Anatomy lecture 2 Flashcards
medial attachement=
- origin
- proximal
lateral attachement=
insertion
= distal
Pectoralis major
- Proximal attachment: clavicular head, anterior 1/2 of medial clavicle, sternocostal head ribs 1-6
- Distal attachment: lateral lip of intertubercular groove (sulcus) of humerus
- Innervation: lateral and medial pectoral
- action: adduction and medial rotation of humerus, draws scapula anteriorly and inferiorly
- ex: climbing, throwing, pushing, hugging
pectoralis minor
proximal attachment: ribs 3-5
distal attachment: coracoid process of scapula
innervation: a medial pectoral nerve
action: stabilize scapula by drawing inferiorly and anteriorly rotating against thoracic wall
Subclavius
- proximal attachment: junction of 1st rib and its costal cartilage
- Distal attachment: inferior surface of middle third of clavicle
- innervation: subclavian nerve
- action: actors and depresses clavicle
Serratus anterior
- Proximal attachment: 1st to 8th ribs
- Distal attachment: medial border of scapula
- innervation: long thoracic nerve
- action: move scapula forward, boxers muscle (hold scapula against wall)
What is the action of Trapezius ?
- descending (superior) part elevates “shoulder shrugging”
- ascending (inferior) part depresses and middle part retracts (pulls posteriorly) scapula
- shoulder drop if injured
What is the action of Latissimus Doris?
- extend, adduction and medial rotation of shoulder joint (striking action ex blow, hammering, swimming, and rowing)
- raises body towards arm during climbing
Ability to bow hunt is impaired due to injury to
dorsal scapular nerve/levetator scapulae
SSIT
Subscapularis-lesser tubercle
Supraspinatus-greater tubercle
Infraspinatus-
aTeres minor
0-15 degrees of arm abduction
supraspinatous
15-90 degrees of arm abduction
medial deltoid
> 90 degree of arm abduction
upper trapezius
SITS for rotator cuff
Supraspinatus- helps deltoid abduct arm 15
Infraspinatus- laterally rotates arm
Teres minor- adducts and laterally rotate arm
Subscapularis- medially rotates and adducts arm
Rotator cuff injury common in
baseball pitcher
Will have pain in neck and at the tip of the shoulder
All muscles will pull towards…
the origin
Brachial plexus
nerve supply to upper limb
-extends from cervical region to axilla
-formed by anterior rami of C5 to T1 (roots of brachial plexus)
Anterior rami roots
C5-C8, T1
anterior rami (roots)—->
trunks
——–>
divisions
——–>
cords
——->
terminal branches
Trunks
-Superior trunnk
-Middle trunk
-Inferior trunk
Cords
- Lateral cord
- Posterior cord
- Medial cord
Terminal branches
- musculocutaneous nerve
- radial nerve
-median nerve
-ulnar nerve
Brachial plexus injury
second most common postop peripheral neuropathy
Axillary nerve
innervates the deltoid and teres minor
Musculocutaneous nerve
sends fibers to coracobrachialis, biceps brachii and brachialis
(flexion at elbow)
Median
branches to most of the flexor muscles of forearm and opponens pollicis
-pronation of forearm
-flexion of wrist
- opposition of thumb
-flexion of lateral three fingers
Ulnar nerve
supplies the flexor carpi ulnarus and half of the flexor digitorum profundus
- flexion of wrist
- adduction of fingers
-flexion of medial two fingers
Radial nerve
supplies ALL extensors of arm and forearm muscles
- extension at elbow
- supination of forearm
- extension of wrist and fingers
Intercostobrachial nerve
-terminal cutaneous nerve
-can be blocked to reduce pain from tourniquet inflation during IV regional neural anesthesia
Erb-Duchenne palsy
injury to superior trunk C5, C6 roots in newborn due to excess stretch during delivery that leads to tear of the roots.
Axillary, musculocutaneous and suprascapular nerves are paralyzed
-limb hangs by the side with adducted shoulder, forearm is pronated, waiter’s tip position
Klumpke paralysis
injury of inferior trunk C8, T1
Damage to ulnar nerve. Claw hand.
What is the action of the Pectoral’s Major?
- Adduction and medial rotation of humerus
- draws scapula anterior and inferiorly
- (climbing, throwing, pushing, hugging and bench press)
What is the action of the Subslavius?
anchors and depresses clavicle
what is the action of the Levator scapulae?
elevate the scapula
Trapezius lateral and medial attachment
Medial attachment: medial third of superior nuchal line; external occipital protuberance, nuchal ligament; spinous processes of C7-T12 vertebrae
Lateral attachment: lateral 1/3 of clavicle, acromion and spine of scapula
Innervation: spine accessory nerve (Cranial nerve XI) and C3, C4 spinal nerve
Rhomboids (major and minor) attachments and innervation
medial attachment: spinous processes of C7 and T1 (minor); spinous processes of T2-T5 (major)
Lateral attachment: medial border of scapula
Innervation: dorsal scapuar nerve
Axillary nerve injury is associated with
surgical neck fracture of humerus, shoulder dislocation, IM injection
can lead to atrophy of deltoid
Supraspinatus
- Proximal attachment: supraspinous fossa of scapula
- Distal attachment: greater tubercle of humerus
- Innervation: suprascapular nerve
Supraspinatus action
initiate abduction (first 15 degrees of arm)
Infraspinatus
- Proximal attachment: infraspinous fossa of scapula
- Distal attachment: greater tubercle of humerus
- Innervation: suprascapular nerve (also supplies supraspinatus)
Infraspinatus action
laterally rotates shoulder joint
Teres minor main action
laterally rotates shoulder joint
Teres minor attachments and innervation
proximal attachment: middle part of lateral border of scapula
Distal attachment: greater tubercle of humerus
Innervation: axillary nerve
What is the action of Subscapularis?
medially rotate and adduct of shoulder joint
Teres major attachment
Proximal attachment: inferior part of lateral border of scapula
Distal attachment: medial lip of intertubercular sulcus of humerus
Innervation: lower subscapular nerve
Teres major action
medially rotates and adducts the shoulder joint
Subscapularis attachment and innervation
proximal attachment: subscapular fossa of scapula
distal attachment: lesser tubercle of humerus
innervation: upper and lower subscapular nerves
What 4 muscles make up the rotator cuff?
1) spuraspinatus
2) infraspinatus
3) Teres Minor
4) Subscapularis
The Left Axillary artery turns into the Left brachial artery after what muscle?
- Left Teres major
What happens if the long thoracic nerve is injured?
- winging of scapula due to paralysis of serratus anterior
