Anatomy Flashcards
Long term nerve compression at the spinoglenoid notch results in
Infraspinatus atrophy
Degree of retroversion of glenoid
5 degrees
First bone in body to ossify and last to fuse.
Clavicle
When does the clavicle start to ossify? Fuse?
5 weeks AOG. 25 years
Most common musculoskeletal birth injury
Clavicular fracture
Important for superoanterior restraint in rotator cuff deficiencies. Should be preserved during debridement of painful massive rotator cuff tears that cannot be surgically repaired
Coracoacromial ligament
Shoulder internal rotators
Pectoralis major, latissimus dorsi, teres major, subscapularis
Shoulder external rotators
Teres minor, infraspinatus
Attachment of rotator cuff muscles
Greater tuberosity (except subscapularis)
Why are posterior shoulder dislocations more common?
Shoulder internal rotators are stronger than external rotators
Describe anatomy of the brachial plexus
See Miller p147, Netter p 98
Muscle innervation of rotator cuff muscles
C5 and C6 of brachial plexus
Preganglionic brachial plexus lesions produce what deformity?
Medial scapular winging
Medial scapular winging, produced by preganglionic brachial plexus lesions, are caused by?
Paralysis of long thoracic nerve -> serratus anterior dysfunction
Spinal accessory nerve injury causes?
Trapezius dysfunction and scapular trapezius winging (lateral winging)
Trapezius dysfunction and scapular trapezius winging (lateral winging) is caused by
Spinal accessory nerve injury
Long thoracic nerve injury (c5-c7) causes
Serratus anterior dysfunction. Medial scapular winging.
Serratus anterior dysfunction, Medial scapular winging is caused by injury to?
Long thoracic nerve
Obstetric Brachial Plexus Palsy. Waiter’s tip.
Erb-Duchenne
Obstetric Brachial Plexus Palsy. Poor prognosis
Klumpke’s Palsy
Obstetric Brachial Plexus Palsy. C5, C6
Erb-Duchenne
Obstetric Brachial Plexus Palsy. Weakness of wrist flexors and i trinsic apparatus. Horner’s syndrome
Klumpke’s palsy
Obstetric Brachial Plexus Palsy. Flaccid arm
Total plexus palsy
Describe shoulder vasculature
Aorta-> left subclavian; brachiocephalic trunk -> rightsubclavian/ will become axillary artery which is divided into 3 parts based on relationship to pectoralis minor. See Miller, table 2-11, p150.
Muscle innervation of all rotator cuff muscles
C5 and C6 of brachial plexus
Nerve supply. Serratus anterior
Long thoracic nerve
Nerve supply. Rhomboid muscle
Dorsal scapular nerve
Nerve supply. Supraspinatus and infraspinatus
Suprascapular nerve
Nerve supply. Teres minor
Axillary nerve
Weakness results in LATERAL scapular winging
Trapezius
Weakness results in MEDIAL scapular winging
Serratus anterior
Can rupture off humeral insertion, results in defect in axillary fold
Pectoralis major
Lighthouse to the shoulder
Coracoid process
Nerve that passes through quadrangular space
Axillary nerve
Nerve that passes triangular interval
Radial nerve
Where do the rami of the brachial plexus exit?
Between anterior and medial scalene
Latissimus dorsi. Origin
T7-T12, iliac crest
Latissiumus dorsi. Insertion
Humerus (intertubercular groove)
Latissiumus dorsi. Innervation
Thoracodorsal nerve
Trapezius. Origin
C7-T12 spinous process
Trapezius. Insertion
Clavicle, acromion, spine of scapula
Deltoids. Origin
Clavicle, acromion, spine of scapula
Deltoids. Innervation
Axillary nerve
Serratus anterior. Origin
Ribs1-8 (lateral)
Serratus anterior insertion
Scapula (anteromedial border)
Serratus anterior innervation
Long thoracic nerve
Paralysis of serratus anterior results in
Medial winging of scapula
Blood supply of the humeral head and proximal humerus
Anterior humeral circumflex artery
Nerve injury commonly associated with shoulder fractures
Axillary nerve injury. Innervates deltoids and teres minor
Fulcrum for lateral movement pf the arm
Clavicle
Muscles connecting upper limb to vertebral column
Trapezius
Lats
Both rhomboids
Levator scapulae
Muscles connecting upper limb to thoracic wall
Pecs
Subclavius
Serratus anterior
Muscles acting on shoulder joint itself
Deltoid
Teres major
Four rotator cuff muscles
Injury to what nerve will cause medial scapular winging
Long thoracic nerve
Injury to what nerve will cause lateral scapular winging
Spinal accessory nerve (CN XI)
Medial scapular winging muscle involved
Serratus anterior
Muscle involved. Lateral scapular winging
Trapezius
At risk during mid shaft clavicular fractures
Brachial plexus