Anatomy Ch6 upper limbs PDF

Preview

Summary

Upper Limbs Extremeties plus more...

Description

Chapter 6: Extremities- Upper Limb

6.2.a Scapula ● Back of the shoulder ● Anterior (subscapular fossa) and posterior surfaces ● Spine of scapula o Divides posterior surface into two parts- supraspinous and infraspinous fossae o Acromion process: lateral expansion; articulates with the clavicle ● 3 borders- Medial, lateral, and superior borders ● 3 angles- superior, inferior, and lateral angles ● Glenoid cavity o Site of articulation with the head of humerous o Location: Lies at the lateral angle of scapula; the supraglenoid tubercle and infraglenoid tuberble are seen above and below ● Coracoid process: (beak-shaped) above the glenoid cavity and extends anterolaterally; o Gives origin to or is an insertion site for three muscles ▪ Origins: short head od the biceps brachii & coracobrachialis muscle ▪ Insertion: pectoralis minor ● Suprascapular notch: bridged at its upper boundary by superior transverse scapular ligament o Contents: suprascapular nerve and vessels 6.2.b Clavicle ● Superior/inferior surfaces; anterior and posterior border; two ends ● Sternal and Acromial ends o Covered by cartilage and form articular facets to articulate with sternum at the sternal end and with the acromion at the acromial end o Acromial end of clavicle articulates with acromion process of scapula → plane-type joint (permits sliding/gliding movements) ● Ball-and-socket type synovial joint o Clavicle articulates with sternum at the sternoclavicular joint (BS-type) ● Clinical: Ossification of the clavicle occurs in the connective tissue similar to that of the skull during fetal development o Two ends have endochondral  ossification, which appears in second decade of life, and the ossified centers fuse to each other after that. 6.2.c Humerus ● Comprised of shaft and two ends, proximal and distal ● Proximal end- bears the head of humerus, which articulates with glenoid cavity of scapula in shoulder joint o Head: covered by hyaline cartilage → fits into glenoid cavity of scapula and forms the shoulder joint o Circumference: inferior to head; articular surface ends here o Anatomical neck → greater (lateral) tubercle → intertubercular (bicipital) groove, the tendon of long head of biceps brachii muscle passes here →   lesser (medial) tubercle →   surgical neck (inferior to tubercles) ● Body/ Shaft o Upper section: cylindrical o Lower section: triangular o Three surfaces (anteromedial, anterolateral, and posterior) and borders o Deltoid tuberosity: lateral aspect of middle of shaft o Radial/spiral groove: lies on the posterior surface in the muddle of the shaft of the humerus

▪ Contents: radial nerve & deep brachial vessels Distal end- articulates with radius and ulna in elbow joint o Two sharp edges/ridge → medial and lateral suprachondylar edge (continues distally to the medial and lateral nonarticular epicondyles of the humerus ▪ Medial epicondyle: larger and bears ulnar groove posteriorly (ulnar nerve passes thru groove, and then beneath the skin) ● Capitulum → articulates with head of radius; radial fossa above capitulum ● Trochlea → articulates with ulna at trochlear notch; coronoid fossa above trochea 6.2.d Shoulder Joint ● Ball-and-socket type synovial joint between head of humerus (ball) and glenoid cavity (socket) → expanded by the articular lip/glenoid lip/articular labrum at its border ● Rotator cuff muscles help strengthen the shoulder joint o Capsule of the joint is supported by several ligaments → coracohumeral ligament (restricts movement) superiorly and three week glenohumeral ligaments (superior, middle, and inferior) ● Movements of shoulder joint: abduction, adduction, anteversion (flexion), retroversion (extension), lateral, and medial rotation, and circumduction of the arm ●

