Chapter 10

[Audio] Good morning everyone today we will present to you about the gross anatomy of the muscular system. We will discuss the attachment of muscles to bones via tendons the naming and function of specific muscles in allowing movements and stabilizing joints. We hope that this presentation will provide you with a better understanding of the complex interactions between the muscular and skeletal systems..

[Audio] Understanding the names of these muscle groups and their functions is important for moving your body properly and efficiently..

[Audio] Discuss Muscle Terminology. The origin of a muscle is attached to a more stationary bone. The insertion of a muscle is attached to the bone that has the greatest movement. The belly of a muscle is the largest portion of the muscle between the origin and insertion. Tendons are the fibrous connective tissues that attach muscles to bones. An aponeurosis is a very broad tendon that is found in the abdominal wall of mammals. An agonist is a muscle that contracts to produce an action. An antagonist is a muscle that works in opposition to the agonist. For example the biceps brachii can be used to lift weights and is the agonist but when you move a bowling ball back to prepare to bowl the biceps is the antagonist. Synergists are muscles that work together to produce a movement. The prime mover is the muscle that plays the major role in accomplishing the movement. Fixators are the muscles that stabilize the joints crossed by the prime mover and prevent the movement of the origin of the prime mover..

[Audio] Muscles play a vital role in human movement and stability. We will focus on muscle attachment and movements in this slide. The illustration represents the origins of biceps brachii on the scapula near the shoulder and biceps brachii (the agonist in flexion) in the anterior compartment of the arm. Triceps brachii(the antagonist in flexion) have origins on the scapula and humerus with insertion on the olecranon process in the posterior elbow. Triceps brachii(the agonist in extension) have insertion on the radial tuberosity in the elbow where it flexes the forearm and supinates the forearm. Understanding muscle attachment and movements is important to comprehend the function and function of the muscular system as a whole..

[Audio] The muscular system is the body's system of muscles which are responsible for movement support and maintaining posture. The table shows the data in the order: Pattern of fascicle arrangement Shape of muscle Examples. There are three different patterns of muscle fiber organization: circular convergent parallel and pennate. The circular pattern has fascicles arranged in a circle around an opening and the fascicle is circular with an opening in the center. Examples of this type include the Orbicularis oris and Orbicularis oculi. The convergent pattern has broadly distributed fascicles that converge at a single tendon. Examples of this type include the Pectoralis major and Pectoralis minor. The parallel pattern has fascicles that lie parallel to one another and the long axis of the muscle. Examples of this type include the Trapezius Rhomboidal and Quadrate. The pennate pattern has fascicles that originate from a tendon that runs the length of the entire muscle. There are three different types of pennate fiber organization: unipennate bipennate and multipennate. Unipennate has fascicles on only one side of the tendon bipennate has fascicles on both sides of the tendon and multipennate has fascicles arranged at many places around the central tendon. They are spread out at angles to many smaller tendons. Examples of this type include the Palmar interosseous and Semimembranosus. The fusiform pattern has fascicles that lie parallel to the long axis of the muscle and the belly of the muscle is larger in diameter than the ends. Examples of this type include the Biceps brachii (two-headed) and Triceps brachii (three-headed)..

[Audio] Discuss the classification and function of muscles based on their location size shape orientation of fascicles origin insertion and number of heads. For example the pectoralis gluteus is a large quadrangular muscle located in the chest with rectangularly oriented fascicles originating in the sternocleidomastoid and inserting in the brachioradialis having two heads and functioning as an extensor. Similarly the brachial is a large deltoid-shaped muscle located in the arm with obliquely oriented fascicles originating in the sternocleidomastoid and inserting in the brachioradialis having two heads and functioning as an extensor. The terms maximus minimus longus and brevis are used to describe the size of the muscle while the terms deltoid quadratus and teres are used to describe its shape. The terms rectus and oblique are used to describe the orientation of the fascicles while the terms sternocleidomastoid and brachioradialis are used to describe the origin and insertion of the muscle. The terms biceps and triceps are used to describe the number of heads of the muscle while the terms extensor abductor adductor and masseter are used to describe its function..

