Muscles Of Upper Lims-trunk -ruan-2015.ppt

I. Muscles of the thorax Two groups: 1. Extrinsic muscles (Muscles of the Pectoral Region) ① Pectoralis major ② Pectoralis minor ③ Serratus anterior ④ Subclavius 2. Intrinsic muscles ① External intercostal ② Internal intercostal ③ Innermost intercostal

1. Extrinsic muscles ① Pectoralis major • a thick, fan-shaped muscle, situated at the chest (anterior) of the body. • O: medial half of clavicle,sternum,1th-6th costal cartilages. • I: greater tubercle of humerus. • A: flexes, adducts and rotates arm medially; when arm fixed, elevates trunk; elevates ribs 16,aidding in forced inspiration. • N: lateral pectoral nerve and medial pectoral nerve

② Pectoralis minor • a thin, triangular muscle underneath the pectoralis major. • O: the rib 3-5 • I: coracoid process of the scapula. • A: depresses the point of the shoulder, drawing the scapula inferior and medial, towards the thorax, moves up the rib cage. • N: Medial pectoral nerve (C8, T1)

③Serratus anterior muscles • O: fleshy slips from the outer surface of upper 8 or 9 ribs • I: costal aspect of medial margin of the scapula • A: pulls the scapula forward, helps to stabilize the scapula, assists in rotating the scapula (glenoid fossa) upward. • N: by the long thoracic nerve.

④Subclavius • a small triangular muscle, placed between the clavicle and the first rib. • A: depresses the shoulder, carrying it downward and forward.

• N: nerve to subclavius

Muscles of the Pectoral Region

2. Intrinsic muscles ① External intercostal O: inferior border of rib above I: superior border of rib below A: elevates rib cage, contracts during inspiration. N: from the intercostal nerve

② Internal intercostal • O: superior border of rib below • I: inferior border of rib above • A: depresses rib cage, contract during expiration. • N: from the intercostal nerve

③ Innermost intercostal •

A layer of muscle parallel to the internal intercostal muscle but separated from it by the intercostal vessels and nerves.

• O:Upper border of a rib • I:Inferior border of the rib above • N:intercostal nerves

• A:assists in expiration.

II. Muscles of upper limbs 1. Superficial group of muscles of the back 2. Muscles of shoulder

3. Muscles of arm 4. Muscles of forearm

5. Muscles of hand

1. Superficial group of muscles of the back 5 pairs of muscles in the superficial layer (3 are deep to the trapezius):

① trapezius ② latissimus dorsi

③ rhomboid major ④ rhomboid minor

⑤ levator scapulae

①Trapezius • O: external occipital protuberance,

ligamentum nuchae, spines of C7, T1-T12 • I: lateral 1/3 clavicle, acromion and scapular spine • Actions - elevates (upper fibers) and depresses (lower fibers) shoulder, retracts

scapula and extends head • Innervations: by accessory nerve (Cranial nerve XI)

ligamentum nuchae (Nuchal ligament) • a fibrous membrane – represents the supraspinal

ligaments of the neck – extends from the external occipital protuberance and median nuchal line to the spinous process of the seventh

cervical vertebra.

②latissimus dorsi • • • •

O: Vertebral spines (T6-T12), thoracolumbar fascia, iliac crest; I : Intertubercular (bicipital) groove Actions - Adducts, extends, and medially rotates arm Innervation- Thoracodorsal nerve

③levator scapulae • O: C1-C4 transverse processes • I: sup. angle and medial border of the scapula • Action: If the head is fixed, the levator scapulæ raises the medial angle of the scapula. If the shoulder is fixed, the muscle inclines the neck to the corresponding side. The levator scapulae, along with the trapezius muscle, makes a shrug possible. • Innervation: dorsal scapular nerve

④Rhomboid major • O: Vertebrae T2-T5 spines • I: Scapula (med. border)

⑤Rhomboid minor • O: Vertebrae (C7, T1 spines) • I: Scapula (med. Border) • Action-All elevate and adduct scapula • Innervation - All by dorsal scapular nerve

2. Muscles of shoulder ① Deltoid ② supraspinatus ③ Infraspinatus

④ Teres minor ⑤ subscapularis ⑥ Teres major

Rotator cuff

①Deltoid muscle • Form the rounded contour of the shoulder. • Origin: – Anterior fibers: from lateral clavicle. – Middle fibers: from the acromion – Posterior fibers: from the spine of the scapula. • Insertion: the V-shaped deltoid tuberosity on the middle of the lateral aspect of the humerus. • Nerve(N): innervated by the axillary nerve.