6.2.e Forearm Bones: Radius and Ulna ● Radius o Proximal end- consists head with articular fovea/facet and articular circumference, and neck (inferior to this is the radial tuberosity) o Body- triangular-like; body has three surfaces (anterior, lateral, and posterior) and three borders (anterior, posterior, medial/interosseous) o Distal end- expanded and has a sharp tip inferiorly (styloid process); ulnar notch is located medially for articulation with head of the ulna; the carpal anticular surface is location distally for articulation with the proximal row of carpal bones ● Ulna o Proximal end ▪ Trochlear notch: articulates with the trochlea of the distal humerus ▪ Coronoid process: anteriorly, on lower edge of trochlear notch ▪ Radial notch: articulation with the circumference of the head of the radius ▪ Olecranon process ▪ Ulnar tuberosity: site of attachment of the brachialis muscle o Body- three surfaces (anterior, medial, and posterior); three borders (anterior, posterior, medial/interosseous); supinator crest o Distal End- Bears the head (articular circumference for articulation with ulnar notch of distal radius); Wrist joint= radiocarpal joint; Styloid process 6.2.f Elbow Joint ● Synovial joint ● Capsule has three joint→ humeroulnar, humeroradial, and proximal radioulnar joints = compound joints ● Two collateral ligaments (medial/ulnar and lateral/radial) → restrict movements ● Movement: flexion, extension, supination, and pronation of forearm → supination and pronation assisted by the middle and distal radioulnar joints ● Proximal radioulnar articulation- pivot joint ● Head of radius- supported by surrounding annular ligament ● Joint between radius and ulna= middle radioulnar joint (interosseous membrane) = continuous joint ● Distal radioulnar joint= synovial and pivot-type joint 6.2.g Carpal Bones ● Scaphoid, lunate, triquetrum, pisiform, trapezius, trapezoid, capitate, and hamate → bones are firmly held together as a unit= carpal groove o Covered by flexor retiaculum, forming the carpal tunnel, through which several muscles and median nerve pass ● Proximal Row o Includes scaphoid (largest in this row), which has a prominent tubercle of scaphoid at its palmar (anterior surface) →   articulates with radius superiorly (proximally) and with neighboring carpal bones inferiorly and medially) o Lunate, triquetrum and pisiform

Distal row o Distal row: ▪ 1) Trapezium: it has a tubercle on its anterior aspect, and medial to the tubercle is a grove through which the tendon of the flexor carpi radialis muscle passes ▪ 2)Trapezoid ▪ 3) Capitate (largest bone in second row) ▪ 4) Hamate: most medial; bears hamulus on its anterior surface ● Carpal groove→ Concave anteriorly and contains the tendons or several muscles and median nerve (Carpal tunnel) o Carpal tunnel: The flexor retinaculum that covers the carpal groove forms the carpal tunnel o Contents: tendons of some flexor muscles of wrist and hand, median nerve ● Flexor retinaculum → Two different fibrous structures with different histological characteristics o 1) Superficial layer- in continuity with the antebrachial fascia (reinforcement) o 2) Deeper layer- composed of strong lamina, with histological features similar to those of a ligament 6.2.h Wrist (radiocarpal) Joint ● Type: Ellipsoid synovial joint ● Movements: abduction, adduction, flexion and dorsiflexion, and circumduction ● Contents: ligaments include ulnar and radial collateral ligaments, the palmar and dorsal radiocarpal ligaments, the palmar ulnocarpal ligament, and others ● Midcarpal joint: little movement between the bones of the first row, but almost no movement at all between the second row, and between these joints and the metacarpal bones, except for the first carometacarpal joint (of the thumb) 6.2.i Metacarpal bones ● 5 bones, the first on the thumb and the fifth on the side of the little finger ● Structure: body, head, and base 6.2.j Carpometacarpal joints ● First carpometacarpal joint is a saddle joint, but the others have very limited movement ● Movement: abduction, adduction, position, reposition, and circumduction of the thumb 6.2.k The Phalanges ● The bones of the digits ● Three phalangeal bones= proximal, middle, distal → every digit but the thumb has three bones. ● Each phalanx has a proximal base and distal head (distal flattened border, which has dentations) 6.2.l Metacarpophalangeal joints ● Synovial joints that are Ball-and-socket shaped, however, all freedom of movement is restricted because of collateral ligaments ● Sesamoid bones are found near the first metacarpophalangeal joint 6.2.m Interphalangeal Joints ● Hinge-type synovial joints and are supported by the collateral and palmar ligaments ● Movements: flexion and extension of digits 6.3.a Brachial Plexus ●

● ●

Origin: C5-T1 roots

● ● ●

Location: posterior triangle of the neck, between the anterior and middle scalene muscles in the scalene triangle (gap); it then runs behind the clavicle at the root of the neck Branches/terminal nerves: median, radial, ulnar, axillary, and musculocutaneous nerves Origin nerve: collateral branches originate o Motor nerves to the muscles in vicinity ▪ Nerve to rhomboid muscles ▪ Long thoracic nerve to serratus anterior muscle ▪ Medial and lateral pectoralis nerves to pectoralis muscles ▪ Suprascapular nerve to the supra and infraspinatus muscles, as well as the thoracodorsal to the latissimus dorsi

● Region- Shoulder girdle Muscle/Bone

Innervation

Function

Deltoid

Axillary nerve (C5-C6)

Supraspinatus muscle

Suprascapular nerve (C4-C6)

Infraspinatus muscle

Suprascapular nerve (C4-C6)

Teres minor Teres major

Axillary nerve (C5-C6) Lower subscapular nerve (C6-C7) Thoracodorsal nerve (C6-C8), a branch of the

