahyoid muscles-are superior to the hyoid bone and connect it to the skull. Infrahyoid muscles-are inferior to the hyoid bone and connect it to the sternum, clavicle, and scapula.

Muscles can also act as

Synergists ( working together) by promoting or assisting a specific action or by reducing unnecessary movements while the action is performed.

An antagonist muscle directly opposes a specific action.

The triceps brachii extends the forearm and is an antagonist muscle that opposes flexion.

The deep back (erector spinae) muscles flex the vertebral column

True

The sternocleidomastoid separates the anterior and posterior triangles in the neck.

True

There are three layers of abdominal oblique muscles.

True

The Gastrocnemius is

a large superficial muscle in the posterior leg (calf). One of it's functions is plantar flexion of the foot, which allows you to stand on your toes.

The Masseter is

a muscle of mastication ( chewing). It is attached to the lateral surface of the mandible and the zygomatic arch. the muscle elevates the mandible.

An agonist or prime mover is

a muscle that directly brings about a specific action. for example, the biceps brachii is an agonist for flexion of the forearm.

A lever is

a rigid object that moves on a fixed point, called a fulcrum, when a force is applied. In the body, when a muscle contracts, it applies a force that causes a bone to move at a joint.

muscle: frontalis

action: raises eyebrows; wrinkles forehead.

The muscles of the lower limbs

are important for locomotion, support, and erect posture.

Extrinsic tongue muscles

are involved in voluntary tongue movements during chewing, swallowing, and speaking. 1. palatoglossus 2. styloglossus 3. genioglossus 4. hyoglossus

Most skeletal muscles are attached to bones by dense regular connective tissue in the form of

cordlike tendons or membranous sheets called aponeuroses

The muscles of the upper limb are

essential for our ability to carry out fine motor skills.

The deep back muscles

extend, rotate, and laterally flex the vertebral column and head, and they have an important role in maintaining normal posture.

Brachioradialis

flexes the forearm and stabilizes the elbow joint.

The axial muscles are

head, neck, and trunk include about 60% of all skeletal muscles in the body.

The erector spinae muscles

iliocostalis, longissimus, spinalis

The appendicular muscles

include the muscles upper and lower limbs.

rectus sheath

is formed by the aponeuroses of the three oblique muscles. Encloses the rectus abdominis muscles.

The Linea alba

is formed by the interlacing fibers of the rectus sheath and separates the two rectus abdominis muscles.

When an action occurs, one bony attachment, the Origin

remains fixed or stationary, whereas the other attachment, the insertion, moves.

The transversospinalis

semispinalis, multifidus, rotatores

Splenius muscles

splenius capitis and splenius cervicis

Glossus refers to the

tongue