Upper limbs Flashcards
The upper limb
- It is a freely mobile organ of manual activity
- not weight bearing; hence stability compromised for mobility
- divided into shoulder, arm, elbow, forearm, wrist, and hand
Trapezius
O- external occiptal protuberance, superior nuchal line, ligamentum nuchae, spinous processes of C7-T12
I-lateral 1/3 of clavicle, acromion, and spine and base of spine of scapula
N- spinal accessory nerve
A- superior fibers elevate scapula; middle fibers retract scapula; inferior fibers depress scapula
Latissimus Dorsi
O- spines of T7-T12, thoracolumbar fascia, iliac crest, ribs 9-12
I- floor of bicipital (intertubercular) groove of humerus
N- thoracodorsal nerve
A-adducts, extends, and medially rotates humerus
Levator Scapulae
O- transverse processes of C1-C4
I- upper part of medial border of scapula, from superior angle to spine
N- dorsal scapular nerve and C3-C4
A- elevates and rotates scapula inferiorly
Rhomboids (major/minor)
-lie deep to trapezius
O- nuchal ligament and spinous process of C7-T5
I- medial border of scapula
N- dorsal scapula nerve
A- retracts, elevates scapula, and rotates glenoid fossa inferiorly
Serratus posterior muscles
(superior) O- spinous processes of C7-T3 vertebrae I- ribs 2-4 N- intercostal nn. A- elevates ribs 2-4 during inspiration
(inferior) O- spinous processes of T11-L2 vertebrae I- ribs 8-12 N- intercostal nn. A- depresses the inferior-most 3 or 4 ribs during inspiration
Pectoralis Major
O- clavicle, sternum, and upper 6 costal cartilage
I- lateral lip of inter-tubercular groove of humerus
N- medial and lateral pectoral nerves
A- adducts and medially rotates humerus; clavicular fibers flex humerus; sternocostal fibers extend the humerus
Pectoralis minor
-It forms an important landmark for vessels and nerves that supply the arm
O-3-5th ribs
I- coracoid process of scapula
N- medial pectoral nerve
A- stabilizes scapula by drawing it inferiorly and anteriorly
Subclavius
O- junction of 1st rib and cartilage
I- inferior surface of clavicle
N- subclavian n.
A- not much- depresses and anchors the clavicle
Serratus Anterior
O- first 8 ribs I- medial border of scapula N- long thoracic nerve A- draws scapula forward around thoracic wall; rotates scapula superiorly (esp. when raising arm). -It is called "the boxer's muscle
Deltoid
O- lateral third of clavicle, acromion, and spine of scapula
I- deltoid tuberosity of humerus
N- axillary nerve
A- abducts, flexes, extends, medially and laterally rotates humerus
Rotator Cuff Muscles
S- supraspinatus
I- infraspinatus
T- teres minor
S- subscapularis
- maintain function is to hold the head of humerus in the glenoid cavity
-also rotates the humerus about its longtitudinal axis
Supraspinatus
O- supraspinous fossa
I- greater tubercle (superior part) of humerus
N- suprascapular nerve
A- abduction of humerus; stabilizes shoulder joint
-pts with this muscle paralyzed, can still initiate abduction, by leaning to the side or by pushing their elbow out with a jerk of their hip
Infraspinatus
O- infraspinous fossa
I- greater tubercle (middle part) of humerus
N- suprascapular nerve
A- holds humerus in place; laterally rotates humerus
Teres minor
O- superior part of lateral border of scapula
I- greater tubercle (inferior part) of humerus
N- axillary nerve
A- laterally rotates and adducts humerus
Teres Major
O- dorsal surface of inferior angle of scapula
I- medial lip of bicipital groove of humerus
N- lower subscapular nerve
A- adducts and medially rotates humerus
Subscapularis
O-subscapular fossa
I- lesser tubercle of humerus
N- upper and lower subscapular nerve
A- medially rotates and adducts humerus; stabilizes shoulder joint
Splenius capitis
O-nuchal ligament and spinous process of lower cervical and upper thoracic vertebrae
I: mastoid process and superior nuchal line of occipital bone
N- segmentally posterior rami
A- unilaterally-laterally flexes and roates head and neck to same side
Bilaterally- extends/hyperextends neck
Splenius cervicis
O- nuchal ligament and spinous process of upper thoracic vertebrae
I- transverse process of upper cervical vertebrae
N- segmentally by posterior rami
A- unilaterally- laterally flexes and rotates neck to same side
Bilaterally-extends/hyperextends neck
Regions of upper limb
- Name the scientific name of each parts and joints associated.