Abduction of the arm, up to 90 degrees. ● Anterior/clavicular – adducts, flexes, and medially rotates arm ● Middle/acromial- abducts the arm and aids the clavicular part in anteversion (flexion) ● Posterior/spinal- extends/ retroversion the arm and lateral rotation of arm Acts as an abductor of arm, and belongs to the rotator cuff muscle group Lateral rotator of the arm, and belongs to rotator cuff muscle group Acts as lateral rotator of the arm Adduction and medial rotation of the arm Medial rotation, extension, and adduction of arm by acting on

Latissimus dorsi

Clinical Associations/Content s

●

Coughing and forced expiration

Subscapularis Pectoralis major

Pectoralis Minor

Cobracobrachialis

Serratus Anterior

posterior cord coming form the brachial plexus Subscapular nerves (C5-C7) The lateral and medial pectoreal nerves (C5-T1), originating from the laterl and medial cord of the brachial plexus, respectively Medial pectoreal nerve (C8-T1) Musculocutaneous nerve (C5-C7), originating from the lateral cord of the brachial plexus Long thoracic nerve (C5-C7), extending down from the proximal parts of the brachial plexus. The nerve lies on the medial wall of the axillary region between the lymph node

humerus Adduction and medial rotation of the arm Adduction and medial rotation of the arm and also lowers the arm when it’s raised. Clavicular part= flexor of upper arm

Muscles assists respiration by expanding the thoracic cage during forced respiration

Pulls the scapula for/downward; rotation of scapula (glenoid cavity faces downward) Flexion and adduction of arm Antevertor of arm Elevation of arm over 90 degrees→ protraction/rotation the scapula, holding it against the thoracic wall and rating the scapula laterally to elevate the arm, so that the glenoid cavity faces upward

Long thoracic nerve may be injured during surgical removal of the lymph nodes Accessory muscle during respiration by lifting ribs Keep scapular closer to the wall If injured, have winged scapula (paralysis)

Innervation

Function

Biceps brachii

Musculocutaneous nerve (C5-C6), branching from lateral cord of the brachial plexus

Brachialis

Triceps Brachii

Musculocutaneous nerve (C5-C6), and to some of its LATERAL parts, by radial nerve Main Radial nerve (C6-C8)

Acts on two joints: 1) Elbow join- flexor and strong supinator 2) Both aids in flexion of shoulder joint Long head= abductor and medial rotator of arm Short head= adductor Powerful flexor of elbow joint

Clinical Associations/Content s Bicep jerk

Anconeus

Radial nerve

Region- Arm (Brachial) Muscle/Bone

Region- Elbow (cubital)

Strong extensor of forearm at elbow joint Long head- shoulder joint (retroversion and adduction) and elbow joint ( works with other heads and mediates extension) It assists the triceps brachii muscle in the extension of the elbow

Tendon inside the shoulder joint! Tricep jerk

Region- Forearm (antebrachial) Muscle/Bone Innervation

Function

Palmaris Longus

Median nerve (C7-C8)

Palmaris longus flexes the hand and tenses the palmar aponeurosis

Protonator Teres

Median nerve (C7-C8), which also passes between two heads of the pronator teres)

Pronation of forearm and flexion of elbow

Flexor Carpi radialis

Median nerve (C7-C8)

Flexor Digitorum superficialis

Median nerve (C7, C8, T1)

Palmar flexion and radial abduction of the hand Flexes and pronates the elbow Flexion of the elbow, wrist and fingers

Flexor Carpi Ulnaris Flexor Pollicis Longus

Ulnar nerve (C7-C8) Median nerve (anterior interosseous branch) (C8-T1) Medina nerve (anterior interosseous branch) laterally (C8-T1), and the ulnar nerve medilly ( C8-T1)

Flexor and adductor of the hand Flexor of the terminal phalanx

Brachioradialis

Median nerve (anterior interosseous branch) Radial nerve (C5,C6, C7)

Extensor carpi radialis longus

Main Radial nerve

Extensor carpi radialis brevis

Deep branch of the radial nerve (C7) – deep radial nerve Posterior interosseous branch of the deep radial

Pronates the forearm (together with pronator teres) Pronate or supinate the forearm and bring it into mid-position between pronation and supination: in this midprone position, it acts as a flexor (forearm flexor) at elbow joint Extension and radial abduction of the hand at wrist joint; weak flexor of the elbow and aids in pronation and supination of the forearm Extensor and abductor of the hand at wrist joint and a weak flexor of elbow

Flexor digitorum profundus

Pronator Quadratus

Extensor digitorum

Flexes the wrist, including the midcarpal joints, as well as the metacarpophalangeal and phalangeal joints

Extends the four medial fingers (not thumb) and is responsible for the

Clinical Associations/Content s Has long tendon running toward the center of the palm of hand Pronator syndrome: lower motor neuron disease → lifters and body builders grow a lot of muscles and squishes the nerves= compression Has its own canal in the groove of trapezium The muscle has 3-4 bellies connected to each other, which end in four tendons that run within the carpal tunnel and insert onto the middle phalangeal bones

