back - anterior compartment of hand

pronator teres

origin: ulnar head, coronoid process of ulna

humeral head, medial epicondyle of the humerus

insertion: middle of convexity of lateral surface of radius
innervation: median nerve c6, c7
action: pronate forearm; flexes elbow joint

flexor carpi radialis

origin: medial epicondyle of humerus

insertion: base of 2nd (3rd) metacarpal
innervation: median nerve c6, c7
action: flex and abducts hand at wrist

palmaris longus

origin: medial epicondyle of humerus
insertion: distal half of flexor retinaculum, palmar aponeurosis
innervation: median nerve c7, c8
action: flexes hand (at wrist) and tenses palmar aponeuruosis

flexor carpi ulnaris

origin ulnar head, olecranon and posterior border of ulna (via aponeurosis),

humeral head, medial epicondyle of humerus
insertion: pisiform, hook of hamate, 5th metacarpal
innervation: ulnar nerve c7, c8
action: flexes and adducts hand at the wrist

flexor digitorum superficialis

origin: humero-ulnar head: medial epicondyle of humerus and coronoid process of ulna
radial head: oblique line of radius
insertion: shafts (bodies) of middle phalaanges of digits 2-5
innervation: median nerve c7, c8, t1
action: flexes wrist joint, carpometacarpal joints, proximal interphaalangeal joints: acting more strongly, it also flexes proximal phalanges at metacarpophalangeal joints

flexor digitorum profundus

origin: proximal three quarters of medial and anterior surfaces of ulna and interosseous membrane

insertion: base of distal phalanges of 2-5
innervation: digits 2-3 median nerve c8-t1 anterior interosseous branch, digits 4-5 ulnar nerve c8-t1
action: flexes wrist joint, carpometacarpal joints, flexes interphalangeal joints 2-5, assists with wrist flexion

flexor policis longus

origin: anterior surface of radius and adjacent interosseous membrane

insertion: base of distal phalanx of thumb
innervation: anterior interossues nerve median nerve c8, t1
action: flexes wrist joint, carpometacarpal joints, flexes metacarpophalangeal and interphalangeal joints of thumb

pronator quadratus

origin: distal quarter of anterior surface of ulna

insertion: distal quarter of anterior surface of radius
innervation: anterior interosseus nerve, median nerve c8, t1
action: pronates forearm; deep fibers bind radius and ula together

supraspinatus

origin supraspinous fossa of scapula
insertion superior facet of greater tubercle of humerus
innervation suprascapular nerve c5, c6
action initiats and assists deltoid in ABduction of shoulder joint and acts with other rotator cuff muscles

infraspinatus

origin infraspinous fossa of scapula
insertion middle facet of greater tubercle of humerus
innervation suprascapular nerve c5, c6
action laterally rotates shoulder joint, help humeral head in glenoid cavity of scapula

teres minor

origin middle part of the lateral border of scapula
insertion inferior facet of greater tubercle of humerus
innervation axillary nerve c5, c6
action laterally rotates shoulder joint, help humeral head in glenoid cavity of scapula

teres major

origin inferior part of lateral border of scapula and posterior surface of inferior angle of scapula
insertion medial lip of intertubercle sulcus of humerus
innervation lower subscapular nerve c5, c6
action adducts and medially rotates shoulder joint

deltoid

origin lateral third of clavicle: acromion and spine of scapula
insertion deltoid tuberosity of humerus
innervation axillary nerve c5, c6
action clavicular (anterior) part flexes and medially rotate shoulder joint; acromion (middle) part aBDucts the shoulder joint; spinal (posterior) part extends and laterally rotates shoulder joint

serratus anterior

origin external surface of the lateral parts of 1st-8th ribs
insertion anterior surface of medial border of scapula
innervation long thoracic nerve c5, c6, c7
action protracts scapula and hold it against thoracic wall, rotates scapula

latissimus dorsi

origin spinous process of inferior 6 thoracic vertebrae, thorocolumbar fascia, iliac crest, and inferior 3 or 4 ribs (medial)
insertion foor of intertubercle sulcus of humerus

innervation thoracodorsal nerve c6,c7,c8

action medially rotate glenoid cavity, extend and adduct arm, moves body to arm when climbing

subscapularis

origin subscapular fossa (most of anterior surface of scapula)
insertion lesser tubercle of humerus
innerveration upper and lower subscapular nerves c5-c7

action shoulder joint: adduction, medial rotation; hold humeral head in glenoid cavity

pectoralis major

origin clavicular head: anterior surface of medial half of clavicle; sternocostal head: anterior surface of sternum, superior 6 costal cartilages, aponeurosis of external oblique muscles
insertion lateral lip of intertubercular sulcus of humerus
innervation lateral and medial pectoral nerves; clavicular head: c5-c6; sternocostal head: c7-c8,t1
action: shoulder joint: adductions, medial rotation; draws scapula anteriorly and inferiorly; alone: clavicular head flexes shoulder joint and sternocostal head adn extends it from the flexed position

pectoralis minor

origin 3rd - 5th ribs near their costal cartilages
insertion medial border and superior surface of coracoid of the scapula
innervation: medial pectoral nerve c8, t1
action: stabilizes scapula by drawing inferiorly and anteriorly against the thoracic wall

