Muscles Flashcards
Pectoralis Major : proximal attachment
Clavicular head: anterior surface of medial 1/2 of clavicle;
Sternocostal head: sternum and superior six costal cartilages, aponeurosis of external oblique muscle
Pectoralis Major: distal attachment
Lateral lip of intertubercular sulcus of humerus
Pectoralis Major: innervation
Lateral and medial pectoral nerves
Pectoralis Major: actions
Addiction and medial rotation of humerus. Draws scapula anteriorly and inferiority. Ex. Climbing, throwing, pushing, hugging, bench press
Pectoralis Minor: proximal attachment
3rd to 5th ribs
Pectoralis minor: distal attachment
Coracoid process of scapula
Pectoralis minor: innervation
Medial pectoral nerve
Pectoralis minor : actions
Stabilizes scapula by drawing inferiorly and anteriorly against thoracic wall
Subclavius : proximal attachment
Junction of first rib and it’s costal cartilage
Subclavius: distal attachment
Inferior surface of middle third of clavicle
Subclavius: innervation
Subclavian nerve
Subclavius : actions
Anchors and depresses clavicle
Serratus anterior: proximal attachment
1st to 8th ribs
Serratus anterior: distal attachment
Medial border of scapula
Serratus anterior: innervation
Long thoracic nerve
Serratus anterior: actions
Protraction of scapula, move scapula forward (pushing and punching); called boxer’s muscle. Holds the scapula against the thoracic wall
What does injury to the long thoracic nerve do?
Paralysis of serratus anterior and causes winging of scapula
Trapezius: medial attachment
Medial third of superior nuchal line; external occipital protuberance, nuchal ligament; spinous processes of C7-T12 vertebrae
Trapezius : lateral attachment
Lateral 1/3 of clavicle, acromion and spine of scapula
Trapezius: innervation
Spinal accessory nerve (CN XI) and C3, C4 spinal nerve
Trapezius: actions
Descending (superior) part elevates “shoulder shrugging”, ascending (inferior) part depresses and middle part retracts (pulls posteriorly) scapula.
CN XI nerve injury is in which muscle
Trapezius
Latissimus dorsi: medial attachment
Spinous processes of T6-T12 thoracic vertebrae, thoracolumbar fascia, iliac crest and inferior 3 or 4 ribs
Latissimus dorsi: lateral attachment
Floor of intertubercular groove of humerus
Latissimus dorsi: innervation
Thoracodorsal nerve
Latissimus dorsi: actions
Extends, adduction and medial rotation of shoulder joint (striking actions ex. Blow, hammering, swimming and rowing); raises body towards arm during climbing
Levator scapulae: medial attachment
Posterior tubercles Of transverse processes of C1-C4
Levator scapulae: lateral attachment
Medial border of scapula superior to root of spine
Levator scapulae : innervation
Dorsal scapulae nerve
Levator scapulae : actions
Elevate scapula
Rhomboid Major: medial attachment
Spinous processes of T2-T5
Rhomboid minor: medial attachment
Spinous processes of C7-T1
Rhomboids (Major and minor) : lateral attachment
Medial border of scapula
Rhomboids (Major and minor): innervation
Dorsal scapular nerve
Rhomboids (Major and minor) : actions
Retract scapula and rotate glenoid cavity inferiorly
Deltoid: proximal attachment
Lateral 1/3 of clavicle, acromion and spine of scapula. (Insertion of trapezius is same as origin of deltoid)
Deltoid: distal attachment
Deltoid tuberosity of humerus
Deltoid: innervation
Axillary nerve
Deltoid: actions
Flex, medially rotates shoulder joint; extends, laterally rotate and abduction of arm
Supraspinatus: proximal attachment
Supraspinous fossa of scapula
Supraspinatus: distal attachment
Greater tubercle of humerus
Supraspinatus: innervation
Suprascapular nerve
Supraspinatus: action
Initiate abduction (15°) of arm
