Axial Flashcards
is a thin sheet-like muscle that has its origin in the fascia covering the pectoral muscles, and its insertion on the skin and muscle at the corner of the mouth. I think of it as an accessory pouting muscle because it pulls the lower lip back and down causing the mouth to sag. It also tenses the skin covering the neck. All the muscles of facial expression are innervated by cranial nerve VII, aptly called the facial nerve, EXCEPT for the levator palpebrae superioris which is innervated by cranial nerve III, the occulomotor.
The platysma
Perpendicular to the midline
transverse
- Muscles that oppose or perform the reverse activity of the prime mover are called ___
- When a prime mover is contracting, the __ must be relaxed or stretch.
- also prevent “overshoot” of the movement by helping to slow down the prime mover.
antagonists
has its origin on the styloid process of the temporal bone. It retracts the tongue.
styloglossus
is a small muscle that draws the eyebrows together and downward. It wrinkles the skin of the forehead as in frowining.
The corrugator supercilii
__ __have short fascicles that attach obliquely to a central tendon. They have a feather-like arrangement to their fascicles (___ comes from penna which means feather).
Pennate muscles
Muscles that have their fascicles arranged in a circular pattern of concentric rings usually surround external openings to the body. These muscles are called ___. When these muscles contract, they close the opening. Examples would include the muscles that surround the eyes and mouth.
sphincters
Larynx, thyroid gland, hyoid bone, common carotid artery and external jugular vein
anterior triangle
A muscle that is providing the major force for a particular movement is called the ___.
prime mover or agonist
- Side-to side grinding movements
- protrudes the mandible as well as functioning in side-to-side jaw movements. All of the muscles of mastication move the jaw at the temporomandibular joint or TMJ.
lateral pterygoid
the effort is applied at one end of the lever, the load is at the other and the fulcrum is in between.
Applied force and resistance are on opposite sides of the fulcrum
Examples of common __ __ that you have encountered in your life outside of A&P include seesaws and scissors.
first-class levers
- Deep to the sternocleidomastoid are the ___ which are muscles of the posterior triangle, and have their origins on the transverse processes of the cervical vertebrae.
- have their origins on the transverse processes of the cervical vertebrae and their insertion of the first and second ribs. The anterior ____ muscles are superficial to the middle and posterior ___ when the body is viewed from the anterior. The middle ___ muscles are the longest of the three, and the posterior___ are the smallest. Working together these muscles flex, laterally flex and rotate the head. They also can function in forced or deep breathing. By pulling the ribs toward the head, the volume of the thoracic cavity is increased thus assisting with forced inspiration. Forced breathing occurs when exercising or under pathological conditions involving diseases of the lungs.
scalenes
- When dissecting muscles, you may be directed to cut through the “___” of a muscle and reflect it so you can view deeper muscle groups.
- The “___” of a muscle is the meaty or thickest part of the muscle that usually lies midway between the muscle’s tendon attachments.
belly
has its origin on the ligamentum nuchae which is a strong, elastic ligament extending from the occipital bone along the spinous processes of the cervical vertebrae binding them together and inhibiting excessive head and neck flexion which prevents damage to the spinal cord. It inserts on the occipital bone and mastoid process of the temporal bone. Its action is to extend, laterally flex, and rotate the head.
The splenius capitis
lies superficial to the frontal bone. It inserts on the skin just above orbit (eyebrows); it raises the eyebrows (surprise), and horizontally wrinkles the skin of the forehead. The occipital belly (occipitalis) has its origin on the occipital and temporal bones and pulls the scalp posteriorly.
The frontal belly or frontalis
which are below the hyoid bone.
the infrahyoid muscles
___ __ have their fascicles running along the long axis of the muscle. These muscles can be flat straps like many of the muscles in our necks or can be spindle shaped (fusiform) with an expanded belly (like the biceps brachii muscle we discussed in the previous slide).
Parallel muscles
widens the throat for swallowing and is innervated by the first cervical nerve.
The geniohyoid
Means straight so a muscle with the word ___ in it means the fibers run parallel to the midline.
rectus
is an antagonist to the zygomaticus which means it draws the corners of the mouth down and laterally as when you are sad.
the depressor anguli oris
Diagonal to the midline
oblique
- Most movements are the result of combined activities of muscle groups that work together to create precise or steady movements. The muscles that are assisting the prime mover are called __.
- They prevent instability, unwanted movements and help the prime mover to work more efficiently.
synergists
then has its origin on the internal surface of the mandible and its insertion at the bottom of the tongue and body of the hyoid bone. It functions mainly to protrude the tongue (stick your tongue out).
