AP 1 M5 5.1: Anatomy of the Muscular System: Introduction & Muscles of the Head, Neck, and Trunk Flashcards
muscular system and the skeletal system
The muscular system and the skeletal system work together to provide movement for the human body.
Muscle tissue
Muscle tissue is found in three distinct types in the body; skeletal, smooth, and cardiac. Skeletal muscles must have a blood and nervous supply to provide movement.
conscious control
Skeletal muscles are under conscious control, meaning that a person can consciously decide to use these muscles to complete an action.
Peripheral nerves
Peripheral nerves carry the signal from the central nervous system (brain and spinal cord) to a specific muscle destination to provide movement.
central nervous system
Peripheral nerves carry the signal from the central nervous system (brain and spinal cord) to a specific muscle destination to provide movement
motor actions
Messages from the central nervous system to a muscle are called motor actions.
sensation or sensory input
Nerves also carry information from the external environment to the central nervous system, called sensation or sensory input (see Figure 5.1 and Figure 5.2). Spinal nerves combine to form complex networks of peripheral nerves throughout the body.
Tendons
Tendons are connective tissues that connect skeletal muscle to bone at each end. Tendons are flexible, can bend at the joints, and help cushion against sudden movement.
Ligaments
Ligaments are connective tissue that connects bone to bone, helping to stabilize joints where bones meet.
muscle to bony site of attachment
All skeletal muscles have an origin, insertion, and action. The origin is the bony site of attachment that is stationary during the movement. The insertion of a muscle is the bony site of attachment that is moved by the muscle contraction
origin and insertion
The origin and insertion can be reversed in different types of movement. For this module, the standard origin and insertion points are referenced from anatomical position.
action
The action of the muscle is what effect is produced by the muscle’s contraction. For example, the triceps are the primary extensor of the forearms.
innervation
The innervation is the peripheral nerve that supplies a muscle with the message from the brain. For example, the innervation of the biceps brachii is the musculocutaneous nerve
Muscles are generally
Muscles are generally studied in groups. The following muscle list is an overview of some of the major muscles in the body. Study the location of the muscle in the body. In addition, if listed, study the origin, insertion, innervation and action of these muscles.
CN
Muscles of Facial Expression
CN is an abbreviation for cranial nerve. There are twelve pairs of cranial nerves that originate on the ventral surface of the brain, controlling muscles and functions of several organs and glands.
Muscles of the Head and Neck
The muscles in this grouping help to facilitate actions that move the head (occiput) and control the neck.
lateral flexion
Muscles of the Head and Neck
Side bending of the neck is also called side flexion or lateral flexion, which refers to moving one of the ears to the same side shoulder.
Neck flexion
Muscles of the Head and Neck
Neck flexion refers to the action of moving the chin towards the sternum.
bilaterally or unilaterally
Muscles of the Head and Neck
Note there are several muscles that have differing actions if acting together on both sides (bilaterally) or acting on one side only (unilaterally).
Vertebral Column: Erector Spinae
The erector spinae group are superficial muscles in the back. These muscles act as the prime extensors of the vertebral column.
Flexion
Vertebral Column: Erector Spinae
Flexion of the spine refers to forward bending the trunk (such as a “cat” stretch)
Extension
Vertebral Column: Erector Spinae
Extension of the spine refers backward bending.
lateral flexion or rotation
Vertebral Column: Erector Spinae
The vertebral column is also able to perform side bending (or lateral flexion) as well as movement around an axis (rotation).
Oblique and Rectus Muscles: Anterior
The abdominal muscles perform many functions. These muscles help to support and protect the abdominal viscera (which are not protected by bony structures). These muscles, along with the muscles in the back (see above) help to provide support for upright posture and balance.
