Muscle of upper limb

The major connection of the upper limb to the body is accomplished by muscles.
These include those that move the scapula and those that move forearm and hand.
The muscles attaching the scapula to the thorax include trapezius,levator scapulae,
rhomboideus muscle, serratus anterior and pectorals.
• The arm is attached to the thorax by several muscles including the pectorals, latissimus
dorsi, deltoid and rotator cuff muscle(SITS).
Rotator cuff muscles
These are the primary muscle that hold head of the humerus in the glenoid cavity.
They are so called because they form a cuff or cap over the proximal humerus.
 The muscles are ;
Subscapularis:
Origin: Subscapular fossa
Insertion: Lesser tubercle of humerus.
Innervation: Upper and lower subscapular nerve(C5 and C6)
Action: Medially rotates arm, hold head of humerus in place.
Teres minor
Origin: Lateral border of border of scapula.
Insertion: Greater tubercle of humerus.
Innervation: Axillary nerve(C5 and C6)
Action: Laterally rotates and adducts arm, it holds head of humerus in place.
Infraspinatus
Origin: Infraspinatus fossa of scapula.
Insertion: Greater tubercle of humerus
Innervation: Suprascapular nerve(C5 and C6)
Action: Laterally rotates arm, hold head of humerus in place.
Supraspinatus
Origin: Supraspinous fossa.
Insertion:Greater tubercle of humerus
Innervation: Suprascapular(C5 and C6)
Deltoid
 It is triangular, thick multipennate muscle forming rounded shoulder muscle mass.
 It is responsible for roundness of shoulder.
 it is a site commonly used for intramuscular injection.
Origin:Lateral 1/3 of clavicle, acromion and spine of scapula.
Insertion: Deltoid tuberosity of humerus
Innervation: Axillary nerve(C4 and C6)
Action:
 Prime mover of arm abduction, anterior fibres act powerfully in flexion and medially rotate humerus.
 It is active during rhythmic arm swinging movements during walking, its posterior fibres help in extension
and lateral rotation of arm.
Coracobrachialis
 It is a small muscles which lies on the upper medial aspect of the arm.
Origin: Coracoid process of scapula
Insertion: Medial surface of humerus
Innervation: Musculocutaneous nerve
Action:Flexion and adduction of the humerus
Bicep brachii (2 heads)
It is two headed fusiform muscle.
Each bellies has its own tendon
Origin: short head arises from coracoid process, long head from supraglenoid
tubercle of scapula.
Insertion: By common tendon in to radial tuberosity.
Innervation: Musculocutaneous nerve.
Action:
 It flexes elbow joint and supinate forearm(when you open a bottle of coke.
Brachialis
It is strong muscle that is immediately deep to biceps brachii on distal humerus.
Origin: From shaft of the humerus and extend across the elbow joint.
Insertion: Corocoid process of ulna
Innervation: Musculocutaneous nerve
Action: It flexes forearm at the elbow joint.
Triceps brachii
It is large fleshy muscle.
The only muscle at posterior compartment of arm.
Origin: one head from the scapula and 2 heads from posterior surface of the humerus.
Insertion: By common tendon in to olecranon process of ulna.
Innervation: Radial nerve
Action:
It is powerful fore arm extensor.
Its long head tendon may help stabilize shoulder joint and assist in arm adduction.
Brachioradialis:
It is superficial muscle of lateral forearm.
It forms the lateral boundary antecubital fossa.
Origin: Lateral supracondylar ridge at distal end of humerus.
Insertion:Base of styloid process of radius.
Innervation:Radial nerve
Pronator quadratus
 It is deepest muscle of distal muscle of distal forearm, passes down ward and laterally.
Origin: Distal portion of anterior ulnar shaft. Insertion: Distal portion of anterior radius Innervation: Median nerve
Action:
 Prime mover of forearm pronation,
 It also helps hold ulna and radius together.
Pronator teres
 It is 2 headed muscle that lies obliquely across the upper third of the front of the forearm.
Origin: Medial epicondyle of humerus,coronoid process of ulna.
Insertion: By common tendon in to lateral surface of the shaft of humerus. Innervation: Median nerve
Action:
 It pronate forearm,
 It is weak flexor of elbow.
Supinator: It is deep muscle at posterior aspect of elbow.
Origin: Lateral epicondyle of humerus Insertion: Proximal end of radius
Innervation: Posterior interroseous nerve Action: Supination of the forearm.
Flexor carpi radialis
 It runs diagonally across forearm.
 Its fleshy belly is replaced by a flat tendon that becomes cord like at wrist.
Origin: Medial epicondyle of humerus.
Insertion: Base of second and third metacarpals.
 It provide guide to portion of radial artery(used for pulse taking) at wrist.
Innervation: Median nerve
Action :
 Powerful flexor of wrist.
 It abducts hand.
Flexor carpi ulnaris
 It is most medial muscle of the group.
 it is 2 headed and ulnar nerve lies lateral to its tendon.
Origin: Medial epicondyle of humerus, olecranon process and posterior surface of ulnar.
Insertion:Pisiform,hamate bones and base of 5th metacarpal.
Innervation: Ulnar nerve.
Action:
 Powerful flexor of wrist
 It also adduct hand.
Extensor carpi ulnaris
 It is medial of superficial posterior muscle.it is long slender muscle.
Origin: Lateral epicondyle of humerus and posterior border of ulna.
Insertion: Base of 5th metacarpal
Innervation: Posterior interroseous nerve
Action:
 It extends and adducts the wrist.
Palmarus longus
 It is small fleshy muscle with long insertion tendon.
Origin: Medial epicondyle of humerus
Insertion: Palmar aponeurosis, skin and fascia of palm.
Innervation: Median nerve
Action:
 It is weak wrist flexor.
 it tenses skin and fascia of palm during hand movement.
Extensor digitorum
 It lies medial to extensor carpi radialis brevis.
Origin: Lateral epicondyle of humurus
Insertion: by tendons In to extensor, And distal phalanges of finger 2-5
Innervation: Posterior interroseous (branch of radial nerve).
Extensor carpi radialis (longus and brevis)

These lie on the posterior aspect of the forearm.

Origin: Lateral epicondyle of humerus.
Insertion: Base of second and third metacarpals.
Innervation: Radial nerve
Action: It extends and abducts wrist.
Assignment
Discuss physiological changes during aging in muscular system.
Axilla
Herniation and inguinal hernia ( types, causes and treatment)