1. 1/2 Pectoral Girdle (shoulder)
2. Shoulder
3. Arm
4. Elbow
5. Forearm
6. Wrist
7. Hand
- 1/2 Pectoral Girdle (shoulder)
- The later portion of clavicle joint with the acromion of the scapular= acromioclavicular joint - Shoulder
- glenohumeral joint btw the humerus & scapula - Arm
- brachium - Elbow
- cubitus
- elbow joint
- proximal radioulnar joint - Forearm
- antebrachium
- distal radioulnar joint - Wrist
- carpus
- midcarpal joint
- carpus
- metacarpus
- phalanges - Hand
- manus
- carpometacarpal joints
- metacarpophalangeal joints
Parts of scapula
Anterior 1. acromion process 2. acromial angle 3. glenoid fossa (cavity) 3a. neck 4. supraglenoid tubercle 4a. infraglenoid tubercle 5. coracoid process 6. suprascapular notch 7. superior border 8. superior angle 9. medial (vertebral) border 10. subscapular fossa 11. inferior angle 12. lateral border Posterior 1. groove for circumflex scapular vessels 2. supraspinous fossa 3. (scapulae) spine 4. infraspinous fossa 5. unnamed notch connecting supraspinous & infraspinous fossae
Right clavicle (collarbone)
commonly fractured:
- indirectly, forced transmitted through upper limb
- directly falling onto shoulder
- in children the fracture is usually incomplete (greenstick fracture)
- sternocleidomastoid muscle pulls medial part superiorly
- lateral part (and shoulder droops)
1. acrominal end
2. sternal end
3. shaft body
4. anterior
5. posterior close to conoid tubercle
6. trapexoid line
7. acromial and sternal facets
8. impression for costoclavicular ligament
Humerus bone anterior/posterior
Anterior 1. head of humerus articulate with glenoid cavity of scapula 2. anatomical neck 3. greater tubercle 4. lesser tubercle 5. surgical neck 6. intertubercular sulcus 7. crest of greater tubercle 8. crest of lesser tubercle 9. deltoid tuberosity 10. lateral/medial supracondylar ridge 11. lateral/medical condyle 12. radial fossa 13. lateral epicondyle 14. capitulum 15. trochlea 16. coronoid fossa 17. medial epicondyle Posterior 1. radial groove (near deltoid tuberosity) 2. lateral/medial supracondylar ridge 3. olecranon fossa 4. trochlea 5. groove for ulnar nerve (near medial epicondyle
Ulna & Radius (proximal end)
- ulnar tuberosity (insertion of brachialis)
- radial tuberosity (insertion of bicep brachii)
Distal end of radius-pronated
- styloid process (of ulna)
- groove for extensor digitorum & extensor indicis muscles
- groove for extensor pollicis longus m.
- dorsal tubercle
- groove for extensor carpi radialis longus & brevis muscles
- styloid process
Wrist & hand bones
- Phalanges (proximal, middle, distal)
- Metacarpals
-1=thumb (pollex)
-2= little finger (digiti minimi) - Carpals
Proximal row
-scaphoid
-lunate
-triquetrum
-pisiform
Distal Row
-hamate
-capitate
-trapezoid
-trapezium
Embryological development
- the dermatomal patterns show primitive segmental arrangement
- 5th week (day 32): limb bud or paddle. Tissue innervation corresponds closely to vertebral level
- dermatomes get “pulled out” with growth
- ventral axial line (underside of the arm) with lower side as the anterior aspect.
Superficial veins
- cephalic- begins on the lateral side of hand empties into subclavian vein
- Basilic- begins on medial side of hand, joins the brachial veins to form the axillary vein
- Median cubital-communication between the cephalic and basilic v v.
- venupuncture in the cubital fossa
Superfical Extrinsic upper limb muscles that are on the back (posterior thoracoappendicular muscles)
- innervated by anterior rami of spinal nerves
- Trapezius
- Levator scapulae
- latissimus dorsi
- Rhomboids major/minor
Intermediate extrinsic muscles and OINA
-serratus posterior muscles
superior/ inferior
Anterior thoracoappendicular muscles
- pectoralis major/ minor
- subclavius
- serratus anterior
muscles of the shoulder
scapulohumeral mm
- Deltoid
- Rotator Cuff muscles
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
Vertebral column (spine)
- role
- shape
- has important role in posture, in support of body weight, in locomotion, and in protecting the spinal cord and nerve roots
- curvatures and the intervertebral discs provide shock-absorbing resilience for the body
- concave anteriorly (kyposis0= thoracic, sacral
- concave posteriorly (lordosis)= lumbar, cervical
Vertebral regions
- consists of 33 vertebrae; only 24 are movable
- cervical (7)
- thoracic (12)
- lumbar (5)
- sacral (5 fused not long after birth)
- coccygeal (3-4 fused during middle life)
- not all people have 33 vertebrae
- always constant= cervical 7; variations for the rest
Primary and Secondary curvatures
Primary
-thoracic, sacral= kyposis
-develop in fetal life
Secondary (lordosis)
-cervical at 3 mos when infant holds head erect
-lumbar curvature as child begins to walk (11-13 months)
Scoliosis- any mediolateral curvature of spine
General vertebrae features
-body- support body weight
-superior/inferior articular facets for articulation with other vertebrae; restricts movement
-transverse process & spinous process for muscle attachments
-Pedicle & lamina form vertebral foramen to protect spinal cord
-Superior/inferior vertebral notchs of adjacent vertebrae form the intervertebral foramen
-
Spinal nerves
