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
