Which muscle is responsible for the hallux extension? extensor hallucis longus.
Actions: Acting bilaterally, the lateral pterygoids protract the mandible, pushing the jaw forwards. Unilateral action produces the ‘side to side’ movement of the jaw. Note: Contraction of the lateral pterygoid will produce lateral movement on the contralateral side.
Function. The medial pterygoid muscle functions to assist with elevation and protrusion of the mandible. It also assists the lateral pterygoid muscle with side to side mandibular motion to help with the grinding of food.
|Masseter||zygomatic arch||Elevates mandible|
|Temporalis||Temporal and frontal bones||Elevates mandible|
|Medial pterygoid||Sphenoid (Lateral pterygoid plate)||Elevates mandible; moves mandible side to side|
|Lateral pterygoid||Sphenoid (Lateral pterygoid plate)||Opens jaws, protrudes mandible; moves mandible side to side|
The lateral pterygoid muscle pulls the mandible forwards (anterior translatory movement). During this process the mandible moves slightly downwards because the condyle is pressed down on the articular tubercle. The mandible is pulled backwards on closing by the posterior fibres of the temporalis muscle.
The medial pterygoid helps to elevate the mandible, while the lateral pterygoid protracts its.
The buccinator muscle plays an active role along with orbicularis oris and superior constrictor muscle during swallowing, mastication, blowing, and sucking. It aids in mastication and blowing by compressing the cheek inwards.
Among all the four muscles of mastication (medial pterygoid, lateral pterygoid, masseter, and temporalis), the lateral pterygoid is the only muscle that depresses the mandible. The action of all the other three muscles of mastication results in elevation of the mandible.
The temporalis muscle is a thin, fan-shaped muscle situated within the temporal fossa of the skull. Along with the medial pterygoid, lateral pterygoid and masseter muscles, it belongs to the group masticatory muscles. The temporalis muscle runs superficially, from the temporal bone to the coronoid process of mandible.
The rami are two vertical processes located on either side of the body; they join the body at the angle of the mandible. At the superior aspect of each ramus, the coronoid and condylar processes articulate with the temporal bone to create the temporomandibular joint which permits mobility.
The masseter muscle provides powerful elevation and protrusion of the mandible by originating from the zygomatic arch and inserting along the angle and lateral surface of the mandible. The temporalis muscle originates from the floor of the temporal fossa and inserts onto the coronoid process of the mandible.
|Origin||Superficial part: maxillary process of zygomatic bone, Inferior border of zygomatic arch (anterior 2/3) Deep part: deep/inferior surface of zygomatic arch (posterior 1/3)|
|Insertion||Lateral surface of ramus and angle of mandible|
|Innervation||Masseteric nerve of mandibular nerve (CN V3)|
The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges.
The jaw muscles move the jaw in a complex three-dimensional manner during jaw movements. There are three jaw-closing muscles (masseter, temporalis, and medial pterygoid) and two jaw-opening muscles (lateral pterygoid and digastric). The basic functional unit of muscle is the motor unit.
Mandibular movement around the horizontal axis is an opening and closing motion. … When the condyles are in their most superior position in the articular fossae and the mouth is purely rotated open, the axis around which movement occurs is called the terminal hinge axis.
Protrusion refers to the movement of a structure in an anterior (forward) direction. … I call protrusion the kissing movement because it occurs when you pucker your lips like you’re going to give someone a kiss or stick out your tongue. Moving the mandible (lower jaw) forward is also an example of protrusion.
The masseter also protracts the mandible; it originates on the zygomatic arch and inserts on the mandible (external surface of angle and ramus). The temporalis muscle additionally retracts the mandible. Its origin is the temporal bone (fossa) and its insertion is the mandible (coronoid process and ramus).
The Lateral Pterygoid can also depress the Mandible.
Consequently they are innervated by a branch of the trigeminal nerve (CN V), the mandibular nerve.
The frontalis muscle is responsible for elevating the eyebrows, while the corrugator supercilii, orbicularis oculi, and procerus play a role in its depression. The function of the forehead is often spared in middle cerebral artery strokes.