The genioglossus
___ has its origin on the maxilla and its insertion on the aponeurosis over the nose. It flares the nostrils.
The nasalis
The orbits are surrounded by a tripartite (having 3 parts) muscle called the__ __ . This muscle is a sphincter and its job is to protect the eyes from bright light & foreign objects. It functions in blinking and squinting, and closes the “eye”.
orbicularis oculi
Deltoid = triangular
Deltoid
Trapezius = trapezoid
Trapezius
Serratus = saw toothed
Serratus anterior
Rhomboideus = diamond shaped
Rhomboideus major
Orbicularis = circular
Orbicularis oculi
Pectinate = comblike
Pectineus
Piriformis = pear-shaped
Piriformis
Platys = flat
Platysma
Quadratus = square
Quadratus femoris
Gracilis = slender
Gracilis
draws the corner of the lip laterally & tenses the lips.
The risorius
We will consider only the larger extrinsic tongue muscles. All of these muscles are innervated by cranial nerve XII, the ___ __ .
Hint: any word that has the term “glossus” in it has something to do with the tongue, and words that contain “genio” are referring to the chin (actually mandible).
the hypoglossal nerve
- is a useful superficial anatomical landmark because it divides the structures in the neck into anterior and posterior triangles.
- is a two-headed muscle with its origins on the sternum and clavicle and insertion on the mastoid process of the temporal bone.
- This muscle is the prime mover of head flexion when both sides contract at the same time. It also moves the head from side to side when only one side contracts—it tilts the head to the side that’s contracting.
The sternocleidomastoid
- One of the prime movers of jaw closure
- elevates mandible
- strongest muscle of mastication
masseter
the effort is applied at one end of the lever and the fulcrum is located at the other, with the load between them. This type of lever system is used when you carry a load in a wheelbarrow or when you stand on your toes. __ __ are power levers.
The resistance lies between the applied force and the fulcrum.
second-class lever systems
is a sphincter surrounding the mouth, but it is multilayered with fibers running in multiple directions as well as circularly. This muscle closes, purses, and protrudes the lips as in kissing or whistling. It is also important for forming words in speech.
The orbicularis oris
- are those that have their origin outside of the organ, but their insertion and action on that organ
- The __ __ of the tongue anchor and move the tongue.
extrinsic muscles
- ___ __ have a broad origin and their fascicles converge onto a single tendon that inserts onto the bone.
Convergent muscles
In addition to the scalenes, two other muscles flex the neck and head; these are the longus capitis and longus colli. They are deep muscles of the anterior triangle. The origin of the longus capitis is from the transverse processes of the cervical vertebrae, and its insertion is on the occipital bone at the base of the skull. Working together, the longus capitis muscles act to flex the head. The longus colli muscles have their origin from the bodies of cervical and superior thoracic vertebrae. These muscles also act to flex the head.
have the effort applied between the load and the fulcrum. These levers operate with great speed, and extensive movement with little shortening of the muscle, but they are always at a mechanical disadvantage. Most skeletal muscles in the body act in __ __ systems.
The force is applied between the resistance and the fulcrum.
Third-class levers
There are four pairs of muscles that are used for biting and chewing (mastication). All are innervated by cranial nerve V (the __ __).
____ muscles look like several feathers grouped together that join one tendon. ____ muscles don’t shorten much, but because they have so many fibers they are quite powerful.
Multipennate
Largest muscle mass of the back
Forms the bulge on either side of vertebral column.
Chief extensor of the vertebral column
Controls flexion, lateral flexion and rotation.
Maintains the lumbar curve
Erector spinae (sacrospinalis)
if the fascicles insert on one side of the tendon, the muscles is ____
unipennate
- are found above (superior to) the hyoid bone
- help to widen the pharynx to receive food when swallowing, they close off the larynx (respiratory passage way) so food isn’t aspirated into the lungs, and they close off the nasal passageways to prevent food from going up into our nasal cavity.