Trapezius

origin: medial third of superior nuchal line, external occipital protuberance, nuchal ligament, spinous process of c7-t12 vertebrae (medial)

insertion: lateral third of clavicle, acromion and spine of scapula (lateral)

innvervation: spinal accssory nerve c3, c4 spinal nerves

action: elevates, rotate glenoid cavity superiorly, extend neck, retract and depress scapula

levator scapulae

origin: posterior tubercles of transverse processes of c1-c4 vertebrae

insertion medial border of scapula superior to root of spine

innvervation: dorsal scapular c5, and cervical c3,c4 spinal nerves

action: elevates scapula, rotate the glenoidhumeral cavity inferiorly

splenius capitus (spinotransversalis)

origin: nuchal ligament and spinous process of c7-t6 vertebrae

insertion: mastoid process and superior nuchal line (occipital bone)

innvervation: posterior rami of spinal nerves

action: alone: laterally flex neck and rotate head to side of active muscles, together: extend head and neck

sternocleidomastoid

origin: lateral surface of mastoid process of temporal bone and lateral half of superior nuchal line

insertion: sternal head: surface of manubrium of sternum; clavicular head: superior surface of medial third of clavicle

innervation: spinal accessory nerve, c2-c3

action: laterally flex ipsilaterally; contralaterally rotates; bilaterally: extends neck at atlanto occipital joint, flexes cervical vertebrae so chin approaches manubrium, chin thrust while head is kept level by extending superior cervical vertebrae while flexing inferior vertebrae (head protraction); when cervical vertebrae fixed, may elevate manubrium and medial end of clavicles to assist deep respiration (pump handle)

anterior scalene

origin: anterior tubercles of transverse process of c3-c6 vertebrae

insertion: 1st rib

innervation: cervical spinal nerves c4-c6

action: flexes neck laterally: elevates 1st rib during forced inspiration

middle scalene

origin: posterior tubercles of transverse process of c4-c7 vertebrae

insertion: superior surface of 1st rib: posterior to groove for subclavian artery

innervation: anterior rami of cervical spinal nerves

action: flexes neck laterally: elevates 1st rib during forced inspiraiton

posterior scalene

origin: posterior tubercles of transverse processes of c4-c6 vertebrae

insertion: external border of 2nd rib

innervation: anterior rami of cervical spinal nerves c7 and c8

action: flexes neck laterally, elevates 2nd rib during forced inspiration

rhomboid minor

origin: nuchal ligament; spinous process c7 and t1 vertebrae (medial)

insertion: triangular area at medial end of the scapular spine (lateral)

innvervation: dorsal sacpular nerve c4,c5

action: retract scapula and rotate glenoid cavity inferioly; fix scapula to thoracic wall

rhomboid major

origin: spinous process of t2-t5 (medial)

insertion: medial border of scapula from level of spine to inferior angle (lateral)

innvervation: dorsal scapular nerve c5

action: retracts scapula and rotates glenoid cavity inferiorly; fix scapula to thoracic wall

thoracolumbar fascia

origin: aponeurosis tendon, superficial layer attaches to superficial muscles and deep layer surrounds deep muscles

splenius capitus (spinotransversalis)

origin: nuchal ligament and spinous process of c7-t6 vertebrae

insertion: mastoid process and superior nuchal line (occipital bone)

innvervation: posterior rami of spinal nerves

action: alone: laterally flex neck and rotate head to side of active muscles, together: extend head and neck

splenius cervicis (spinotransversalis)

origin: nuchal ligament and spinous process of c7-t6 vertebrae

insertion: tubercles of transverse process of c1-c3 or c4

innvervation: posterior rami of spinal nerves

action: alone: laterally flex neck and rotate head to side of active muscles, together: extend head and neck

iliocostalis (sarcospinalis/erector spinae)

origin: posterior iliac crest, posterior sacrum, sacro-iliac ligament, sacral and inferior lumbar spinous processes, supraspinatus ligament