[Audio] We'll be discussing the muscular system and how it works. Focusing on muscle movements which involves the coordinated action of muscles tendons and bones to move parts of the body or the whole body. We'll explore the lever system used in these movements including the fulcrum weight and pull. The fulcrum is the hinge the weight is the load being moved and the pull is the force due to muscle contraction. The lever moves at the hinge to apply a force to the weight..

[Audio] Let's dive into the three types of levers in the muscular system. Class I levers have the fulcrum between the force and the weight such as a seesaw or head movement at the atlantooccipital joint. Class II levers have the weight between the fulcrum and the pull such as a wheelbarrow or standing on toes using the metatarsophalangeal joint. Class I-I-I levers have the pull located between the fulcrum and the weight such as a person using a shovel. The most common type of lever used in the muscular system is the Class I lever with the biceps brachii serving as the fulcrum and the elbow as the point of rotation. This information on the gross anatomy of the muscular system should be helpful..

[Audio] The illustration in the presentation on the gross anatomy of the muscular system shows the body's musculature..

[Audio] The gross anatomy of the muscular system will be our primary focus specifically the body's musculature. Understanding this gross anatomy is essential for comprehending the functions and movements of the body's muscles. The provided image shows the posterior view of the body which can help visualize the different muscle groups and their locations within the body..

[Audio] We can see that the muscular system plays a crucial role in movement and stability of the human body. The neck being a fundamental part of the muscular system contains diverse muscle groups facilitating various movements. Anterior neck muscles enable lateral head movements while deep muscles along the anterior margins of the vertebral bodies support flexion. Posterior neck muscles connected to the occipital bone execute extension. Additionally neck muscles contribute to rotation and abduction with the lateral and posterior groups executing these movements..

[Audio] The table on slide 10.2 lists the muscles that move the head and neck their origin insertion nerve action and lateral movement. The sternocleidomastoid muscle laterally moves the head and neck while the scalene muscles flex laterally flex and rotate the neck. When both sternocleidomastoid muscles contract they flex the neck. Understanding the function and movement of these muscles is vital for our overall health and well-being..

[Audio] The muscles of the head and neck are crucial for maintaining proper body mechanics and preventing injuries. The table below lists the muscles that move the head and neck along with their origin insertion nerve action and posterior view. The longissimus capitis: originates from the upper thoracic and lower cervical vertebrae inserts into the mastoid process and is innervated by the dorsal rami of cervical nerves. The oblique capitis superior: originates from the atlas inserts into the occipital bone and is innervated by the dorsal ramus of C1. The rectus capitis posterior: originates from the axis inserts into the occipital bone and is innervated by the dorsal ramus of C1. The semispinalis capitis: originates from C4-T6 inserts into the occipital bone and is innervated by the dorsal rami of cervical nerves. The splenius capitis: originates from C4-T6 inserts into the superior nuchal line and mastoid process and is innervated by the dorsal rami of cervical nerves. The trapezius: originates from the occipital protuberance nuchal ligament spinous processes of C7-T12 inserts into the clavicle acromion process and scapular spine and is innervated by cranial nerve XI. In conclusion understanding the functions and how these muscles work together is essential for overall health and well-being..

[Audio] Illustration A shows the occipitofrontalis of the forehead levator palpebrate superioris of the eyelid and zygomaticus major around the lips. The occipitofrontalis is responsible for raising the eyebrows and the levator palpebrate superioris for closing the eyelids. The zygomaticus major is involved in smiling and raising the corners of the mouth. Illustration B shows the zygomaticus minor zygomaticus major risorius mentalis and levator anguli oris around the mouth while smiling. The zygomaticus minor and major are responsible for smiling while the risorius is involved in opening the mouth. The mentalis is responsible for biting the lower lip and the levator anguli oris for opening the mouth wide. Illustration C shows the procerus and corrugator supercilii between the eyes orbicularis oculi below the eyes nasalis of the nose levator labii superiors depressor anguli oris and depressor labii Inferioris around the mouth. The procerus and corrugator supercilii are responsible for raising the eyebrows while the orbicularis oculi for closing the eyelids. The nasalis is involved in the movements of the nose the levator labii superiors and depressor anguli oris for opening and closing the mouth and the depressor labii Inferioris for moving the lower lip. Finally illustration D shows the buccinator of the cheek nasalis of the nose orbicular oris of the mouth and platysma of the neck. The buccinator is responsible for moving the cheeks while the nasalis and orbicular oris for the movements of the nose and mouth respectively. The platysma is involved in the movements of the neck and throat. By understanding the functions of cutaneous muscles in the head and neck region we can better appreciate the complexity and importance of the muscular system..