Infraspinatus: proximal attachment
Infraspinous fossa of scapula
Infraspinatus: distal attachment
Greater tubercle of humerus
Infraspinatus: innervation
Suprascapular nerve
Infraspinatus: action
Laterally rotates shoulder joint
Teres minor: proximal attachment
Middle part of lateral border of scapula
Teres minor: distal attachment
Greater tubercle of humerus
Teres minor: innervation
Axillary nerve
Teres minor: action
Laterally rotates shoulder joint (same as infraspinatus)
Teres Major: proximal attachment
Inferior part of lateral border of scapula
Teres Major: distal attachment
Medial lip of intertubercular sulcus of humerus
Teres Major: innervation
Lower subscapular nerve
Teres Major: action
Medially rotates and adducts the shoulder joint
Subscapularis: proximal attachment
Subscapular fossa of scapula
Subscapularis: distal attachment
Lesser tubercle of humerus
Subscapularis: innervation
Upper and lower subscapular nerves
Subscapularis: action
Medially rotates and adduct of shoulder joint
Rotator cuff muscles
SITS: supraspinatus, infraspinatus, teres minor, subscapularis
Injury to thoracodorsal nerve causes
Can be injured during mastectomy. Paralyzes the latissimus dorsi. They cannot climb
Injury to CN XI causes
Shoulder drop
Injury to dorsal scapular nerve
Paralysis of rhomboids
Brachial plexus roots:
Formed by anterior rami of C5 to T1 nerves. Extends from cervical region to axilla. Nerve supply to upper limb
Injury to superior trunk C5, C6 roots in new born
Erb-Duchenne palsy. Excessive stretching of neck during delivery or fall landing on shoulder
Waiters tip position
Injury to C5, C6
Injury of inferior trunk C8, T1
Klumpke paralysis. Occurs when limb is suddenly pulled. Damage to ulnar nerve
Damage to ulnar nerve causes
Claw hand. Loss of sensation over medial palm, ring, and pinky finger
Ulnar nerve compression occurs where
Between medial epicondyle and operating table during surgery causing claw hand
Damage to median nerve due to excessive probing in cubical fossa during venipuncture
Thenar atrophy. Loss of thumb opposition - ape hand
Distal lesion in median nerve
Carpal tunnel syndrome
Damage to radial nerve causes
Wrist drop. “Saturday night palsy”
Injury to long thoracic nerve
Paralysis of serratus anterior. “Winging scapula” due to stab wound, axillary node dissection
Biceps brachii : proximal attachment
Short head: from coracoid process of scapula
Long head: from supraglenoid tubercle of scapula
Biceps brachii: distal attachment
Radial tuberosity
Biceps brachii: innervation
Musculotaneous nerve
Biceps brachii: actions
Flexes elbow and supinate forearm. Ex. Opening a bottle of wine
Brachialis: proximal attachment
Distal half of anterior surface of humerus
Brachialis: distal attachment
Coronoid process of ulna
Brachialis: innervation
Musculotaneous nerve
Brachialis: actions
Flexes elbow joint
Coracobrachialis: proximal attachment
Coracoid process of scapula
Coracobrachialis: distal attachment
Middle third of medial surface of humerus
Coracobrachialis: innervation
Musculotaneous nerve
Coracobrachialis: actions
Flexes and adducts shoulder joint
Triceps brachii: proximal attachment
Long head: infraglenoid tubercle of scapula
Lateral head: humerus superior to radial groove
Medial head: humerus inferior to radial groove
Triceps brachii: distal attachment
Olecranon process of ulna
Triceps brachii: innervation
Radial nerve
Triceps brachii: actions
Chief extensor of elbow joint
Anconeus: proximal attachment
Lateral epicondyle of humerus
Anconeus: distal attachment
Olecranon process of ulna
Anconeus: innervation
Radial nerve
Anconeus: actions
Assists triceps in extending elbow joint