Few bellies connected to each other that end in four tendons, which run within the carpal tunnel and insert into the distal phalangeal bones

Dorsal digital expansion:

nerve (C7-C8)

dorsiflexion of the hand at the wrist

Extension of the fifth digit and dorsiflexion of the hand

Abductor Pollicis longus

Posterior interosseous brancg of the deel radian nerve (C7-C8) Posterior interosseous branch of the radial nerve (C7-C8) Deep branch of the radial nerve (C5-C6) deep radial nerve (C7-C8)

Extensor Pollicis Brevis

deep radial nerve (C7-C8)

Extensor Pollicis Longus

deep radial nerve (C7-C8)

Extensor Indicis

deep radial nerve (C7-C8)

Extensor digiti minimi

Extensor carpi ulnaris

Supinator

●

●

●

intertendinous connections between the tendons of the extensor digitorum on the hand that form the dorsal aponeurosis. More distally, along the phalanges, the four tendons flatten and form extensor expansions

Extends and adducts the hand at the wrist Supinates the forearm Abduction of the thumb and its extension at the carpometacarpal joint Extension of the proximal phalanx at the metacarpophalangeal joint Extends the thumb (at metacarpophalangeal and interphalangeal joints) using the crest on the radius as a fulcrum Index extension and hand dorsiflexion

Contents of Carpal Tunnel: o Tendons covered by palmarcarpal tendon sheaths (protect against friction and provide nutrition via synovial fluid content o Flexor digitorum superficialis o Flexor digitorum profundus o Flexor pollicis longus o Median nerve Posterior Muscles of the Forearm o Generally extensors/dorsiflexors of the wrist and hand o Tendons of several extensor muscles pass through 6 tendon compartments on the dorsal aspect of the wrist, formed by the extensor retinaculum connected deep to the bones around the carpal area through the septae Extensor Retinaculum and its Tendon Compartments o Extensor retinaculum covers the carpal bones dorsally o 6 tendon compartments: (won’t be asked on test but good to know) ▪ First = abductor pollis longus + extensor pollicis brevis ▪ Second = extensors carpi radialis + longus ▪ Third = extensor pollicis longus ▪ Fourth = extensor digitorum and extensor indicis ▪ Fifth = extensor digiti minimi ▪ Sixth= extensor carpi ulnaris o Compartments from septaefextn

Region- Wrist (carpal)

Region- Hand Muscle/Bone

Innervation

Function

Median nerve (C8-T1) Superficial head= median nerve (C8-T1) Deep head= ulnar nerve (C8-T1) Median nerve Deep branch of ulnar nerve (C8-T1)

Abduction of the thumb Flexion of the thumb

Abductor digiti minimi

Deep branch of ulnar nerve (C8-T1)

Abducts 5th  digit

Flexor digiti minimi

Deep branch of ulnar nerve (C8-T1)

Flexes 5th  digit

Oppenens digiti minimi

Deep branch of ulnar nerve (C8-T1)

Opposition of the 5th  finger to thumb

Lumbrical muscles

Two lateral muscles are innervated by median nerve (C8-T1), and the two medial muscles are innervated by the ulnar nerve Ulnar nerve

Flexion of the fingers excluding the thumb at metacarpophalangeal joints; aid in extension of fingers at interphalangeal joints (digits 2-5)

Abductor Pollicis brevis Flexor pollicis brevhis

Opponens Pollicis Adductor pollicis

Palmar interossei Muscles

Thumb opposition Thumb adduction

Clinical Associations/Content s Consist of two heads

Triangular muscle with its apex toward the thumb and its base connected to third metacarpal bone; two heads ( transverse and oblique) Insert: base of the proximal phalanx of the fifth digit Insert: base of the proximal phalanx of the fifth digit Insert: medial (ulnar) aspect of the 5th  metacarpal bone Insert: Lateral sides of the dorsal aponeurosis

Adduction of 2, 4, 5 and assisting the Insert: corresponding lumbrica;s at the proximal phalanges metacarpophalangeal joints and and dorsal extend at the interphalangeal jonts aponeurosis via attachments to the extensor expansions of 2-4 Dorsal Interossei Muscles Ulnar nerve Abduction of digits; fle at Insert: The base of metacarpophalangeal joints and the2-4 proximal extend at the interphalangeal joints phalanges and dorsal of 2-4 aponeurosis ● Palmar aponeruosis: fibrous structure composed of longitudinal and transverse fascicles, which connect into a flat, triangular, tough band (which connects to the overlying skin and underlying deep tendon sheaths and ligaments of the...