- include the (1) Digastric (di = two,) (2) The stylohyoid is innervated by CN VII, and elongates the oral cavity during swallowing. (3) The mylohyoid (mylo = molar) (4) The geniohyoid widens the throat for swallowing and is innervated by the first cervical nerve.
suprahyoid muscles
- A ___ is a special type of synergist that immobilizes the origin of a prime mover so that all the force generated by the muscle is exerted at its insertion.
fixator
if the fascicles insert into the tendon from opposite sides, the muscle is ____.
bipennate
Looking at posterior view of the cervical region (i.e., the back of the neck), are other muscles that assist in moving the head. Most notably, these include the ___ __. They have their origins on the midline of vertebral column (ligamentum nuchae and spinous processes of C7 and T1-6).
the splenius muscles
Supinator: turns palm superiorly or anteriorly
Supinator
Pronator: turns palm inferiorly or posteriorly
Pronator teres
Sphincter: decreases size of opening
External anal sphincter
Tensor: makes a body part rigid
Tensor fasciae latae
Rotator: moves bone around longitudinal axis
is a pair of muscles, a major and a minor. They raise the corners of the mouth upward as in smiling.
The zygomaticus
has its origin on the lesser wing of the sphenoid bone and inserts on the skin of the upper eye lid. This muscle functions to open the eye.
levator palpebrae superioris
- which has an anterior belly that is innervated by cranial nerve V (trigeminal) and has its origin on the inner surface of the mandibular symphysis; its posterior belly originates on the mastoid process of the temporal bone and is innervated by cranial nerve VII (facial). Both bellies insert on the hyoid bone.
- The ___ elevate the hyoid and larynx (attached to the hyoid) during swallowing and speech, and depress the mandible when the hyoid bone is fixed in position.
Digastric (di = two, gastric = belly)
Flexor: decreases joint angle
Flexor carpi radialis
Extensor: increases joint angle
Extensor carpi ulnaris
Abductor: moves bone away from midline
Abductor pollicis longus
Adductor: moves bone closer to midline
Adductor longus
Levator: movement to the superior
Levator scapulae
Depressor: movement to the inferior
Depressor labii inferioris
extends from the thoracic vertebrae to the skull and inserts on the transverse processes of C2-C4. Head extension is accomplished by the splenius muscles which lie deep to the trapezius.
splenius cervicis
is the superior part of a huge muscle mass called the erector spinae that parallels the longitudinal axis of the body on either side of the vertebral column. The origin of the__ ___is from the transverse processes of T1-T4 and the insertion is on the mastoid process of the temporal bone. When both sides contract together, the longissimus capitis extends the head; when one side contracts, the head is rotated so that the face is facing the same side of the contracting muscle.
The longissimus capitis
is innervated by CN VII, and elongates the oral cavity during swallowing.
The stylohyoid
Maximus = largest
Gluteus maximus
Minimus = smallest
Gluteus minimus
Longus = longest
Adductor longus
Brevis = shortest
Peroneus brevis
Vastus = great
Vastus lateralis
Maximus = largest
Gluteus maximus
Minimus = smallest
Gluteus minimus
Longus = longest
Adductor longus
Brevis = shortest
Peroneus brevis
Vastus = great
Vastus lateralis
presses the tongue against the oral cavity during swallowing to move food into the throat (pharynx). It is controlled by CN V. If you want to feel these muscles in action, place your fingers on your Adam’s apple (the large bump on the thyroid cartilage of the larynx) and swallow.
The mylohyoid (mylo = molar)
- Side-to side grinding movements
- aids in elevation of the mandible and assists in side-to-side grinding motions of the jaw.
The medial pterygoid
As you can tell from the name, the ___ ___ ___ raises (levator) the upper (superioris) lip (labii). The __ __ __ pulls the lower lip downward
the levator labii superioris, depressor labii inferioris
runs from the hyoid bone to the tongue, and depresses the tongue.
hyoglossus
The ___ is a muscle of the scalp. It has two bellies, the frontal and occipital which are connected by an aponeurosis (flat, sheet-like tendon) called the galea aponeurotica (or epicranial aponeurosis).
epicranius
(trumpet player) is the muscle of the cheek. It functions in sucking, blowing, and positions food between the teeth during chewing. The duct of the parotid gland salivary gland pierces the ___ to reach the oral cavity.
The buccinator
External jugular vein, passes over SCM. Accessory nerve, cervical plexus and upper trunk of brachial plexus lie under SCM
posterior triangle
- One of the prime movers of jaw closure
- elevates mandible
- also retracts the mandible and is a synergist to the pterygoids.
Temporalis
- have both their origin, insertion and action on the particular organ. The tongue is an organ of the digestive system.
- The ___ __ of the tongue curl, squeeze and fold the it into different shapes when speaking or chewing.
intrinsic muscles
as the name suggests, has its origin on the mandible below the incisors and inserts on the skin of the chin. It protrudes the lower lip and wrinkles the chin.
The mentalis