[Audio] We will discuss different types of muscles and their functions in the body. We will examine an illustration of facial muscles to understand their structure and function. We will illustrate the lateral and anterior views of facial muscles of a cadaver. We will achieve a comprehensive understanding of different types of muscles and their functions in the body..

[Audio] This table provides a detailed overview of the muscles of facial expression. As you can see from the table these muscles play a crucial role in facial expression. The occipitofrontalis originates from the occipital bone and is inserted into the skin of the eyebrow and nose. This muscle is responsible for moving the scalp raising eyebrows and wrinkling the forehead. The corrugator supercilii is located on the nasal bridge and orbicularis oculi and is responsible for depressing the medial portion of the eyebrow drawing eyebrows together and squinting. The levator palpebrae superioris is located near the lesser wing of the sphenoid bone and is responsible for elevating the upper eyelid and opening the eye. The orbicularis oculi is responsible for closing the eyes blinking and winking. The nasalis originates from the maxilla and bridge of the nose and is responsible for dilating the nostril. Finally the procerus originates from the bridge of the nose and frontalis and is responsible for creating horizontal wrinkles between the eyes as in frowning. These muscles work together to create a wide range of facial expressions allowing us to communicate our emotions and feelings to others..

[Audio] We will discuss the role of facial expressions in communication. The orbicularis oris is responsible for drawing the corners of the mouth posteriorly and lowering the corner of the mouth. The buccinator compresses the cheek to hold food between the teeth. The depressor anguli oris depresses the lower lip and frowns. The depressor labii inferioris raises the corner of the mouth and sneers. The mentalis purses the lips and pouts. In addition to its involvement in kissing and smiling the orbicularis oris is also involved in the expression of facial expressions. The risorius elevates and abducts the upper lip and corner of the mouth. The zygomaticus major elevates and abducts the upper lip and smiles. Lastly the platysma depresses the lower lip and wrinkles the skin over the inferior border of the mandible to express fear..

[Audio] We will discuss the role of muscles of mastication in chewing today. Today we will discuss the role of muscles of mastication in chewing..

[Audio] The muscular system is responsible for movement and providing support to the human body. We will focus on the Superficial muscles of the human body. The epicranial aponeurosis occipitofrontalis temporalis orbicularis oculi occipitofrontalis levator labii superioris zygomaticus minor and zygomaticus major masseter buccinator orbicularis oris depressor anguli oris sternocleidomastoid and trapezius are all included in this illustration. We will begin with a lateral view of the human skull featuring the Temporalis zygomatic arch origin for the masseter and part of the temporal muscles buccinator orbicularis oris masseter (cut) and the tendon of temporalis. Next we will examine the Temporalis tendon (cut) lateral pterygoid depresses and protrudes the mandible and medial pterygoid. Finally we will look at the frontal section of the skull including the sphenoid bone temporal bone articular disk head of the mandible lateral pterygoid and medial pterygoid. These Superficial muscles play a vital role in movement and support and understanding their function and location is essential for maintaining healthy movement and overall well-being..

[Audio] The muscles of mastication are responsible for the movement of the jaw and the process of chewing. The Temporalis muscle originates in the temporal fossa and inserts into the anterior portion of the mandibular ramus and coronoid process. It is innervated by the mandibular division of the trigeminal nerve and is responsible for elevating and retracting the mandible as well as being involved in excursion. The Masseter muscle originates in the zygomatic arch and inserts into the lateral side of the mandibular ramus. It is also innervated by the mandibular division of the trigeminal nerve and is responsible for elevating and protracting the mandible as well as being involved in excursion. The Pterygoids are located in the lateral and medial sides of the jaw and are responsible for depressing and protracting the mandible as well as side-to-side movements. These muscles work together to allow for the complex movements of the jaw and the process of chewing. We are grateful for the opportunity to provide you with this information. If you have any questions please do not hesitate to reach out to us..

[Audio] We will now focus on the gross anatomy of the muscular system. Our muscles include the hyoid muscles. These muscles are composed of mylohyoid stylohyoid omohyoid sternohyoid digastric and sternothyroid muscles. In the next section we will examine each of these muscles in greater detail. Let us now move on to the following slide..

