Lab 4

Tips for learning muscles

-Be aware of information learned from the muscle's name -Read description in table, and identify muscle on figure •Helps to relate location and description -Relate muscle's location and attachments to its actions -Act out movements on yourself •Feel for muscles contracting beneath skin

Scalenes

-Capitis and cervicis portions -Broad bipartite superficial muscle (capitis and cervicis parts) extending from upper thoracis vertebrae to skull -Capitis portion known as bandage muscle because it covers andholds down deeper neck muscles

Fixator

-synergist that immobilizes bone or muscles origin -Gives prime mover stable base on which to act

Three columns of erector spinae

1. Iliocostalis 2. Longissimus 3. Spinalis

Skeletal Muscle functional groups- Same muscle may be...

1. Prime mover of one movement 2. Antagonist for different movement 3. Synergist for third movement

Intrinsic Muscles on the back

1. Scalenes 2. Erector Spinae

Muscle Action Types

1. synergist 2. fixator

Anterior Neck Muscles

1.Sternocleidomastoid 2. Scalenes

Nerve Supply of Sternocleidomastoid

Accessory nerve (Cranial nerve XI) and Branches of cervical spinal nerves C2 and C3 (Ventral Rami)

2. Scalenes

Anterior, middle, and posterior

Nerve Supply to Splenius

Cervical spinal nerves (dorsal rami)

Muscle Shape

Distinctive shapes ex./ deltoid muscle (deltoid=triangle)

Action of Scalenes

Elevate first two ribs (aid in inspiration) flex and rotates neck

Number of origin

Ex./ -Biceps (2 origina) -Triceps (Three origins)

Direction of Muscle

Ex./ -Rectus (Fibers run straight) -Transverses (Fibers run at right angles) -Oblique (Fibers run at angles to imaginary defined axis)

Action of Iliocostalis

Extend and laterally flex the vertebral column; maintain erect posture; acting on one side, bend vertebral column to same side

Quadratus Lumborum

Fleshy muscle forming part of posterior abdominal wall

Action of Sternocleidomastoid

Flexes and laterally rotates the head -Simultaneous contraction of both muscles flexes neck -generally against resistance as when raising head when lying on the back -Acting Alone each muscle rotates head toward shoulder on opposite side and tilts or laterally flexes head to its own side

Longissimus

Intermediate tripartite muscle groups of erector spinae; extend by many muscle slips from lumbar region to skull; mainly pass between transverse processes of vertebrae

Action of Quadratus Lumborum

Laterally flexes vertebral colum when acting separately -when pair acts jointly, lumbar spine is extended and 12th rib is fixed -maintains upright posture -assists in forced inspiration

Description of Scalenes

Locates more laterally than anteriorly on neck -deep to platysma and sternocleidomastoid

Prime Mover (Agonist)

Major responsibility for producing specific movement

Iliocostalis

Most lateral muscle group of erector spinae muscles -extends from the pelvis to neck

Origin and Intersection of Splenius

O- Ligamentum nuchae-spinous processes of vertebrae C7-T6 I-Mastoid process of temporal bone (capitis); transverse processes of C2-C4 vertebrae (cervicis)

Origin (O) of and Intersection (I) Sternocleidomastoid

O- Manubrium of sternum and medial portion of clavicle I- Mastoid Process of temporal bone and superior nuchal line of occipital bone

Orginin and Insertion of Scalenes

O- Transverse processes of cervical vertebrae I-Anterolaterally on first two ribs

The origin and intersection of Longissimus

O- transverse processes of lumbar through cervical vertebrae I-Transverse processes of thoracic or cervical vertebrae and to ribs superior to origin as indicated by name; capitis inserts into mastoid process of the temporal lobe

Origin and Intersection of Quadratus Lumborum

O-Illiac crest and lumbar fascia I-Transverse processes of lumbar vertevrae L1-L4 and lower margin of 12th rib

Origin and Intersection of Semispinalis

O-Transverse processes of C7-T12 I-Occipital bone (capitis) and spinous processes of cervical (cervicis) and thoracic vertebrae T1-T4 (thoracis)

Origin and Intersection of Iliocostalis

O-iliac crest (lumborum) inferior 6 ribs (thoraci) ribs 3 to 6 (cervicis) I-angles of ribs (lumborum and thoracis); Transverse processes of cervical vertebrae C4-C6 (cervicis)