①Deltoid muscle • Action (A) – When all its fibers contract simultaneously, abducts the arm. – The anterior fibers are involved in shoulder abduction and shoulder flexion, medial rotation. – The posterior fibers are strongly involved in transverse extension particularly. – The lateral fibers are involved in shoulder abduction and extension, lateral rotation.

Functions of deltoid muscle : • responsible for movement in the shoulder. • attach to the scapula, humerus, and clavicle. • surround the shoulder to form the shoulder cap. Normal deltoid muscle

Deltoid muscle atrophy

②Supraspinatus muscles • O: supraspinatous fossa of the scapula • I: the greater tubercle of the humerus • A:abduction of arm and stabilizes humerus see part on controversy of action. • Nerve: suprascapular nerve

③Infraspinatus muscles • • • •

O: the infraspinatous fossa of the scapula I: the greater tubercle of the humerus Actions: Lateral rotation of arm and stabilizes humerus Nerve: suprascapular nerve

④Teres minor muscles • • • •

O: from lateral border of the scapula I: on the greater tubercle of the humerus humerus Actions: laterally rotates the arm, stabilizes humerus. Nerve: axillary nerve.

⑤Teres major muscles

• O: inferior angle of the scapula • I: intertubercular sulcus of the humerus. (anterior surface) • Actions: Internal rotation (medial rotation) of the humerus, protracts scapula, depress shoulder. • Nerve: Lower subscapular nerve

④ Subscapular muscles • O: the subscapular fossa • I: the lesser tubercle of the humerus • Actions: Internally (medially) rotates humerus; stabilizes shoulder • Nerve: subscapular nerve

Functions of the shoulder muscles • Abductors of the shoulder joint: – Deltoid muscle – Supraspinatus muscles

• Lateral rotation of the shoulder joint: – Infraspinatus muscles – Teres minor muscles

• Medial rotators of the shoulder joint – Teres major muscles – Subscapular muscles

Muscular spaces of the shoulder 1. Triangular space (TS) • Boundaries : – superior border- teres minor – Inferior border – teres major – Lateral border – long head of the triceps brachii • the scapular circumflex vessels pass through this space.

2. Quadrangular space(QS) • Boundaries : – superior border- teres minor – Inferior border – teres major – medial border – long head of the triceps brachii – Lateral border –the surgical neck of the humerus • the axillary nerve and posterior circumflex humeral artery pass through this space

3. Triangular interval(TI) • Boundaries :

– superior border- teres major – Medial border – long head of the triceps brachii – Lateral border – short head of the triceps brachii

• The radial nerve and profunda brachii artery pass through the triangular interval

3. muscles of the arm (1) Anterior group: –

biceps brachii

–

coracobrachialis

–

brachialis

Actions : flexes the arm at glenohumeral joint, flexes elbow joint and supinates forearm. adducts humerus ,

①Biceps brachii • O: short head: coracoid process of the scapula. long head: supraglenoid tubercle • I: radial tuberosity and bicipital aponeurosis into deep fascia on medial part of forearm • A: flexes the arm at glenohumeral joint, flexes elbow and supinates forearm, adducts humerus • N: Musculocutaneous nerve

② Coracobrachialis – O: coracoid process of scapula – I: medial humerus – A: adducts humerus , flexes the arm at glenohumeral joint – N: musculocutaneous nerve ③ Brachialis muscle – O: anterior surface of the humerus, particularly the distal half of this bone – I: coronoid proecess and the tuberosity of the ulna – A: flexion at elbow joint – N: musculocutaneous nerve

(2) The posterior group ①Triceps brachii O: – long head: infraglenoid tubercle of scapula – lateral head: posterior humerus – medial head: posterior humerus I: olecranon process of ulna A: extends the elbow joint and adducts shoulder forearm. N: radial nerve

4. muscles of the forearm (1) The anterior group ( 9) Action: flex elbow joint and twist joint, pronation 1) The first layer (from radial to ulnar ) ① The brachioradialis

② The pronator teres ③ The flexor carpi radialis ④ The palmaris longus

⑤ The flexor carpi ulnaris

① Brachioradialis • O: Lateral supracondylar ridge of the humerus • I: Distal radius (Radial styloid process)

• A: Flexion of forearm • N: radial nerve

②pronator teres O: – humeral head: medial epicondyle of humerus (common flexor tendon) – ulnar head: coronoid process of ulna I: radius A: pronation of forearm, flexes elbow N: median nerve

③flexor carpi radialis • O: medial epicondyle of humerus • I: Bases of second and third metacarpal bones • N: Median nerve • A: Flexion and abduction at wrist

④palmaris longus • O: medial epicondyle of humerus • I: palmar aponeurosis • A: wrist flexor • N: median nerve

⑤flexor carpi ulnaris • O: medial epicondyle (common flexor tendon) • I: pisiform • A: flexion of wrist • N: ulnar nerve

2) The second layer : The flexor digitorum superficialis O: medial epicondyle of the humerus (common flexor tendon) as well as parts of the radius and ulna. I: phalanges A: flexor of fingers (primarily at proximal interphalangeal joints) N: median nerve

3 )The third layer : ① flexor pollicis longus • O: medial epicondyle of the humerus (common flexor tendon) as well as parts of the radius and ulna.

• I: phalanges • A: flexor of fingers (primarily at proximal interphalangeal joints) • N: median nerve

② flexor digitorum profundus • • • •

O: ulna I: distal phalanges A: flex hand, interphalangeal joints N: median (anterior interosseous), muscular branches of ulnar

(4 )The fourth layer : The pronator quadrates O: medial, anterior surface of the ulna I: lateral, anterior surface of the radius A: pronates the forearm N: median nerve (anterior interosseous nerve)

Brachioradialis * Flexor carpi radialis

Palmaris longus

Flexor digitorum Superficialis (sublimis in the cat)

Flexor carpi ulnaris

Flexor digitorum profundus

(2)The posterior group (10) Action: extent elbow joint and twist joint, supination (1) The superficial layer (from radial to ulnar ) ① The extensor carpi radialis longus ② The extensor carpi radialis brevis ③ The extensor digitorum

④ The extensor digiti minimi ⑤ the extensor carpi ulnaris

①extensor carpi radialis longus • O: lateral supracondylar ridge • I: 2nd metacarpal • A: extensor at the wrist joint, abducts

the hand at the wrist • N: radial nerve

② extensor carpi radialis brevis • O: humerus at the anterior of lateral epicondyle (common extensor tendon) • I: base of the 3rd metacarpal • A: extensor and abductor of the hand at the wrist joint • N: deep branch of the radial nerve

③ Extensor digitorum • O: lateral epicondyle (common extensor tendon)

• I: middle and distal phalanges • A: extension of hand, wrist and fingers • N: posterior interosseous nerve

④ Extensor digiti minimi • O: the anterior portion of the lateral epicondyle of the humerus (common extensor tendon) • I: at the extensor expansion, located at the base of the proximal phalanx of digit V on the dorsal side • A: extends the little finger at all joints • N: posterior interosseous nerve

⑤ Extensor carpi ulnaris • O: Common extensor tendon (lateral epicondyle), ulna • I: 5th metacarpal • N: the posterior interosseus nerve, a branch of the radial nerve • A: extends and adducts the wrist

2). The deep layer ( from radial to ulnar ) ① the supinator ② The abductor pollicis longus

③ The extensor pollicis brevis ④ The extensor pollicis longus ⑤ The extensor indicis

① Abductor pollicis longus • O: ulna, radial styloid process • I: first metacarpal • A: abduction, extension of thumb • N: Posterior interosseous nerve ② Extensor pollicis brevis • O: radius • I: thumb, proximal phalanx • A: extension of thumb at metacarpophalangeal joint • N: posterior interosseous nerve

② ①

③Extensor pollicis longus • O: ulna • I: thumb, distal phalanx • A: extension of the thumb (metacarpophalangeal and interphalangeal) • N: posterior interosseus nerve (branching from the radial nerve) ④Extensor indicis • O: ulna • I: index finger (extensor hood) • A: extends index finger, wrist • N: posterior interosseous nerve ⑤Supinator • O: Lateral epicondyle of humerus, supinator crest of ulna, radial collateral ligament, annular ligament • I:Lateral proximal radial shaft • A: Supinates forearm • N: deep branch of radial nerve

④

③

⑤

5. muscles of the hand 1. The lateral group - thenar 2. The medial group - hypothenar 3. The intermediate group – interosseous muscles (7)

– lumbricales (4)

(1) The lateral group : thenar ① ② ③ ④

Abductor Pollicis Brevis Adductor Pollis Flexor Pollicis Brevis Opponens Pollicis

①Abductor Pollicis Brevis • O:Transverse carpal ligament, the Scaphoid and Trapezium • I: Radial base of Thumb Proximal Phalanx and the thumb extensor mechanism • A: Abducts the Thumb basal (carpometacarpal) Joint along with other muscles which palmar abduct and radial abduct the basal joint, and extends the thumb interphalangeal Joint • N: Motor Branch of Median Nerve

②Adductor Pollis • O: – OBLIQUE HEAD: palmar surfaces of the Trapezoid, the Trapezium and Capitate as well as the bases of the Index and Middle metacarpals – TRANSVERSE HEAD: palmar surface of the shaft of the Middle metacarpal

• I: The palmar ulnar base of the Thumb Proximal Phalanx, the Thumb Ulnar MCP Sesamoid, and the Thumb extensor mechanism • A: radially adducts the thumb basal joint along with other muscles which radially adduct the basal joint, and extends the thumb interphalangeal Joint • N: Motor Branch of Ulnar Nerve

③Flexor Pollicis Brevis • O: transverse carpal ligament and the Trapezium • I: radial proximal base of the Thumb Proximal Phalanx and the thumb Radial MCP Sesamoid • F: Flexes the thumb MCP joint and flexes/pronates the basal joint along with other muscles which produce thumb opposition • N: – DEEP head: Motor Branch of Ulnar Nerve – SUPERFICIAL Head: Motor Branch of Median Nerve

④ Opponens Pollicis O: transverse

carpal ligament and

the Trapezium I: Volar radial aspect of the Thumb Metacarpal

A: flexes and pronates the basal joint along with other muscles which produce thumb opposition

N: Motor Branch of the Median Nerve

(2) The medial group : hypothenar ① Abductor Digiti Minimi

② Opponens Digiti Minimi ③ Flexor Digiti Minimi

① Abductor Digiti Minimi • O: Pisiform and the Tendon of the flexor carpi ulnaris • I: Ulnar base of the Small finger proximal phalanx and the aponeurosis of the extensor digiti minimi • F: Abducts the small finger MCP Joint along with the Extensor Digiti Minimi • N: Motor Branch of Ulnar Nerve

② Opponens Digiti Minimi • O: the transverse carpal ligament and the hook of the hamate • I: palmar shaft of the small finger metacarpal • A: flexes and supinates (opposes) the small finger carpometacarpal joint • N: the motor branch of the ulnar nerve

③ Flexor Digiti Minimi O: the transverse carpal ligament and the hook of the hamate I: the ulnar base of the small finger proximal phalanx F: flexes both the small finger carpometacarpal joint and the small finger metacarpophalangeal joint N: the motor branch of the ulnar nerve

④ Palmaris Brevis • O: transverse carpal ligament and the superficial palmar fascia • I: Hypothenar area skin • A: Tightens and corrugates the hypothenar skin, may deepen the concavity of the palm • N: Motor Branch of Ulnar Nerve

3. intermediate group ① The interosseous muscles (7) • Palmar: (addction) – First Palmar Interosseous – Second Palmar Interosseous

– Third Palmar Interosseous

• Dorsal(abdction) – First Dorsal Interosseous

– Second Dorsal Interosseous – Third Dorsal Interosseous – Fourth Dorsal Interosseous

• ② The lumbricales (4) – – – –

•

Index Lumbrical Middle Lumbrical Ring Lumbrical Small Lumbrical

• Muscles of the thumb – Intrinsic (thenar) Abductor Pollicis Brevis Adductor Pollicis Flexor Pollicis Brevis Opponens Pollicis – First Dorsal Interosseous – Extrinsic Abductor Pollicis Longus Extensor Pollicis Brevis Extensor Pollicis Longus Flexor Pollicis Longus