- spinal nerves exit the intervertebral foramen
- older people develop spondylosis, especially in cervical and lumbar regions, when encroachments occur on intervertebral foramina (osteophytes) and on vertebral canal (disc degeneration) that causes pressure on nerve roots resulting in radiculopathy
Cervical vertebrae
- transverse foramen (vertebral artery passes through) are large
- small or non-existant body
- superior articular facets face superiorly
- inferior articular facets face inferiorly
- superior/inferior vertebral notches are equal in size
- spinous processes of 3-6th vertebrae are short and bifid
- 7 processes= 1 spinous process, 2 transverse processes, 4 articular processes
- liver-like= muslces & ligaments are attached to it; act as levers to move vertebrae
1. anterior/posterior tubercle (R & L)
2. transverse foramen
3. uncinate process
4. body
5. transverse process
6. groove for spinal nerve
7. pedicle
7a. lamina
8. superior/inferior articular facets/process (R& L)
9. vertebral foramen
10. spinous process
Atlas (C1) and Axis (C2)
Atlas (C1) -No body -large superior articular facets for occipital condyles of skull -transverse process/foramen (R+L) -tubercle for transverse ligament of atlas -anterior tubercle/arch articular facet for dens -lateral mass -vertebral foramen -posterior arch/tubercle -groove for vertebral artery
Axis (C2) -dens -anterior articular facet for anterior arch of atlas -pedicle -superior articular/process facet for atlas -posterior articular facet for transverse ligament of atlas -interarticular part -transverse process -inferior articular facet/process for C3 -body spinous process -transverse process
Thoracic vertebrae
-costal facets on bodies for articulation with head of ribs
-costal facets on transverse process for articulation with tubercles of ribs
-long inferiorly directed spinous processes
-superior articular facets face posteriorly and the inferior articular facet face anteriorly
Abnormalities
-rib 1 attaches to costal facet of T1 and costal facet on transverse process of T1
- T1-T9 superior & inferior costal facets on body
-T1-T10 one pair of costal facets on transverse processes
-T10-T12 one pair of costal facets on body
-T11-T12 no costal facet on transverse process
Lumbar vertebrae
- large, heavy body support weight of torso, upper limbs, head
- short, sturdy spinous & transverse processes
- superior articular articular facets face medially
- inferior articular facets face laterally
sacrum
5 fused vertebrae
- L5 vertebrae attached superiorly
- hip bones (ilium) attach laterally
- 5% people 5th lumbar partly or completely incorporated into sacrum (hemisacrilization or sacralization of 5th lumbar vertebrae)
- 1st sacral separated from sacrum= lumbbarization of 1st sacral vertebra
- spinous processes and articular processes are fused into jagged ridges
- sacral hiatus provides access to sacral canal
- joint between coccyx and sacrum can move a little. Important during childbirth, fuses at old age
Intervertebral joints
intervertebral disc is composed of:
- nucleus pulposus-gelatinous central mass
- anulus fibrosus; outer fibrous part, composed of fibrocartilage
- Joints allow compression (help to absorb shock of body weight), bending (anterior/posterior or mediolateral, twisting
Movement of vertebrae
three types
- flexion/extension/hyperextension
- lateral bending
- twisting (rotation)
- movement between vertebrae is very small
- when combined, the movement is significant
- movment is greatest in lumbar and cervical regions
- movements in thoracic region is relatively stable due to its connection with sternum, costal cartilages, thinner intervertebral discs and because the spinous processes overlap here
Zygapophyseal joints (Facet Joints) -superior articular facet + inferior articualr facet
- all zygapophyseal facets are plane type of synovial joints and are oriented somewhat superoinferiorly
1. cervical: lots of mobility - facet oriented at 45 degree from horizontal plane
- slope inferiorly from anterior to posterior; help flexion, extension, rotation
- joint capsule loose and broad
2. Thoracic: limited mobility - facet oriented in mostly coronal, sloped almost vertical; limit flexion & extension but permits some rotation
- joint capsule relatively tight
3. Lumbar: moderate mobility - facet oriented in sagittal plane
- facets curved; processes interlock
- allows anteroposterior bending and lateral flexion
- does not allow much rotation
- joint capsule relatively tight
Cervical vertebrae movement
-flexion tends to open up the intervertebral foramina
-extension, lateral bending & rotation crowd the intervertebral foramina
1. flexion
2. extension
3. lateral flexion
4. rotation
(not including atlantoaxial joint)
Thoracic vertebrae movement
- thoracic vertebrae most stable due to articulations with ribs, costal cartilages, sternum
1. rotation
2. limited flexion, extension, lateral flexion
Lumbar vertebrae
- flexion
- extension & lateral flexion
- almost NO rotation
Ligaments that limit movements
- anterior longitudinal ligament- prevents hyperextension of vertebral column; can be severely stretched or torn during severe hyper-extension of the neck as in a rear end automobile collision.