Muscles of Breathing
The diaphragm is the primary muscle necessary for intaking air. The internal intercostals and the external intercostals work in opposite functions. Notice the difference in their muscle fiber orientation
Orbicularis oculi
Muscles of Facial Expression
Action: eye closure
Innervation: facial nerve (CN VII)
Orbicularis oris
Muscles of Facial Expression
Action: mouth closure: closes lips, protrudes lips forward, presses lips against teeth
Innervation: facial nerve (CN VII)
Zygomaticus major/minor
Muscles of Facial Expression
Action: pull corners of lips upward
Innervation: facial nerve (CN VII)
Risorius
Muscles of Facial Expression
Action: pulls the corners of the mouth posteriorly (grin or grimace)
Innervation: facial nerve (CN VII)
Buccinator
Muscles of Facial Expression
Action: compress cheeks
Innervation: facial nerve (CN VII)
Frontalis (occipitofrontailis)
Muscles of Facial Expression
Action: raise eyebrows
Innervation: facial nerve (CN VII)
Masseter
Muscles of Facial Expression
Action: jaw closure
Innervation: trigeminal nerve (CN V, mandibular branch)
Temporalis
Muscles of Facial Expression
Action: Elevates mandible, closes jaw
Innervation: trigeminal nerve (CN V, mandibular branch)
Semispinalis Capitis
Muscles of the Head and Neck
Origin: articular processes of inferior cervical & transverse process of superior thoracic vertebrae
Insertion: occipital bone
Action:
Bilateral extend head
Unilateral laterally flexes neck to same side
Innervation: spinal nerves
Sternocleidomastoid
Muscles of the Head and Neck
Origin: sternal end of clavicle and manubrium
Insertion: mastoid region of skull
Action:
Bilateral: neck flexion
Unilateral: turns face to opposite side
Innervation: accessory nerve (CN XI)
Thyrohyoid
Muscles of the Head and Neck
Origin: thyroid cartilage of larynx
Insertion: hyoid bone
Action: elevates thyroid, depresses hyoid bone
Innervation: hypoglossal nerve
Splenius Capitis
Muscles of the Head and Neck
Origin: spinous process/ligaments of inferior cervical vertebrae
Insertion: mastoid process, occipital bone of skull
Action:
Bilateral: extend head
Unilateral: laterally flexes neck to same side
Innervation: cervical spinal nerves
Longissimus cervicis
Muscles of the Head and Neck
Origin: transverse processes of superior thoracic vertebrae
Insertion: transverse process of middle and superior cervical vertebrae
Action:
Bilateral extend head
Unilateral laterally flexes neck to same side
Innervation: cervical and thoracic spinal nerves
Longissimus thoracis
Muscles of the Head and Neck
Origin: transverse process of all thoracic and lumbar vertebrae
Insertion: transverse processes of all thoracic vertebrae
Action:
Bilateral extension of spine
Unilaterally: lateral flexion of spine
Innervation: thoracic and lumbar spinal nerves
Scalenes (anterior, middle, posterior)
Muscles of the Head and Neck
Origin: transverse processes of C2- C7
Insertion: first and second ribs
Action: elevates ribs 1 & 2
Innervation: cervical spinal nerves
Longissimus
Vertebral Column: Erector Spinae
Intermediate column of erector spinae
Made up of three divisions (longissimus thoracis, longissimus cervicis, longissimus capitits)
Spinalis
Vertebral Column: Erector Spinae
Medial column of erector spinae
Made up of three divisions (spinalis thoracis, spinalis cervicis, and spinalis capitis)
Iliocostalis
Vertebral Column: Erector Spinae
Lateral column of erector spinae
Made up of three divisions (iliocostalis lumborum, iliocostalis thoracis, iliocostalis cervicis)
Rectus abdominis
Oblique and Rectus Muscles: Anterior
Origin: pubic crest, pubic symphysis
Insertion: cartilages of ribs 5-7, xiphoid process
Action: flexion of spine, compression of abdominal viscera
Innervation: spinal nerves (T 7-T 12)
External oblique
Oblique and Rectus Muscles: Anterior
Origin: sternum, ribs (5-12)
Insertion: linea alba, iliac crest
Action:
Bilaterally: flexion of the spine, compress the abdomen;
Unilaterally: flexes trunk to same side, rotates to opposite side
Innervation: lower intercostal, ilioinguinal nerves
Internal oblique
Oblique and Rectus Muscles: Anterior
Origin: iliac crest, lumbodorsal fascia
Insertion: inferior ribs, linea alba
Action: compresses abdomen, depresses ribs, flexes spine
Innervation: lower intercostal, ilioinguinal nerves
Transverse abdominis – deep to internal oblique
Oblique and Rectus Muscles: Anterior
Origin: lateral inguinal ligament, inner iliac crest
Insertion: linea alba, pubis
Action: compression of abdomen
Innervation: first lumbar nerve (T 7- L1), iliohypogastric (T12-L1), ilioinguinal (T12-L1)
Diaphragm
Muscles of Breathing
Origin: cartilage of ribs 7-12, xiphoid process, lumbar vertebrae
Insertion: anterior longitudinal ligament (vertebral column)
Action: expands thoracic cavity, compresses abdominal cavity
Innervation: phrenic nerve (C3-5)
Internal Intercostals
Muscles of Breathing
Origin: superior border of ribs 2-12
Insertion: inferior of ribs above (1-11)
Action: depresses ribs (forced expiration)
Innervation: intercostal nerves
External Intercostals
Muscles of Breathing
Origin: lower border of ribs 1-11
Insertion: upper border of ribs below (2-12)
Action: elevates ribs (normal inspiration)
Innervation: intercostal nerves