Orbicularis oris muscle, also known as musculus orbicularis oris is a complex, multi-layered muscle which attaches through a thin, superficial musculoaponeurotic system to the dermis of the upper lip and lower lip and serves as an attachment site for many other facial muscles around the oral region.
The risorius muscle is a narrow bundle of muscle fibers that becomes narrower from its origin at the fascia of the lateral cheek over the parotid gland and superficial masseter and platysma muscles, to its insertion onto the skin of the angle of the mouth.
The buccinator muscle is a thin quadrilateral facial muscle that is the main component of the cheek.
Temporalis muscleOrigintemporal lines on the parietal bone of the skull and the superior temporal surface of the sphenoid boneInsertioncoronoid process of the mandible and retromolar fossaArterydeep temporal arteriesNervedeep temporal nerves, branches of the anterior division of the mandibular nerve (V3)
The temporalis muscle attaches above to the bone and fascia in the temporal fossa, superior to the zygomatic arch, and below to the coronoid process of the mandible and along the mandibular ramus (Figure 6-17). The temporalis muscles primarily close the jaw while the middle fibers bilaterally retrude the mandible.
OriginMedial aspects of maxilla and mandible, perioral skin and muscles, modiolusActionCloses mouth, compresses and protrudes lips
The trapezius is a muscle that starts at the base of your neck, goes across your shoulders and extends to the middle of your back. The trapezius (traps muscle) helps you move your head, neck, arms, shoulders and torso. It also stabilizes your spine and helps with posture.
The temporalis muscle is a fan-shaped muscle located near the temples of the head/face. The temporalis muscle originates from the temporal fossa (the depressed area of the temporal bone) and the temporal fascia (the tendinous connective tissue that lies beneath the skin on top of the temporal bone).
The maxilla (plural: maxillae /mækˈsɪliː/) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. … The mandible is the movable part of the jaw.
The temporalis muscle inserts on the coronoid process of the mandible, with some fibers inserting further down on the ventral margin of the masseteric fossa. The lateral pterygoid muscle inserts on the medial surface of the mandibular condyle.
Each mandibular fossa or glenoid fossa forms the temporal component of the TMJ. It is a concave area on the inferior border of the squamous part of the temporal bone that is also referred to as the articular fossa.
The masseter is a rectangular-shaped muscle in your face and jaw and is one of the primary muscles of mastication, or chewing. It consists of three distinct layers and works with nearby muscles to move your temporomandibular joint and jaw bone.
The muscles of facial expression (also known as the mimetic muscles) can generally be divided into three main functional categories: orbital, nasal and oral. These striated muscles broadly originate from the surface of the skull and insert onto facial skin.
Shape: The deltoid (triangular), trapezius (trapezoid), serratus (saw‐toothed), and rhomboideus major (rhomboid) muscles have names that describe their shapes.
A skeletal muscle attaches to bone (or sometimes other muscles or tissues) at two or more places. If the place is a bone that remains immobile for an action, the attachment is called an origin. If the place is on the bone that moves during the action, the attachment is called an insertion.
The quadratus lumborum is a thick, square-shaped muscle located at the very back of the abdominal wall. Specifically, this muscle originates from the iliac crest and then travels up the lower back and inserts on the 12th rib on both sides of the rib cage as well as the first four lumbar vertebrae (L1–L4).
Muscles that helpful in expanding the thoracic cavity are called the inspiratory muscles because they help in inhalation, while those that compress the thoracic cavity are called expiratory muscles and they induce exhalation.
The diaphragm is the primary muscle used in the process of inspiration, or inhalation. It is a dome-shaped sheet of muscle that is inserted into the lower ribs. Lying at the base of the thorax (chest), it separates the abdominal cavity from the thoracic cavity.
The most important muscle of inspiration is the diaphragm; however, the external intercostals assist with normal quiet breathing. Contraction of the diaphragm increases the space in the thoracic cavity and the lungs fill with air from the external environment.
Mylohyoid: The mylohyoid is a broad flat muscle which forms the floor of the oral cavity. It originates from the mandible and attaches to the hyoid bone. Geniohyoid: The deepest of the suprahyoid muscles, the geniohyoid muscle originates from the mandible and attaches to the hyoid bone.