Muscles of neck, torso, and upper limbs (LAB)

diaphragm

broad muscle pierces by the aorta, inferior vena cava, and esophagus, and forms the floor of the thoracic cavity

diaphragm origin

inferior, internal surface of ribcage and sternum and costal cartilages of the last 6 ribs and lumbar vertebrae

diaphragm insertion

central tendon

diaphragm function

prime mover of inspiration and flattens on contraction

internal intercostals

11 pairs of muscles that lie between ribs

internal intercostals origin

superior border of rib below

internal intercostals insertion

inferior border (costal groove) of rib above

internal intercostals function

draws ribs together to depress the ribcage

external intercostals

11 pairs of muscles that lie between ribs

external intercostals origin

inferior border of rib above

external intercostals insertion

superior border of rib below

external intercostals function

pulls ribs toward one another to elevate the ribcage

quadratus lumborum

fleshy back muscle that forms part of the posterior abdominal wall

quadratus lumborum origin

iliac crest and lumbar fascia

quadratus lumborum insertion

transverse process of lumbar vertebrae L₁-L₄ and lower margin of 12th rib

quadratus lumborum function

laterally flexes vertebral column

semispinalis capitis

composite muscle forming part of the deep layer of the intrinsic back muscle

semispinalis capitis origin

transverse process of C₇-T₁₂

semispinalis capitis insertion

occipital bone

semispinalis capitis function

extends the vertebral column and head and rotates them to opposite sides

Iliocostalis lumborum

most lateral muscle group of the erector spinae (back) muscles and extends from pelvis to neck

Iliocostalis lumborum origin

iliac crest

Iliocostalis lumborum insertion

angles of ribs

Iliocostalis lumborum function

extend and laterally flexes the vertebral column

longissimus thoracis and capitis

intermediate tripartite of erector spinae (back)

longissimus thoracis and capitis origin

transverse process of lumbar through cervical vertebrae

longissimus capitis insertion

mastoid process of temporal bone

longissimus thoracis insertion

transverse process of thoracic vertebrae and ribs superior to origin

longissimus capitis function

extends head and turns face towards the same sides

longissimus thoracis function

extends and laterally flexes vertebral column

spinalis thoracis

most medial muscle column of erector spinae (back)

spinalis thoracis origin

spinous process of the upper lumbar and lower thoracic vertebrae

spinalis thoracis insertion

spinous process of upper thoracic and cervical vertebrae

spinalis thoracis function

extends vertebral column

rectus abdominis

medial superficial muscle pair that extends from the pubis to ribcage

rectus abdominis origin

pubic crest and symphysis

rectus abdominis insertion

xiphoid process and costal cartilage of ribs 5-7

rectus abdominis function

flexes and rotates the lumbar region of the vertebral column

external oblique

largest and most superficial of the 3 lateral muscles

external oblique origin

by fleshy strips from outer surfaces of lower 8 ribs

external oblique insertion

most insert into the Linea alba, some insert into the pubic crest and pubic tubercle and iliac crest

external oblique function

flex vertebral column and compresses the abdominal wall and aids the back muscles in rotating the trunk and flexing laterally

internal oblique origin

lumbar fascia, iliac crest, and inguinal ligament

internal oblique insertion

Linea alba, pubic crest, last 3-4 ribs, and costal margin

internal oblique function

flex vertebral column and compresses the abdominal wall and aids the back muscles in rotating the trunk and flexing laterally

transverse abdominis

deepest muscle of abdominal wall

transverse abdominis origin

cartilages of last 6 ribs; lumbar fascia, iliac crest, and inguinal ligament

transverse abdominis insertion

pubic crest and linea alba

transverse abdominis function

compresses abdominal contents

pectoralis minor

flat, thin muscle directly beneath and obscured by the pectoralis major

pectoralis minor origin

anterior surfaces of ribs 3-5 (or 2-4)

pectoralis minor insertion

coracoid process of scapula

pectoralis minor function

draws the scapula forward and downward when the ribs are fixed

serratus anterior

fan shaped muscle that lies deep to the scapula and pectoral muscles

serratus anterior origin

by a series of muscle slips from ribs 1-8 (or 9)

serratus anterior insertion

entire anterior surface of the vertebral border of scapula

serratus anterior function

rotates scapula so its inferior angle moves laterally and upward

subclavius

small cylindrical muscle extending from rib 1 to clavicle

subclavius origin

costal cartilage of rib 1

subclavius insertion

groove on the inferior surface of clavicle

subclavius function

helps stabilize and depress the pectoral girdle

trapezius

most superficial muscle of the posterior thorax that is flat and triangular

trapezius origin

occipital bone, ligamentum nuchae, and the spinous process of C₇ and all thoracic vertebrae

trapezius insertion

continuous insertion along acromion and spine of scapula and lateral 3rd of clavicle

trapezius function

stabilizes, elevates, retracts, and rotates scapula

levator scapulae

straplike muscle located at the back and side of the neck, deep to the trapezius

levator scapulae origin

transverse processes of C₁-C₄

levator scapulae insertion

medial border of scapula superior to spine

levator scapulae function

elevates/adducts scapula

rhomboid major and minor

2 roughly diamond-shaped muscles deep to trapezius

rhomboid major origin

spinous processes of C7 and T1

rhomboid minor origin

spinous processes of T2-T5

rhomboid major and minor insertion

medial border of scapula

rhomboid major and minor function

stabilizes sacpula

pectoralis major

large, fan shaped muscle covering the superior portion of the chest

pectoralis major origin

sternal end of clavicle, sternum, cartilages of ribs 1-6 (or 7), and aponeurosis of external oblique muscle

pectoralis major insertion

fibers converge to insert by a short tendon into the intertubercular sulcus and the greater tubercle of humerus

pectoralis major function

adducts and medially rotates arm

deltoid

thick, multipennate muscle forming rounded shoulder muscle mass

deltoid origin

lateral third of clavicle, acromion, and spine of scapula

deltoid insertion

deltoid tuberosity of humerus

deltoid function

prime mover of arm adduction when all its fibers contract simultaneously

latissimus dorsi

broad, flat, triangular muscle of lower back

latissimus dorsi origin

indirect attachment via lumbodorsal fascia into spines of lower 3-4 ribs, iliac crest, and scapulas inferior angle

latissimus dorsi insertion

spirals around the teres major to insert in the floor of the intertubercular sulcus of humerus

latissimus dorsi function

prime mover of arm extension, powerful arm adductor, and medially rotates arm at shoulder

subscapularis

forms part of posterior wall of axilla

subscapularis origin

subscapular fossa of scapula

subscapularis insertion

lesser tubercle of humerus

subscapularis function

chief medial rotator of the arm

supraspinatus

rotator cuff muscle posterior to scapula and deep to trapezius

supraspinatus origin

supraspinous fossa of scapula

supraspinatus insertion

superior part of the greater tubercle of humerus

supraspinatus function

initiates abduction of arm