- posterior longitudinal ligament
- ligamentum flavum
- interspinous ligament
- supraspinous ligament
Intrinsic muscles of the back
- all innervated segmentally by posterior rami of spinal nerves
1. splenius capitis
2. splenius cervicis
intermediate intrinsic muscles of the back
Erector spinae muscles- extend the back from a flexed postion
- Iliocostalis
- longissimus
- spinalis
Deep intrinsic muscles of the back
- all segmentally by posterior rami nerve
1. transversospinal muscles - semispinalis
- multifidus
- rotatores
2. levator costarum
3. interspinales
4. intertransversarii
Suboccipital triangle msucles
- Deep to semispinalis capitis muscle; contains vertebral artery and suboccipital nerve
- all innervated by suboccipital nerve
- extend and rotate the head
1. obliquus capitus superior
2. obliquus capitus inferior
3. rectus capitus posterior major
4. rectus capitus posterior minor
Somatic pathways
- all spinal cord levels C1-Co1
- sensory side–> dorsal=posterior
- motor side–> ventral=anterior
- dermomyotome=both
- dermatome- cutaneous (skin) sensory territory of a single spinal nerve
- myotome- mass of muscle innervated by a single spinal nerve
Iliocostalis
O- scarum, iliac crest
I- angle of the ribs
N- segmentally by posterior rami
A- extend/laterally bend vertebral column
Longissimus
O-sacrum, iliac crest, spinous processes of sacrum & inferior lumbar vertebrae
I- transverse processes of vertebrae, between angle & tubercles of ribs
N- segmentally by posterior rami
A- extend/laterally bend vertebral column; extends head
Spinalis
O-sacrum, iliac crest, spinous processes of sacrum, inferior lumbar vertebrae
I- spinous processes of vertebrae
N- segmentally by posterior rami
A- extend/laterally bend vertebral column
Semispinalis
O- transverse processes of cervical & thoracic vertebrae
I- occipital bone, spinous processes; spans 4-6 segments
N-segmentally by posterior rami
A- extends head and thoracic/cervical region of vertebral column
Multifidus
O- mainly sacrum & ilium
I- spinous processes; spans 2-4 segments
N-segmentally by posterior rami
A- stablizes vertebrae
Rotatores
O- transverse processes of vertebrae; most well developed in thoracic region
I- lamina & spinous process of vertebrae 1-2 segments above
N-segmentally by posterior rami
A- stablizes vertebrae
Levatores costarum
O-tips of transverse processes
I- between tubercle and angle of rib below
N-segmentally by posterior rami
A- elevates ribs (assists with inspiration)
Interspinales
Intertransversarii
Interspinales
-between spinous processes of adjacent vertebrae
Intertransversarii
-between transverse processes of adjacent vertebrae
Rectus capitus posterior major
O-spinous process of C2 (Axis)
I- inferior nuchal line of occipital bone
N- suboccipital nerve
A- unilaterally rotates head; bilaterally extends neck
Rectus capitus posterior minor
O-posterior arch of C1 (atlas)
I- inferior nuchal line of occipital bone
N- suboccipital nerve
A- unilaterally rotates head; bilaterally extends neck
Obliquus capitus superior
O- transverse process of C1 (Atlas)
I- inferior nuchal line of occipital bone
N- suboccipital nerve
A- extends neck
Obliquus capitus inferio
r
O- spinous process of C2
I- transverse process of C1
N- suboccipital nerve
A- unilaterally rotates head; bilaterally extends neck
Protraction & retraction of scapula
- Protraction
- shoulder moves anteriorly
- scapula slides laterally
- pectoralis minor & serratus anterior - Retraction
- shoulder moves posteriorly
- scapula slides medially
- rhmomboid major/minor, middle trapezius, latissimus dorsi
superior rotation of glenoid fossa & depression of glenoid fossa
- Superior rotation of glenoid fossa
- superior trapezius move up from acromion process
- medial part of scapular spine moves down by inferior trapezius
- inferior angle of scapula with serratus anterior inferior part muscle moves downward
- rotation elevating glenoid fossa upward - Depression of glenoid fossa
- gravity is a prime mover
- pectoralis minor weakly rotates
- latissimus dorsi indirectly attached, can assist with rotation
- rhomboid major & minor are the prime movers for rotating glenoid fossa inferiorly
Injury to axillary n
- posterior deltoid extends and laterally rotates
- anterior deltoid flexes and medially rotates
- injury to axillary n (supplies deltoid) or suprascapular n. or C5 & C6 segments of spinal cord affects abduction of arm
Rotator Cuff Muscles
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
- tendons of 4 muscles blend together to form the rotator cuff
- main function is to hold the head of humerus in the glenoid cavity
- also rotates the humerus about its longitudinal axis
Muscle Actions of Glenohumeral Joint
- Flexion
- Extension
- Abduction
- Adduction
- Medial rotation
- Lateral rotation
Flexion 1. Prime mover- pectoralis major 2. synergist- anterior deltoid Extension 1. prime mover- latissimus dorsi 2. synergist- posterior deltoid Abduction 1. prime mover- deltoid 2. synergist- supraspinatus Adduction 1. prime mover-latissimus dorsi, pectoralis major 2. synergist- teres major Medial Rotation 1. prime mover- subscapularis, teres major 2. synergist- pectoralis major, anterior deltoid, latissimus dorsi Lateral Rotation 1. primer mover-infraspinatus,teres minor 2. synergist- posterior deltoid
Axilla 9armpit)
-pyramidal in shape
-has four sides, an apex, and a base
-has seves as a passage for nerves and vessels of upper limb
Contents
1. branches of brachial plexus
2. axillary vessels
3. axillary lymph nodes
Arteries of Upper Limb
Aortic arch–>(brachiocephalic trunk on right side)–>subclavian a.–>axillary a.–> brachial a.
Subclavian artery
- vertebral a.
- thyrocervical trunk
- internal thoracic a.
axillary artery location
; three parts
part 1: between 1st rib and pectoralis minor
part 2: lies posterior to pectoralis minor
part 3: from pectoralis minor to teres major
arteries that branch from the subclavian artery
- superior thoracic a
- thoracoacromial a (trunk). lateral thoracic a.