[Audio] We are discussing the hyoid muscles and their role in the muscular system. The hyoid muscles are divided into two groups: suprahyoid and infrahyoid. These muscles help stabilize the hyoid bone and assist in movement of the mandible and larynx. We have provided a table that shows the origin insertion nerve action and function of these muscles. This table can help you understand the anatomy and function of these muscles in the human body..

[Audio] The muscular system plays an important role in our body. The tongue is crucial for both mastication and speech. It manipulates food in the mouth holds food in place while teeth grind pushes food up to the palate and toward the pharynx to initiate swallowing and changes shape to modify sound during speech. The tongue consists of both intrinsic and extrinsic muscles. Intrinsic muscles are found entirely in the tongue while extrinsic muscles are found outside of the tongue but are attached to it..

[Audio] The muscular system of the tongue will be discussed with a focus on intrinsic and extrinsic muscles. The table presents the data on the tongue muscles: Longitudinal transverse and vertical muscles within the tongue Hypoglossal nerve changes tongue shape Extrinsic muscles Genioglossus Mental protuberance of mandible Styloglossus Styloid process Side of tongue Depresses and protrudes tongue Palatoglossus Soft palate Retracts and depresses side of tongue Elevates posterior tongue Tongue Pharyngeal plexus.

[Audio] These areas are the home to several muscles that are vital in swallowing and speech. When ingesting food the palatopharyngeus muscles elevate the pharynx aiding in transporting food into the esophagus. Furthermore the salpingopharyngeus muscles contract the pharynx from top to bottom forcibly pushing food into the esophagus. This intricate series of muscle contractions allows for the efficient and effective movement of food through the upper digestive tract..

[Audio] The muscles involved in swallowing and the anatomy of the larynx are explained through the table..

[Audio] Discuss the gross anatomy of the muscular system of swallowing..

[Audio] Discussing the gross anatomy of the muscular system. Our illustration shows the Palate Pharynx and Larynx muscles. These muscles are important for the functioning of the respiratory system. Our illustration provides a closer look at the same muscles..

[Audio] We will be discussing the gross anatomy of the muscular system specifically the muscles that move the eye. There are six main muscles that are responsible for moving the eye and we will be discussing each of them in more detail. These muscles are: The lateral rectus The superior rectus The inferior oblique The medial rectus The superior oblique The inferior rectus Please take a moment to review the table below and familiarize yourself with the information: The table shows the origin insertion nerve action and obliquity of each of these muscles..

[Audio] We can divide trunk muscles into two groups: deep and superficial. The deep group runs from one vertebra to the next while the superficial group extends from vertebrae to ribs..

[Audio] We are now discussing the gross anatomy of the muscular system specifically focusing on the muscles that act on the vertebral column. Let's take a closer look at some of the key muscles listed in table 10.9. Erector spinae is a muscle that is divided into three columns: iliocostalis thoracis and lumborum. These muscles are responsible for extending laterally flexing and rotating the vertebral column. They receive innervation from the dorsal rami of thoracic nerves and help maintain the stability of the spine. Longissimus is another important muscle that extends the vertebral column. This muscle is innervated by the dorsal rami of thoracic and lumbar nerves and plays a crucial role in maintaining the stability of the spine particularly in the thoracic and lumbar regions. Spinalis is another important muscle that acts on the vertebral column. It extends the vertebral column and is innervated by the dorsal rami of cervical thoracic and lumbar nerves. Cervicis is a muscle that extends the head and neck. This muscle is innervated by the dorsal rami of cervical nerves and is responsible for maintaining the stability of the neck and head. In summary these muscles play a critical role in the movement and stability of the vertebral column and are essential for maintaining proper posture and preventing injury..

[Audio] Discuss the gross anatomy of the muscular system. Neck muscles: Semispinalis Cervicis Transverse processes of T2–T5 Spinous processes of C2–C5 Dorsal rami of cervical nerves Extends neck Thoracis Transverse processes of T5–T11 Spinous processes of C5–T4 Dorsal rami of thoracic nerves Extends vertebral column Splenius cervicis Spinous processes of C3–C5 Transverse processes of C1–C3.

