Module 6 - Muscular System (Part 1)

• Pectoralis

• Gluteus

• Brachial

Muscle Location:

Pectoralis

located in the chest

Gluteus

located in the buttock

Brachial

located in the arm

• Maximus

• Minimus

• Longus

• Brevis

Muscle Size:

Gluteus maximus

largest muscle

Gluteus minimus

smallest muscle

Longus muscle

longer than brevis

Brevis muscle

shorter than longus

• Deltoid

• Quadratus

• Teres

Muscle Shape:

Deltoid

triangular in shape

Quadratus

rectangular in shape

Teres

round in shape

• Rectus

• Oblique

Orientation of fascicles:

Rectus

muscle fascicles running in the same direction as the structure with which the muscle is oriented

Oblique

lie at an angle to the length of the structure

• Sternocleidomastoid

• Brachioradialis

Origin and Insertion:

Sternocleidomastoid

Origin: sternum and clavicle

Insertion: Mastoid process of the temporal bone

Brachioradialis

Origin: arm

Insertion: radius

• Biceps

• Triceps

Number of Heads:

Biceps

muscle has two heads

Triceps

muscle has three heads

Abduction

moves a structure away from the midline

Adduction

moves a structure towards the midline

Occipitofrontalis

raises the eyebrows; furrow the skin of the forehead

Orbicularis oculi

around the eyes; closes the eyelids and causes “crow’s-feet” wrinkles at the lateral corners of the eye

Orbicularis oris

around the mouth

Buccinator

walls of the cheeks

Risorius

smiling, involved in sardonic grin in Tetanus

Zygomaticus

elevate the upper lip and corner of the mouth

Levator labii superioris

elevates one side of the upper lip

Depressor anguli oris

frowning and pouting; depresses the corner of the mouth

• Temporalis

• Masseter

• Pterygoids

Muscles of Mastication:

Temporalis

elevates and draws mandible posteriorly

Masseter

elevates and draws mandible anteriorly

Lateral pterygoid

pushes mandible anteriorly and depresses mandible

Medial pterygoid

pushes mandible anteriorly and elevates mandible

• Intrinsic muscles

• Genioglossus

• Hyoglossus

• Styloglossus

• Palatoglossu

Muscles for Tongue movement:

Intrinsic muscles

located entirely within the tongue and change its shape

Extrinsic muscles

located outside the tongue but are attached to and move the tongue

Muscles of Vertebral Colum

to extend the neck and vertebral column

• Iliocostalis

• Longissimus

• Spinalis

Erector Spinae Group of Muscles:

Longissimus

accounts for most of the muscle mass in the lower back

Muscles of the Thorax

control of breathing; determine airflow into and out of the lungs

Diaphragm

muscle responsible for normal, quiet breathing, dome-shaped muscle. contraction causes the volume of the thoracic cavity to increase and resulting in inhalation

External intercostals

elevate ribs during quiet, resting inhalation

Internal intercostals

depress the ribs during forced exhalation

Muscles of abdominal wall

flex and rotate the vertebral column; aid in such functions as forced expiration, vomiting, defecation, coughing, and childbirth

• Rectus abdominis

• External abdominal oblique

• Internal abdominal oblique

• Transversus abdominis

Muscle of abdominal wall:

• Coccygeus

• Levator ani

Pelvic floor:

Perineum

diamond-shaped area just inferior to the pelvic floor

Muscles of scapula

permit a wide range of movements of the upper limb

• Levator scapulae

• Pectoralis minor

• Rhomboids major & minor

• Serratus anterior

• Trapezius

Muscles of scapula:

Levator scapulae

elevates, retracts, and rotates scapula; laterally flexes neck

Pectoralis minor

depresses scapula or elevates ribs

Rhomboids major

retracts, rotates, and fixes scapula

Rhomboids minor

retracts, slightly elevates, rotates, and fixes scapula

Serratus anterior

rotates and protracts scapula; elevates ribs

Trapezius

elevates, depresses, retracts, rotates, and fixes scapula; extends neck

Shoulder & Arm muscles

muscles moving the arm are involved in flexion, extension, abduction, adduction, rotation, and circumduction

• Pectoralis major

• Latissimus dorsi

• Deltoid

Shoulder & Arm muscles:

Pectoralis major

flexes shoulder; extends shoulder from flexed position; adducts and medially rotates arm

Latissimus dorsi

extends shoulder, adducts and medially rotates arm

Deltoid

flexes and extends shoulder; abducts and medially and laterally t

Biceps brachii

flexes elbow; supinates forearm; flexes shoulder

Triceps brachii

extends elbow; extends shoulder; adducts arm

• Supinator

• Biceps brachii

Muscles that supinate the forearm and hand:

• Pronator quadratus

• Pronator teres

Muscles that pronate the forearm and hand:

Anterior forearm muscles

flexion of the wrist and fingers

Posterior forearm muscles

extension of the wrist and fingers

Anterior hip muscles

flex the hip; iliopsoas

Posterolateral hip muscles

extend the hip; gluteus maximus, gluteus medius, gluteus minimus, tensor fasciae latae

Quadriceps femoris:

• Rectus femoris

• Vastus lateralis

• Vastus medialis

• Vastus intermedius

• Sartorius

Anterior thigh muscles:

Hamstring muscles:

• Biceps femoris

• Semimembranosus

• Semitendinosus

Posterior thigh muscles:

• Gastrocnemius

• Soleus

• Plantaris

• Achilles tendon

Posterior leg muscles: