Anatomy Muskuloskeletal Pectoral Girdle & Upper Limb

Anatomy Musculoskeletal: Pectoral Girdle and Upper Limb

ANATOMY MUSCULOSKELETAL

PECTORAL GIRDLE

&

UPPER LIMB

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Matrix No: ________________________

Created by Hermizan Halihanafiah 20121


Pectoral Girdle : Bones, Articulation and Movements

Bone Specification Explanation

Clavicle

Type long bone

Position lies horizontally in the superior and anterior to the thoracic cage, superior to the 1st rib

Structure

Shaft – S shape, medial 2/3 convex anteriorly, lateral 1/3 concave anteriorly

Sternal end / medial end – slightly expanded, quadrangular (rounded), medial aspect of the clavicle

Acromial end / lateral end – slightly expanded, flattened / broad, lateral aspect of the clavicle.

Conoid tubercle – postero-inferior aspect of the acromial end, attachment for coracoclavicular ligament.(conoid ligament)

Trapezoid line – ridge extending laterally from the conoid tubercle, attachment for coracoclavicular ligament.(trapezoid ligament)

Costal tuberosity – inferior aspect of the sternal end, attachment for costoclavicular ligament.

Articulation

Sternoclavicular joint

- Articulation between sternal end of the clavicle and clavicular notch of manubrium sternum.

- Synovial saddle joint

- Supporting ligament – sternoclavicular ligament (ant/post), interclavicular ligament (superiorly), costoclavicular ligament (inferiorly).

- Movement – elevation, depression, anterior movement in a horizontal direction.

- Clinical importance – rare

Acromioclavicular joint

- Articulation between acromial end of the clavicle and acromion process of the scapula.

- “ Point of the Shoulder”

- Synovial planar joint

- Supporting ligaments – AC joint is a weak joint, strengthen via

Acromioclavicular ligament – from superior aspect of the acromion process to the superior aspect of the clavicle (acromial end)

Coracoclavicular ligament - anchor clavicle to the coracoid process of the



scapula , consist 2 part (conoid lig – from conoid tubercle, trapezoid lig – trapezoid line)

Coracoacromial ligament – attach between coracoid process and acromion process & form the ligamentous arch – protection for the head of humerus (stability for the GH joint).

- Subluxation and dislocation due to fall on the shoulder.




Scapula

Type flat, irregular and triangular

Position Posterior bone of the pectoral girdle, lying on the posterolateral aspect of the thoracic cage and extending from 2nd – 7th ribs.

Structure

Posterior Aspect

Body – triangular in shape

Spine - posterior surface of the scapula, diving posterior surface into supraspinous fossa (upper 1/3) and infraspinous fossa (lower 2/3), attachment for trapezius and deltoid muscles.

Supraspinous fossa – shallow depression above the spine, attachment for the supraspinatus muscle.

Infraspinous fossa – shallow depression below the spine, attachment for the infraspinatus muscle.

Acromion process – broadened, lateral aspect of the spine, at the medial border have facet for articulation with clavicle.

Superior angle – the junction between superior and middle borders

Inferior angle – the junction between lateral and medial borders

Lateral angle / acromial angle – the junction between superior and lateral borders.

Medial / vertebral border – facing vertebra column, palpable for most of its length, attachment site for several muscles (teres minor, teres major, rhomboid major, rhomboid minor, levator scapulae, serratus anterior)

Lateral border / axillary border – facing axilla, attachment for several muscles (teres major and teres minor)

Lateral Aspect

Head of scapula – referred to lateral angle, the junction between superior border and lateral borders.

Glenoid cavity – pear shaped depression, articulation with head of humerus

Supraglenoid tubercle – blunt projection, superior to the glenoid cavity, attachment for long head of biceps brachii.

Infraglenoid tubercle – blunt projection, inferior to the glenoid cavity, attachment for the long head of triceps.

Anterior Aspect

Subscapular fossa – large anteriorly depression, attachment site for the



Structure

subscapularis muscle.

Scapular notch – depression at lateral end of the superior border, pathway for the suprascapular nerve.

Coracoid process – anterior projection from the superior border, attachment site for ligament (coracoclavicular ligament) and several muscles (pectoralis minor, coracobrachialis & short head of biceps brachii)

Articulation

Acromioclavicular joint – Articulation between acromial end of clavicle and acromion process of scapula.

Glenohumeral joint / shoulder joint

- Articulation between head of humerus and glenoid cavity of scapula

- Type – synovial ball and socket

- Most mobile, least stable and vulnerable to injury.

- Strengthening structure:

Extracapsular structure

o Ligaments – coracohumeral ligaments (from coracoid process of scapula to the greater tubercle of humerus), glenohumeral ligament (superior, inferior and middle – attach from glenoid cavity of scapula to the lesser tubercle and anatomical neck of humerus), transverse humeral ligament (attach between lesser and greater tubercle, turn the bicipital groove into tunnel, holding tendon of long head of biceps)

o Rotator cuff muscles – supraspinatus, infraspinatus, teres minor and subscapularis (contraction these muscles pulled head of humerus into glenoid cavity).

o Bursae – subscapular bursa, subacromial bursa, subdeltoid bursa, subcoracoid bursa (avoid friction)

Intracapsular structure

o Glenoid labrum/rim – fibrocartilaginous rim surround the edge of the glenoid cavity, deepened the socket

- Movement – flexion / extension, abduction/adduction, medial rotation/lateral rotation, horizontal adduction/horizontal abduction, circumduction.

- Clinical importance – anterior and posterior dislocation, recurrent dislocation, frozen shoulder

- Superior portion – impingement area, this area contain structures that can be damage due to repeated overuse (suprapinatus, long head of biceps, glenoid labrum, coracohumeral ligament, subacromial bursa. The actual impingement occurs in the abducted position with the arm rotated.



Scapulothoracic joint / scapulocostal joint

- Physiologic joint - Not a true joint (holding by musculotendinous structure)

- Don’t have any synovial capsule and ligamentous attachment.

- Articulation between anterior surface of the scapula and posterior surface of the 2nd – 7th ribs

- Highly mobile joint

- Stabilization via several muscle – trapezius, rhomboid major, rhomboid minor, serratus anterior

- Movement gliding – abduction / adduction (protraction / retraction), elevation / depression, upward rotation / downward rotation.

- Movement of the scapulothoracic joint – increase the ROM of the GH joint.

Arm : Bones, Articulations and Movements




Humerus

Type Long bone

Position Largest bone of upper limb, bony part of the arm (brachium)

Structure

Proximal part

Head – rounded in shape, articulate with glenoid cavity of scapula

Anatomical neck – constriction area adjoining the head

Greater tubercle (tuberosity) – blunt projection, posterolaterally, attachment site for several muscles (supraspinatus, infraspinatus, teres minor)

Lesser tubercle (tuberosity) – blunt projection, anteriorly, attachment site for subscapularis muscle.

Intertubercular sulcus / bicipital groove – between greater and lesser tubercle, cover by transverse humeral ligament, contain tendon for long head of biceps.

Surgical neck – constricted area, adjoining site between shaft and proximal part, mostly fracture occur here.

Shaft/body

Long, proximally cylindrical in shape, and gradually become flat and triangular in shape distally.

Deltoid tuberosity – roughen area located anterolaterally, attachment site for the deltoid muscles.

Radial/spiral groove – posterior surface, extend obliquely from medial to lateral site of the shaft, location for the radial nerve

Distal part

Distal end of the lateral border – lateral supracondylar ridge, lateral epicondyle and capitulum.

Lateral supracondylar and lateral epicondyle – attachment for the extensor hand muscles.

Capitulum – rounded in shape, articulate with head of radius

Radial fossa – superior to the capitulum, receive head of radius during elbow flexion

Distal end of the medial border – medial supracondylar ridge, medial epicondyle, trochlear

Medial epicondyle –attachment site for the several ligaments and flexor hand muscles, at the posterior surface – pathway for the ulnar nerve

Trochlea – pulley/spool in shape, articulate with trochlear notch of ulna.

Coronoid fossa – anteriorly, superior to the trochlea, rceive coronoid process



of ulna during elbow flexion.

Olecranon fossa – posteriorly, superior to the trochlea, receive olecranon of ulna during elbow extension.

Articulation

Proximally – glenohumeral / shoulder joint

Distally – Elbow joint (include humeroulnar, humeroradial and proximal radioulnar joint) – these joints enclose by single fibrous capsule

Humeroulnar joint (true elbow joint)

- Articulation between trochlea of humerus and trochlear notch of ulna.

- Synovial hinge joint.

- Strengthening structure

Ulnar collateral ligament – on the medial side of the joint, attach from medial epicondyle of humerus to the coronoid process and olecranon process of ulna.

Provide Valgus stability of the elbow

- Movement - flexion / extension

Humeroradial joint

- Articulation between capitulum and head of radius.

- Synovial hinge joint


Radial collateral ligament – on the lateral side of the elbow, attach form the lateral epicondyle of the humerus to the annular ligament.

Provide Varus stability for the elbow.

- Movement - flexion / extension

Proximal radioulnar joint

- Articulation between head of radius and radial notch of ulna.

- Synovial pivot joint.


Annular ligament – surrounds head of radius and attach to the edge of the radial notch of ulna.

Support head of radius.

- Movement – pronation / supination

Forearm : Bones, Articulations and Movements




Radius

Type Long Bone

Position Lateral bone of forearm

Structure

- Head – rounded, with concave superior surface, articulate with capitulum of humerus and radial notch of ulna.

- Neck – narrow/constricted portion, distal to head

- Radial tuberosity – distal to the neck, on the medial aspect, attachment site for the biceps brachii muscles.

- Interosseous border – on the medial surface of the shaft, attachment for the intersosseous membrane that connects with the shaft of ulna to form middle radioulnar joint.

- Ulnar notch – distal end, located on the medial side, articulates with the head of ulna to form distal radioulnar joint.

- Radial styloid process – distal end, prominent process on the lateral aspect which can be palpated.

- Distal surface articulates with scaphoid, lunate and triquetrum to form radiocarpal joint / wrist joint.

Articulation

Humeroradial joint

- Articulation between head of radius and capitulum of humerus


- Articulation between head of radius and radial notch of ulna

Middle radioulnar joint

- Articulation between shaft of radius and shaft of ulna connect via interosseous membrane.

- Synarthroses / immovable joint

Distal radioulnar joint

- Articulation between head of ulna and ulnar notch of radius

- Synovial pivot joint

- Movement – pronation / supination

- Strengthen via palmar and distal radioulnar ligaments.

Radiocarpal Joint/wrist joint

- Articulation between distal end of radius and radial styloid process with



scaphoid, lunate and triquetrum

- Synovial condyloid / ellipsoidal joint

- Strengthen by

Ulnar collateral ligament – medial aspect of the wrist, attached to the ulnar styloid process and the triquetrum and pisiform

Radial collateral ligament – lateral aspect of the wrist – attached to the radial styloid process and the scaphoid

Palmar radiocarpal ligament – anterior aspect of the wrist, attached from the radius to the scaphoid, lunate and the triquetrum.

Dorsal radiocarpal ligament – posterior aspect of the wrist, attached form the radius to the scaphoid, lunate and triquetrum.

Palmar ulnocarpal ligament. – anterior aspect of the wrist, attached from the ulnar styloid process to the lunate and triquetrum.

- Movement – flexion / extension, radial deviation (abduction) /ulnar deviation (adduction).




Ulnar

Type Long Bone

Position Medial aspect of forearm

Structure

- Olecranon – proximal end, postero-superior projection, articulates with olecranon fossa of humerus when elbow extension, can be palpated, attachment site for the triceps brachii.

- Coronoid process – proximal end, antero-inferior projection, articulates with coronoid fossa of humerus when elbow flexion.

- Ulnar tuberosity – anterior surface, distal to the coronoid process, attachment site for the brachialis muscle.

- Trochlear notch – depression between coronoid process and olecranon process, articulates with the trochlea of humerus.

- Radial notch – depression located lateral aspect of the coronoid process, articulate with head of radius.

- Interosseous border – located lateral aspect of the shaft, attachment site for interosseous membrane.

- Head of ulna – distal end, small and rounded, surrounds by articular disc

- Ulnar styloid process – project medial and posteriorly which can be palpated.

Articulation

Humeroulnar joint

- Artculation between trochlea of humerus and trochlear notch of ulna.


- Articulation between head of radius and radial notch of ulna

Middle radioulnar joint

- Articulation between shaft of radius and shaft of ulna connect via interosseous membrane.

Distal radioulnar joint

- Articulation between head of ulna and ulnar notch of radius



Hand : Bones, Articulations and Movements


Carpal

Type Short bone (except pisiform – sesamoid)

Position - 2 rows of carpal bones form the wrist region.

- Proximal row, form lateral to medial – scaphoid, lunate, triquetrum and pisiform

- Distal row, from lateral to medial – trapezium, trapezoid, capitate and hamate.

Structure

Scaphoid

- Boatlike in shape

- the largest of the proximal row of carpal bone

- Consist tubercle on its palmar surface – attachment for the palmar aponeuresis & muscle.

- Articulate with radius, lunate, trapezium and trapezium.

- The most frequently fractured of the carpal bones – fall onto outstretched hand.

Lunate

- Moonlike in shape

- Articulate with radius, scaphoid, triquetrum and capitate.

Triquetrum

- Three cornered in shape

- Attachment site for the ulnar collateral ligament.

- Articulate with radius, pisiform, lunate and hamate.

Pisiform

- Pea-like in shape.

- Sesamoid bone – embedded within tendon flexor carpi ulnaris

- Protect the tendon and increase the mechanical effect.

- Articulate with triquetrum.

Trapezium

- Four sided figure

- At its palmar surface, contain tubercle and groove



Carpal

Structure

- Groove – contain tendon of flexor carpi radialis and flexor retinaculum.

- Tubercle – attachmen for the thenar muscles

- Articulation with trapezoid, scaphoid, 1st and 2nd metacarpals.

Trapezoid

- Small and irregular

- Articulation with 2nd metacarpal, capitate, trapezium and scaphoid.

Capitate

- Head shaped

- The largest of the carpal bone

- Articulation with 2nd – 4th metacarpals, hamate, lunate, scaphoid and trapezoid.

Hamate

- Hooked like structure

- Consist hamulus (hook) which projects on the palmar surface.

- Hamulus is contributed to the medial wall of the carpal tunnel and also attachment for the flexor retinaculum.

- Articulation with the triquetrum, capitate, 4th and 5th metacarpals.

Articulation

Radiocarpal joint

- Articulation between distal end of the radius and the scaphoid, lunate and triquetrum of the carpal bones.

Intercarpal joint

- Proximal row - Articulation between scaphoid, lunate, triquetrum and pisiform

- Distal row - Articulation between trapezium, trapezoid, capitate and hamate

- Synovial planar joint

- Movement – gliding motion

Midcarpal joint

- Articulation between proximal row and distal row of carpal bone. (Articulation between the scaphoid, lunate and triquetrum (proximally) and trapezium, trapezoid, capitate and hamate (distally).

- Synovial planar joint.



Carpal

Articulation

- Movement – gliding motion

Carpometacarpal joint

- Articulation between distal row of carpal bones and metacarpal.

- 5 carpometacarpal joint

- 1st carpometacarpal joint

Modified saddle joint

Articulation between 1st metacarpal (base) and the distal surface of the trapezium.

Supporting ligaments

Lateral ligament - lateral surface of the trapezium to the lateral side of the base of metacarpal.

Palmar ligament - oblique band, from palmar surface of the trapezium to the medial side of the base metacarpal.

Dorsal ligament - oblique band, from dorsal surface of the trapezium to the medial side of the base metacarpal.

Movement – flexion / extension, abduction / adduction, rotation, opposition / reposition

Permitting the ability to hold and manipulate objects (pinch grip, tripod pinch and chuck grip)

- 2nd – 5th carpometacarpal joint

Articulation between distal row of carpal bones and 2nd – 5th base of metacarpal

Synovial ellipsoidal joint

Supporting ligaments

- Dorsal ligament – the strongest ligament, attached from the dorsal surface of the carpal and metacarpal.

- Palmar ligament - attached from the palmar surface of the carpal and metacarpal.

- Interosseous ligament – attached from capitate and hamate to the 3rd and 4th metatarsal.

Movement – gliding motion




Metacarpal

Type Miniature long bones

Position - 5 metacarpal bones, numbered I – V (lateral to medial) form the palmar of the hand,

- Distal to distal row of carpal bones and proximal to the phalanges.

Structure

- Head – rounded, located distally, and articulates with corresponding phalanx.

- Shaft / body – middle portion, anterior border concave longitudinal.

- Base – expanded, articulate with appropriate carpal bones. The base of 2nd – 5th metacarpal articulates each other.

Articulation

Carpometacarpal joint

Metacarpophalangeal joint

- Articulation between proximal head of metacarpal and base of proximal phalanges.

- Synovial ellipsoidal joint

- Strengthen by – collateral ligament (strong and flank the joints), palmar ligaments and deep transverse metacarpal ligaments.

- Movement –flexion / extension, abduction / adduction

Intermetacarpal joint

- Articulation between based of the 2nd – 5th metacarpal.

- Strengthen by palmar ligament, dorsal ligament and interosseous ligament.

- Movement – slightly gliding.




Phalanges

Type Miniature long bones

Position Distal to the metacarpal, forming the 14 fingers (14 digits)

Structure

There are 14 phalanges. Every digits consist 3 phalanges (proximal, intermediate and distal), except thumb only have 2 phalanges (proximal and distal)

- Head – distally, expanded, distal phalanges support the tissue of the finger tips

- Shaft / body – intermediate portion, anterior border are concave longitudinally.

- Base – proximally, expanded, articulates with either the phalanges or the metacarpal to it.

Articulation

Metacarpophalangeal joint

Interphalangeal Joint

- Articulation between phalanges bone itself

- Synovial hinge joint

- All digits compose by 2 interphalangeal joints; proximal IP and distal IP, except thumb only have one.

- Strengthen ligaments – palmar ligament / volar plate (floor of the IP) and 2 collateral ligaments (on the lateral and medial side of the IP).

- Movement – flexion / extension



Muscles of the Pectoral Girdle

Attachment Site Joint Muscle Origin Insertion Action

Clavicle – humerus GH Anterior fibre of Deltoid Lateral 1/3 (anterior surface)

Deltoid tuberosity Flexion

Clavicle origin of pectoralis major

Medial half (anterior surface)

Bicipital groove (lateral lip) of humerus

Flexion, medial rotation, horizontal adduction

Sternum – humerus GH Sternocostal fibre of pectoralis major

Anterior surface of sternum, costal cartilages of upper 6th or 7th ribs.

Bicipital groove (lateral lip) of humerus

Extension , medial rotation, horizontal adduction

Scapula – humerus GH Coracobrachialis Coracoid process Middle shaft (opposite to deltoid tubesoity)

Flexion and adduction

Middle fiber of deltoid Acromion process Deltoid tuberosity Abduction

Posterior fiber of deltoid Spine Deltoid tuberosity Extension

Supraspinatus Supraspinous fossa Greater tubercle (upper aspect)

Initially abduction (15 degrees)

Infraspinatus Infraspinous fossa Greater tubercle (middle aspect)

Lateral rotation

Subscapularis Subscapular fossa Lesser tubercle Medial rotation

Teres minor Upper 2/3, lateral border

Greater tubercle (postero-inferior aspect)

Lateral rotation

Teres major Inferior angle and lateral border

Bicipital groove (medial lip)

Adduction, extension

Vertebrae – ribs - humerus

GH Latissimus dorsi Spinous processes T7-T12, L1-L5, last 3 / 4 ribs, posterior iliac crest, inferior angle of scapula.

Bicipital groove Extension, adduction medial rotation.

Ribs – clavicle SC Subclavius 1st costal cartilage Inferior surface of acromial end

Pulls clavicle forward and downward.

Ribs – scapula SCo, AC

Pectoralis minor 3rd – 5th ribs (near costal cartilage)

Coracoid process Protraction, downward rotation, assist in force inhalation

Serratus anterior Upper 8 or 9 ribs Medial border Protraction, upward rotation

Scapula – radius EL, GH Long head of biceps Supraglenoid tubercle Radial tuberosity & Elbow flexion,



bicipital aponeuresis assist shoulder flexion

Short head of biceps Coracoid process Radial tuberosity & bicipital aponeuresis.

Elbow flexion, assist shoulder flexion

Scapula – ulna EL, GH Long head of triceps Infraglenoid tubercle Olecranon process Elbow extension, assist in shoulder extension.

Vertebra – clavicle SC Upper fiber of trapezius Superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous C7

Lateral 1/3 Elevation of scapula

Vertebra - scaoula SCo, AC

Middle fiber of trapezius Spinous process T1-T5 Acromion process Retraction and assist in upward rotation

Lower fiber of trapezius Spinous Process T6-T12

Spine Depression, retraction and upward rotation.

Levator scapulae Transverse process C1-C4

Medial border (between superior angle and root of spine)

Elevation and assist in downward rotation.

Rhomboid minor Spinous process C7 & T1

Medial border (root of spine)

Retraction, and assist in elevation and downward rotation.

Rhomboid major Spinous process T2-T5 Medial border (between root of spine and inferior angle)

Retraction, and assist in elevation and downward rotation.

Adaptation from Florence P. Kendall (2005)

*GH – Glenohumeral Jt, SC – Sternocostal Jt, AC – Acromioclavicular Joint, SCo – Scapulocostal Jt, EL – Elbow Joint,



Muscles of the Elbow

24 muscles cross the elbow joint. Some of them act on the elbow joint exclusively, and others act on the wrist and hand joints. Most of these muscles are capable of producing as many as three movements at the elbow, wrist and fingers joint and usually one movement is dominant. There are four main muscles group; anterior flexors, posterior extensor, lateral extensor – supinators, and medial flexor-pronators.

Elbow Flexors

Muscle Joint Origin Insertion Action

Long head of biceps

GH, EL & RU Supraglenoid tubercle of scapula

Radial tuberosity & bicipital aponeuresis

Elbow flexion, assist in shoulder flexion and elbow supination.

Short head of biceps

GH, EL & RU Coracoid process of scapula Radial tuberosity & bicipital aponeuresis


Brachialis EL Anterior surface, distal half shaft of humerus

Ulnar tuberosity & coronoid process of ulna.

Elbow flexion

Brachioradialis EL Lateral supracondylar ridge of humerus

Styloid process of radius Elbow flexion

* The brachialis plays a bigger role when forearm in the pronated position

* The biceps brachii plays a bigger role when forearm in the supinated position

* The brachioradialis plays a bigger role when forearm in the neutral position (midpronation)

Elbow Extensors


Long head of triceps

GH, EL Infraglenoid tubercle of humerus

Olecranon process of ulna Elbow extension, assist in shoulder extension

Lateral head of triceps

EL Lateral and posterior of humerus (superior to radial groove)

Olecranon process of ulna Elbow extension,

Medial head of triceps

EL Posterior surface of humerus (inferior to radial groove)

Olecranon process of ulna Elbow extension,

Anconeus EL Lateral epicondyle of humerus Olecranon process of ulna Elbow extension,

* GH – Glenohumeral joint, EL – Elbow joint, RU – Radioulnar joint



Elbow Supinators


Long head of biceps

GH, EL & RU Supraglenoid tubercle of scapula

Radial tuberosity & bicipital aponeuresis


Short head of biceps

GH, EL & RU Coracoid process of scapula Radial tuberosity & bicipital aponeuresis


Supinator EL, RU Lateral epicondyle of humerus Lateral surface proximal 1/3 shaft of radius

Elbow supination

Elbow Pronators


Pronator teres RU, EL Medial epicondyle of humerus and coracoid process of ulna

Mid-lateral surface of radius Elbow pronation, assist in elbow flexion

Pronator quadratus

RU Medial surface, distal ¼ of the ulna

Lateral surface, distal ¼ of the radius

Elow pronation

* GH – Glenohumeral joint, EL – Elbow joint, RU – Radioulnar joint



Muscles of the Wrist and Hand

Most of the muscles that act at the wrist and finger joints originate outside the hand in the region of the elbow joint. These groups of muscles known as an extrinsic hand muscles. These muscles enter the hand as tendons that can be quiet long and either terminate at the carpal bones, or reach the tips of the phalanges. The tendon that crossing wrist are held by flexor retinaculum anteriorly and extensor retinaculum posteriorly.

39 muscles work on the wrist and hand, and no muscles work alone; agonist and antagonist work in pairs. The extrinsic hand muscles provide considerable strength and dexterity to the fingers without adding muscle bulk to the hand.

There are muscles that act on the hand joint and have an origin and insertion within the hand. These muscles termed as an intrinsic hand muscles. Intrinsic hand muscles will create the movement at the MCP and IP and form the fleshy musculature of the hand.

Extrinsic Hand Muscles

Most of the extrinsic hand muscles originate from elbow region. These muscles can be divided into; anterior compartment muscles of forearm (flexor) and posterior compartment muscles of forearm (extensor).

Anterior compartment Muscles (Flexors)

Superficial Muscles Group


Flexor Carpi Radialis

EL, RC Medial epicondyle of humerus Base of 2nd and 3rd metacarpal Radial deviation (abduction) and assist in wrist flexion

Palmaris longus EL, RC Medial epicondyle of humerus Flexor retinaculum and palmar aponeuoresis.

Assist wrist flexion

Flexor carpi ulnaris

EL, RC Medial epicondyle of humerus Pisiform, hamate and base of 5th metacarpal.

Ulnar deviation (adduction) and assist in wrist flexion.

Flexor digitorum superficialis

EL, RC, MCP, PIP

Medial epicondyle of humerus, coronoid process of ulna and oblique line of the radius

Middle phalanges of the 2nd – 5th digits.

PIP flexion, assist MCP flexion and Wrist flexion.

Deep Muscles Group

Flexor pollicis longus

EL, RC, TMC, MCP, IP

Medial epicondyle of humerus, coronoid process of ulna, anterior surface shaft of radius and interosseous membrane.

Base of the distal phalanx of thumb.

IP flexion, assist MCP flexion, Assist TMC flexion and RC flexion.

Flexor digitorum profundus

EL,RC, MCP, PIP, DIP

Anteromedial surface proximal ¾ of the ulna and interosseous membrane.

Base of the distal phalanges (except thumb)

DIP flexion, assist in PIP flexion, MCP flexion, RC flexion

*EL – Elbow joint, RC – Radiocarpal joint, MCP – Metacarpophalangeal joint, PIP – Proximal Interphalangeal joint,

DIP – Distal Interphalangeal joint, TMC – Trapeziometacarpal joint.



Posterior Compartment Muscles of Forearm (mostly Extensor)

Superficial Muscles Group


Extensor carpi radialis longus

EL, RC Lateral supracondylar ridge of humerus

Dorsal surface, base of 2nd metacarpal.

Wrist Radial deviation (abduction), assist wrist extension

Extensor carpi radialis brevis

EL, RC Lateral epicondyle of humerus, Dorsal surface, base of 3rd metacarpal.

Wrist extension, assist wrist radial deviation (abduction)

Extensor digitrum

EL, RC, MCP, DIP, PIP

Lateral epicondyle of humerus Dorsal surface, base of distal and middle phalanges of 2nd – 5th digits.

PIP and DIP extension, assist in MCP extension, RC extension

Extensor digiti minimi

EL, RC. MCP, PIP, DIP

Lateral epicondyle of humerus Blend together with tendon extensor digitorum of 5th digit.

Extension PIP and DIP, assist in MCP and RC extension.

Extensor carpi ulnaris

EL, RC Lateral epicondyle of humerus and posterior border of ulna.

Base of 5th metacarpal Wrist ulnar deviation, assist in wrist extension.

Deep Muscles Group

Abductor pollicis longus

TMC, RC Posterior surface mid-shaft of radius and ulna, interosseous membrane

Base of 1st metacarpal (thumb) TMC abduction and extension, wrist radial deviation and wrist flexion.

Extensor pollicis brevis

MCP, TMC, RC Posterior surface body of radius, interosseous membrane

Dorsal surface, base of proximal phalanx of the thumb.

MCP extension, TMC extension & abduction, assist in RC radial deviation.

Extensor pollicis longus

IP, MCP, TMC, RC

Posterior surface middle 1/3 of the radius, interosseous membrane.

Dorsal surface, base of the distal phalanx of the thumb

IP extension, assist in MCP and TMC extension, assist in RC extension and radial deviation

Extensor indicis PIP, DIP, MCP Posterior surface body of ulna Blend together with tendon extensor digitorum of the index finger

MCP extension, IP extension

*EL – Elbow joint, RC – Radiocarpal joint, MCP – Metacarpophalangeal joint, PIP – Proximal Interphalangeal joint,

DIP – Distal Interphalangeal joint, TMC – Trapeziometacarpal joint.



Intrinsic Hand Muscles

Intrinsic hand muscles are the muscles that have origin and insertion within the hand and it give bulky appearance to the hand. Intrinsic hand muscles produce weak but very intricate and precise movements of the digits (fine motor movements). These muscles can be divided into thenar muscles, hypothenar muscles and intermediate muscles.

Thenar Muscles Group (move the thumb)


Abductor pollicis brevis

MCP, TMC Flexor retinaculum, scaphoid and trapezium

Base of the proximal phalanx of the thumb

MCP and TMC abduction

Opponens pollicis

TMC Flexor retinaculum, trapezium Entire length of the 1st metacarpal

TMC opposition (flexes, abducts and slightly medial rotates)

Flexor pollicis brevis

TMC, MCP Flexor retinaculum, trapezium, trapezoid, capitate

Base of the proximal phalanx of the thumb

MCP and TMC flexion

Adductor pollicis MCP, TMC Oblique head: capitate and base of 2nd and 3rd metacarpal

Transverse head:palmar surface of 3rd metacarpal.

Base of the proximal phalanx of the thumb.

MCP and TMC adduction

Hypotenar Muscles Group (move the little finger)

Abductor digiti minimi

MCP Tendon flexor carpi ulnaris and pisifom.

Base of the proximal phalanx of the little finger

MCP abduction

Flexor digiti minimi brevis

MCP Flexor retinaculum, hamate Base of the proximal phalanx of the little finger

MCP flexion

Opponens digiti minimi

5th CMC Flexor retinaculum, hamate Entire length of the 5th metacarpal

CMC opposition

Intermediate Muscles Group

lumbricalis DIP, PIP, MCP 1st & 2nd: lateral surface of the Flexor digi Profundus of the index and middle finger

3rd : adjacent side of the FDP of the middle and ring finger

4th:adjacent side of the FDP of the ring and little fingers

Lateral border of the tendon extensor digitorum of the respective fingers.

IP extension, simultaneously MCP flexion (2nd – 5th digits)

Palmar interossei MCP, DIP, PIP 1st : base of 1st metacarpal, medial side

2nd: length of 2nd metacarpal, medial side

1st: base of proximal phalanx (thumb), medial side

2nd: base of proximal phalanx (index finger), medial side.

MCP adduction of 1st, 2nd, 3rd and 4th digits.

Assist in IP extension of 2nd, 3rd and 4th digits.



3rd: length of 4th metacarpal, lateral side

4th: length of 5th metacarpal, lateral side

3rd: base of proximal phalanx (ring finger), lateral side.

4th: base of proximal phalanx (little finger), lateral side

Dorsal Interossei MCP, PIP, DIP Adjacent sides of the metacarpals in each interspace (for example: 1st dorsal interossei – adjacent sides between 1st and 2nd metacarpals)

1st: base of proximal phalanx of index finger (lateral side)

2nd: base of proximal phalanx of middle finger (lateral side)

3rd base of proximal phalanx of middle finger (medial side)

4th :base of proximal phalanx of ring finger (medial side)

MCP abduction (2nd, 3rd and 4th digits)

Assist in MCP flexion and PIP and DIP extension.

* MCP – Metacarpophalangeal joint, PIP – Proximal Interphalangeal joint, DIP – Distal Interphalangeal joint, TMC – Trapeziometacarpal joint, CMC – Carpometacarpal joint



Nerves Supply of the Shoulder and Upper Limb

The sources of the nerves supply to the shoulder girdle and the entire of upper limb mostly from the networks of the ventral rami of spinal nerves termed as a brachial plexus and also some contribution from the cervical plexus.). Brachial plexus have a root from ventral rami of cervical spinal nerves C5 until C8 and thoracic spinal nerve T1 and give motor and cutaneous distribution to the shoulder and upper limb region. (Please refer to the text books and ppt for further explanation

Source Level Spinal Segment (root) NervesMotor / sensory

Muscles

Cervical plexus

Cervical nerve and cranial nerve (XI)

C(1), C2, C3 & Cranial nerve (XI)

Spinal accessory nerve Motor and

Sensory

Sternocleidomastoid

C2, C3, C4 & Cranial nerve (XI)

Spinal accessory nerve

Fiber of trapezius

Brachial Plexus

Roots

C3, C4, C5 Dorsal scapular nerve

Motor

Levator scapulae

C4, C5 Dorsal scapular nerveRhomboid major and rhomboid

minor

C5, C6, C7, C(8) Long thoracic nerve Serratus anterior

Superior Trunk

(middle & inferior - no nerves arise)

C5, C6 Subclavian nerve

Motor

subclavius

C4, C5, C6 Suprascapular nerve Supraspinatus and infraspinatus

Posterior cord

C5, C6, C7Upper and lower

subscapular nervesMotor Subcapularis and teres major

C6, C7, C8 Thoracodorsal nerve Motor Latissimus dorsi

C5, C6 Axillary nerveMotor and

sensoryDeltoid and teres minor

C5, C6, C7, C8, T1 Radial NerveMotor and

sensory

Triceps, anconeus, supinator, brachioradialis, extrinsic hand

muscles (extensor group)

Lateral cord C5, C6, C7 Lateral pectoral nerve Motor Pectoralis major (upper)

C5, C7Musculocutaneous

nerve Motor and

sensorycoracobrachialis

C5, C6Musculocutaneous

nerveMotor and

sensoryBiceps brachii, brachialis

C5, C6, C7 Lateral root of median nerve

Motor and sensory

Pronator teres and quadratus, All flexor group of extrinsic hand muscles (except FCU, medial

half FDP), 1st & 2nd Lumbricalis, OP, APB, FPB



Medial cord

C8, T1 Medial pectoral nerve Motor Pectoralis major (lower),

pectoralis minor

C8, T1Medial root of median

nerveMotor and

sensory

Pronator teres and quadratus, All flexor group of extrinsic hand muscles (except FCU, medial

half FDP), 1st & 2nd Lumbricalis, OP, APB, FPB

C8, T1 Ulnar nerveMotor and

sensory

FCU, medial half FDP, most of the intrinsic hand muscles

(except LOAF innervates by median nerve)



Peripheral Nerves of Upper Limb

Five terminal branches arise from the brachial plexus and innervate most of the skin and muscles of the pectoral girdle and upper limb. These five nerves are axillary, musculocutaneous, radial, median and ulnar nerves.

Nerve Root Pathway Motor innervation

Sensory innervation Nerve lesion

Axillary C5, C6

- Posterior cord- Lies anterior to

subscapularis m and posterior to axillary artery.

- Winds posteriorly around the neck of humerus

- Terminates as a anterior and posterior branches

Anterior branch – anterior and lateral fiber of deltoidPosterior branch – posterior fiber of deltoid and teres minor

Posterior branch will terminates as a upper lateral brachial cutaneous nerve – skin lower part of the deltoid

Dislocation of the GH joint, fracture of the humeral neck – weakness of the deltoid (muscle wasting).

Musculocutameous C5 – C7

- Lateral cord- Opposite lower border of the

pectoralis minor- Pierce coracobrachialis m and descends laterally between biceps and brachialis to the lateral side of the arm.- Pierce the deep fascia on the elbow and continue to the forearm as a lateral anterbrachial cutaneous nerve.

Along the pathway, supply coracobrachialis, biceps brachii and brachialis

Antebrachial cutaneous nerve – divide into anterior and posterior branchesAnterior branch – skin of anterolateral surface of forearm as far as ball of the thumbPosterior branch – skin of posterolateral surface of forearm

Fracture of the humerus, patient with neuralgic amyothrophyWeakness of elbow flexion

Radial C5 – T1

-Posterior cord-Descend posterior to the axillary artery-Enter the radial groove at the back of the humerus and enter anterior compartment of the arm.-Continue the jurney between brachialis and brachioradialis-At the distal part of humerus, passes anterior to the lateral epicondyle and enter the forearm-And terminate as superficial and deep terminal branches.

Arm: triceps brachii, anconeus, supinator, brachioradialisForearm: extrinsic hand muscles (extensor group)

ArmPosterior Brachial Cutaneous nerve – skin back on the armInferior lateral brachial cutaneous nerve – skin at the lower lateral aspect of the armForearmPosterior antebrachial cutaneous nerve – skin at the back of the forearmHandSuperficial branch – back of the hand

Fracture of the midshaft of humerus (radial groove) – ‘wrist drop’- the hand can’t be lifted against gravity and the power grip is weak.



Ulnar C7 – T1

-Medial cordPasses down the medial side of the arm between biceps and triceps-At the elbow, the nerve lies behind, and contact with the medial epicondyle of humerusAt the forearm give motor branches to FCU and medial half of FDP.-Just above the wrist, the nerve branch off to the superficial and deep branch.

Forearm – FCU and medial half FDPHand – via deep branch supply hypothenar muscles, palmar & dorsal interossei, medial half of lumbricalis and adductor pollicis

Superficial branch supply Skin anterior and posterior of the hand( medial aspect of the hand, ring and little fingers)

Injury to the elbow whether traumatic or entrapment near to the medial epicondyle.Ulnar nerve lesion will give appearance known as a claw hand.Claw hand – little and ring finger curl in flexion deformity and MCP hyperextension – due to paralysis of lumbricalis.

Median C5-T1

-Lateral and medial cords -Passes down the arm with the brachial artery and medial to the MC nerve. At the elbow lies on the brachialis and medial to the tendon of biceps.-Passes anterior to the elbow joint (within cubital fossa) and then down and supply flexor muscles of forearm.-In the hand, passes through the carpal tunnel and then divide into motor and cutaneous branch.

Elbow – pronator teres, FCR, Palmaris Longus, FDSForearm – lateral half FDP, FPL, and pronator quadratusHand – thenar muscles (except adductor pollicis) and lateral half lumbricalis.

Cutaneous branches - skin of the palmar aspect of the thumb and the lateral 2 ½ fingers and the distal ends of the same fingers and skin of distal phalanx on same finger

Carpal tunnel syndrome – compression of median nerve (pain, numbness and tingling) within carpal tunnel.



Important Area of the Upper Limb

Area Borders Contents Clinical ImportanceAxillaPyramidal space inferior to GH joint. Provide passageway for vessels and nerves going to and from the upper limb.

Apex: Cervico-axillary canal (space between neck and axilla, posterior to the clavicle)Base: skin, subcutaneous tissue (axillary fossa)Anterior wall: Pectoralis major and minor and form anterior axillary foldPosterior wall: subscapularis, scapula, teres major and latissimus dorsi. Teres major and latissimus dorsi form posterior axillary fold.Medial wall: thoracic wall and underlying serratus anteriorLateral wall: Intertubecular sulcus of humerus

- Axillary artery and its branches

- Axillary veins and its tributaries-Nerves of the

cords and branches of the brachial plexus

- Lymphatic vessels- Several groups of

axillary lymph nodes.

Enlargement of axillary lymph nodes – due to infection on upper limbInjury to axillary vein – profuse bleeding and risk of the air emboli.

Superior view of the axilla region and its related contents



Area Borders Contents Clinical ImportanceCubital FossaShallow triangular depression on the anterior surface of elbow.

Superior: imaginary line connection between medial and lateral epicondyle of humerusMedial : pronator teresLateral: brachioradialisFloor: brachialis and supinatorRoof: Bicipital aponeurosis, subcutaneous tissue and skin

- Terminal part of brachial artery and veins

- Biceps brachii tendon

- Median nerve- Radial nerveIn the subcutaneous tissue – medial cubital vein, basilic vein and cephalic vein.

Venous blood drainage from median cubital vein, cephalic vein and basilica vein.Blood pressure measurement – brachial artery

Anterior View of cubital fossa and its related structures

Area Borders Contents Clinical ImportanceCarpal Lateral border: scaphoid and Tendon Flexor Carpal Tunnel



TunnelConcave surface located at the palmar surface of the wrist

trapeziumMedial border: pisiform and hamateRoof: Flexor retinaculum (transverse carpal ligament) attach between bones of the medial and lateral borders.

digitorum profundusTendon flexor digitorum superficialisTendon flexor pollicis longusMedian nerve

SyndromeCompression of the median nerve, microvascular insufficiency of the median nerve and prolong vibration of the median nerve.Numbness, pain and tingling of the hand.


Health & Medicine

Anatomy Muskuloskeletal Pectoral Girdle & Upper Limb