- subscapular a., anterior & posterior circumflex humeral aa.
Axillary Vein
- axillary vein is a continuation of Brachial vein
- it begins at the inferior margin of Teres Major and ends at the outer border of the first rib as the subclavian vein
- it is joined by the cephalic and basilic veins
Arteries of the arm:
Brachial artery
- continuation of axillary artery
- begins at inferior border of teres major
- ends at cubital fossa opposite the neck of the radius
- divides into radial and ulnar arteries
- deep artery of the arm (profunda brachii) accompanies radial nerve in the radial groove–>radial collateral a
- superior & inferior ulnar collateral arteries
- middle collateral a. posterior to humerus
Collateral arteries
- anastomosis (plural is anastomese)
- allows blood to reach forearm when brachial artery is blocked
- regardless of elbow flexion or extension, blood can reach the forearm
Upper limb compartments
anterior compartment mm= flexors posterior compartment mm= extensors hand: 50/50 flexor/extensor forearm: 2/3 flexors; 1/3 extensors hand: 100% flexor
Anterior rami of spinal nerves
- anterior divisions/flexor compartments
- posterior dorsal divisions/extensor compartments
- pectoral and pelvic limbs are outgrowths of the ventral body—> innervated by the anterior rami of the spinal nerves
Brachial Plexus, in situ
- it is a network of nerves supplying motor, sensory, sympathetic fibers to the upper limb
- it is formed by the union of ventral primary rami of nerves from C5-T1
Classification of brachial plexus injuries
- upper root injuries
- lower root injuries
- complete or total nerve injury
- upper root injuries
- Erb’s palsy or Erb-Duchenne palsy
- injury to C5-6 with shoulder & biceps weakness or paralysis
- can involve C7 with forearm paralysis - lower root injuries
- Klumpke’s palsy
- paralysis of C8-T1 (sometomes C7)
- weakeness of distal upper extremity only - complete or total nerve injury
- Erb-Klumpke’s or total paralysis
- involves the complete plexus (C5-T1)
- associated with Horner’s syndrome in 1/3 of those severely affected
Upper brachial plexus injuries:
- dorsal & venteal root
- C5-C6 rami
- superior trunk
- posterior cord
- dorsal & venteal root
- paralysis & loss of sensation of muscles of back and upper limb - C5-C6 rami
- loss of sensation (lateral aspect), paralysis of some muscles - superior trunk
- Erb’s palsy - posterior cord
- Crutch palsy; produces wrist drop inability to extend elbow, writst, fingers
Lesions of C5, C6, Superior Trunk Nerve lesion/affected tissues/motor dysfucntion 1. Suprascapular 2. axillary n. 3. radial n 4. musculocutaneous n 5.
- suprascapular n.–> supraspinatus m.–> adducted arm
- axillary n–> deltoid m.–> adducted arm
- suprascular n–> infraspinatus m–> medially roated arm
- axilalry n–> teres minor m–> medially rotated arm
- radial n–> supinator m–> protonated forearm
- musculocutaneous n–> beceps brachii m–> protonated forearm
- musculocutaneous n–> forearm flexors–> elbow extension
C5, C6 lesions–> greatly disabled shoulder and arm
Lower Brachial Plexus Injuries
- mainly affects ulnar nerve
- wrist flexion and hand movements affected
- loss of sensation on ulnar side of arm, forearm, hand
- cervical rib syndrome: due to cervical rib; exerts pressure on vessels and lower trunk; produces tingling and numbness (neurovascular compression syndrome)
Lesions of C5, C6, Superior Trunk Nerve lesion/affected tissues/motor dysfucntion 1. Suprascapular 2. axillary n. 3. radial n 4. musculocutaneous n 5.
- suprascapular n.–> supraspinatus m.–> adducted arm
- axillary n–> deltoid m.–> adducted arm
- suprascular n–> infraspinatus m–> medially roated arm
- axilalry n–> teres minor m–> medially rotated arm
- radial n–> supinator m–> protonated forearm
- musculocutaneous n–> beceps brachii m–> protonated forearm
- musculocutaneous n–> forearm flexors–> elbow extension
C5, C6 lesions–> greatly disabled shoulder and arm
Lower Brachial Plexus Injuries
- mainly affects ulnar nerve
- wrist flexion and hand movements affected
- loss of sensation on ulnar side of arm, forearm, hand
- cervical rib syndrome: due to cervical rib; exerts pressure on vessels and lower trunk; produces tingling and numbness (neurovascular compression syndrome)
Anterior muscles of arm
- muscles of arm are contained in 2 compartments: anterior (flexors), posterior (extensors)
- coracobrachialis, short & long head biceps brachii, brachialis
- all three innervated by musculocutaneous nerve
OINA Biceps Brachii
O- short head: tip of coracoid process of scapula
Long head: supraglenoid tubercle of scapula
I: radial tuberosity & fascia of forearm via bicipital aponeurosis
N: musculocutaneous nerve
A: supinates forearm; flexes forearm when supine; assists in flexing arm
-Biceps brachii pulls on radial tuberosity to supinate forearm
OINA Brachialis
O- distal half of anterior surface of humerus
I- coronoid process & tuberosity of ulna
N- musculocutaneous nerve
A- flexes forearm
OINA Coracobrachialis
O- tip of coracoid process of scapula
I- middle 1/3 of medial surface of humerus
N- musculocutaneous nerve
A- helps to flex & adduct arm
Lesion in fibers that form the Musculocutaneous nerve results in:
WHy?
-lesions in fibers that form musculocutaneous n results in:
(lateral cord give rise to musculocutaneous)
1. weakened flexion of elbow
2. weakened supination of forearm
3. lesion of musculocutaneous n result in weakended flexion of elbow not complete paralysis because…..
OINA Triceps Brachii long, lateral, medial heads
Origin:
- long head- infraglenoid tubercle of scapula
- lateral head- posterior surface of humerus, superior to radial groove
- medial head- posterior surface of humerus, inferior to radial groove
Insertion- proximal end of olecranon of ulna & fascia of forearm
N- radial nerve
A- extends forearm
OINA Anconeus
O- lateral epicondyle of humerus
I- lateral surface of olecranon and superior part of posterior surface of ulna
N- radial nerve
A- abducts ulna during protonation, assists in extending forearm; stabilizes elbow joint.
injury to radial nerve
- result in
1. paralysis/weakness of triceps, brachioradialis, supinator, extensors of wrist, thumb, fingers
2. loss of sensation in areas of skin supplied by this nerve - lesion in radial nerve results in
1. wrist drop (inability to extend wrist)
2. inability to extend elbow (does not occur if injury is at radial groove)
3. gravity will usually pull it into an extended position
Flexors and extensors of the arm
Flexors:
- brachialis
- bicep brachi
- (brachioradialis)
Extensors
1. triceps brachii (anconeus)
Muscle actions of elbow joints
Flexion
- prime mover- brachialis
- synergist- biceps brachii, brachioradialis, pronator teres
Extension
- prime mover- triceps brachii
- synergist- anconeus
Artery of the arm
-brachial artery
- continuation of axillary artery
- begins at inferior border of teres major
- ends at cubital fossa opposite the neck of radius
- divides into radial & ulnar arteries
Collateral arteries
- anastomosis
- allows blood to reach forearm when brachial artery is blocked
- regardless of elbow flexion/extension, blood can reach forearm
Cubital fossa
contents:
- biceps brachii tendon
- end of brachial artery, beginning of ulnar and radial arteries; accompanying veins
- median nerve: middle of cubital fossa
- radial nerve: passes anterior to lateral epicondyle of humerus, divides into deep and superficial branches
Nerves of the arm
4 main nerves pass through
- median
- ulnar
- . musculocutaneous
- radial
- median & ulnar supply no branches to the arm but supply elbow joint and anterior forearm.
Muscles of anterior forearm
8 muscles divided into 3 layers
- all anterior compartment muscles are innervated by median nerve, except for flexor carpi ulnaris & medial 1/2 flexor digitorum profundus (ulnar n)
1. superficial - pronator teres
- flexor carpi radialis
- palmaris longus
- flexor carpi ulnaris
2. Intermediate - flexor digitorum superficialis
3. Deep - flexor digitorum profundus
- flexor pollicis longus
- pronator quadratus
Septum
- median n & radial a
- ulnar n & ulnar a
Superficial & intermediate flexor layers arise from
arise by common flexor tendon from the medial epicondyle of humerus
pronator teres OINA
O- medial epicondyle of humerus (humeral head) and coronoid process of ulna (ulnar head)
I- lateral side of middle radius
N- median nerve
A- pronates the forearm, with some flexion at elbow
Flexor carpi radialis
O- medial epicondyle of humerus
I- base of 2nd metacarpal
N- median nerve
A- flexion & abduction of hand at wrist
-its tendon is used as a guide to radial artery to obtain the radial pulse
-the artery lies just lateral to the tendon
Palmaris longus OINA
O- medial epicondyle of humerus
I- distal flexor retinaculum & palmar aponeurosis
N- median nerve
A- flexion at wrist, tightens palmar aponeurosis, retracts claws in cats
-this muscle is absent in 14% of people
-its tendon is used a guide to median nerve which lies just lateral to it
Flexor carpi ulnaris
O- medial epicondyle of humerus (humeral head), olecranon and posterior aspect of ulna (ulnar head)
I- proximal 5th metacarpal, pisiform bone and hamate bone
N- ulnar nerve
A- flexion and adduction of hand at wrist
-its tendon is a guide to ulnar nerve and artery which are on its lateral side at wrist
Intermediate layer:
Flexor digitorum superficialis
O- medial epicondyle of humerus, coronoid process of ulna (humeroulnar head) and upper half of anterior radius (radial head)
I- middle phalanges of digits 2-5
N- median nerve
A- flexes: wrist, metacarpophalangeal (MCP) joints, fingers at proximal interphalangeal (PIP) joints
Deep flexor layer are? arises frim?
- flexor pollicis longus (FPL)
- flexor digitorum profundus (FDP)
- pronator quadratus
- none of these muscles arise from humerus
- they aris from radius or ulna
Flexor Pollicus longus OINA
O- middle part of anterior radius and interosseous membrane
I- distal phalanx of thumb
N- median nerve (anterior interosseous branch)
A- flexes MCP & IP joint of thumb
Flexor digitorum profundus OINA
O- proximal 3/4 of ulna and interosseous membrane
I- distal phalanges of digits 2-5
N- medial 1/2: ulnar nerve; lateral 1/2 median nerve
A- flexes fingers at distal interphalangeal (DIP) joints and help flex wrist
-FDP is prime mover for finger flexion
-FDS recruited when greater speed or strength is needed
pronator quadratus
O- distal anterior ulna
I- distal anterior radius
N- median nerve (anterior interosseus branch)
pronates forearm
muscle actions of radio-ulnar joint
Supination
- prime mover- supinator
- synergist- biceps brachii
Pronation
- prime mover- pronator quadratus
- synergist- pronator teres
Arteries of the forearm
brachial artery
- radial artery
- radial recurrent artery (to elbow)
- past the wrist, continues as deep palmar arch
- ulnar artery
- ulnar recurrent arteries (to elbow)
- common interosseous artery
a) anterior interosseus artery
b) posterior interosseus artery - past the wrist, continues as superficial arch
except for posterior interosseous artery. All arteries of forearm are in anterior compartment
Anastomoses around elbow joint
- Middle collateral a= common interosseus a
- radial collateral a= radial recurrent a
- superior ulnar collateral a= posterior ulnar recurrent a
- inferior ulnar collateral a= anterior ulnar recurrent a
Nerves of forearm
- radial n
- passess anterior to lateral epicondule of humerus splits into
a) deep radial n- passes into posterior compartment and becomes posterior interosseus n.
b) superficial radial n- to skin of lateral forearm and dorsum of hand - median n
- crosses cubital fossa medial to brachial a.
a) anterior interosseous branch supplies deeper muscles
- descends forearm sandwiched btw FDS & FDP
- travels through carpal tunnel of wrist into hand - ulnar n
- passes posterior to medial epicondyle of humerus
- travels down medial forearm medial to ulnar artery
- crosses wrist superficial to flexor retinaculum
Flexor retinaculum
Carpal tunnel
- flexor retinaculum= transverse carpal ligament
- holds flexor tendons in place at wrist to prevent bowstringing of tendons during wrist flexion
- forms roof of carpal tunnel
Carpal tunnel consists of tendons of:
- flexor carpi radialis
- flexor digitorum superficialis
- flexor pollicis longus
- flexor digitorum profundus
- median nerve
Median nerve lesion-at elbow
- paralysis of forearm pronators
- paralysis of long flexor mm. of wrist and finger (except FCU and ulnar half of FDP)
- paralysis of mm. of thenar eminence (retention of adductor and extensor pollicis mm.)
hand of benediction
- paralysis of median n at elbow
- cannot flex 2 & 3 rd digit
- cannot flex thumb at proximal interphalangeal joint
- can weakly flex 4th & 5th digits (medial part of FDP innervated by ulnar n.)
carpal tunnel syndrome
- compression of medial nerve occurs if any lesion reduces the size of carpal tunnel
- causes tingling (parasthesia), loss of sensation (anesthesia), or diminished sensation (hypoesthesia) in lateral 3.5 fingers
- can eventually result in atrophy of thenar muscles
Posterior compartment of forearm innerated by?
- all innervated by radial n.
- arranged in 2 ayers= superficial and deep layer
Extensor tendons held in place by ? to prevent?
held in place by extensor retinaculum at wrist to prevent bowstringing of tendons during hyperextension
Brachioradialis OINA
O- lateral suprpacondylar ridge of humerus
I- lateral side of distal radius
N- radial nerve
A- flexor of the forearm (at elbow joint)
- brachioradialis is part of posterior compartment innervated by radial n)
- but brachioradialis flexes the forearm
extensor carpi radialis longus
O- lateral supracondylar ridge of humerus
I- base of 2nd metacarpal
N- radial nerve
A- extension and abduction at wrist
extensor carpi radialis brevis
O- lateral epicondyle of humerus (common extensor tendon)
I- base of 3rd metacarpal
N- radial nerve
A- extension and abduction at wrist
extensor digitorum
O- lateral epicondyle of humerus (common extensor tendon)
I- extensor expansions of 4 fingers
N- radial nerve (posterior interosseous nerve)
A- extension of 4 fingers and extension of hand at wrist
extensor expansion
- common insertion for the tendons of:
1. extensor digitorum and extensor digiti minimi
2. interosseous muscles
3. lumbrical muscles
Extensor digiti minimi OINA
O- lateral epicondyle of humerus (common extensor tendon)
I- extensor expansions of 5th digit
N- radial nerve (posterior interosseous nerve)
A- extension of 5th digit
extensor carpi ulnaris
O- lateral epicondyle of humerus (common extensor tendon) and posterior surface of ulna
I- base of 5th metacarpal
N- radial nerve (posterior interosseous nerve)
A- extension and adduction at wrist
deep extensor layers act on thumb & index finger
Act on thumb
- abductor pollicis longus
- extensor pollicis longus