[Audio] This slide illustrates the human body's muscular system specifically the neck and deep neck muscles. The sternocleidomastoid trapezius splenius cervicis deltoid infraspinatus teres minor and major triceps brachii and latissimus dorsi muscles are all long diamond-shaped and positioned in the neck and shoulder regions. The sternocleidomastoid muscles connect the sternum clavicle and mastoid process while the trapezius muscles are located beneath the sternocleidomastoid and contribute to arm movement and rotation. The splenius cervicis muscles are located in the neck region and connect the cervical vertebrae and sternum. The deltoid muscles are responsible for raising the arm away from the body while the infraspinatus teres minor and major and triceps brachii muscles contribute to arm movement and rotation. The latissimus dorsi muscle is a large flat muscle located on the back of the neck and shoulders and assists in arm and shoulder movement. The deep neck muscles including the semispinalis capitis longissimus cervicis rectus capitis posterior and levator scapulae connect to the cervical vertebrae and are responsible for maintaining the stability and alignment of the neck and shoulders. In summary this slide provides an extensive overview of the muscular system's gross anatomy specifically focusing on the neck and deep neck muscles..

[Audio] Deep neck and back muscles play a crucial role in supporting the spine and providing stability to the neck and back. These muscles include the multifidus semispinalis thoracis splenius capitis longissimus thoracis iliocostalis thoracis and iliocostalis lumborum. Each of these muscles has a different function but they all work together to support the spine and provide stability to the neck and back. By understanding the anatomy of these muscles you can maintain proper posture and prevent injuries. In this presentation we will provide a closer look at each of these muscles and their functions..

[Audio] An illustration shows the vertebral muscles. These muscles play an important role in supporting the spine and allowing for movement. The interspinous and intervertebral muscles which run along the length of the spine and the multifiducial muscles which run perpendicular to the spine are examples of the vertebral muscles. Understanding the anatomy of these muscles can help to prevent injury and promote proper function..

[Audio] The muscular system plays a crucial role in breathing. During quiet breathing the diaphragm flattens and increases the volume of the thoracic cavity resulting in inspiration. However during expiration the ribs are depressed by the internal intercostals and transversus thoracis while the external intercostals elevate the ribs. Additionally the scalenes elevate the first two ribs during inspiration. This complex system of muscles works together to facilitate normal breathing..

[Audio] We will discuss the muscles of the thorax specifically those that are found in the region between the ribs and the sternum. Table 10.10 will be examined which illustrates the different muscles in this area including the diaphragm intercostals scalene muscles and the muscles that elevate the first rib. The diaphragm is a large muscle that is responsible for breathing originating in the interior of the ribs sternum and lumbar vertebrae and attached to the central tendon. When the diaphragm contracts it depresses the floor of the thorax allowing air to enter the lungs. The intercostals are a group of muscles that are found between the ribs responsible for quiet inspiration elevating the ribs and for forced expiration depressing the ribs. The scalene muscles are a group of muscles that are located in the neck and are responsible for elevating the first rib. Finally the muscles that elevate the first rib are responsible for elevating the first rib which is important for breathing..

[Audio] We will discuss the gross anatomy of the muscular system focusing on the thorax. The thorax is divided into two main parts: the anterior and lateral walls. The anterior wall is the front part of the thorax while the lateral walls are the sides. There are several muscles in the thorax including the intercostal muscles the sternocleidomastoid muscles and the trapezius muscles. The intercostal muscles are located between the ribs and are responsible for movement of the rib cage during inhalation and exhalation. The sternocleidomastoid muscles are located at the front of the neck and are responsible for movement of the head and neck. The trapezius muscles are located over the scapula and are responsible for movement of the shoulder blades. In terms of the anterior view the thorax is divided into three regions: the thoracic cavity the mediastinum and the pericardium. The thoracic cavity is the largest region and contains the heart lungs and major blood vessels..

[Audio] The abdominal wall muscles play an essential role in maintaining the stability and function of the human body. These muscles flex and rotate the vertebral column decreasing the volume of the abdominal and thoracic cavities which enables activities such as forced expiration vomiting defecation urination and childbirth. The crossing pattern of these muscles adds strength to the abdominal wall allowing it to support the organs within the abdominal cavity..

