Back and Upper Limb Muscles Flashcards
Superficial intrinsic back muscles
Splenius capitus and splenius cervicis
Capitis
O: l. nuchae & spinous processes (C7-T3)
I: mastoid process and occipital bone
Cervicis:
O: Spinous process (T3-T6)
I: Transverse processes (C1-C3)
A: Laterally flexes neck (unilateral), extends head & neck (bilateral)
N: dorsal rami
Intermediate intrinsic back muscles
Erector spinae (spinalis, longissimus, iliocostalis)
O: spinous processes (T9-T12)
I: spinous processes (T1-T2)
N: dorsal rami branches
A: Laterally flexes vertebral column (unilateral), extends the vertebral column (aka controls the flexed vertebral column) (bilateral)
Deep intrinsic back muscles
Transversospinal muscles (semispinalis, multifidus, rotatores)
O: transverse process
I: spinous process
N: dorsal rami
A: rotates to contralateral side (opposite), extends head & vertebral column
Extrinsic shoulder muscle (posterior) - Trapezius
O: external occipital protruberance, nuchal ligament, medial superior nuchal line, spinous processes (C7-T12)
I: lateral third of clavicle, acromion process, spine of scapula
N: accessory n (CN XI)
cervical n (C3-C4)
C3-C4 (proprioception - provides info about positions of body parts, shape size weight of objects held in hand, range and direction of movement)
A: superior part - elevates scapula
middle part - retracts scapula
inferior part - depresses scapula
Extrinsic shoulder muscle (posterior) - Latissiumus dorsi)
O: Spinous processes (T7-L5), thoracolumbar fascia, iliac crest, inferior 3-4 ribs, inferior angle of scapula
I: Intertubercular sulcus (bicipital groove) of humerus
N: Thoracodorsal n. (C6-C8)
A: Extends, adducts and medially rotates humerus
Extrinsic shoulder muscle (posterior) - Levator scapulae
O: Posterior tubercles of transverse processes (C1-C4)
I: Superior part of medial border of scapula
N: Dorsal scapular n (C5)
Cervical nn. (C3-C4)
A: Elevates scapula
Rotates scapula to direct glenoid cavity inferiorly
Extrinsic shoulder muscle (posterior) - Rhomboid major and minor
O: Major - spinous processes (T2-T5); Minor - l. nuchae & spinous processes (C7-T1)
I: medial border of scapula
N: dorsal scapular n. (C4-C5)
Cervical nn. (C3-C4)
A: Retracts scapula
Rotates scapula to direct glenoid cavity inferiorly
Extrinsic shoulder muscle (anterior) - Pectoralis major
O: Clavicular head - anterior surface of medial half of clavicle
Sternocostal head - anterior surface of sternum, superior six costal cartilages
I: Greater tuberosity of humerus
N: Lateral and medial pectoral nn. (clavicular head: C5-C6; sternocostal head: C6-T1)
A: Both heads working together - adducts & medially rotates humerus
Clavicular head - flexes humerus
Sternocostal head - extends humerus (from flexed position)
Extrinsic shoulder muscle (anterior) - Pectoralis minor
O: Ribs 3-5
I: Coracoid process
N: Medial pectoral n. (C8-T1)
Some innervation from lateral pectoral n.
A: Stabilizes scapula (draws it inferiorly & anteriorly against thoracic wall)
Extrinsic shoulder muscle (anterior) - Serratus anterior
O: Ribs 1-8 I: Medial border of scapula N: Long thoracic n. (C5-C7) A: Protracts scapula Rotates scapula to direct glenoid cavity superiorly Holds scapula against thoracic wall
Intrinsic shoulder muscle - Deltoid
O: lateral 1/3 of clavicle, acromion, spine of scapula
I: deltoid tuberosity of humerus
N: axillary n. (C5-C6)
A: Clavicular (anterior) part - flexes and medially rotates arm
Acromial (middle) part - abducts arm
Spinal (posterior) part - extends & laterally rotates arm
Intrinsic shoulder muscle - Teres major
O: Inferior angle of scapula (posterior)
I: Medial lip of intertubercular sulcus (bicipital groove of humerus)
N: Lower subscapular n. (C5-C6)
A: Adducts and medially rotates arm
Intrinsic shoulder muscle (rotator cuff muscle) - Supraspinatus
O: Supraspinous fossa of scapula I: Greater tubercle of humerus N: Suprascapular n. (C4-C6) A: Initiates abduction of arm Assists deltoid in abduction of arm As a rotator cuff muscle - helps hold head of humerus in glenoid cavity