- extensor pollicis brevis
Act on index finger
1. extensor indicis
abductor pollicis longus OINA
O- posterior surface of ulna & radius, and interosseous membrane
I- base of 1st metacarpal
N- radial nerve (posterior interosseous nerve)
A- abducts and extends thumb
extensor pollicis longus OINA
O- posterior surface of ulna and interosseous membrane
I- base of distal phalanz of thumb
N- radial nerve (posterior interosseous nerve)
A- extends thumb at MP & IP joints
Extensor Polliis brevis OINA
O- posterior radius & interosseous membrane
I- base of proximal phalanx of thumb
N- radial nerve (posterior interosseous nerve)
A- extends thumb
Extensor Indicis IONA
O- posterior surface of ulna and interosseous membrane
I- extensor expansion of index finger
N- radial nerve (posterior interosseous nerve)
A- extends index finger
Supinator OINA
O-lateral epicondule, radial collateral & anular ligaments (humeral head); supinator fossa, supinator crest (ulnar head)
I- anterior, lateral and posterior surfaces of proximal radius
N- radial nerve (deep branch)
A- supination of forearm
- wraps around posterior then lateral to radius
- supinates forearm along with biceps brachii
Movement of radioulnar (wrist) joint muscles involved 1. flexion 2.Extension 3. adduction 4. abduction
muscles involved
- flexion
- FCU (Flexor capris Ulnaris)
- FCR (Flexor capris radialis) - Extension
- ECU
- ECRL
- ECRB - adduction
- FCU
- ECU - abduction
- FCR
- ECRL
- ECRB
- flexion & extension occur simultaneously in radiocarpal joint and midcarpal joint
- adduction is greater than abduction
- abduction limited by styloid process of radius
Muscle actions of wrist
flexion & extension
Flexion
- prime mover- flex carpi radialis, flex carpi ulnaris, palmaris L
- synergist: flex digitorum superficialis & profundus, flex pollicis L, abductor policis L
Extension
- prime mover- extensor carpi Rad L& B, Ext carpi ulnaris
- synergist- ext digitorum, ext pollicis L & B, ext indicis, ext digiti minimi
Muscle actions of wrist
Abduction
Adduction
Abduction
- prime mover- flex carpi radialis, ext carpi radialis longus & brevis
- synergist- abductor pollicis L, ext pollicis L & B
Adduction
1. prime mover- ext carpi ulnaris, flex carpi ulnaris
-adduction is freer than abduction because ulnar styloid process does not extend distally as radial styloid process
power finger flexion requires wrist extensors
finger flexors:
- flexor digitorum superficialis & profundus mm.
- flexor poollicis longus & brevis mm.
- wrist extensor mm. (extensor carpi radialis longus & brevis mm. & extensor carpi ulnaris m)
power grip mechanics
- extensors of wrist (ext carpi radialis L&B, ext carpi ulnaris) activate to:
1. oppose FDS & FDP from flexing the wrist
2. extend wrist, which lengthens flexor muscles, allowing them to contract more forecefully - flexor digitorum muscles will cause carpometacarpal joint to flex as well as the digits
length-tension curve
- for max force, there is an optimum middle range muscle length
- to generate max force form group of muscles, joint should be positioned so muscle length is near this optimum
radial nerve lesion around elbow
- loss of power grip
- wrist drop, inability to extend fingers
Abductor Polllicis brevis OINA
O- scaphoid, trapezium and flexor retinaculum
I- lateral base of proximal phalanx of thumb
N- median nerve (recurrent br)
A- abducts thumb and help oppose it
flexor pollicis brevis OINA
O- scaphoiod, trapexium, flexor retinaculum
I- lateral base of proximal phalanx of thumb
N- median nerve (recurrent br)
A- flexes thumb, helps in opposition
Opponens Pollicis OINA
O- scaphoid, trapezium, flexor retinaculum
I- lateral side of metacarpal of thumb
N- median nerve (recurrent br)
A- opposition of thumb; medially rotates thumb metacarpal
adductor pollicis OINA
O-oblique head: capitate & bases of 2nd & 3rd metacarpals; transverse head: 3rd metacarpal
I- medial base of proximal phalanx of thumb
N- ulnar nerve
A- adduction of thumb assists in opposition
Hypothenar muscles:
abductor digiti minimi OINA
O- pisiform bone
I- medial base of proximal phalanx of 5th digit
N- ulnar nerve
A- abducts 5th digit
flexor digiti minimi OINA
O- hook of hamate & flexor retinaculum
I- medial base of proximal phalanx of 5th digit
N- ulnar nerver
A- flexes 5th digit
Opponens digiti minimi
O- hook of hamate and flexor retinaculum
I- medial side of metacarpal of 5th digit
N- ulnar nerve
A- rotates 5th digit laterally into opposition with thumb
Lumbricals (4) OINA
O- tendons of flexor digitorum profundus
I- lateral side of extensor expansions of fingers
N- median nerve (digits 2&3); ulnar nerve (digits 4&5)
A- flexes fingers at MP joint; extends at IP joint
Dorsal interossei (4) OINA
O- adjacent metacarpals (bipennate)
I- base of proximal phalanx and extensor expansions of digits 2-4
N- ulnar nerve
A- abduct fingers and assists lumbricals in flexion at MP joints and extension at IP joints
Palmar interossei (e) OINA
O- 2,4, 5th metacarpal bones
I- base of proximal phalanx and extensor expansions of digits 2, 4, 5
N- ulnar nerve
A- addut fingers and assists lumbricals in flexion at MP joints nad extension at IP joints