Nerve Supply for Iliocostalis

Spinal Nerves (Dorsal Rami)

Nerve Supply

Spinal nerves (dorsal Rami)

Nerve Supply to Semispinalis

Spinal nerves (dorsal rami)

Nerve Supply to Quadratus Lumborum

T12 and upper lumbar spinal nerves (ventral rami)

Action of Longissimus

Thoracis and cervicis act together to extend and laterally flex vertebral column -Capitis extends head and turns the face toward same side

Spinalis

Thoracis and cervicis parts -Most medial muscle column of erector spinae -Cervicis usually rudimentary and poorly defined

Semispinalis

Thoracis, cervicis, and capitis regions -Composite muscle forming part deep layer of intrinsic back muscles -extends from thoracic region to the head

1. Sternocleidomastoid

Two- Headed Muscle located deep to platysma on anterolateral surface of neck -Fleshy parts on either side of neck delineate limits of anterior and posterior triangles -Key muscular landmark in neck

Flexion

a muscle that crosses on the anterior side of a joint

Abduction

a muscle that crosses on the lateral side of a joint

Adduction

a muscle that crosses on the medial side of a joint

Extension

a muscle that crosses on the posterior side of a joint produces extension

Muscle location

bone or body region with which muscle associated ex./ temporalis (over temporal bone)

Scalenes Nerve Supply

cervical spinal nerves

Nerve Supply to Longissimus

dorsal rami of spinal nerves

Muscle size

ex./ Maximus (largest) Minimus (smallest) Longus (Long)

Action of Splenius

extend or hyperextend head -when splenius muscles on one side are activated -head rotates and bends laterally toward same side

Action of Spinalis

extends vertebral column

Action of Semispinalis

extends vertebral column and head and rotates them to opposite side -acts synergistically with sternocleidomastoid muscle of opposite side

Synergist

helps prime movers -adds extra force to same movement -reduces undesirable or unnecessary movement

Locations of Attachments

named according to point of origin and insertion (origin named first) -Example: sternocleidomastoid attaches to sternum and clavicle, with insertion on mastoid process

Muscle Action

named for action they produce -Example: flexor or extensor •Several criteria can be combined -Example: extensor (extends) carpi (wrist) radialis (radius) longus (length is long)

Antagonist

opposes or reverses particular movement -Prime mover and antagonist are located on opposite sides of joint across which they act

Origin and Insertion of Spinalis

origin: spinous processes at upper lumbar and lower thoracic vertebrae insertion: spinous processes at superior (upper) vertebral levels and base of skull (cervical vertebrae)

erector spinae

prime mover of back extension; a deep composite muscle consisting of three columns -provide resistance that helps control action of bending forward at the waist and act as powerful extensions to promote return to erect position -during full felxion (ie when touching fingertips to the floor), erector spinae are relaxed and strain is bourne entirely by ligaments of the back - On reversing the movement, these muscles are initially inactive, and extension is initiated by hamstring muscles of thighs and gluteus maximus muscles of buttocks. As a result of this peculiarity, lifting a load or moving suddenly from a bent-over position can injure muscles and ligaments of the back and intervertebral discs -Erector spinae muscles readily fo into painful spasms following injury to back structures

The ligamentum nuchae

strong, elastic ligament extending from occipital bone of the skill along the tips of the spinous processes of the cervical vertebrae; binds the cervical vertebrae together and inhibits excessive head and neck flexion, preventing damage to the spinal cord

Major Skeletal Muscles of the Body

•> 600 muscles; grouped by function and location •Muscle tables include following information: -Description, which includes location relative to other muscles -Origin and insertion: usually a joint between origin and insertion -Actions: movement that contraction causes -Innervation: name of major nerve that supplies muscle

Fascile Arrangements

•All skeletal muscles consist of fascicles (bundles of fibers) •Fascicle arrangements vary, resulting in muscles with different shapes and functional capabilities •The most common patterns of arrangement -Circular -Convergent -Parallel -Pennate

Muscles of the Neck and Vertebral Column: Head Movements and Trunk Extension

•Two functional groups Anterolateral neck muscles: move head Intrinsic muscles of the back: extend trunk and maintain posture