[Audio] Review table 10.11 and discuss the origin insertion nerve action and function of the rectus abdominis external abdominal oblique and internal abdominal oblique. Additionally discuss the function of the transversus abdominis which is a muscle that compresses the abdominal wall. This information will be helpful to understand the structure and function of the abdominal wall muscles..

[Audio] The illustrations on slide 41 depict an anterior view of the abdominal wall muscles. These illustrations are intended to help you visualize the different muscles that make up this essential part of the human body. By comprehending the anatomy of these muscles you can better grasp how they function together to support and move the body. We look forward to proceeding with our presentation on this intriguing subject..

[Audio] The muscular system particularly the muscles of the anterior abdominal wall will be explored in detail. An illustration of the anterior abdominal wall muscles will be shown highlighting their structure. We will present an anterolateral view of a cadaver providing a more detailed and realistic look at the muscles of the anterior abdominal wall. Examining these illustrations will allow us to gain a better understanding of the structure and function of these important muscles..

[Audio] We will discuss the gross anatomy of the muscular system specifically the pelvic diaphragm and the perineum. The pelvic diaphragm is a funnel-shaped muscle that supports the pelvic viscera and is pierced by the anal canal urethra (and vagina). The perineum is a diamond-shaped area inferior to the pelvic diaphragm with the anterior half being the urogenital triangle and the posterior half being the anal triangle..

[Audio] This slide provides a comprehensive view of the pelvic diaphragm and perineum muscles and their function. The pelvic diaphragm is a dome-shaped muscle that separates the pelvic cavity from the abdominal cavity playing an important role in breathing and supporting the organs in the pelvic cavity. The perineum is the area between the anus and genitals and contains several muscles that work together to control urination defecation and childbirth. The illustration shows the individual components of these muscles and how they work together. By understanding the anatomy of these muscles we can appreciate their importance in maintaining overall health and well-being..

[Audio] We will now be focusing on the gross anatomy of the muscular system specifically the muscles of the pelvic diaphragm and perineum. A table summarizes information about these muscles including their origin insertion nerve action and relationship to the pelvic diaphragm and perineum. The table includes data for the coccygeus levator ani ischiocavernosus and external anal sphincter muscles. These muscles play essential roles in supporting the pelvic floor and maintaining continence. The coccygeus and levator ani muscles form the pelvic floor and support pelvic organs while the ischiocavernosus muscle compresses the base of the penis or clitoris ejects urine or semen and erects the penis. The external anal sphincter keeps the orifice of the anal canal closed and relaxes during defecation. Understanding the anatomy and function of these muscles is essential for maintaining overall health and wellbeing..

[Audio] In our presentation on the gross anatomy of the muscular system we discuss the major connections of the upper limb to the body. We explain that scapular movements are accomplished by the muscles that originate on the axial skeleton such as the trapezius levator scapulae rhomboideus serratus anterior and pectoralis minor. These muscles play a crucial role in allowing a wide range of movements of the scapula and clavicle which are major components of the upper limb..

[Audio] Discussing the Gross Anatomy of the Muscular System. Please refer to the tables for more information..

[Audio] The muscular system plays a vital role in movement and maintaining posture. The scapula is a flat bone located in the shoulder region and plays a crucial role in arm movement. An illustration of the posterior view of muscles acting on the scapula is shown including the triceps infraspinatus and latissimus dorsi which help extend the arm and stabilize the scapula. An anterior view of muscles acting on the scapula is also shown including the pectoralis major and deltoid which help flex the arm and stabilize the scapula. An illustration of muscles acting on the scapula from both the posterior and anterior views is presented providing a comprehensive understanding of the relationship between the muscles and the scapula in arm movement. Understanding the relationship between muscles and the scapula can help prevent injury and improve overall function..

[Audio] The muscular system with over 600 muscles attached to bones through tendons facilitates movement and aids in performing daily activities. Understanding the gross anatomy of the muscular system provides insight into its complexity and functioning. We will explore the different components of the muscular system and how they work together to enable movement in this section..

[Audio] Covered essential muscles. Pectoralis major and latissimus dorsi provide stability and support to the shoulder. Deltoid muscle acts as both a flexor and extensor of the shoulder responsible for abducting and medially and laterally rotating the arm. Rotator cuff muscles critical to arm's movement and stability as they move the arm and hold the head of the humerus in the glenoid cavity..