insertion: angles of lower ribs, cervical transverse process

innervation: posterior rami of spinal nerves

action: acting bilaterally: extend vetebral column and head; as back is flexed control movemnt by gradually lengthening their fibers Acting Unilaterlly: laterally flex vetebral column

longtissmus (sarcospinalis/erector spinae)

origin: posterior iliac crest, posterior sacrum, sacro-iliac ligament, sacral and inferior lumbar spinous processes, supraspinous ligament

insertion:: ribs b/w tubercles and angles to transverse processes in thoracic and cervical region to mastoid proces

innervation: posterior rami of spinal nerves

action: acting bilaterally: extend vetebral column and head; as back is flexed control movemnt by gradually lengthening their fibers Acting Unilaterlly: laterally flex vetebral column

spinalis (sarcospinalis/erector spinae)

origin: posterior iliac crest, posterior sacrum, sacro-iliac ligament, sacral and inferior lumbar spinous processes, supraspinous ligament

insertion: spinous process in upper thoracic region to cranium

innervation: posterior rami of spinal nerves

action: acting bilaterally: extend vetebral column and head; as back is flexed control movemnt by gradually lengthening their fibers Acting Unilaterlly: laterally flex vetebral column

semispinalis (transversospinalis)

origin: transverse process of c4-t10

insertion: fibers run superomedially to occipital bone and spinous processes in upper thoracic and cervical regions, spanning four to six segments

innervation: posterior rami of spinal nerves

action: acting bilaterally: extend vetebral column and head; as back is flexed control movemnt by gradually lengthening their fibers Acting Unilaterlly: laterally flex vetebral column

multifidus (transversospinalis)

origin: posterior sacrum, posterior iliac spine of ilium, aponeruosis of erector spinae, sacro-iliac ligaments, mamilary processes of lumbar vertebrae, transverse processes of thoracic vertebrae, and articular processes of c4-c7

insertion: thickest in lumbar region, superomedially to entire length of spinous processes of vertebrae located 2-4 segments superior to origin

innervation: posterior rami of spinal nerves

action: acting bilaterally: extend vetebral column and head; as back is flexed control movemnt by gradually lengthening their fibers Acting Unilaterlly: laterally flex vetebral column

rotatores (transversospinalis)

origin: transverse process of vertebrae (best developed in thoracic region)

insertion: superomedially attach to junction of lamina and transverse process or spinous process immediately superior to vertebrae of origin

innervation: posterior rami of spinal nerves

action: acting bilaterally: extend vetebral column and head; as back is flexed control movemnt by gradually lengthening their fibers Acting Unilaterlly: laterally flex vetebral column

interspinalis (segmental)

origin: superior surface of spinous process of cervical and lumbar vertebrae

insertion: inferior surfaces of spinous process of vertebrae superior to vertebrae origin

innervation: posterior rami of spinal nerves

action: extension and rotation of vertebral column

intertransversi (segmental)

origin: transverse process of cervical and lumbar vertebrae

insertion: transverse process of adjacent vertebrae

innervation: posterior and anterior rami of spinal nerves

action: lateral flexion of vertebral column/bilaterally stabilizes vertebral column

obliquus capitis superior (suboccipital)

origin: transverse process of c1

insertion: occipital bone between the superior and inferior nuchal lines

innervation: posterior ramus of c1: suboccipital nerve

action: extend the head on c1, rotate head and c1 on c2 vertebrae

obliquus capitis inferior (suboccipital)

origin: spinous process of c2

insertion: transverse process of c1

innervation: posterior ramus of c1: suboccipital nerve

action: extend the head on c1, rotate head and c1 on c2 vertebrae

rectus capitis posterior major (suboccipital)

origin: spinous process of c2

insertion:lateral part of the inferior nuchal line and the occipital bone

innervation: posterior ramus of c1: suboccipital nerve

action: extend the head on c1, rotate head and c1 on c2 vertebrae

rectus capitus posterior minor (suboccipital)

origin: posterior tubercle of the arch of posterior arch of c1

insertion: medial third of the inferior nuchal line

innervation: posterior ramus of c1: suboccipital nerve

action: extend the head on c1, rotate head and c1 on c2 vertebrae

biceps brachii

origin: short head: tip of coracoid process of scapula; longhead: supraglenoid tubercle of scapula
insertion: tuberosity of radius and fascia of forearm via bicipital aponeurosis
innervation: musculocutaneous c5,c6
action: supinates forearm and when it is supinated, flexes elbow joint; flexes shoulder joint: short head resists dislocation of shoulder